Bio

Clinical Focus


  • Orthopaedic Surgery

Academic Appointments


Administrative Appointments


  • Chief, Orthopaedic Spine Service, Department of Orthopaedic Surgery (2013 - Present)

Professional Education


  • Residency: Hospital for Special Surgery Orthopaedic Surgery Residency (1989) NY
  • Internship: Beth Israel Medical Center (1985) NY
  • Medical Education: McGill University Faculty of Medicine (1984) Canada
  • Board Certification: American Board of Orthopaedic Surgery, Orthopaedic Surgery (1992)
  • Fellowship: Rancho Los Amigos Medical Center (1990) CA

Teaching

2020-21 Courses


Stanford Advisees


Publications

All Publications


  • The effect of anterior lumbar interbody fusion staging order on perioperative complications in circumferential lumbar fusions performed within the same hospital admission. Neurosurgical focus Safaee, M. M., Tenorio, A., Osorio, J. A., Choy, W., Amara, D., Lai, L., Hu, S. S., Tay, B., Burch, S., Berven, S. H., Deviren, V., Dhall, S. S., Chou, D., Mummaneni, P. V., Eichler, C. M., Ames, C. P., Clark, A. J. 2020; 49 (3): E6

    Abstract

    OBJECTIVE: Anterior lumbar interbody fusion (ALIF) is a powerful technique that provides wide access to the disc space and allows for large lordotic grafts. When used with posterior spinal fusion (PSF), the procedures are often staged within the same hospital admission. There are limited data on the perioperative risk profile of ALIF-first versus PSF-first circumferential fusions performed within the same hospital admission. In an effort to understand whether these procedures are associated with different perioperative complication profiles, the authors performed a retrospective review of their institutional experience in adult patients who had undergone circumferential lumbar fusions.METHODS: The electronic medicals records of patients who had undergone ALIF and PSF on separate days within the same hospital admission at a single academic center were retrospectively analyzed. Patients carrying a diagnosis of tumor, infection, or traumatic fracture were excluded. Demographics, surgical characteristics, and perioperative complications were collected and assessed.RESULTS: A total of 373 patients, 217 of them women (58.2%), met the inclusion criteria. The mean age of the study cohort was 60 years. Surgical indications were as follows: degenerative disease or spondylolisthesis, 171 (45.8%); adult deformity, 168 (45.0%); and pseudarthrosis, 34 (9.1%). The majority of patients underwent ALIF first (321 [86.1%]) with a mean time of 2.5 days between stages. The mean number of levels fused was 2.1 for ALIF and 6.8 for PSF. In a comparison of ALIF-first to PSF-first cases, there were no major differences in demographics or surgical characteristics. Rates of intraoperative complications including venous injury were not significantly different between the two groups. The rates of postoperative ileus (11.8% vs 5.8%, p = 0.194) and ALIF-related wound complications (9.0% vs 3.8%, p = 0.283) were slightly higher in the ALIF-first group, although the differences did not reach statistical significance. Rates of other perioperative complications were no different.CONCLUSIONS: In patients undergoing staged circumferential fusion with ALIF and PSF, there was no statistically significant difference in the rate of perioperative complications when comparing ALIF-first to PSF-first surgeries.

    View details for DOI 10.3171/2020.6.FOCUS20296

    View details for PubMedID 32871562

  • Preoperative epidural steroid injections are not associated with increased rates of infection and dural tear in lumbar spine surgery. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society Koltsov, J. C., Smuck, M. W., Alamin, T. F., Wood, K. B., Cheng, I., Hu, S. S. 2020

    Abstract

    PURPOSE: The study objectives were to use a large national claims data resource to examine rates of preoperative epidural steroid injections (ESI) in lumbar spine surgery and determine whether preoperative ESI or the timing of preoperative ESI is associated with rates of postoperative complications and reoperations.METHODS: A retrospective longitudinal analysis of patients undergoing lumbar spine surgery for disc herniation and/or spinal stenosis was undertaken using the MarketScan databases from 2007-2015. Propensity-score matched cohorts were constructed to compare rates of complications and reoperations in patients with and without preoperative ESI.RESULTS: Within the year prior to surgery, 120,898 (46.4%) patients had a lumber ESI. The median time between ESI and surgery was 10weeks. 23.1% of patients having preoperative ESI had more than one level injected, and 66.5% had more than one preoperative ESI treatment. Patients with chronic pain were considerably more likely to have an ESI prior to their surgery [OR 1.62 (1.54, 1.69), p<0.001]. Patients having preoperative ESI within in close proximity to surgery did not have increased rates of infection, dural tear, neurological complications, or surgical complications; however, they did experience higher rates of reoperations and readmissions than those with no preoperative ESI (p<0.001).CONCLUSION: Half of patients undergoing lumbar spine surgery for stenosis and/or herniation had a preoperative ESI. These were not associated with an increased risk for postoperative complications, even when the ESI was given in close proximity to surgery. Patients with preoperative ESI were more likely to have readmissions and reoperations following surgery.

    View details for DOI 10.1007/s00586-020-06566-6

    View details for PubMedID 32789696

  • A Simple Goal Elicitation Tool Improves Shared Decision Making in Outpatient Orthopedic Surgery: A Randomized Controlled Trial. Medical decision making : an international journal of the Society for Medical Decision Making Mertz, K., Shah, R. F., Eppler, S. L., Yao, J., Safran, M., Palanca, A., Hu, S. S., Gardner, M., Amanatullah, D. F., Kamal, R. N. 2020: 272989X20943520

    Abstract

    Introduction. Shared decision making involves educating the patient, eliciting their goals, and collaborating on a decision for treatment. Goal elicitation is challenging for physicians as previous research has shown that patients do not bring up their goals on their own. Failure to properly elicit patient goals leads to increased patient misconceptions and decisional conflict. We performed a randomized controlled trial to test the efficacy of a simple goal elicitation tool in improving patient involvement in decision making. Methods. We conducted a randomized, single-blind study of new patients presenting to a single, outpatient surgical center. Prior to their consultation, the intervention group received a demographics questionnaire and a goal elicitation worksheet. The control group received a demographics questionnaire only. After the consultation, both groups were asked to complete the Perceived Involvement in Care Scale (PICS) survey. We compared the mean PICS scores for the intervention and control groups using a nonparametric Mann-Whitney Wilcoxon test. Secondary analysis included a qualitative content analysis of the patient goals. Results. Our final cohort consisted of 96 patients (46 intervention, 50 control). Both groups were similar in terms of demographic composition. The intervention group had a significantly higher mean (SD) PICS score compared to the control group (9.04 [2.15] v. 7.54 [2.27], P < 0.01). Thirty-nine percent of patient goals were focused on receiving a diagnosis or treatment, while 21% of patients wanted to receive education regarding their illness or their treatment options. Discussion. A single-step goal elicitation tool was effective in improving patient-perceived involvement in their care. This tool can be efficiently implemented in both academic and nonacademic settings.

    View details for DOI 10.1177/0272989X20943520

    View details for PubMedID 32744134

  • Percutaneous plasma decompression alters cytokine expression in injured porcine intervertebral discs. The spine journal : official journal of the North American Spine Society O'Neill, C. W., Liu, J. J., Leibenberg, E., Hu, S. S., Deviren, V., Tay, B. K., Chin, C. T., Lotz, J. C. ; 4 (1): 88–98

    Abstract

    Discectomy is a surgical technique commonly used to treat bulging or herniated discs causing nerve root compression. Clinical data suggest discectomy may also help patients with contained discs and no clear neural compromise. However, the mechanisms of clinical efficacy are uncertain, and consequently bases for treatment optimization are limited.To determine the effect of percutaneous plasma decompression on the histologic, morphologic, biochemical and biomechanical features of degenerating intervertebral discs.An adult porcine model of disc degeneration was used to establish a degenerative baseline against which to evaluate discectomy efficacy.Cytokines interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor (TNF)-alpha were measured from tissue samples using enzyme-linked immunosorbent assay. Histology and morphology images were rated for degenerative findings (of cells and matrix) in both the nucleus and annulus. Proteoglycan content was determined, and intact specimen stiffness and flexibility were measured biomechanically. Magnetic resonance images were collected for biomechanical specimens.Using a retroperitoneal surgical approach, stab incisions were made in four or five lumbar discs per spine in 12 minipigs. Animals were allocated into one of three groups: 6-week recovery, 12-week recovery and percutaneous plasma decompression using an electrosurgical device at 6 weeks with recovery for 6 additional weeks. Four additional animals served as controls.Discs treated with discectomy had a significant increase in IL-8 and a decrease in IL-1 as compared with the 12-week, nontreated discs. There were no significant differences in morphologic and biomechanical parameters or proteoglycan content between treated discs and time-matched, nontreated discs.Our results demonstrate that percutaneous plasma discectomy alters the expression of inflammatory cytokines in degenerated discs, leading to a decrease in IL-1 and an increase in IL-8. Whereas both IL-1 and IL-8 have hyperalgesic properties, IL-1 is likely to be a more important pathophysiologic factor in painful disc disorders than IL-8. Therefore, the alteration in cytokine expression that we observed is consistent with this effect as a mechanism of pain relief after discectomy. In addition, given that IL-1 is catabolic in injured tissue and IL-8 is anabolic, our results suggest that a percutaneous plasma discectomy may be capable of initiating a repair response in the disc.

    View details for DOI 10.1016/s1529-9430(03)00423-6

    View details for PubMedID 14749197

  • Spinal infections. The Journal of the American Academy of Orthopaedic Surgeons Tay, B. K., Deckey, J., Hu, S. S. ; 10 (3): 188–97

    Abstract

    Spinal infections can occur in a variety of clinical situations. Their presentation ranges from the infant with diskitis who is unwilling to crawl or walk to the adult who develops an infection after a spinal procedure. The most common types of spinal infections are hematogenous bacterial or fungal infections, pediatric diskitis, epidural abscess, and postoperative infections. Prompt and accurate diagnosis of spinal infections, the cornerstone of treatment, requires a high index of suspicion in at-risk patients and the appropriate evaluation to identify the organism and determine the extent of infection. Neurologic function and spinal stability also should be carefully evaluated. The goals of therapy should include eradicating the infection, relieving pain, preserving or restoring neurologic function, improving nutrition, and maintaining spinal stability.

    View details for DOI 10.5435/00124635-200205000-00005

    View details for PubMedID 12041940

  • Cervical Epidural Steroid Injections: Incidence and Determinants of Subsequent Surgery. The spine journal : official journal of the North American Spine Society Kleimeyer, J. P., Koltsov, J. C., Smuck, M. W., Wood, K. B., Cheng, I., Hu, S. S. 2020

    Abstract

    BACKGROUND CONTEXT: Cervical epidural steroid injections (CESIs) are sometimes used in the management of cervical radicular pain in order to delay or avoid surgery. However, the rate and determinants of surgery following CESIs remain uncertain.PURPOSE: This study sought to determine: 1) the proportion of patients having surgery following CESI, and 2) the timing of and factors associated with subsequent surgery.STUDY DESIGN: Retrospective analysis of a large, national administrative claims database.PATIENT SAMPLE: The study included 192,777 CESI patients (age 50.9±11.3 years, 55.2% female) who underwent CESI for imaging-based diagnoses of cervical disc herniation or stenosis, a clinical diagnosis of radiculopathy, or a combination thereof.OUTCOME MEASURES: The primary outcome was the time from index CESI to surgery.METHODS: Inclusion criteria were CESI for cervical disc herniation, stenosis, or radiculopathy, age ≥18, and active enrollment for 1 year prior to CESI to screen for exclusions. Patients were followed until they underwent cervical surgery, or their enrollment lapsed. Rates of surgery were assessed with Kaplan-Meier survival curves and 99% confidence intervals. Factors associated with subsequent surgery were assessed with multivariable Cox proportional hazard models.RESULTS: Within 6 months of CESI, 11.2% of patients underwent surgery, increasing to 14.5% by 1 year and 22.3% by 5 years. Male patients and those aged 35-54 had an increased likelihood of subsequent surgery. Patients with radiculopathy were less likely to undergo surgery following CESI than those with stenosis or herniation, while patients with multiple diagnoses were more likely. Patients with comorbidities including CHF, other cardiac comorbidities or chronic pain were less likely to undergo surgery, as were patients in the northeast US region. Some 33.5% of patients underwent >1 CESI, with 84.6% of these occurring within 1 year. Additional injections were associated with reduced rates of subsequent surgery.CONCLUSIONS: Following CESI, over one in five patients underwent surgery within 5 years. Multiple patient-specific risk factors for subsequent surgery were identified, and patients undergoing repeated injections were at lower risk. Determining which patients may progress to surgery can be used to improve resource utilization and to inform shared decision-making.

    View details for DOI 10.1016/j.spinee.2020.06.012

    View details for PubMedID 32565316

  • Perioperative Anticoagulation Management in Spine Surgery: Initial Findings From the AO Spine Anticoagulation Global Survey GLOBAL SPINE JOURNAL Louie, P., Harada, G., Harrop, J., Mroz, T., Al-Saleh, K., Brodano, G., Chapman, J., Fehlings, M., Hu, S., Kawaguchi, Y., Mayer, M., Menon, V., Park, J., Qureshi, S., Rajasekaran, S., Valacco, M., Vialle, L., Wang, J. C., Wiechert, K., Riew, D., Samartzis, D. 2020
  • Cost Analysis of Single-Level Lumbar Fusions. Global spine journal Beckerman, D., Esparza, M., Lee, S. I., Berven, S. H., Bederman, S. S., Hu, S. S., Burch, S., Deviren, V., Tay, B., Mummaneni, P. V., Chou, D., Ames, C. P. 2020; 10 (1): 39–46

    Abstract

    Cost analysis of a retrospectively identified cohort of patients who had undergone primary single-level lumbar fusion at a single institution's orthopedic or neurosurgery department.The purpose of this article is to analyze the determinants of direct costs for single-level lumbar fusions and identify potential areas for cost reduction.Adult patients who underwent primary single-level lumbar fusion from fiscal years 2008 to 2012 were identified via administrative and departmental databases and were eligible for inclusion. Patients were excluded if they underwent multiple surgeries, had previous surgery at the same anatomic region, underwent corpectomy, kyphectomy, disc replacement, surgery for tumor or infection, or had incomplete cost data. Demographic data, surgical data, and direct cost data in the categories of supplies, services, room and care, and pharmacy, was collected for each patient.The cohort included 532 patients. Direct costs ranged from $8286 to $73 727 (median = $21 781; mean = $22 890 ± $6323). Surgical approach was an important determinant of cost. The mean direct cost was highest for the circumferential approach and lowest for posterior instrumented spinal fusions without an interbody cage. The difference in mean direct cost between transforaminal lumbar interbody fusions, anterior lumbar interbody fusions, and lateral transpsoas fusions was not statistically significant. Surgical supplies accounted for 44% of direct costs. Spinal implants were the primary component of supply costs (84.9%). Services accounted for 38% of direct costs and were highly dependent on operative time. Comorbidities were an important contributor to variance in the cost of care as evidenced by high variance in pharmacy costs and length of stay related to their management.The costs of spinal surgeries are highly variable. Important cost drivers in our analysis included surgical approach, implants, operating room time, and length of hospital stay. Areas of high cost and high variance offer potential targets for cost savings and quality improvements.

    View details for DOI 10.1177/2192568219853251

    View details for PubMedID 32002348

    View details for PubMedCentralID PMC6963351

  • Outcomes and Quality of Life Improvement After Multilevel Spinal Fusion in Elderly Patients. Global spine journal Ibrahim, J. M., Singh, P., Beckerman, D., Hu, S. S., Tay, B., Deviren, V., Burch, S., Berven, S. H. 2020; 10 (2): 153–59

    Abstract

    Retrospective case series.Both the rate and complexity of spine surgeries in elderly patients has increased. This study reports the outcomes of multilevel spine fusion in elderly patients and provides evidence on the appropriateness of complex surgery in elderly patients.We identified 101 patients older than70 years who had ≥5 levels of fusion. Demographic, medical, and surgical data, and change between preoperative and >500 days postoperative health survey scores were collected. Health surveys were visual analogue scale (VAS), EuroQoL 5 Dimensions (EQ-5D), Oswestry Disability Index (ODI), Scoliosis Research Society questionnaire (SRS-30), and Short Form health survey (SF-12) (physical composite score [PCS] and mental composite score [MCS]). Minimal clinically important differences (MCIDs) were defined for each survey.Complications included dural tears (19%), intensive care unit admission (48%), revision surgery within 2 to 5 years (24%), and death within 2 to 5 years (16%). The percentage of patients who reported an improvement in health-related quality of life (HRQOL) of at least an MCID was: VAS Back 69%; EQ-5D 41%; ODI 58%; SRS-30 45%; SF-12 PCS 44%; and SF-12 MCS 48%. Improvement after a primary surgery, as compared with a revision, was on average 13 points higher in ODI (P = .007). Patients who developed a surgical complication averaged an improvement 11 points lower on ODI (P = .042). Patients were more likely to find improvement in their health if they had a lower American Society of Anesthesiologists or Charlson Comorbidity Index score or a higher metabolic equivalent score.In multilevel surgery in patients older than 70 years, complications are common, and on average 77% of patients attain some improvement, with 51% reaching an MCID. Physiological status is a stronger predictor of outcomes than chronological age.

    View details for DOI 10.1177/2192568219849393

    View details for PubMedID 32206514

    View details for PubMedCentralID PMC7076597

  • Perioperative Anticoagulation Management in Spine Surgery: Initial Findings From the AO Spine Anticoagulation Global Survey. Global spine journal Louie, P., Harada, G., Harrop, J., Mroz, T., Al-Saleh, K., Brodano, G. B., Chapman, J., Fehlings, M., Hu, S., Kawaguchi, Y., Mayer, M., Menon, V., Park, J. B., Qureshi, S., Rajasekaran, S., Valacco, M., Vialle, L., Wang, J. C., Wiechert, K., Riew, K. D., Samartzis, D. 2020; 10 (5): 512–27

    Abstract

    Cross-sectional, international survey.This study addressed the global perspectives concerning perioperative use of pharmacologic thromboprophylaxis during spine surgery along with its risks and benefits.A questionnaire was designed and implemented by expert members in the AO Spine community. The survey was distributed to AO Spine's spine surgeon members (N = 3805). Data included surgeon demographic information, type and region of practice, anticoagulation principles, different patient scenarios, and comorbidities.A total of 316 (8.3% response rate) spine surgeons completed the survey, representing 64 different countries. Completed surveys were primarily from Europe (31.7%), South/Latin America (19.9%), and Asia (18.4%). Surgeons tended to be 35 to 44 years old (42.1%), fellowship-trained (74.7%), and orthopedic surgeons (65.5%) from academic institutions (39.6%). Most surgeons (70.3%) used routine anticoagulation risk stratification, irrespective of geographic location. However, significant differences were seen between continents with anticoagulation initiation and cessation methodology. Specifically, the length of a procedure (P = .036) and patient body mass index (P = .008) were perceived differently when deciding to begin anticoagulation, while the importance of medical clearance (P < .001) and reference to literature (P = .035) differed during cessation. For specific techniques, most providers noted use of mobilization, low-molecular-weight heparin, and mechanical prophylaxis beginning on postoperative 0 to 1 days. Conversely, bridging regimens were bimodal in distribution, with providers electing anticoagulant initiation on postoperative 0 to 1 days or days 5-6.This survey highlights the heterogeneity of spine care and accentuates geographical variations. Furthermore, it identifies the difficulty in providing consistent perioperative anticoagulation recommendations to patients, as there remains no widely accepted, definitive literature of evidence or guidelines.

    View details for DOI 10.1177/2192568219897598

    View details for PubMedID 32677576

  • The impact of obesity on perioperative complications in patients undergoing anterior lumbar interbody fusion. Journal of neurosurgery. Spine Safaee, M. M., Tenorio, A., Osorio, J. A., Choy, W., Amara, D., Lai, L., Molinaro, A. M., Zhang, Y., Hu, S. S., Tay, B., Burch, S., Berven, S. H., Deviren, V., Dhall, S. S., Chou, D., Mummaneni, P. V., Eichler, C. M., Ames, C. P., Clark, A. J. 2020: 1–10

    Abstract

    Anterior approaches to the lumbar spine provide wide exposure that facilitates placement of large grafts with high fusion rates. There are limited data on the effects of obesity on perioperative complications.Data from consecutive patients undergoing anterior lumbar interbody fusion (ALIF) from 2007 to 2016 at a single academic center were analyzed. The primary outcome was any perioperative complication. Complications were divided into those occurring intraoperatively and those occurring postoperatively. Multivariate logistic regression was used to assess the association of obesity and other variables with these complications. An estimation table was used to identify a body mass index (BMI) threshold associated with increased risk of postoperative complication.A total of 938 patients were identified, and the mean age was 57 years; 511 were females (54.5%). The mean BMI was 28.7 kg/m2, with 354 (37.7%) patients classified as obese (BMI ≥ 30 kg/m2). Forty patients (4.3%) underwent a lateral transthoracic approach, while the remaining 898 (95.7%) underwent a transabdominal retroperitoneal approach. Among patients undergoing transabdominal retroperitoneal ALIF, complication rates were higher for obese patients than for nonobese patients (37.0% vs 28.7%, p = 0.010), a difference that was driven primarily by postoperative complications (36.1% vs 26.0%, p = 0.001) rather than intraoperative complications (3.2% vs 4.3%, p = 0.416). Obese patients had higher rates of ileus (11.7% vs 7.2%, p = 0.020), wound complications (11.4% vs 3.4%, p < 0.001), and urinary tract infections (UTI) (5.0% vs 2.5%, p = 0.049). In a multivariate model, age, obesity, and number of ALIF levels fused were associated with an increased risk of postoperative complication. An estimation table including 19 candidate cut-points, odds ratios, and adjusted p values found a BMI ≥ 31 kg/m2 to have the highest association with postoperative complication (p = 0.012).Obesity is associated with increased postoperative complications in ALIF, including ileus, wound complications, and UTI. ALIF is a safe and effective procedure. However, patients with a BMI ≥ 31 kg/m2 should be counseled on their increased risks and warrant careful preoperative medical optimization and close monitoring in the postoperative setting.

    View details for DOI 10.3171/2020.2.SPINE191418

    View details for PubMedID 32330881

  • Decompression With or Without Fusion for Lumbar Stenosis: A Cost Minimization Analysis. Spine Ziino, C., Mertz, K., Hu, S., Kamal, R. 2020; 45 (5): 325–32

    Abstract

    Retrospective database review.Compare 1-year episode of care costs between single-level decompression and decompression plus fusion for lumbar stenosis.Lumbar stenosis is the most common indication for surgery in patients over 65. Medicare direct hospital costs for lumbar surgery reached $1.65 billion in 2007. Despite stenosis being a common indication for surgery, there is debate as to the preferred surgical treatment. Cost-minimization analysis is a framework that identifies potential cost savings between treatment options that have similar outcomes. We performed a cost-minimization analysis of decompression versus decompression with fusion for lumbar stenosis from the payer perspective.An administrative claims database of privately insured patients (Humana) identified patients who underwent decompression (n = 5349) or decompression with fusion (n = 8540) for lumbar stenosis with and without spondylolisthesis and compared overall costs. All patients were identified and costs identified for a 1-year period. Complication rates and costs were described using summary statistics.Mean treatment costs at 1 year after surgery were higher for patients who underwent decompression and fusion compared to patients who underwent decompression alone ($20,892 for fusion vs. $6329 for decompression; P < 0.001). Facility costs (P < 0.001), surgeon costs (P < 0.001), and physical therapy costs (P < 0.001) were higher in the fusion group. Cost differences related to infection or durotomy reached significance (P < 0.04). No difference in cost was identified for supplies.Decompression had significantly lower costs for the treatment of lumbar stenosis, including treatment for postoperative complications. If cost minimization is the primary goal, decompression is favored for surgical treatment of lumbar stenosis. Other factors including shared decision-making directed toward patient's values, patient-reported outcomes, and preferences should also be recognized as drivers of healthcare decisions.3.

    View details for DOI 10.1097/BRS.0000000000003250

    View details for PubMedID 32045402

  • Factors Affecting the Decision to Initiate Anticoagulation After Spine Surgery: Findings From the AOSpine Anticoagulation Global Initiative. Global spine journal Gandhi, S. D., Khanna, K., Harada, G., Louie, P., Harrop, J., Mroz, T., Al-Saleh, K., Brodano, G. B., Chapman, J., Fehlings, M. G., Hu, S. S., Kawaguchi, Y., Mayer, M., Menon, V., Park, J. B., Rajasekaran, S., Valacco, M., Vialle, L., Wang, J. C., Wiechert, K., Riew, K. D., Samartzis, D. 2020: 2192568220948027

    Abstract

    Cross-sectional, international survey.To identify factors influencing pharmacologic anticoagulation initiation after spine surgery based on the AOSpine Anticoagulation Global Survey.This survey was distributed to the international membership of AOSpine (n = 3805). A Likert-type scale described grade practice-specific factors on a scale from low (1) to high (5) importance, and patient-specific factors a scale from low (0) to high (3) importance. Analysis was performed to determine which factors were significant in the decision making surrounding the initiation of pharmacologic anticoagulation.A total of 316 spine surgeons from 64 countries completed the survey. In terms of practice-specific factors considered to initiate treatment, expert opinion was graded the highest (mean grade ± SD = 3.2 ± 1.3), followed by fellowship training (3.2 ± 1.3). Conversely, previous studies (2.7 ± 1.2) and unspecified guidelines were considered least important (2.6 ± 1.6). Patient body mass index (2.0 ± 1.0) and postoperative mobilization (2.3 ± 1.0) were deemed most important and graded highly overall. Those who rated estimated blood loss with greater importance in anticoagulation initiation decision making were more likely to administer thromboprophylaxis at later times (hazard ratio [HR] = 0.68-0.71), while those who rated drain output with greater importance were likely to administer thromboprophylaxis at earlier times (HR = 1.32-1.43).Among our global cohort of spine surgeons, certain patient factors (ie, patient mobilization and body mass index) and practice-specific factors (ie, expert opinion and fellowship training) were considered to be most important when considering anticoagulation start times.

    View details for DOI 10.1177/2192568220948027

    View details for PubMedID 32911980

  • Timing of Lumbar Spinal Fusion Affects Total Hip Arthroplasty Outcomes. Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews Bala, A., Chona, D. V., Amanatullah, D. F., Hu, S. S., Wood, K. B., Alamin, T. F., Cheng, I. 2019; 3 (11): e00133

    Abstract

    Many patients are affected by concurrent disease of the hip and spine, undergoing both total hip arthroplasty (THA) and lumbar spinal fusion (LSF). Recent literature demonstrates increased prosthetic dislocation rates in patients with THA done after LSF. Evidence is lacking on which surgery to do first to minimize complications. The purpose of this study was to evaluate the effect of timing between the two procedures on postoperative outcomes.Methods: We queried the Medicare standard analytics files between 2005 and 2014. Four groups were identified and matched by age and sex: THA with previous LSF, LSF with previous THA, THA with spine pathology without fusion, and THA without spine pathology. Revision THA or LSF and bilateral THA were excluded. Comorbidities and Charlson Comorbidity Index were identified. Postoperative complications at 90 days and 2 years were calculated after the most recent surgery. Four-way chi-squared and standard descriptive statistics were calculated.Results: Thirteen thousand one hundred two patients had THA after LSF, 10,482 patients had LSF after THA, 104,820 had THA with spine pathology, and 492,654 had THA without spine pathology. There was no difference in the Charlson Comorbidity Index score between the THA after LSF and LSF after THA groups. There was a statistically significant difference in THA dislocation rate, with LSF after THA at 1.7%, THA without spine pathology at 2.3%, THA with spine pathology at 3.3%, and THA after LSF at 4.6%. There was a statistically significant difference in THA revision rate, with THA without spine pathology at 3.3%, LSF after THA at 3.7%, THA with spine pathology at 4.2%, and THA after LSF at 5.7%.Conclusion: LSF after THA is associated with a reduced dislocation rate compared with THA after LSF. Reasons may include decreasing pelvic mobility in a stable, well-healed THA or early postoperative spine precautions after LSF restricting positions of dislocation.

    View details for DOI 10.5435/JAAOSGlobal-D-19-00133

    View details for PubMedID 31875203

  • Short-Term Outcomes of Staged Versus Same-Day Surgery for Adult Spinal Deformity Correction. Spine deformity Arzeno, A. H., Koltsov, J., Alamin, T. F., Cheng, I., Wood, K. B., Hu, S. S. 2019; 7 (5): 796

    Abstract

    STUDY DESIGN: Retrospective cohort study.OBJECTIVES: Assess differences between staged (≤3 days) and same-day surgery in perioperative factors, radiographic measures, and complications.SUMMARY OF BACKGROUND DATA: Surgical adult spinal deformity correction may require combined anterior and posterior approaches. To modulate risk, some surgeons perform surgery that is expected to be longer and/or more complex in two stages. Prior studies comparing staged (≥7 days) and same-day surgery demonstrated mixed results and none have examined results with shorter staging intervals.METHODS: Retrospective review of adults undergoing combined anterior/posterior approaches for spinal deformity over a 3-year period at a single institution (n=92). Univariate differences between staged and same-day surgery were assessed with chi-squared, Fisher exact, and Mann-Whitney U tests. Generalized estimating equations assessed whether differences in perioperative outcomes between groups remained after adjusting for differences in demographic and surgical characteristics.RESULTS: In univariate analyses, staged surgery was associated with a length of stay (LOS) 3 days longer than same-day surgery (9.2 vs. 6.3 days, p < .001), and greater operative time, blood loss, transfusion requirement, and days in intensive care unit (p < .001 for each). Staged surgery had a higher rate of thrombotic events (p = .011) but did not differ in readmission rates or other complications. Radiographically, improvements in Cobb angle (average 13° vs. 17°, p = .028), lumbar lordosis (average 14° vs. 23°, p = .019), and PI-LL mismatch (average 10° vs. 2° p = .018) were greater for staged surgery, likely related to more extensive use of osteotomies in the staged group. After risk adjustment, taking into account the procedural specifics including longer fusion constructs and greater number of osteotomies, LOS no longer differed between staged and same-day surgery; however, the total operative time was 98 minutes longer for staged surgery (p < .001). Differences in blood loss between groups was accounted for by differences in operative time and patient and surgical characteristics.CONCLUSIONS: Although univariate analysis of our results were in accordance with previously published works, multivariate analysis allowing individual case risk adjustment revealed that LOS was not significantly increased in the staged group as reported in previous studies. There was no difference in infection rates as previously described but an increase in thrombotic events was observed.LEVEL OF EVIDENCE: Level III.

    View details for DOI 10.1016/j.jspd.2018.12.008

    View details for PubMedID 31495481

  • Local Application of Vancomycin in Spine Surgery Does Not Result in Increased Vancomycin-Resistant Bacteria-10-Year Data. Spine deformity Khanna, K., Valone, F. 3., Tenorio, A., Grace, T., Burch, S., Berven, S., Tay, B., Deviren, V., Hu, S. S. 2019; 7 (5): 696–701

    Abstract

    STUDY DESIGN: Case-control study.OBJECTIVES: To analyze the microbial flora in surgical spine infections and their antibiotic resistance patterns across time and determine the correlation between vancomycin application in the wound and vancomycin-resistant microbes.SUMMARY OF BACKGROUND DATA: Prior studies show a reduction in surgical site infections with intrawound vancomycin placement. No data are available on the potential negative effects of this intervention, in particular, whether there would be a resultant increase in vancomycin-resistant organisms or bacterial resistance profiles.METHODS: All culture-positive surgical site infections at a single institution were analyzed from 2007 to 2017. Each bacterium was assessed independently for resistance patterns. The two-tailed Fisher exact test was used to determine the correlation between vancomycin application and the presence of vancomycin-resistant bacteria, polymicrobial infections, or gram-negative bacterial infections.RESULTS: One hundred and eight bacteria were isolated from 113 surgical site infections from 2007 to 2017. The most common organisms were staphylococcus with varying resistance patterns and Escherichia coli. Vancomycin-resistant Enterococcus faecium was isolated in three infections. Out of the 4,878 surgical cases from 2011 to 2017, vancomycin was placed in 48.3%, and no vancomycin in 51.7%. There were 33 infections (1.4%) in the vancomycin group and 20 infections (0.8%) in the no-vancomycin group (chi2 = 0.0521). There was no correlation between vancomycin application in the wound and vancomycin-resistant microbes (chi2 = 0.2334) and polymicrobial infections (chi2 = 0.1328). There was an increased rate of gram-negative organisms in infections after vancomycin application in the wound versus no vancomycin (chi2 = 0.0254).CONCLUSIONS: Topical vancomycin within the surgical site is not correlated with vancomycin-resistant bacteria. However, there was an increased incidence of gram-negative organisms in infections after vancomycin application in the wound versus no vancomycin. Continued surveillance with prospectively collected randomized data is necessary to better understand bacterial evolution against current antimicrobial techniques.LEVEL OF EVIDENCE: Level III.

    View details for DOI 10.1016/j.jspd.2019.01.005

    View details for PubMedID 31495468

  • Reliability of radiological measurements of type 2 odontoid fracture SPINE JOURNAL Karamian, B. A., Liu, N., Ajiboye, R. M., Cheng, I., Hu, S. S., Wood, K. B. 2019; 19 (8): 1324–30
  • Asymmetric Pedicle Subtraction Osteotomy for Adult Spinal Deformity with Coronal Imbalance: Complications, Radiographic and Surgical Outcomes. Operative neurosurgery (Hagerstown, Md.) Chan, A. K., Lau, D., Osorio, J. A., Yue, J. K., Berven, S. H., Burch, S., Hu, S. S., Mummaneni, P. V., Deviren, V., Ames, C. P. 2019

    Abstract

    BACKGROUND: Asymmetric pedicle subtraction osteotomy (APSO) can be utilized for adult spinal deformity (ASD) with fixed coronal plane imbalance. There are few reports investigating outcomes following APSO and no series that include multiple revision cases.OBJECTIVE: To detail our surgical technique and experience with APSO.METHODS: All thoracolumbar ASD cases with a component of fixed, coronal plane deformity who underwent APSO from 2004 to 2016 at one institution were retrospectively reviewed. Preoperative and latest follow-up radiographic parameters and data on surgical outcomes and complications were obtained.RESULTS: Fourteen patients underwent APSO with mean follow-up of 37-mo. Ten (71.4%) were revision cases. APSO involved a mean 12-levels (range 7-25) and were associated with 3.0 L blood loss (range 1.2-4.5) and 457-min of operative time (range 283-540). Surgical complications were observed in 64.3%, including durotomy (35.7%), pleural injury (14.3%), persistent neurologic deficit (14.3%), rod fracture (7.1%), and painful iliac bolt requiring removal (7.1%). Medical complications were observed in 14.3%, comprising urosepsis and 2 cases of pneumonia. Two 90-d readmissions (14.3%) and 5 reoperations (4 patients, 28.6%) occurred. Mean thoracolumbar curve and coronal vertical axis improved from 31.5 to 16.4 degrees and 7.8 to 2.9 cm, respectively. PI-LL mismatch, mean sagittal vertical axis, and pelvic tilt improved from 40.0 to 27.9-degrees, 10.7 to 3.5-cm, and 34.4 to 28.3-degrees, respectively.CONCLUSION: The APSO, in both a revision and non-revision ASD population, provides excellent restoration of coronal balance-in addition to sagittal and pelvic parameters. Employment of APSO must be balanced with the associated surgical complication rate (64.3%).

    View details for DOI 10.1093/ons/opz106

    View details for PubMedID 31214712

  • Outcomes and Quality of Life Improvement After Multilevel Spinal Fusion in Elderly Patients GLOBAL SPINE JOURNAL Ibrahim, J. M., Singh, P., Beckerman, D., Hu, S. S., Tay, B., Deviren, V., Burch, S., Berven, S. H. 2019
  • Reliability of Radiological Measurements of Type-2 Odontoid Fracture. The spine journal : official journal of the North American Spine Society Karamian, B. A., Liu, N., Ajiboye, R. M., Cheng, I., Hu, S. S., Wood, K. B. 2019

    Abstract

    It is recognized that radiological parameters of type 2 dens fractures, including displacement and angulation, are predictive of treatment outcomes and are used to guide surgical decision-making. The reproducibility of such measurements, therefore, is of critical importance. Past literature has shown poor inter-observer reliability for both displacement and angulation measurements of type 2 dens fractures. Since such studies however, various advancements of radiological review systems and measurement tools have evolved to potentially improve such measurements.To re-examine the interrater reliability of measuring displacement and angulation of type 2 dens fractures utilizing modern radiologic review systems. Besides quantitative measurements, the reliability of raters in identifying diagnostic classifications based on translational and angulational displacement was also examined.Radiographic measurement reliability and agreement study.Thirty-seven patients seen at a single institution between 2002 and 2017 with primary diagnosis of acute type II dens fracture with complete CT imaging.Radiological measurements included displacement and angulation. Diagnostic classifications based on consensus-based clinical cut-off points were also recorded.Measurements were performed by five surgeons with varying years of experience in spine surgery using the hospital's electronic medical record radiological measuring tools. The radiological measurements included displacement and angulation. Diagnostic classifications based on consensus-based clinical cut-off points were also recorded. Each rater received a graphic demonstration of the measurement methods, but had the autonomy to select a best cut from the sagittal CT to measure. All raters were blinded to patient information.Measurements for displacement and angulation among the five raters demonstrated "excellent" reliability. Intra-rater reliability was also "excellent" in measuring displacement and angulation. The reliability of diagnostic classification of displacement (above vs. below 5mm), was found to be "very good" among the raters. The reliability of diagnostic classification of angulation (above vs. below 11°) demonstrated "good" reliability.Advancement of radiological review systems, including review tools and embedded image processing software, has facilitated more reliable measurements for type-2 odontoid fractures.

    View details for PubMedID 31078698

  • Short-Term Outcomes of Staged Versus Same-Day Surgery for Adult Spinal Deformity Correction. Spine deformity Arzeno, A. H., Koltsov, J., Alamin, T. F., Cheng, I., Wood, K. B., Hu, S. S. 2019; 7 (5): 796–804

    Abstract

    Retrospective cohort study.Assess differences between staged (≤3 days) and same-day surgery in perioperative factors, radiographic measures, and complications. Surgical adult spinal deformity correction may require combined anterior and posterior approaches. To modulate risk, some surgeons perform surgery that is expected to be longer and/or more complex in two stages. Prior studies comparing staged (≥7 days) and same-day surgery demonstrated mixed results and none have examined results with shorter staging intervals.Retrospective review of adults undergoing combined anterior/posterior approaches for spinal deformity over a 3-year period at a single institution (n=92). Univariate differences between staged and same-day surgery were assessed with chi-squared, Fisher exact, and Mann-Whitney U tests. Generalized estimating equations assessed whether differences in perioperative outcomes between groups remained after adjusting for differences in demographic and surgical characteristics.In univariate analyses, staged surgery was associated with a length of stay (LOS) 3 days longer than same-day surgery (9.2 vs. 6.3 days, p < .001), and greater operative time, blood loss, transfusion requirement, and days in intensive care unit (p < .001 for each). Staged surgery had a higher rate of thrombotic events (p = .011) but did not differ in readmission rates or other complications. Radiographically, improvements in Cobb angle (average 13° vs. 17°, p = .028), lumbar lordosis (average 14° vs. 23°, p = .019), and PI-LL mismatch (average 10° vs. 2° p = .018) were greater for staged surgery, likely related to more extensive use of osteotomies in the staged group. After risk adjustment, taking into account the procedural specifics including longer fusion constructs and greater number of osteotomies, LOS no longer differed between staged and same-day surgery; however, the total operative time was 98 minutes longer for staged surgery (p < .001). Differences in blood loss between groups was accounted for by differences in operative time and patient and surgical characteristics.Although univariate analysis of our results were in accordance with previously published works, multivariate analysis allowing individual case risk adjustment revealed that LOS was not significantly increased in the staged group as reported in previous studies. There was no difference in infection rates as previously described but an increase in thrombotic events was observed.Level III.

    View details for DOI 10.1016/j.jspd.2018.12.008

    View details for PubMedID 31975196

  • The Relationship Between Lumbar Lateral Listhesis and Radiculopathy in Adult Scoliosis. Spine Kleimeyer, J. P., Liu, N., Hu, S. S., Cheng, I., Alamin, T., Grottkau, B. E., Kukreja, S., Wood, K. B. 2019; 44 (14): 1003–9

    Abstract

    Retrospective review and prospective validation study.To develop a classification system of lumbar lateral listhesis that suggests different likelihoods of having radiculopathy in adult scoliosis.The association of lumbar lateral listhesis with radiculopathy remains uncertain.A retrospective cohort of patients with adult scoliosis enrolled from 2011 to 2015 was studied to develop a classification system of lateral listhesis that can stratify the likelihood of having radiculopathy. Four radiological aspects of lateral listhesis, including Nash and Moe vertebral rotation, L4-L5 lateral listhesis, the number of consecutive listheses, and the presence of a contralateral lateral listhesis at the thoracolumbar junction above a caudal listhesis, were evaluated on radiographs. Their associations with the presence of radicular leg pain were evaluated using multivariable logistic regression. The classification system of lateral listhesis was thus developed using the most influential radiological factors and then validated in a prospective cohort from 2016 to 2017.The retrospective cohort included 189 patients. Vertebral rotation is more than or equal to grade 2 (odds ratio [OR] = 9.45, 95% confidence interval [CI]: 4.07-25.14) and L4-5 listhesis (OR = 4.56, 95%CI: 1.85-12.35) were the two most influential listhesis factors associated with radiculopathy. The classification system of lateral listhesis was thus built based on the combinations of their respective presence: Type 0, 1, 2, 3 were defined as not having listhesis at all, none of the two factors present, one of the two presents, and both present, respectively. This classification significantly stratified the probability of radiculopathy, in both the retrospective cohort (0%, 6.4%, 33.8%, and 68.4% in Type 0, 1, 2, and 3, respectively; P < 0.001) and a prospective cohort of 105 patients (0%, 16.7%, 46.9%, and 72.7%; P < 0.001).Lumbar lateral listhesis is associated with the presence of radiculopathy in adult scoliosis. Types 2 and 3 lateral listhesis on radiographs may alert surgeons treating patients with spinal deformity.2.

    View details for DOI 10.1097/BRS.0000000000002986

    View details for PubMedID 30664100

  • Local Application of Vancomycin in Spine Surgery Does Not Result in Increased Vancomycin-Resistant Bacteria-10-Year Data. Spine deformity Khanna, K., Valone, F., Tenorio, A., Grace, T., Burch, S., Berven, S., Tay, B., Deviren, V., Hu, S. S. 2019; 7 (5): 696–701

    Abstract

    Case-control study.To analyze the microbial flora in surgical spine infections and their antibiotic resistance patterns across time and determine the correlation between vancomycin application in the wound and vancomycin-resistant microbes. Prior studies show a reduction in surgical site infections with intrawound vancomycin placement. No data are available on the potential negative effects of this intervention, in particular, whether there would be a resultant increase in vancomycin-resistant organisms or bacterial resistance profiles.All culture-positive surgical site infections at a single institution were analyzed from 2007 to 2017. Each bacterium was assessed independently for resistance patterns. The two-tailed Fisher exact test was used to determine the correlation between vancomycin application and the presence of vancomycin-resistant bacteria, polymicrobial infections, or gram-negative bacterial infections.One hundred and eight bacteria were isolated from 113 surgical site infections from 2007 to 2017. The most common organisms were staphylococcus with varying resistance patterns and Escherichia coli. Vancomycin-resistant Enterococcus faecium was isolated in three infections. Out of the 4,878 surgical cases from 2011 to 2017, vancomycin was placed in 48.3%, and no vancomycin in 51.7%. There were 33 infections (1.4%) in the vancomycin group and 20 infections (0.8%) in the no-vancomycin group (χ2 = 0.0521). There was no correlation between vancomycin application in the wound and vancomycin-resistant microbes (χ2 = 0.2334) and polymicrobial infections (χ2 = 0.1328). There was an increased rate of gram-negative organisms in infections after vancomycin application in the wound versus no vancomycin (χ2 = 0.0254).Topical vancomycin within the surgical site is not correlated with vancomycin-resistant bacteria. However, there was an increased incidence of gram-negative organisms in infections after vancomycin application in the wound versus no vancomycin. Continued surveillance with prospectively collected randomized data is necessary to better understand bacterial evolution against current antimicrobial techniques.Level III.

    View details for DOI 10.1016/j.jspd.2019.01.005

    View details for PubMedID 31975209

  • The comprehensive anatomical spinal osteotomy and anterior column realignment classification JOURNAL OF NEUROSURGERY-SPINE Uribe, J. S., Schwab, F., Mundis, G. M., Xu, D. S., Januszewski, J., Kanter, A. S., Okonkwo, D. O., Hu, S. S., Vedat, D., Eastlack, R., Berjano, P., Mummaneni, P. 2018; 29 (5): 565–75

    Abstract

    OBJECTIVE Spinal osteotomies and anterior column realignment (ACR) are procedures that allow preservation or restoration of spine lordosis. Variations of these techniques enable different degrees of segmental, regional, and global sagittal realignment. The authors propose a comprehensive anatomical classification system for ACR and its variants based on the level of technical complexity and invasiveness. This serves as a common language and platform to standardize clinical and radiographic outcomes for the utilization of ACR. METHODS The proposed classification is based on 6 anatomical grades of ACR, including anterior longitudinal ligament (ALL) release, with varying degrees of posterior column release or osteotomies. Additionally, a surgical approach (anterior, lateral, or posterior) was added. Reliability of the classification was evaluated by an analysis of 16 clinical cases, rated twice by 14 different spine surgeons, and calculation of Fleiss kappa coefficients. RESULTS The 6 grades of ACR are as follows: grade A, ALL release with hyperlordotic cage, intact posterior elements; grade 1 (ACR + Schwab grade 1), additional resection of the inferior facet and joint capsule; grade 2 (ACR + Schwab grade 2), additional resection of both superior and inferior facets, interspinous ligament, ligamentum flavum, lamina, and spinous process; grade 3 (ACR + Schwab grade 3), additional adjacent-level 3-column osteotomy including pedicle subtraction osteotomy; grade 4 (ACR + Schwab grade 4), 2-level distal 3-column osteotomy including pedicle subtraction osteotomy and disc space resection; and grade 5 (ACR + Schwab grade 5), complete or partial removal of a vertebral body and both adjacent discs with or without posterior element resection. Intraobserver and interobserver reliability were 97% and 98%, respectively, across the 14-reviewer cohort. CONCLUSIONS The proposed anatomical realignment classification provides a consistent description of the various posterior and anterior column release/osteotomies. This reliability study confirmed that the classification is consistent and reproducible across a diverse group of spine surgeons.

    View details for DOI 10.3171/2018.4.SPINE171206

    View details for Web of Science ID 000448969400014

    View details for PubMedID 30141765

  • Selective Anterior Lumbar Interbody Fusion for Low Back Pain Associated With Degenerative Disc Disease Versus Nonsurgical Management SPINE Kleimeyer, J. P., Cheng, I., Alamin, T. F., Hu, S. S., Cha, T., Yanamadala, V., Wood, K. B. 2018; 43 (19): 1372–80

    Abstract

    This is a retrospective cohort study.To evaluate the long-term outcomes of selective one- to two-level anterior lumbar interbody fusions (ALIFs) in the lower lumbar spine versus continued nonsurgical management.Low back pain associated with lumbar intervertebral disc degeneration is common with substantial economic impact, yet treatment remains controversial. Surgical fusion has previously provided mixed results with limited durable improvement of pain and function.Seventy-five patients with one or two levels of symptomatic Pfirrmann grades 3 to 5 disc degeneration from L3-S1 were identified. All patients had failed at least 6 months of nonsurgical treatment. Forty-two patients underwent one- or two-level ALIFs; 33 continued multimodal nonsurgical care. Patients were evaluated radiographically and the visual analog pain scale (VAS), Oswestry Disability Index (ODI), EuroQol five dimensions (EQ-5D), and Patient-Reported Outcomes Measurement Information System scores for pain interference, pain intensity, and anxiety. As-treated analysis was performed to evaluate outcomes at a mean follow-up of 7.4 years (range: 2.5-12).There were no differences in pretreatment demographics or nonsurgical therapy utilization between study arms. At final follow-up, the surgical arm demonstrated lower VAS, ODI, EQ-5D, and Patient-Reported Outcomes Measurement Information System pain intensity scores versus the nonsurgical arm. VAS and ODI scores improved 52.3% and 51.1% in the surgical arm, respectively, versus 15.8% and -0.8% in the nonsurgical arm. Single-level fusions demonstrated improved outcomes versus two-level fusions. The pseudarthrosis rate was 6.5%, with one patient undergoing reoperation. Asymptomatic adjacent segment degeneration was identified in 11.9% of patients.Selective ALIF limited to one or two levels in the lower lumbar spine provided improved pain and function when compared with continued nonsurgical care. ALIF may be a safe and effective treatment for low back pain associated with disc degeneration in select patients who fail nonsurgical management.3.

    View details for PubMedID 29529003

  • Lumbar Epidural Steroid Injections for Herniation and Stenosis: Incidence and Risk Factors of Subsequent Surgery. The spine journal : official journal of the North American Spine Society Koltsov, J. C., Smuck, M. W., Zagel, A., Alamin, T. F., Wood, K. B., Cheng, I., Hu, S. S. 2018

    Abstract

    BACKGROUND CONTEXT: Lumbosacral ESIs have increased dramatically despite a narrowing of the clinical indications for use. One potential indication is to avoid or delay surgery, yet little information exists regarding surgery rates after ESI.PURPOSE: The purpose of this research was to determine the proportion of patients having surgery after lumbar epidural steroid injection (ESI) for disc herniation or stenosis and to identify the timing and factors associated with this progression STUDY DESIGN/SETTING: This study was a retrospective review of nationally-representative administrative claims data from the Truven Health MarketScan databases from 2007 - 2014.PATIENT SAMPLE: The study cohort was comprised of 179,025 patients (54±15 years, 48% female) having lumbar epidural steroid injections (ESIs) for diagnoses of stenosis and/or herniation.OUTCOME MEASURES: The primary outcome measure was the time from ESI to surgery.METHODS: Inclusion criteria were ESI for stenosis and/or herniation, age ≥18 years, and health plan enrollment for 1 year prior to ESI to screen for exclusions. Patients were followed longitudinally until they progressed to surgery or had a lapse in enrollment, at which time they were censored. Rates of surgery were assessed with the Kaplan-Meier survival curves. Demographic and treatment factors associated with surgery were assessed with multivariable Cox proportional hazard models. No external funding was procured for this research and the authors' conflicts of interest are not pertinent to the present work.RESULTS: Within 6 months, 12.5% of ESI patients underwent lumbar surgery. By 1 year, 16.9% had surgery, and by 5 years, 26.1% had surgery. Patients with herniation had surgery at rates of up to 5 to 7 fold higher, with the highest rates of surgery in younger patients and those with both herniation and stenosis. Other concomitant spine diagnoses, male sex, previous tobacco use, and residence a rural areas or regions other than the Northeastern United States were associated with higher surgery rates. Medical comorbidities (previous treatment for drug use, CHF, obesity, COPD, hypercholesterolemia, and other cardiac complications) were associated with lower surgery rates.CONCLUSIONS: In the long-term, more than 1 out of every 4 patients undergoing ESI for lumbar herniation or stenosis subsequently had surgery, and nearly 1 of 6 had surgery within the first year. After adjusting for other patient demographics and comorbidities, patients with herniation were more likely have surgery than those with stenosis. The improved understanding of the progression from lumbar ESI to surgery will help to better inform discussions regarding the value of ESI and aid in the shared decision making process.

    View details for PubMedID 29959098

  • What Is the State of Quality Measurement in Spine Surgery? CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Bennett, C., Xiong, G., Hu, S., Wood, K., Kamal, R. N. 2018; 476 (4): 725–31

    Abstract

    Value-based healthcare models rely on quality measures to evaluate the efficacy of healthcare delivery and to identify areas for improvement. Quality measure research in other areas of health care has generally shown that there is a limited number of available quality measures and that those that exist disproportionately focus on processes as opposed to outcomes. The purpose of this study was to assess the current state of quality measures and candidate quality measures in spine surgery.(1) How many quality measures and candidate quality measures are currently available? (2) According to Donabedian domains and National Quality Strategy (NQS) priorities, what aspects or domains of care do the present quality measures and candidate quality measures represent?We systematically reviewed the National Quality Forum, the Agency for Healthcare Research and Quality, and the Physician Quality Reporting System for quality measures relevant to spine surgery. A systematic search for candidate quality measures was also performed using MEDLINE/PubMed and Embase as well as publications from the American Academy of Orthopaedic Surgeons, Congress of Neurological Surgeons, and the North American Spine Society. Clinical practice guidelines were included as candidate quality measures if their development was in accordance with Institute of Medicine criteria for the development of clinical practice guidelines, they were based on consistent clinical evidence including at least one Level I study, and they carried the strongest possible recommendation by the developing body. Quality measures and candidate quality measures were then pooled for analysis and categorized by clinical focus, NQS priority, and Donabedian domain. Our initial search yielded a total of 3940 articles, clinical practice guidelines, and quality measures, 74 of which met criteria for inclusion in this study.Of the 74 measures studied, 29 (39%) were quality measures and 45 (61%) were candidate quality measures. Fifty of 74 (68%) were specific to the care of the spine, and 24 of 74 (32%) were related to the general care of spine patients. The majority of the spine-specific measures were process measures (45 [90%]) and focused on the NQS priority of "Effective Clinical Care" (44 [88%]). The majority of the general care measures were also process measures (14 [58%]), the highest portion of which focused on the NQS priority of "Patient Safety" (10 [42%]).Given the large number of pathologies treated by spine surgeons, the limited number of available quality measures and candidate quality measures in spine surgery is inadequate to support the transition to a value-based care model. Additionally, current measures disproportionately focus on certain aspects or domains of care, which may hinder the ability to appropriately judge an episode of care, extract usable data, and improve quality. Physicians can steward the creation of meaningful quality measures by participating in clinical practice guideline development, assisting with the creation and submission of formal quality measures, and conducting the high-quality research on which effective guidelines and quality measures depend.

    View details for PubMedID 29480884

  • Does timing of transplantation of neural stem cells following spinal cord injury affect outcomes in an animal model? Journal of spine surgery (Hong Kong) Cheng, I., Park, D. Y., Mayle, R. E., Githens, M., Smith, R. L., Park, H. Y., Hu, S. S., Alamin, T. F., Wood, K. B., Kharazi, A. I. 2017; 3 (4): 567–71

    Abstract

    Background: We previously reported that functional recovery of rats with spinal cord contusions can occur after acute transplantation of neural stem cells distal to the site of injury. To investigate the effects of timing of administration of human neural stem cell (hNSC) distal to the site of spinal cord injury on functional outcomes in an animal model.Methods: Thirty-six adult female Long-Evans hooded rats were randomized into three experimental and three control groups with six animals in each group. The T10 level was exposed via posterior laminectomy, and a moderate spinal cord contusion was induced by the Multicenter Animal Spinal Cord Injury Study Impactor (MASCIS, W.M. Keck Center for Collaborative Neuroscience, Piscataway, NJ, USA). The animals received either an intrathecal injection of hNSCs or control media through a separate distal laminotomy immediately, one week or four weeks after the induced spinal cord injury. Observers were blinded to the interventions. Functional assessment was measured immediately after injury and weekly using the Basso, Beattie, Bresnahan (BBB) locomotor rating score.Results: A statistically significant functional improvement was seen in all three time groups when compared to their controls (acute, mean 9.2 vs. 4.5, P=0.016; subacute, mean 11.1 vs. 6.8, P=0.042; chronic, mean 11.3 vs. 5.8, P=0.035). Although there was no significant difference in the final BBB scores comparing the groups that received hNSCs, the group which achieved the greatest improvement from the time of cell injection was the subacute group (+10.3) and was significantly greater than the chronic group (+5.1, P=0.02).Conclusions: The distal intrathecal transplantation of hNSCs into the contused spinal cord of a rat led to significant functional recovery of the spinal cord when injected in the acute, subacute and chronic phases of spinal cord injury (SCI), although the greatest gains appeared to be in the subacute timing group.

    View details for PubMedID 29354733

  • The Relationship Between Cervical Degeneration and Global Spinal Alignment in Patients With Adult Spinal Deformity CLINICAL SPINE SURGERY Fujimori, T., Le, H., Schairer, W., Inoue, S., Iwasaki, M., Oda, T., Hu, S. S. 2017; 30 (4): E423-E429

    Abstract

    To examine the relationship between cervical degeneration and spinal alignment by comparing patients with adult spinal deformity versus the control cohort.The effect of degeneration on cervical alignment has been controversial.Cervical and full-length spine radiographs of 57 patients with adult spinal deformity and 78 patients in the control group were reviewed. Adult spinal deformity was classified into 3 types based on the primary characteristics of the deformity: "Degenerative flatback" group, "Positive sagittal imbalance" group, and "Hyperthoracic kyphosis" group. Cervical degeneration was assessed using the cervical degeneration index scoring system.The "Degenerative flatback" group had significantly higher total cervical degeneration index score (25±7) than the control group (16±8), the "Positive sagittal imbalance" group (18±8), and the "Hyperthoracic kyphosis" group (12±7) (P<0.01). The "Degenerative flatback" group had significantly less cervical lordosis than the other groups. This reduced amount of cervical lordosis was thought to be induced by a compensatory decrease in thoracic kyphosis. In this group, increased cervical degeneration was significantly associated with a decrease in cervical lordosis. Significantly greater compensatory increase in cervical lordosis was noted in the "Positive sagittal imbalance" group (20±15 degrees) and the "Hyperthoracic kyphosis" group (26±9 degrees) compared with the control group (11±12 degrees) (P<0.02).Flat cervical spine coexisted with cervical degeneration when compensatory hypothoracic kyphosis was induced by degenerative flatback. In other situations, cervical lordosis could increase as a compensatory reaction against sagittal imbalance or hyperthoracic kyphosis.

    View details for Web of Science ID 000400485600016

    View details for PubMedID 28437348

  • Predicting complication risk in spine surgery: a prospective analysis of a novel risk assessment tool. Journal of neurosurgery. Spine Veeravagu, A., Li, A., Swinney, C., Tian, L., Moraff, A., Azad, T. D., Cheng, I., Alamin, T., Hu, S. S., Anderson, R. L., Shuer, L., Desai, A., Park, J., Olshen, R. A., Ratliff, J. K. 2017: 1-11

    Abstract

    OBJECTIVE The ability to assess the risk of adverse events based on known patient factors and comorbidities would provide more effective preoperative risk stratification. Present risk assessment in spine surgery is limited. An adverse event prediction tool was developed to predict the risk of complications after spine surgery and tested on a prospective patient cohort. METHODS The spinal Risk Assessment Tool (RAT), a novel instrument for the assessment of risk for patients undergoing spine surgery that was developed based on an administrative claims database, was prospectively applied to 246 patients undergoing 257 spinal procedures over a 3-month period. Prospectively collected data were used to compare the RAT to the Charlson Comorbidity Index (CCI) and the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Surgical Risk Calculator. Study end point was occurrence and type of complication after spine surgery. RESULTS The authors identified 69 patients (73 procedures) who experienced a complication over the prospective study period. Cardiac complications were most common (10.2%). Receiver operating characteristic (ROC) curves were calculated to compare complication outcomes using the different assessment tools. Area under the curve (AUC) analysis showed comparable predictive accuracy between the RAT and the ACS NSQIP calculator (0.670 [95% CI 0.60-0.74] in RAT, 0.669 [95% CI 0.60-0.74] in NSQIP). The CCI was not accurate in predicting complication occurrence (0.55 [95% CI 0.48-0.62]). The RAT produced mean probabilities of 34.6% for patients who had a complication and 24% for patients who did not (p = 0.0003). The generated predicted values were stratified into low, medium, and high rates. For the RAT, the predicted complication rate was 10.1% in the low-risk group (observed rate 12.8%), 21.9% in the medium-risk group (observed 31.8%), and 49.7% in the high-risk group (observed 41.2%). The ACS NSQIP calculator consistently produced complication predictions that underestimated complication occurrence: 3.4% in the low-risk group (observed 12.6%), 5.9% in the medium-risk group (observed 34.5%), and 12.5% in the high-risk group (observed 38.8%). The RAT was more accurate than the ACS NSQIP calculator (p = 0.0018). CONCLUSIONS While the RAT and ACS NSQIP calculator were both able to identify patients more likely to experience complications following spine surgery, both have substantial room for improvement. Risk stratification is feasible in spine surgery procedures; currently used measures have low accuracy.

    View details for DOI 10.3171/2016.12.SPINE16969

    View details for PubMedID 28430052

  • Intervertebral disc/bone marrow cross-talk with Modic changes. European spine journal Dudli, S., Sing, D. C., Hu, S. S., Berven, S. H., Burch, S., Deviren, V., Cheng, I., Tay, B. K., Alamin, T. F., Ith, M. A., Pietras, E. M., Lotz, J. C. 2017

    Abstract

    Cross-sectional cohort analysis of patients with Modic Changes (MC).Our goal was to characterize the molecular and cellular features of MC bone marrow and adjacent discs. We hypothesized that MC associate with biologic cross-talk between discs and bone marrow, the presence of which may have both diagnostic and therapeutic implications.MC are vertebral bone marrow lesions that can be a diagnostic indicator for discogenic low back pain. Yet, the pathobiology of MC is largely unknown.Patients with Modic type 1 or 2 changes (MC1, MC2) undergoing at least 2-level lumbar interbody fusion with one surgical level having MC and one without MC (control level). Two discs (MC, control) and two bone marrow aspirates (MC, control) were collected per patient. Marrow cellularity was analyzed using flow cytometry. Myelopoietic differentiation potential of bone marrow cells was quantified to gauge marrow function, as was the relative gene expression profiles of the marrow and disc cells. Disc/bone marrow cross-talk was assessed by comparing MC disc/bone marrow features relative to unaffected levels.Thirteen MC1 and eleven MC2 patients were included. We observed pro-osteoclastic changes in MC2 discs, an inflammatory dysmyelopoiesis with fibrogenic changes in MC1 and MC2 marrow, and up-regulation of neurotrophic receptors in MC1 and MC2 bone marrow and discs.Our data reveal a fibrogenic and pro-inflammatory cross-talk between MC bone marrow and adjacent discs. This provides insight into the pain generator at MC levels and informs novel therapeutic targets for treatment of MC-associated LBP.

    View details for DOI 10.1007/s00586-017-4955-4

    View details for PubMedID 28138783

    View details for PubMedCentralID PMC5409869

  • A Comparison of Implants Used in Open-Door Laminoplasty: Structural Rib Allografts Versus Metallic Miniplates. Clinical spine surgery Tabaraee, E., Mummaneni, P., Abdul-Jabbar, A., Shearer, D., Roy, E., Amin, B., Ames, C., Burch, S., Deviren, V., Berven, S., Hu, S., Chou, D., Tay, B. K. 2017; 30 (5): E523–E529

    Abstract

    A retrospective case-controlled study.Open-door laminoplasty has been successfully used to address cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. Two common implants include rib allograft struts and metallic miniplates.The goals of this study were to compare outcomes, complications, and costs associated with these 2 implants.A retrospective review was done on 51 patients with allograft struts and 55 patients with miniplates. Primary outcomes were neck visual analog scale (VAS) pain scores and Nurick scores. Secondary outcomes included length of the procedure, estimated blood loss, rates of complications, and the direct costs associated with the surgery and inpatient hospitalization.There were no differences in demographic characteristics, diagnoses, comorbidities, and preoperative outcome scores between the 2 treatment groups. Mean follow-up was 27 months. The postoperative neck VAS scores and Nurick scores improved significantly from baseline to final follow-up for both groups, but there was no difference between the 2 groups. The average length of operation (161 vs. 136 min) and number of foraminotomies (2.7 vs. 1.3) were higher for the allograft group (P=0.007 and 0.0001, respectively). Among the miniplate group, there was no difference in complications but a trend for less neck pain for patients treated without hard collar at final follow-up (1.8 vs. 2.3, P=0.52). The mean direct costs of hospitalization for the miniplate group were 15% higher.Structural rib allograft struts and metallic miniplates result in similar improvements in pain and functional outcome scores with no difference in the rate of complications in short-term follow-up. Potential benefits of using a plate include shorter procedure length and less need for postoperative immobilization. When costs of bracing and operative time are included, the difference in cost between miniplates and allograft struts is negligible.

    View details for PubMedID 28525472

  • Graft Subsidence and Revision Rates Following Anterior Cervical Corpectomy: A Clinical Study Comparing Different Interbody Cages. Clinical spine surgery Weber, M. H., Fortin, M., Shen, J., Tay, B., Hu, S. S., Berven, S., Burch, S., Chou, D., Ames, C., Deviren, V. 2017; 30 (9): E1239–E1245

    Abstract

    Retrospective cohort study.To assess the subsidence and revision rates associated with different interbody cages following anterior cervical corpectomy and reconstruction.Different interbody cages are currently used for surgical reconstruction of the anterior and middle columns of the spine following anterior cervical corpectomy. However, subsidence and delayed union/nonunion associated with allograft and cage reconstruction are common complications, which may require revision with instrumentation.We reviewed the cases of 75 patients who underwent cervical corpectomy and compared the radiographic graft subsidence and revision rates for fibula allograft, titanium mesh cage, titanium expandable cage, and carbon fiber cages. Subsidence was calculated by comparing the immediate postoperative lateral x-ray films to those obtained during follow-up visits.The average graft subsidence was 3 mm and revision rate was 25% for fibula allograft versus 2.9 mm and 11.1%, 2.9 mm and 18.8% for titanium mesh cages and titanium expandable cages, respectively. The average graft subsidence for carbon fiber cages was 0.7 mm with no revision surgery in this subset.Our findings suggest that subsidence and revision rates following anterior corpectomy and interbody fusion could be minimized with the use of a carbon fiber cage.

    View details for DOI 10.1097/BSD.0000000000000428

    View details for PubMedID 27623304

  • Adult Lumbar Scoliosis: Nonsurgical Versus Surgical Management. Instructional course lectures Falakassa, J., Hu, S. S. 2017; 66: 353–60

    Abstract

    Adult spinal deformity has become an increasingly recognized condition, with a 32% incidence in the adult population and a 68% incidence in the elderly population. Often, patients with adult spinal deformity are initially offered nonsurgical treatment for their symptoms despite the lack of data to support its efficacy because of the high complication rate associated with surgical treatment in this age group. Determining which patients would benefit the most from nonsurgical versus surgical treatment remains a challenge. Limited evidence exists to support guidelines on the most effective way to treat patients with adult spinal deformity. Treatment decisions for patients with adult spinal deformity often rely on individual surgeon experience and patient preferences.

    View details for PubMedID 28594511

  • Current Evidence Regarding Diagnostic Imaging Methods for Pediatric Lumbar Spondylolysis: A Report From the Scoliosis Research Society Evidence-Based Medicine Committee. Spine deformity Ledonio, C. G., Burton, D. C., Crawford, C. H., Bess, R. S., Buchowski, J. M., Hu, S. S., Lonner, B. S., Polly, D. W., Smith, J. S., Sanders, J. O. 2017; 5 (2): 97–101

    Abstract

    Spondylolysis is common among the pediatric population, yet no formal systematic literature review regarding diagnostic imaging has been performed. The Scoliosis Research Society (SRS) requested an assessment of the current state of peer reviewed evidence regarding pediatric spondylolysis.Literature was searched professionally and citations retrieved. Abstracts were reviewed and analyzed by the SRS Evidence-Based Medicine Committee. Level I studies were considered to provide Good Evidence for the clinical question. Level II or III studies were considered Fair Evidence. Level IV studies were considered Poor Evidence. From 947 abstracts, 383 full texts reviewed. Best available evidence for the questions of diagnostic methods was provided by 27 studies: no Level I sensitivity/specificity studies, five Level II and two Level III evidence, and 19 Level IV evidence.Pain with hyperextension in athletes is the most widely reported finding in history and physical examination. Plain radiography is considered a first-line diagnostic test for suspected spondylolysis, but validation evidence is lacking. There is consistent Level II and III evidence that pars defects are detected by advanced imaging in 32% to 44% of adolescents with spondylolysis based on history and physical. Level III evidence that single-photon emission computed tomography (SPECT) is superior to planar bone scan and plain radiographs but limited by high rates of false-positive and false-negative results and by high radiation dose. Computed tomography (CT) is considered the gold standard and most accurate modality for detecting the bony defect and assessment of osseous healing but exposes the pediatric patient to ionizing radiation. Magnetic resonance imaging (MRI) is reported to be as accurate as CT and useful in detecting early stress reactions of the pars without a fracture.Plain radiographs are widely used as screening tools for pediatric spondylolysis. CT scan is considered the gold standard but exposes the patient to a significant amount of ionizing radiation. Evidence is fair and promising that MRI is comparable to CT.

    View details for DOI 10.1016/j.jspd.2016.10.006

    View details for PubMedID 28259272

  • In Patients with Lumbar Spinal Stenosis, Adding Fusion Surgery to Decompression Surgery Did Not Improve Outcomes at 2 Years. journal of bone and joint surgery. American volume Hu, S. S. 2016; 98 (22): 1936-?

    View details for PubMedID 27852913

  • The Relationship Between Cervical Degeneration and Global Spinal Alignment in Patients With Adult Spinal Deformity. Clinical spine surgery Fujimori, T., Le, H., Schairer, W., Inoue, S., Iwasaki, M., Oda, T., Hu, S. S. 2016: -?

    Abstract

    To examine the relationship between cervical degeneration and spinal alignment by comparing patients with adult spinal deformity versus the control cohort.The effect of degeneration on cervical alignment has been controversial.Cervical and full-length spine radiographs of 57 patients with adult spinal deformity and 78 patients in the control group were reviewed. Adult spinal deformity was classified into 3 types based on the primary characteristics of the deformity: "Degenerative flatback" group, "Positive sagittal imbalance" group, and "Hyperthoracic kyphosis" group. Cervical degeneration was assessed using the cervical degeneration index scoring system.The "Degenerative flatback" group had significantly higher total cervical degeneration index score (25±7) than the control group (16±8), the "Positive sagittal imbalance" group (18±8), and the "Hyperthoracic kyphosis" group (12±7) (P<0.01). The "Degenerative flatback" group had significantly less cervical lordosis than the other groups. This reduced amount of cervical lordosis was thought to be induced by a compensatory decrease in thoracic kyphosis. In this group, increased cervical degeneration was significantly associated with a decrease in cervical lordosis. Significantly greater compensatory increase in cervical lordosis was noted in the "Positive sagittal imbalance" group (20±15 degrees) and the "Hyperthoracic kyphosis" group (26±9 degrees) compared with the control group (11±12 degrees) (P<0.02).Flat cervical spine coexisted with cervical degeneration when compensatory hypothoracic kyphosis was induced by degenerative flatback. In other situations, cervical lordosis could increase as a compensatory reaction against sagittal imbalance or hyperthoracic kyphosis.

    View details for PubMedID 26469769

  • Effect of Expectations on Treatment Outcome for Lumbar Intervertebral Disc Herniation. Spine Lurie, J. D., Henderson, E. R., McDonough, C. M., Berven, S. H., Scherer, E. A., Tosteson, T. D., Tosteson, A. N., Hu, S. S., Weinstein, J. N. 2016; 41 (9): 803–9

    Abstract

    Secondary analysis of randomized and nonrandomized prospective cohorts.To examine the effect of patient treatment expectations on treatment outcomes for patients with intervertebral disc herniation.Patient expectations about treatment effectiveness may have important relationships with clinical outcomes.Subgroup and reanalysis of the Spine Patient Outcomes Research Trial, a randomized trial and comprehensive cohort study enrolling patients between March 2000 and November 2004 from 13 multidisciplinary spine clinics in 11 US states. Overall, 501 randomized and 744 observational patients (1244 total) who were surgical candidates with radiculopathy and imaging confirmed lumbar intervertebral disc herniation were enrolled. The primary study compared surgical discectomy to usual nonoperative care; this subgroup analysis reassessed outcomes on the basis of treatment expectations at baseline. Expectations about symptomatic and functional improvement for both surgery and nonoperative care were assessed on 5-point scales (1="No Chance (0%)" to 5="Certain (100%)"). Outcomes were assessed using longitudinal regression models analyzed by treatment received.Among 1244 IDH SPORT participants, 1168 provided data on both outcomes and baseline expectations and were included in the current analysis: 467 from the randomized and 701 from the observational cohort. Low expectations of outcomes with surgery predicted poorer outcome regardless of treatment. High expectations of outcomes with nonoperative care predicted better nonoperative outcomes but did not affect surgical results. These differences were of similar magnitude to the difference in outcomes between surgery and nonoperative care.High expectations of treatment benefit had clinically significant positive associations with outcomes.2.

    View details for DOI 10.1097/BRS.0000000000001333

    View details for PubMedID 26641853

    View details for PubMedCentralID PMC4853251

  • The fellowship match process: the history and a report of the current experience. journal of bone and joint surgery. American volume Cannada, L. K., Luhmann, S. J., Hu, S. S., Quinn, R. H. 2015; 97 (1)

    View details for DOI 10.2106/JBJS.M.01251

    View details for PubMedID 25568401

  • Current Evidence Regarding the Etiology, Prevalence, Natural History, and Prognosis of Pediatric Lumbar Spondylolysis: A Report from the Scoliosis Research Society Evidence-Based Medicine Committee. Spine deformity Crawford, C. H., Ledonio, C. G., Bess, R. S., Buchowski, J. M., Burton, D. C., Hu, S. S., Lonner, B. S., Polly, D. W., Smith, J. S., Sanders, J. O. 2015; 3 (1): 12–29

    Abstract

    Structured literature review.To assess the current state of evidence as a first step in the development of practice guidelines for pediatric spondylolysis.Progress in published medical knowledge, changes in societal expectations, and developments in health care economics have led medical organizations to develop evidence-based documents and products.A comprehensive literature search for pediatric spondylolysis was performed with the assistance of a medical librarian. The authors reviewed citations and abstracts. Abstracts were reviewed for exclusions and data from included studies were analyzed by committee. A total of 44 articles provided the best available evidence for the questions of etiology, prevalence, natural history, and prognosis: 9 were graded as level I evidence, 23 were level II, 3 were level III, and 9 were level IV. No level V studies were included in the final list.There is good evidence that pediatric lumbar spondylolysis is an acquired fracture of the pars interarticularis that can occur unilaterally or bilaterally. Evidence shows that when chronic, bilateral pars defects develop, 43% to 74% of patients will progress to grade 1 or 2 spondylolisthesis. In addition, unilateral, incomplete, and early lesions can obtain bony union. With or without bony union or spondylolisthesis, short-term symptom resolution is the norm. Long-term prognosis is less clear, but there is fair evidence that most patients will have lumbar symptoms compared with the general population. There is also fair evidence that some patients will develop significant symptoms as adults and will undergo surgical treatment. There is insufficient knowledge to predict which patients will continue to do well in the long term with conservative or no treatment and which patients will develop symptoms significant enough to warrant early intervention.The current medical literature provides fair to good evidence for clinically relevant questions regarding the etiology, prevalence, natural history, and prognosis of pediatric spondylolysis.

    View details for DOI 10.1016/j.jspd.2014.06.005

    View details for PubMedID 27927448

  • Ossification of the posterior longitudinal ligament of the cervical spine in 3161 patients: a CT-based study. Spine Fujimori, T., Le, H., Hu, S. S., Chin, C., Pekmezci, M., Schairer, W., Tay, B. K., Hamasaki, T., Yoshikawa, H., Iwasaki, M. 2015; 40 (7): E394–403

    Abstract

    A cross-sectional study.To examine the prevalence of ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) of the cervical spine in the San Francisco area.The prevalence of OPLL and ONL is unknown in the non-Asian population.This computed tomography-based cross-sectional study assessed the prevalence of OPLL and ONL within the cervical spine of patients treated at a level 1 trauma center between 2009 and 2012. The prevalence of both OPLL and ONL was compared between racial groups.Of the 3161 patients (mean age, 51.2 ± 21.6 yr; 66.1% male), there were 1593 Caucasians (50.4%), 624 Asians (19.7%), 472 Hispanics (14.9%), 326 African Americans (10.3%), 62 Native Americans (2.0%), and 84 Others (2.7%). The prevalence of cervical OPLL was 2.2% (95% confidence interval [CI]: 1.7-2.8). The adjusted prevalence was 1.3% in Caucasian Americans (95% CI: 0.7-2.3), 4.8% in Asian Americans (95% CI: 2.8-8.1), 1.9% in Hispanic Americans (95% CI: 0.9-4.0), 2.1% in African Americans (95% CI: 0.9-4.8), and 3.2% in Native Americans (95% CI: 0.8-12.3). The prevalence of OPLL in Asian Americans was significantly higher than that in Caucasian Americans (P = 0.005). ONL was detected in 346 patients and the prevalence was 10.9% (95% CI: 10.0-12.0). The adjusted prevalence of ONL was 7.3% in Caucasian Americans (95% CI: 5.8-9.3), 26.4% in Asian Americans (95% CI: 21.9-31.5), 7.4% in Hispanic Americans (95% CI: 5.2-10.5), 2.5% in African Americans (95% CI: 1.2-4.9), and 25.8% in Native Americans (95% CI: 16.5-37.5). ONL was significantly more common in Asian Americans than in Caucasian Americans, Hispanic Americans, and African Americans (P = 0.001).This study also demonstrated that OPLL and ONL were significantly more common in Asian Americans than in Caucasian Americans.3.

    View details for DOI 10.1097/BRS.0000000000000791

    View details for PubMedID 25811134

  • Does Transforaminal Lumbar Interbody Fusion Have Advantages over Posterolateral Lumbar Fusion for Degenerative Spondylolisthesis? Global spine journal Fujimori, T., Le, H., Schairer, W. W., Berven, S. H., Qamirani, E., Hu, S. S. 2015; 5 (2): 102–9

    Abstract

    Study Design Retrospective cohort study. Objective To compare the clinical and radiographic outcomes of transforaminal lumbar interbody fusion (TLIF) and posterolateral lumbar fusion (PLF) in the treatment of degenerative spondylolisthesis. Methods This study compared 24 patients undergoing TLIF and 32 patients undergoing PLF with instrumentation. The clinical outcomes were assessed by visual analog scale (VAS) for low back pain and leg pain, physical component summary (PCS) of the 12-item Short-Form Health Survey, and the Oswestry Disability Index (ODI). Radiographic parameters included slippage of the vertebra, local disk lordosis, the anterior and posterior disk height, lumbar lordosis, and pelvic parameters. Results The improvement of VAS of leg pain was significantly greater in TLIF than in PLF unilaterally (3.4 versus 1.0; p = 0.02). The improvement of VAS of low back pain was significantly greater in TLIF than in PLF (3.8 versus 2.2; p = 0.02). However, there was no significant difference in improvement of ODI or PCS between TLIF and PLF. Reduction of slippage and the postoperative disk height was significantly greater in TLIF than in PLF. There was no significant difference in local disk lordosis, lumbar lordosis, or pelvic parameters. The fusion rate was 96% in TLIF and 84% in PLF (p = 0.3). There was no significant difference in fusion rate, estimated blood loss, adjacent segmental degeneration, or complication rate. Conclusions TLIF was superior to PLF in reduction of slippage and restoring disk height and might provide better improvement of leg pain. However, the health-related outcomes were not significantly different between the two procedures.

    View details for DOI 10.1055/s-0034-1396432

    View details for PubMedID 25844282

    View details for PubMedCentralID PMC4369196

  • Revision surgery for lumbar pseudarthrosis. The spine journal : official journal of the North American Spine Society Dede, O., Thuillier, D., Pekmezci, M., Ames, C. P., Hu, S. S., Berven, S. H., Deviren, V. 2015; 15 (5): 977–82

    Abstract

    Revision surgery for pseudarthrosis after a lumbar spinal fusion has unpredictable functional results.The aim of this study was to determine the clinical outcomes of revision surgery to fuse the pseudarthrosis site based on the two most common diagnoses (degenerative disc disease [DDD] vs. spondylolisthesis).Patients who had a revision surgery between 1995 and 2004 for lumbar pseudarthrosis after short segment lumbar spinal fusion were identified through the institution's Spine Center surgery database. A retrospective chart review of clinical, hospital, and anesthesia records was then performed.Sixty-six patients were included in the study (28 patients with DDD and 38 patients with spondylolisthesis). Inclusion criteria were a surgical diagnosis of pseudarthrosis with a prior fusion of one or two motion segments, minimum 24 months of follow-up, and a diagnosis of either symptomatic DDD or spondylolisthesis as the primary indication for the index fusion surgery.The Oswestry disability index (ODI) and a self-assessment questionnaire were used to evaluate clinical outcomes.A retrospective chart and radiographic review was performed. Statistical analysis was done using Student t test for ODI scores and chi-square test for discrete variables from the outcome questionnaires.Follow-up radiographs were available for 64 patients (97%), and a fusion rate of 100% was found in both groups for the radiographs examined. The mean postoperative ODI score was 53.3 (30-84.4) for DDD patients and 37.2 (2.5-76) for the spondylolisthesis group (p<.01). Only 50% of the patients in the DDD group felt that their overall well-being had improved since the surgery. In the spondylolisthesis group, 64% of patients stated that their overall well-being had improved since their revision surgery.The clinical outcomes after revision surgery for pseudarthrosis are worse in patients with DDD compared with spondylolisthesis despite successful repair of nonunion. Risks and benefits should be well discussed with the patients before deciding on surgical treatment for the management of pseudarthrosis, especially in patients with previous short-segment fusions done for DDD.

    View details for DOI 10.1016/j.spinee.2013.05.039

    View details for PubMedID 23876307

  • Current Evidence Regarding the Surgical and Nonsurgical Treatment of Pediatric Lumbar Spondylolysis: A Report from the Scoliosis Research Society Evidence-Based Medicine Committee. Spine deformity Crawford, C. H., Ledonio, C. G., Bess, R. S., Buchowski, J. M., Burton, D. C., Hu, S. S., Lonner, B. S., Polly, D. W., Smith, J. S., Sanders, J. O. 2015; 3 (1): 30–44

    Abstract

    Structured literature review.The Scoliosis Research Society requested an assessment of the current state of peer-reviewed evidence regarding pediatric spondylolysis with the goal of identifying both what is really known and what research remains essential to further understanding.Spondylolysis is common among children and adolescents and no formal synthesis of the published literature regarding treatment has been previously performed.A comprehensive literature search was performed. The researchers reviewed abstracts and analyzed by committee data from included studies. From 947 initial citations with abstract, 383 articles underwent full text review. The best available evidence for clinical questions regarding surgical and nonsurgical treatment was provided by 58 included studies. None of the studies were graded as level I or level II evidence. Two of the studies were graded as level III evidence. Fifty-six of the studies were graded as level IV evidence. No level V (expert opinion) studies were included in the final list.Although natural history studies suggest a benign, relatively asymptomatic course for spondylolysis in most patients, both nonsurgical and surgical treatment series suggest that a substantial number of patients present with pain and activity limitations attributed to spondylolysis. Pain resolution and return to activity are common with both nonsurgical and surgical treatment (80% to 85%, respectively). Although it is implied that most surgically treated patients have failed nonsurgical treatment, the specific treatment modalities and duration required before failure is declared are not well defined. There is insufficient evidence to know which patients will benefit from specific treatment modalities (both nonsurgical and surgical).Because of the preponderance of uncontrolled case series and the lack of comparative studies, only low-quality evidence is available to guide the treatment of pediatric spondylolysis.

    View details for DOI 10.1016/j.jspd.2014.06.004

    View details for PubMedID 27927449

  • The Increased Prevalence of Cervical Spondylosis in Patients With Adult Thoracolumbar Spinal Deformity JOURNAL OF SPINAL DISORDERS & TECHNIQUES Schairer, W. W., Carrer, A., Lu, M., Hu, S. S. 2014; 27 (8): E305-E308

    Abstract

    Retrospective cohort study.To assess the concomitance of cervical spondylosis and thoracolumbar spinal deformity.Patients with degenerative cervical spine disease have higher rates of degeneration in the lumbar spine. In addition, degenerative cervical spine changes have been observed in adult patients with thoracolumbar spinal deformities. However, to the best of our knowledge, there have been no studies quantifying the association between cervical spondylosis and thoracolumbar spinal deformity in adult patients.Patients seen by a spine surgeon or spine specialist at a single institution were assessed for cervical spondylosis and/or thoracolumbar spinal deformity using an administrative claims database. Spinal radiographic utilization and surgical intervention were used to infer severity of spinal disease. The relative prevalence of each spinal diagnosis was assessed in patients with and without the other diagnosis.A total of 47,560 patients were included in this study. Cervical spondylosis occurred in 13.1% overall, but was found in 31.0% of patients with thoracolumbar spinal deformity (OR=3.27, P<0.0001). Similarly, thoracolumbar spinal deformity was found in 10.7% of patients overall, but was increased at 23.5% in patients with cervical spondylosis (OR=3.26, P<0.0001). In addition, increasing severity of disease was associated with an increased likelihood of the other spinal diagnosis. Patients with both diagnoses were more likely to undergo both cervical (OR=3.23, P<0.0001) and thoracolumbar (OR=4.14, P<0.0001) spine fusion.Patients with cervical spondylosis or thoracolumbar spinal deformity had significantly higher rates of the other spinal diagnosis. This correlation was increased with increased severity of disease. Patients with both diagnoses were significantly more likely to have received a spine fusion. Further research is warranted to establish the cause of this correlation. Clinicians should use this information to both screen and counsel patients who present for cervical spondylosis or thoracolumbar spinal deformity.

    View details for DOI 10.1097/BSD.0000000000000119

    View details for Web of Science ID 000359974800009

    View details for PubMedID 24901877

  • Venous Thromboembolism After Spine Surgery. Spine Schairer, W. W., Pedtke, A. C., Hu, S. S. 2014; 39 (11): 911–18

    Abstract

    Retrospective cohort study.To measure the rate of postoperative venous thromboembolic events (VTE) after spine decompression and fusion procedures.VTE after spine surgery is a serious complication, but chemoprophylaxis is not without significant risk due to the concern of epidural hematoma. Current literature report widely variable rates of VTE, and have weaknesses in sample size, specificity of diagnosis, and methodological problems with adequate patient follow-up.State-level inpatient, ambulatory surgery, and emergency department administrative databases were used to track patients for clinically significant VTE within 90 days of discharge after a spine procedure.Of 357,926 patients enrolled, one-third underwent spine decompression alone, whereas two-thirds received a spine fusion. The overall rate of VTE was 1.37% (95% CI: 1.33-1.41), but varied widely depending on diagnosis, 1.03% for structural degenerative diagnoses to 10.7% for spine infection. Posterior cervical fusion had a higher rate of VTE than anterior cervical fusion, whereas anterior thoracolumbar and lumbosacral fusions had higher rates than the respective posterior approaches. Additional risk factors included patients receiving long spine fusions and having multiple procedures during the hospitalization. Forty percent of VTEs discovered after discharge were diagnosed at a different hospital.The rate of spine VTE varies widely depending on diagnosis and procedure. It is important to risk-stratify patients who present for spine surgery to identify patients at increased risk who should be monitored for the development of VTE. It is important to know that nearly half of VTEs that occur after discharge are diagnosed at different hospitals, and thus the primary surgeon may be initially unaware of the complication. These results from a large selection of historical patients may provide a tool for estimating patient risk depending on diagnosis and type of procedure.2.

    View details for PubMedID 24718077

  • Hospital readmission rates after surgical treatment of primary and metastatic tumors of the spine. Spine Schairer, W. W., Carrer, A., Sing, D. C., Chou, D., Mummaneni, P. V., Hu, S. S., Berven, S. H., Burch, S., Tay, B., Deviren, V., Ames, C. 2014; 39 (21): 1801–8

    Abstract

    Retrospective cohort study.This study aimed to identify the rates and causes of unplanned hospital readmission at 30 days and 1 year after surgical treatment of primary and metastatic spinal tumors.Primary spine tumors and non-spine tumors metastatic to the spine can represent complex problems for surgical treatment, but surgical intervention can provide significant patients with significant improvements in quality of life. However, recent emphasis on decreasing the cost of health care has led to a focus on quality measures such as hospital readmission rates.At a large referral spine center between 2005 and 2011, 197 patients with primary (n = 33) or metastatic (n = 164) tumors of the spine were enrolled. Hospital readmissions within 1 year were reviewed. Kaplan-Meier analysis was performed to estimate unplanned hospital readmission rates, and risk factors were evaluated using a Cox proportional hazards model.Unplanned hospital readmission rates were 6.1% and 16.8% at 30 days for primary and metastatic tumors (P = 0.126), respectively, and 27.5% and 37.8% at 1 year (P = 0.262). Metastatic tumors with aggressive biology (i.e., lung, osteosarcoma, stomach, bladder, esophagus, pancreas) caused higher rates of readmission than other types of metastatic tumors. One-third of readmissions were due to recurrent disease, whereas 23.3% were due to surgical complications and 43.3% due to medical complications. Numerous medical comorbidities increased the risk of unplanned hospital readmission.Unplanned hospital readmissions after surgical intervention for spine tumors are common, and patients with aggressive metastatic tumors are at increased risk. In addition, comorbid medical problems are important risk factors that increase the chance that a patient will require hospital readmission within 1 year.3.

    View details for DOI 10.1097/BRS.0000000000000517

    View details for PubMedID 25029220

  • The concomitance of cervical spondylosis and adult thoracolumbar spinal deformity. Evidence-based spine-care journal Weber, M. H., Hong, C. H., Schairer, W. W., Takemoto, S., Hu, S. S. 2014; 5 (1): 6–11

    Abstract

    Study Design Retrospective cross-sectional study. Clinical Question What is the prevalence of cervical spondylosis (CS) and thoracolumbar (TL) spinal deformity in an administrative database during a 4-year study period? Is the prevalence of CS or TL deformity higher in patients who have the other spine diagnosis compared with the overall study population? Are patients with both diagnoses more likely to have undergone spine surgery? Patients and Methods An administrative claims database containing 53 million patients with either Medicare (2005-2008) or private payer (2007-2010) insurance was used to identify patients with diagnoses of CS and/or TL deformity. Disease prevalence between groups was compared using a χ (2) test and reported using prevalence ratios (PR). Results The prevalence of CS was higher in patients with TL deformity than without TL deformity, for both Medicare (PR = 2.81) and private payer (PR = 1.79). Similarly, the prevalence of TL deformity was higher in patients with CS than without CS for both Medicare (PR = 3.19) and private payer (PR = 2.05). Patients with both diagnoses were more likely to have undergone both cervical (Medicare, PR = 1.44; private payer, PR = 2.03) and TL (Medicare, PR = 1.68; private payer, PR = 1.74) spine fusion. All comparisons were significant with p < 0.0001. Conclusions Patients with either CS or TL deformity had a higher prevalence of the other spinal diagnosis compared with the overall disease prevalence in the study population. Patients with both diagnoses had a higher prevalence of having spine surgery compared with patients with only one diagnosis. More studies to identify a causal mechanism for this relationship are warranted.

    View details for DOI 10.1055/s-0034-1368668

    View details for PubMedID 24715867

    View details for PubMedCentralID PMC3969428

  • Long fusion from sacrum to thoracic spine for adult spinal deformity with sagittal imbalance: upper versus lower thoracic spine as site of upper instrumented vertebra. Neurosurgical focus Fujimori, T., Inoue, S., Le, H., Schairer, W. W., Berven, S. H., Tay, B. K., Deviren, V., Burch, S., Iwasaki, M., Hu, S. S. 2014; 36 (5): E9

    Abstract

    Despite increasing numbers of patients with adult spinal deformity, it is unclear how to select the optimal upper instrumented vertebra (UIV) in long fusion surgery for these patients. The purpose of this study was to compare the use of vertebrae in the upper thoracic (UT) versus lower thoracic (LT) spine as the upper instrumented vertebra in long fusion surgery for adult spinal deformity.Patients who underwent fusion from the sacrum to the thoracic spine for adult spinal deformity with sagittal imbalance at a single medical center were studied. The patients with a sagittal vertical axis (SVA) ≥ 40 mm who had radiographs and completed the 12-item Short-Form Health Survey (SF-12) preoperatively and at final follow-up (≥ 2 years postoperatively) were included.Eighty patients (mean age of 61.1 ± 10.9 years; 69 women and 11 men) met the inclusion criteria. There were 31 patients in the UT group and 49 patients in the LT group. The mean follow-up period was 3.6 ± 1.6 years. The physical component summary (PCS) score of the SF-12 significantly improved from the preoperative assessment to final follow-up in each group (UT, 34 to 41; LT, 29 to 37; p = 0.001). This improvement reached the minimum clinically important difference in both groups. There was no significant difference in PCS score improvement between the 2 groups (p = 0.8). The UT group had significantly greater preoperative lumbar lordosis (28° vs 18°, p = 0.03) and greater thoracic kyphosis (36° vs 18°, p = 0.001). After surgery, there was no significant difference in lumbar lordosis or thoracic kyphosis. The UT group had significantly greater postoperative cervicothoracic kyphosis (20° vs 11°, p = 0.009). The UT group tended to maintain a smaller positive SVA (51 vs 73 mm, p = 0.08) and smaller T-1 spinopelvic inclination (-2.6° vs 0.6°, p = 0.06). The LT group tended to have more proximal junctional kyphosis (PJK), although the difference did not reach statistical significance. Radiographic PJK was 32% in the UT group and 41% in the LT group (p = 0.4). Surgical PJK was 6.4% in the UT group and 10% in the LT group (p = 0.6).Both the UT and LT groups demonstrated significant improvement in clinical and radiographic outcomes. A significant difference was not observed in improvement of clinical outcomes between the 2 groups.

    View details for DOI 10.3171/2014.3.FOCUS13541

    View details for PubMedID 24785491

  • Intervertebral discs from spinal nondeformity and deformity patients have different mechanical and matrix properties. The spine journal : official journal of the North American Spine Society Cheng, K. K., Berven, S. H., Hu, S. S., Lotz, J. C. 2014; 14 (3): 522–30

    Abstract

    It is well-established that disc mechanical properties degrade with degeneration. However, prior studies utilized cadaveric tissues from donors with undefined back pain history. Disc degeneration may present with pain at the affected motion segment, or it may be present in the absence of back pain. The mechanical properties and matrix quantity of discs removed and diagnosed for degeneration with patient chronic pain may be distinct from those with other diagnoses, such as spinal deformity.To test the hypothesis that discs from nondeformity segments have inferior mechanical properties than deformity discs owing to differences in matrix quality.In vitro study comparing the mechanical and matrix properties of discs from surgery patients with spinal nondeformity and deformity.We analyzed nucleus and annulus samples (8-11 specimens per group) from surgical discectomy patients as part of a fusion or disc replacement procedure. Tissues were divided into two cohorts: nondeformity and deformity. Dynamic indentation tests were used to determine energy dissipation, indentation modulus, and viscoelasticity. Tissue hydration at a physiologic pressure was assessed by equilibrium dialysis. Proteoglycan, collagen, and collagen cross-link content were quantified. Matrix structure was assessed by histology.We observed that energy dissipation was significantly higher in the nondeformity nucleus than in the deformity nucleus. Equilibrium dialysis experiments showed that annulus swelling was significantly lower in the nondeformity group. Consistent with this, we observed that the nondeformity annulus had lower proteoglycan and higher collagen contents.Our data suggest that discs from nondeformity discs have subtle differences in mechanical properties compared with deformity discs. These differences were partially explained by matrix biochemical composition for the annulus, but not for the nucleus. The results of this study suggest that compromised matrix quality and diminished mechanical properties are features that potentially accompany discs of patients undergoing segmental fusion or disc replacement for disc degeneration and chronic back pain. These features have previously been implicated in pain via instability or reduced motion segment stiffness.

    View details for DOI 10.1016/j.spinee.2013.06.089

    View details for PubMedID 24246750

    View details for PubMedCentralID PMC3944996

  • Hospital readmission after spine fusion for adult spinal deformity. Spine Schairer, W. W., Carrer, A., Deviren, V., Hu, S. S., Takemoto, S., Mummaneni, P., Chou, D., Ames, C., Burch, S., Tay, B., Sawyer, A., Berven, S. H. 2013; 38 (19): 1681–89

    Abstract

    Retrospective cohort study.To assess the rate, causes, and risk factors of unplanned hospital readmission after spine fusion for the treatment of adult spinal deformity.Hospital readmissions in the elderly are common, and with increasing emphasis on the quality of health care, readmission rates are used to assess hospital performance. Spine surgery has seen rapidly increased utilization during the past 2 decades. Surgical treatments of complex spinal deformity are known to have higher rates of complications than other types of spine surgery. However, there are no reports describing the rates and causes of hospital readmission after deformity surgery.Patients were identified at a single institution from 2006 through 2011 that received a spine fusion for the treatment of adult spinal deformity. All hospital readmissions within 90 days of discharge were reviewed for cause. Unplanned readmission rates were calculated via Kaplan-Meier failure analysis. Rates were compared across patients receiving different lengths of spine fusion (short: 2-3 vertebra, medium: 4-8, long: 9 or more). Risk factors were assessed using a Cox proportional hazards multivariate model.Eight hundred thirty-six patients were enrolled (111 short, 402 medium, and 323 long fusions). The overall unplanned readmission rate was 8.4% at 30 days and 12.3% at 90 days. Patients with long spine fusion had higher rates of readmission than patients with medium or short length fusions. Surgical site infection accounted for 45.6% of readmissions. Risk factors for readmission include longer fusion length, higher patient severity of illness, and specific medical comorbidities.Unplanned hospital readmissions after spine fusion for adult spinal deformity are common, and are most often due to surgical site infection. Patient medical comorbidities are an important part of assessing risk and can be used by providers and patients to better assess individual risk prior to treatment.

    View details for DOI 10.1097/BRS.0b013e31829c08c9

    View details for PubMedID 23698572

  • Proximal junctional kyphosis and clinical outcomes in adult spinal deformity surgery with fusion from the thoracic spine to the sacrum: a comparison of proximal and distal upper instrumented vertebrae. Journal of neurosurgery. Spine Ha, Y., Maruo, K., Racine, L., Schairer, W. W., Hu, S. S., Deviren, V., Burch, S., Tay, B., Chou, D., Mummaneni, P. V., Ames, C. P., Berven, S. H. 2013; 19 (3): 360–69

    Abstract

    Proximal junctional kyphosis (PJK) is a common and significant complication after corrective spinal deformity surgery. The object of this study was to compare-based on clinical outcomes, postoperative proximal junctional kyphosis rates, and prevalence of revision surgery-proximal thoracic (PT) and distal thoracic (DT) upper instrumented vertebra (UIV) in adults who underwent spine fusion to the sacrum for the treatment of spinal deformity.In this retrospective study the authors evaluated clinical and radiographic data from consecutive adults (age > 21 years) with a deformity treated using long instrumented posterior spinal fusion to the sacrum in the period from 2007 to 2009. The PT group included patients in whom the UIV was between T-2 and T-5, whereas the DT group included patients in whom the UIV level was between T-9 and L-1. Perioperative surgical data were compared between the PT and DT groups. Additionally, segmental, regional, and global spinal alignments, as well as the sagittal Cobb angle at the proximal junction, were analyzed on preoperative, early postoperative, and final standing 36-in. radiographs. Patient-reported outcome measurements (visual analog scale, Scoliosis Research Society Patient Questionnaire-22, Oswestry Disability Index, and the 36-Item Short-Form Health Survey) were compared.Eighty-nine patients, 22 males and 67 females, had a minimum follow-up of 2 years, and thus were eligible for participation in this study. Sixty-seven patients were in the DT group and 22 were in the PT group. Operative time (p = 0.387) and estimated blood loss (p < 0.05) were slightly higher in the PT group. The overall rate of revision surgery was 48.0% and 54.5% in the DT and PT groups, respectively (p = 0.629). The prevalence of PJK according to radiological criteria was 34% in the DT group and 27% in the PT group (p = 0.609). The percent of patients with PJK that required surgical correction (surgical PJK) was 11.9% (8 of 67) in the DT group and 9.1% (2 of 22) in the PT group (p = 1.0). The onset of surgical PJK was significantly earlier than radiological PJK in the DT group (p < 0.01). The types of PJK were different in the PT and DT groups. Compression fracture at the UIV was more prevalent in the DT group, whereas subluxation was more prevalent in the PT group. Postoperatively, the PT group had less thoracic kyphosis (p = 0.02), less sagittal imbalance (p < 0.01), and less pelvic tilt (p = 0.04). In the DT group, early postoperative radiographs demonstrated that the proximal junctional angle of patients with surgical PJK was greater than in those without PJK and those with radiological PJK (p < 0.01). Clinical outcomes were significantly improved in both groups, and there was no significant difference between the groups.Both PT and DT UIVs improve segmental and global sagittal plane alignment as well as patient-reported quality of life in those treated for adult spinal deformity. The prevalence of PJK was not different in the PT and DT groups. However, compression fracture was the mechanism more frequently observed with DT PJK, and subluxation was the mechanism more frequently observed in PT PJK. Strategies to avoid PJK may include vertebral augmentation to prevent fracture at the DT spine and mechanical means to prevent vertebral subluxation at the PT spine.

    View details for DOI 10.3171/2013.5.SPINE12737

    View details for PubMedID 23848349

  • Predictive factors for proximal junctional kyphosis in long fusions to the sacrum in adult spinal deformity. Spine Maruo, K., Ha, Y., Inoue, S., Samuel, S., Okada, E., Hu, S. S., Deviren, V., Burch, S., William, S., Ames, C. P., Mummaneni, P. V., Chou, D., Berven, S. H. 2013; 38 (23): E1469–76

    Abstract

    A retrospective study.To assess the mechanisms and the independent risk factors associated with proximal junctional kyphosis (PJK) in patients treated surgically for adult spinal deformity with long fusions to the sacrum.The occurrence of PJK may be related to preoperative and postoperative sagittal parameters. The mechanisms and risk factors for PJK in adults are not well defined.Consecutive patients who underwent long instrumented fusion surgery (≥6 vertebrae) to the sacrum with a minimum of 2 years of follow-up were retrospectively studied. Risk factors included patient factors, surgical factors, and radiographical parameters such as thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis, pelvic tilt, and pelvic incidence.Ninety consecutive patients (mean age, 64.5 yr) met inclusion criteria. Radiographical PJK occurred in 37 of the 90 (41%) patients with a mean follow-up of 2.9 years. The most common mechanism of PJK was fracture at the upper instrumented vertebra (UIV) in 19 (51%) patients. Twelve (13%) patients with PJK were treated surgically with proximal extension of the instrumented fusion. Preoperative TK more than 30°, preoperative proximal junctional angle more than 10°, change in LL more than 30°, and pelvic incidence more than 55° were identified as predictors associated with PJK. Achievement of ideal global sagittal realignment (sagittal vertical axis <50 mm, pelvic tilt <20°, and pelvic incidence-LL <±10°) protected against the development of PJK (19% vs. 45%). A multivariate regression analysis revealed changes in LL more than 30°, and preoperative TK more than 30° were the independent risk factors associated with PJK.Fracture at the UIV was the most common mechanism for PJK. Change in LL more than 30° and pre-existing TK more than 30° were identified as independent risk factors. Optimal postoperative alignment of the spine protects against the development of PJK. A surgical strategy to minimize PJK may include preoperative planning for reconstructions with a goal of optimal postoperative alignment.3.

    View details for DOI 10.1097/BRS.0b013e3182a51d43

    View details for PubMedID 23921319

  • Surgical site infections in spine surgery: identification of microbiologic and surgical characteristics in 239 cases. Spine Abdul-Jabbar, A., Berven, S. H., Hu, S. S., Chou, D., Mummaneni, P. V., Takemoto, S., Ames, C., Deviren, V., Tay, B., Weinstein, P., Burch, S., Liu, C. 2013; 38 (22): E1425–31

    Abstract

    Retrospective analysis.The objective of this study was to describe the microbiology of surgical site infection (SSI) in spine surgery and relationship with surgical management characteristics.SSI is an important complication of spine surgery that results in significant morbidity. A comprehensive and contemporary understanding of the microbiology of postoperative spine infections is valuable to direct empiric antimicrobial treatment and prophylaxis and other infection prevention strategies.All cases of spinal surgery associated with SSI between July 2005 and November 2010 were identified by the hospital infection control surveillance program using Centers for Disease Control National Health Safety Network criteria. Surgical characteristics and microbiologic data for each case were gathered by direct medical record review.Of 7529 operative spine cases performed between July 2005 and November 2010, 239 cases of SSI were identified. The most commonly isolated pathogen was Staphylococcus aureus (45.2%), followed by Staphylococcus epidermidis (31.4%). Methicillin-resistant organisms accounted for 34.3% of all SSIs and were more common in revision than in primary surgical procedures (47.4% vs. 28.0%, P = 0.003). Gram-negative organisms were identified in 30.5% of the cases. Spine surgical procedures involving the sacrum were significantly associated with gram-negative organisms (P < 0.001) and polymicrobial infections (P = 0.020). Infections due to gram-negative organisms (P = 0.002) and Enterococcus spp. (P = 0.038) were less common in surgical procedures involving the cervical spine. Cefazolin-resistant gram-negative organisms accounted for 61.6% of all gram-negative infections and 18.8% of all SSIs.Although gram-positive organisms predominated, gram-negative organisms accounted for a sizeable portion of SSI, particularly among lower lumbar and sacral spine surgical procedures. Nearly half of infections in revision surgery were due to a methicillin-resistant organism. These findings may help guide choice of empiric antibiotics while awaiting culture data and antimicrobial prophylaxis strategies in specific spine surgical procedures.3.

    View details for DOI 10.1097/BRS.0b013e3182a42a68

    View details for PubMedID 23873240

  • Spontaneous improvement of cervical alignment after correction of global sagittal balance following pedicle subtraction osteotomy. Journal of neurosurgery. Spine Smith, J. S., Shaffrey, C. I., Lafage, V., Blondel, B., Schwab, F., Hostin, R., Hart, R., O'Shaughnessy, B., Bess, S., Hu, S. S., Deviren, V., Ames, C. P. 2012; 17 (4): 300–307

    Abstract

    Sagittal spinopelvic malalignment is a significant cause of pain and disability in patients with adult spinal deformity. Surgical correction of spinopelvic malalignment can result in compensatory changes in spinal alignment outside of the fused spinal segments. These compensatory changes, termed reciprocal changes, have been defined for thoracic and lumbar regions but not for the cervical spine. The object of this study was to evaluate postoperative reciprocal changes within the cervical spine following lumbar pedicle subtraction osteotomy (PSO).This was a multicenter retrospective radiographic analysis of patients from International Spine Study Group centers. Inclusion criteria were as follows: adults (>18 years old) with spinal deformity treated using lumbar PSO, a preoperative C7-S1 plumb line greater than 5 cm, and availability of pre- and postoperative full-length standing radiographs.Seventy-five patients (60 women, mean age 59 years) were included. The lumbar PSO significantly improved sagittal alignment, including the C7-S1 plumb line, C7-T12 inclination, and pelvic tilt (p <0.001). After lumbar PSO, reciprocal changes were seen to occur in C2-7 cervical lordosis (from 30.8° to 21.6°, p <0.001), C2-7 plumb line (from 27.0 mm to 22.9 mm), and T-1 slope (from -38.9° to -30.4°, p <0.001). Ideal correction of sagittal malalignment (postoperative sagittal vertical alignment < 50 mm) was associated with the greatest relaxation of cervical hyperlordosis (-12.4° vs -5.7°, p = 0.037). A change in cervical lordosis correlated with changes in T-1 slope (r = -0.621, p <0.001), C7-T12 inclination (r = 0.418, p <0.001), T12-S1 angle (r = -0.339, p = 0.005), and C7-S1 plumb line (r = 0.289, p = 0.018). Radiographic parameters that correlated with changes in cervical lordosis on multivariate linear regression analysis included change in T-1 slope and change in C2-7 plumb line (r(2) = 0.53, p <0.001).Adults with positive sagittal spinopelvic malalignment compensate with abnormally increased cervical lordosis in an effort to maintain horizontal gaze. Surgical correction of sagittal malalignment results in improvement of the abnormal cervical hyperlordosis through reciprocal changes.

    View details for DOI 10.3171/2012.6.SPINE1250

    View details for PubMedID 22860879

  • Value-based care in the management of spinal disorders: a systematic review of cost-utility analysis. Clinical orthopaedics and related research Indrakanti, S. S., Weber, M. H., Takemoto, S. K., Hu, S. S., Polly, D., Berven, S. H. 2012; 470 (4): 1106–23

    Abstract

    Spinal disorders are a major cause of disability and compromise in health-related quality of life. The direct and indirect costs of treating spinal disorders are estimated at more than $100 billion per year. With limited resources, the cost-utility of interventions is important for allocating resources.We therefore performed a systematic review of the literature on cost-utility for nonoperative and operative interventions for treating spinal disorders.We searched four databases for cost-utility analysis studies on low back pain management and identified 1004 items. The titles and abstracts of 752 were screened before selecting 27 studies for inclusion; full texts of these 27 studies were individually evaluated by five individuals.Studies of nonoperative treatments demonstrated greater value for graded activity over physical therapy and pain management; spinal manipulation over exercise; behavioral therapy and physiotherapy over advice; and acupuncture and exercise over usual general practitioner care. Circumferential fusion and femoral ring allograft had greater value than posterolateral fusion and titanium cage, respectively. The relative cost-utility of operative versus nonoperative interventions was variable with the most consistent evidence indicating superior value of operative care for treating spinal disorders involving nerve compression and instability.The literature on cost-utility for treating spinal disorders is limited. Studies addressing cost-utility of nonoperative and operative management of low back pain encompass a broad spectrum of diagnoses and direct comparison of treatments based on cost-utility thresholds for comparative effectiveness is limited by diversity among disorders and methods to assess cost-utility. Future research will benefit from uniform methods and comparison of treatments in cohorts with well-defined pathology.

    View details for DOI 10.1007/s11999-011-2141-2

    View details for PubMedID 22042716

    View details for PubMedCentralID PMC3293951

  • In vivo intervertebral disc characterization using magnetic resonance spectroscopy and T1ρ imaging: association with discography and Oswestry Disability Index and Short Form-36 Health Survey. Spine Zuo, J., Joseph, G. B., Li, X., Link, T. M., Hu, S. S., Berven, S. H., Kurhanewitz, J., Majumdar, S. 2012; 37 (3): 214–21

    Abstract

    An in vivo study of intervertebral disc degeneration by using quantitative magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS).To quantify water and proteoglycan (PG) content in the intervertebral disc by using in vivo MRS and to evaluate the relationship between MRS-quantified water/PG content, T1ρ, Pfirrmann score, clinical self-assessment, and discography.Previous in vitro studies have investigated the relationship between MRS-quantified water/PG content and degenerative grade by using cadaveric intervertebral discs. T1ρ has been shown to relate to Pfirrmann grade and clinical self-assessment. However, the associations between MRS-quantified water/PG content, MRI-based T1ρ, self-assessment of health status, and clinical response to discography have not been studied in vivo.MRS and MRI were performed in 26 patients (70 discs) with symptomatic intervertebral degenerative disc (IVDD) and 23 controls (41 discs). Patients underwent evaluation of intervertebral discs with provocative discography. All subjects completed the Short Form-36 Health Survey and Oswestry Disability Index questionnaires.The water/PG peak area ratio was significantly elevated in (a) patients (compared with controls) and in (b) discs with positive discography (compared with negative discography). Magnetic resonance (MR) T1ρ exhibited similar trends. A significant association was found between T1ρ and normalized PG content (R = 0.61, P < 0.05) but not between T1ρ and normalized water content (R = 0.24, P > 0.05). The water/PG peak area ratio, normalized water, normalized PG, and Pfirrmann grade were significantly associated with patient self-assessment of disability and physical composite score, while disc height was not.This study demonstrated a relationship between in vivo MRS spectroscopy (water content and PG content), imaging parameters (T1ρ and Pfirrmann grade), discography results, and clinical self-assessment, suggesting that MRS-quantified water, PG, and MR T1ρ relaxation time may potentially serve as biomarkers of symptomatic IVDD.

    View details for DOI 10.1097/BRS.0b013e3182294a63

    View details for PubMedID 21697767

    View details for PubMedCentralID PMC3633556

  • Direct lateral approach to lumbar fusion is a biomechanically equivalent alternative to the anterior approach: an in vitro study. Spine Laws, C. J., Coughlin, D. G., Lotz, J. C., Serhan, H. A., Hu, S. S. 2012; 37 (10): 819–25

    Abstract

    A human cadaveric biomechanical study of lumbar mobility before and after fusion and with or without supplemental instrumentation for 5 instrumentation configurations.To determine the biomechanical differences between anterior lumbar interbody fusion (ALIF) and direct lateral interbody fusion (DLIF) with and without supplementary instrumentation.Some prior studies have compared various surgical approaches using the same interbody device whereas others have investigated the stabilizing effect of supplemental instrumentation. No published studies have performed a side-by-side comparison of standard and minimally invasive techniques with and without supplemental instrumentation.Eight human lumbosacral specimens (16 motion segments) were tested in each of the 5 following configurations: (1) intact, (2) with ALIF or DLIF cage, (3) with cage plus stabilizing plate, (4) with cage plus unilateral pedicle screw fixation (PSF), and (5) with cage plus bilateral PSF. Pure moments were applied to induce specimen flexion, extension, lateral bending, and axial rotation. Three-dimensional kinematic responses were measured and used to calculate range of motion, stiffness, and neutral zone.Compared to the intact state, DLIF significantly reduced range of motion in flexion, extension, and lateral bending (P = 0.0117, P = 0.0015, P = 0.0031). Supplemental instrumentation significantly increased fused-specimen stiffness for both DLIF and ALIF groups. For the ALIF group, bilateral PSF increased stiffness relative to stand-alone cage by 455% in flexion and 317% in lateral bending (P = 0.0009 and P < 0.0001). The plate increased ALIF group stiffness by 211% in extension and 256% in axial rotation (P = 0.0467 and P = 0.0303). For the DLIF group, bilateral PSF increased stiffness by 350% in flexion and 222% in extension (P < 0.0001 and P = 0.0008). No differences were observed between ALIF and DLIF groups supplemented with bilateral PSF.Our data support that the direct lateral approach, when supplemented with bilateral PSF, is a minimally invasive and biomechanically stable alternative to the open, anterior approach to lumbar spine fusion.

    View details for DOI 10.1097/BRS.0b013e31823551aa

    View details for PubMedID 21971125

  • Surgical site infection in spinal surgery: description of surgical and patient-based risk factors for postoperative infection using administrative claims data. Spine Abdul-Jabbar, A., Takemoto, S., Weber, M. H., Hu, S. S., Mummaneni, P. V., Deviren, V., Ames, C. P., Chou, D., Weinstein, P. R., Burch, S., Berven, S. H. 2012; 37 (15): 1340–45

    Abstract

    Retrospective analysis.The objective of this study was to investigate the accuracy of using an automated approach to administrative claims data to assess the rate and risk factors for surgical site infection (SSI) in spinal procedures.SSI is a major indicator of health care quality. A wide range of SSI rates have been proposed in the literature depending on clinical setting and procedure type.All spinal surgeries performed at a university-affiliated tertiary-care center from July 2005 to December 2010 were identified using diagnosis-related group, current procedural terminology, and International Classification of Diseases, Ninth Revision (ICD-9) codes and were validated through chart review. Rates of SSI and associated risk factors were calculated using univariate regression analysis. Odds ratios were calculated through multivariate logistic regression.A total of 6628 hospital visits were identified. The cumulative incidence of SSI was 2.9%. Procedural risk factors associated with a statistically significant increase in rates of infection were the following: sacral involvement (9.6%), fusions greater than 7 levels (7.8%), fusions greater than 12 levels (10.4%), cases with an osteotomy (6.5%), operative time longer than 5 hours (5.1%), transfusions of red blood cells (5.0%), serum (7.4%), and autologous blood (4.1%). Patient-based risk factors included anemia (4.3%), diabetes mellitus (4.2%), coronary artery disease (4.7%), diagnosis of coagulopathy (7.8%), and bone or connective tissue neoplasm (5.0%).Used individually, diagnosis-related group, current procedural terminology, and ICD-9 codes cannot completely capture a patient population. Using an algorithm combining all 3 coding systems to generate both inclusion and exclusion criteria, we were able to analyze a specific population of spinal surgery patients within a high-volume medical center. Within that group, risk factors found to increase infection rates were isolated and can serve to focus hospital-wide efforts to decrease surgery-related morbidity and improve patient outcomes.

    View details for DOI 10.1097/BRS.0b013e318246a53a

    View details for PubMedID 22210012

  • Diagnostic tools and imaging methods in intervertebral disk degeneration. The Orthopedic clinics of North America Majumdar, S., Link, T. M., Steinbach, L. S., Hu, S., Kurhanewicz, J. 2011; 42 (4): 501–11, viii

    Abstract

    Low back pain has a negative impact on the economy and society. Intervertebral disk degeneration is linked to the occurrence of low back pain. MRI provides three-dimensional morphologic and biochemical information regarding the status of the disk. This article reviews new and evolving MRI disk-imaging techniques, including grading, relaxation-time measurements, diffusion, and contrast perfusion. In addition, high-resolution magic-angle spinning methods to correlate in vitro disk degeneration (with pain, etc) and in vivo spectroscopic results are discussed. With the potential for morphologic and biochemical characterization of the intervertebral disk, MRI shows promise as a tool to quantitatively assess disk health.

    View details for DOI 10.1016/j.ocl.2011.07.007

    View details for PubMedID 21944587

  • Iliac crest bone graft: are the complications overrated? The spine journal : official journal of the North American Spine Society Hu, S. S. 2011; 11 (6): 538–39

    View details for DOI 10.1016/j.spinee.2011.03.016

    View details for PubMedID 21729802

  • Modi HN, Suh SW, Yang JH, et al. False-negative transcranial motor-evoked potentials during scoliosis surgery causing paralysis. Spine 2009;34:e896–900. Spine Lieberman, J. A., Berven, S., Gardi, J., Hu, S., Lyon, R., MacDonald, D. B., Schwartz, D., Sestokas, A., Yingling, C. 2010; 35 (6): 717–18; discussion 714–17, 718–20

    View details for DOI 10.1097/BRS.0b013e3181d3cf5e

    View details for PubMedID 24736508

  • The effect of type of osteotomy on the risk of postoperative spinal infections. The spine journal : official journal of the North American Spine Society Hu, S. S. 2010; 10 (5): 451–53

    View details for DOI 10.1016/j.spinee.2010.03.028

    View details for PubMedID 20421078

  • Do 1-year outcomes predict 2-year outcomes for adult deformity surgery? The spine journal : official journal of the North American Spine Society Glassman, S. D., Schwab, F., Bridwell, K. H., Shaffrey, C., Horton, W., Hu, S. 2009; 9 (4): 317–22

    Abstract

    Health-related quality-of-life (HRQOL) measures are being used more frequently in the evaluation of the adult deformity patient. This is due in part to the validation of the deformity-specific Scolios Research Society-22 (SRS-22). Hence, relationships between HRQOL outcomes and traditional measures of success such as deformity correction, fusion healing, and complications are being established.To examine the pattern of HRQOL outcome responses after adult deformity surgery.Analysis of prospective multicenter cohort.Two hundred and eighty-three adult deformity patients with preoperative, 1-, and 2-year postoperative outcome measures.SRS-22, Short Form-12 (SF-12), Oswestry Disability Index (ODI), and back and leg pain numeric rating scale scores.Preoperative versus postoperative health status measures were evaluated by matched-pairs sample t test statistics and post hoc analysis of variance (ANOVA) findings.SRS-22 improved from a mean 3.03 points at baseline to 3.21 points at 6 months, 3.71 points at 1 year, and 3.70 points at 2 years post-op. Mean ODI score was 37.0 points pre-op and improved to 27.0 points at 6 months, and 22.8 points at 1 and 2 years post-op. Mean SF-12 physical component score was 33.7 points at baseline, improving to 36.9 points at 6 months, 40.6 points at 1 year, and 40.5 points at 2 years post-op. Paired samples analysis comparing 6-month and 1-year post-op scores showed deterioration for numeric rating scale leg pain (p=0.05). There was a trend for improvement in SF-12 physical component score (p=0.06). Significant improvement between 6 months and 1 year post-op was noted for ODI (p=0.02) and SRS total score (p<0.0001). Comparison of 1- versus 2-year postoperative scores revealed no statistically significant differences for any of the HRQOL parameters.This study supports the application of HRQOL measures, including the deformity-specific SRS-22, as a valuable tool in the assessment of adult deformity patients. Change in outcome score stabilized after the 1-year postoperative interval, for most patients.

    View details for DOI 10.1016/j.spinee.2008.06.450

    View details for PubMedID 18774752

  • Clinical outcome of deep wound infection after instrumented posterior spinal fusion: a matched cohort analysis. Spine Mok, J. M., Guillaume, T. J., Talu, U., Berven, S. H., Deviren, V., Kroeber, M., Bradford, D. S., Hu, S. S. 2009; 34 (6): 578–83

    Abstract

    Retrospective case control study.Determine the impact of infection on clinical outcome in patients undergoing posterior spinal fusion surgery.The outcome of patients treated for infection after spinal surgery is not well established because of variability in cohort identification, definition of infection, outcomes instrument, use of a control group, and/or sample size.Thirty-two patients were included. Sixteen patients ("infection group") met inclusion criteria of deep wound infection after spinal fusion with posterior segmental instrumentation (including combined approach). A 1:1 matched cohort ("control group") was created based on primary or revision status, length of fusion, diagnosis, and age. Postoperative patient outcomes were evaluated using the physical components of SF-36 v2.0 with minimum 2-year follow-up.No significant difference in the Physical Function, Role Physical, Bodily Pain, and General Health domains was detected between the infection group and control group. Mean follow-up was 62 months. Mean Physical Component Summary was 41.4 in the infection group and 44.3 in the control group (P = 0.6). Infection occurred early in 12 patients and late in 4 patients. Most common organisms isolated were Staphylococcus epidermidis, Enterococcus sp., and Staphylococcus aureus. Multiple debridements were significantly associated with polymicrobial infections and later pseudarthrosis requiring reoperation.An aggressive approach to deep wound infection emphasizing early irrigation and debridement allowed preservation of instrumentation and successful fusion in most cases. At the conclusion of treatment, patients can expect a medium-term clinical outcome similar to patients in whom this complication did not occur.

    View details for DOI 10.1097/BRS.0b013e31819a827c

    View details for PubMedID 19240667

  • The factors that play a role in the decision-making process of adult deformity patients. Spine Pekmezci, M., Berven, S. H., Hu, S. S., Deviren, V. 2009; 34 (8): 813–17

    Abstract

    Retrospective matched cohort.To investigate the factors that may affect the decision-making process of adult deformity patients.Adult deformity is a significant cause of morbidity in the elderly population. Despite high complication rates a significant number of patients still prefer operative treatment. Analysis of the factors that drive these patients to operative treatment would help surgeons to better evaluate these patients.Adult deformity patients who are evaluated in a single institute were reviewed. The inclusion criteria were being >18 years old, having a coronal curve magnitude of >30 degrees , having no previous surgery or associated neuromuscular or inflammatory condition, having completed SF-12, SRS-30, and Oswestry Disability Index questionnaires in the initial visit, and having a complete set of radiographs. The demographic data as well as back and leg pain incidences and magnitudes were collected. The eligible patients were compared first as age-gender-curve type matched cohorts.Functional domain scores particularly walking in Oswestry Disability Index and vitality in the SRS-30 were significantly worse in the operative treatment group, whereas the pain scores were similar in both groups in all outcomes assessment questionnaires. Besides, there was no difference among 2 groups with respect to either the incidence or the magnitude of back or leg pain.These results suggest that functional limitations are more important than pain for adult deformity patients when deciding for operative or nonoperative treatment.

    View details for DOI 10.1097/BRS.0b013e3181851ba6

    View details for PubMedID 19365250

  • Relaxation of forces needed to distract cervical vertebrae after discectomy: a biomechanical study. Journal of spinal disorders & techniques Aryan, H. E., Newman, C. B., Lu, D. C., Hu, S. S., Tay, B. K., Bradford, D. S., Puttlitz, C. M., Ames, C. P. 2009; 22 (2): 100–104

    Abstract

    In vitro and in vivo biomechanical stress measurements are made of the intervertebral disc segment distraction force during anterior cervical discectomy.The purpose of this study is to determine the short-term force relaxation of the native intervertebral disc segment and to determine the short-term force relaxation of the segment after removal of the intervertebral disc, as is commonly performed in anterior cervical discectomy with fusion and arthroplasty.No published data examine the issue of intraoperative distraction force of the cervical intervertebral disc segment. This is a novel research in this area.In vitro and in vivo studies under institutional review board approval were performed to determine the mechanical behavior of the normal and diseased cervical functional spinal unit. Seven in vitro and 11 in vivo spines were studied. Strain measurements between distracting Caspar-type pins were made before, at various points during, and after discectomy to assess how removal of the disc and other spinal components affects the force-displacement behavior of the spinal unit.The in vitro data show progressive reduction in force needed for distraction after discectomy and uncovertebral joint resection. Greatest reduction is noted after discectomy. The in vivo data indicate that, on average, the cervical functional spinal unit requires 20 N less force to achieve the same degree of distraction after removal of the intervertebral disc.A sharp reduction in the strain across the intervertebral space occurs after distraction. The removal of the cervical intervertebral disc significantly reduces the viscoelastic response of the cervical motion segment. The long-term force used to stabilize intervertebral grafts or implants is less than what is achieved at the time of distraction. The exact magnitude of the resultant force on graft or device at a given distraction force is unknown and would depend also upon fit.

    View details for DOI 10.1097/BSD.0b013e318168d9c0

    View details for PubMedID 19342931

  • Surgical compared with nonoperative treatment for lumbar degenerative spondylolisthesis. four-year results in the Spine Patient Outcomes Research Trial (SPORT) randomized and observational cohorts. The Journal of bone and joint surgery. American volume Weinstein, J. N., Lurie, J. D., Tosteson, T. D., Zhao, W., Blood, E. A., Tosteson, A. N., Birkmeyer, N., Herkowitz, H., Longley, M., Lenke, L., Emery, S., Hu, S. S. 2009; 91 (6): 1295–1304

    Abstract

    The management of degenerative spondylolisthesis associated with spinal stenosis remains controversial. Surgery is widely used and has recently been shown to be more effective than nonoperative treatment when the results were followed over two years. Questions remain regarding the long-term effects of surgical treatment compared with those of nonoperative treatment.Surgical candidates from thirteen centers with symptoms of at least twelve weeks' duration as well as confirmatory imaging showing degenerative spondylolisthesis with spinal stenosis were offered enrollment in a randomized cohort or observational cohort. Treatment consisted of standard decompressive laminectomy (with or without fusion) or usual nonoperative care. Primary outcome measures were the Short Form-36 (SF-36) bodily pain and physical function scores and the modified Oswestry Disability Index at six weeks, three months, six months, and yearly up to four years.In the randomized cohort (304 patients enrolled), 66% of those randomized to receive surgery received it by four years whereas 54% of those randomized to receive nonoperative care received surgery by four years. In the observational cohort (303 patients enrolled), 97% of those who chose surgery received it whereas 33% of those who chose nonoperative care eventually received surgery. The intent-to-treat analysis of the randomized cohort, which was limited by nonadherence to the assigned treatment, showed no significant differences in treatment outcomes between the operative and nonoperative groups at three or four years. An as-treated analysis combining the randomized and observational cohorts that adjusted for potential confounders demonstrated that the clinically relevant advantages of surgery that had been previously reported through two years were maintained at four years, with treatment effects of 15.3 (95% confidence interval, 11 to 19.7) for bodily pain, 18.9 (95% confidence interval, 14.8 to 23) for physical function, and -14.3 (95% confidence interval, -17.5 to -11.1) for the Oswestry Disability Index. Early advantages (at two years) of surgical treatment in terms of the secondary measures of bothersomeness of back and leg symptoms, overall satisfaction with current symptoms, and self-rated progress were also maintained at four years.Compared with patients who are treated nonoperatively, patients in whom degenerative spondylolisthesis and associated spinal stenosis are treated surgically maintain substantially greater pain relief and improvement in function for four years.

    View details for DOI 10.2106/JBJS.H.00913

    View details for PubMedID 19487505

    View details for PubMedCentralID PMC2686131

  • Reoperation after primary fusion for adult spinal deformity: rate, reason, and timing. Spine Mok, J. M., Cloyd, J. M., Bradford, D. S., Hu, S. S., Deviren, V., Smith, J. A., Tay, B., Berven, S. H. 2009; 34 (8): 832–39

    Abstract

    Retrospective cohort study of consecutive patients undergoing primary fusion with segmental fixation for adult spinal deformity.We sought to determine the survivorship of primary fusion for adult spinal deformity and identify patient-specific predictors of complications requiring reoperation.Compared with the adolescent population, surgery for adult deformity is often more complex and technically difficult, contributing to a high reported rate of complications that can result in the need for reoperation. Reported complication rates vary widely.From 1999-2004 all patients who underwent primary instrumented fusion for nonparalytic adult spinal deformity at a single center were included. Inclusion criteria included minimum age at surgery of 20 years and minimum fusion length of 4 motion segments. Surgical, demographic, and comorbidity data were recorded. Reoperation was defined as any additional surgery involving levels of the spine operated on during the index procedure and/or adjacent levels. Comparisons were performed between patients who required reoperation and those who did not.Eighty-nine patients met inclusion criteria. Endpoint (minimum 2 years follow-up or reoperation) was reached for 91%. Mean follow-up was 3.8 years. Cumulative reoperation rate was 25.8%. Survival was 86.4% at 1 year, 77.2% at 2 years, and 75.2% at 3 years. Reasons for reoperation included infection (n = 8), pseudarthrosis (n = 3), adjacent segment problems (n = 5), implant failure (n = 4), and removal of painful implants (n = 3). Multivariate analysis showed smoking was significantly higher in the reoperation group.Using a strict definition of reoperation for a well-defined cohort, in the presence of relevant risk factors, many patients undergoing primary fusion for adult spinal deformity required reoperation. The results indicate that complex medical and surgical factors contribute to the treatment challenges posed by patients with adult spinal deformity. This represents the largest cohort reported to date of patients undergoing primary fusion using third-generation instrumentation techniques.

    View details for DOI 10.1097/BRS.0b013e31819f2080

    View details for PubMedID 19365253

  • AOA symposium. Current state of fellowship hiring: is a universal match necessary? Is it possible? journal of bone and joint surgery. American volume Harner, C. D., Ranawat, A. S., Niederle, M., Roth, A. E., Stern, P. J., Hurwitz, S. R., Levine, W. N., DeRosa, G. P., Hu, S. S. 2008; 90 (6): 1375-1384

    View details for DOI 10.2106/JBJS.G.01582

    View details for PubMedID 18519333

  • Spondylolisthesis and spondylolysis. Instructional course lectures Hu, S. S., Tribus, C. B., Diab, M., Ghanayem, A. J. 2008; 57: 431–45

    Abstract

    Spondylolisthesis is a common condition that can be managed both nonsurgically and surgically. More than 80% of children treated nonsurgically have resolution of symptoms. For those patients requiring surgical treatment, fusion in situ may provide adequate treatment for young patients. Patients with neural compression may require decompression to relieve symptoms, and fusion is also usually indicated. High-grade and degenerative spondylolisthesis require care that is unique to those conditions. Spondylolysis is a defect in the pars interarticularis that occurs in approximately 5% of the general population. Approximately 15% of individuals with a pars interarticularis lesion have progression to spondylolisthesis.

    View details for PubMedID 18399601

  • Extravasation of rhBMP-2 with use of postoperative drains after posterolateral spinal fusion. Spine Mok, J. M., Durrani, S. K., Piper, S. L., Hu, S. S., Deviren, V., Berven, S. H., Burch, S. 2008; 33 (15): 1668–74

    Abstract

    Prospective measurement of rhBMP-2 from drains in a cohort of patients undergoing posterolateral spinal fusion.To quantify the amount of rhBMP-2 that extravasates into drains after posterolateral fusion using its current commercially available form, rhBMP-2 within an absorbable collagen sponge.Retention of rhBMP-2 at the fusion site is essential for clinical efficacy and avoidance of unintentional bony growth in other areas of the spine. In vitro studies have shown a large degree of rhBMP-2 release from the sponge within the first 48 hours. It is unknown what effect drainage may have on changing the local concentration of BMP at the posterolateral site.The entire contents of drains were collected for 48 hours after surgery from 9 patients who underwent instrumented posterolateral fusion with rhBMP-2. The total amount collected was calculated from the concentration of BMP-2 as measured by enzyme-linked immunosorbent assay.A median 68 microg of BMP-2 (range, 13-498) was recovered from drains, representing a median 0.58% (range, 0.21%-4.2%) of the amount implanted; adjusted for yield rate, a median 1.08% was recovered. No significant relationships were found between percentage of BMP-2 extravasation and amount implanted, number of levels, blood loss, and drainage output. A mean 54% of the total amount recovered was in the drain within the first 6 hours.The greater bleeding and muscular compression associated with posterolateral fusion did not result in a substantial amount of rhBMP-2 extravasation into postoperative drains. Based on the small rates of recovery, suction drains may be placed after even complex surgeries involving large blood loss without the loss of significant amounts of the implanted rhBMP-2 into the drain.

    View details for DOI 10.1097/BRS.0b013e31817b6229

    View details for PubMedID 18594460

  • Anterior arthrodesis with instrumentation for thoracolumbar scoliosis: comparison of efficacy in adults and adolescents. Spine Deviren, V., Patel, V. V., Metz, L. N., Berven, S. H., Hu, S. H., Bradford, D. S. 2008; 33 (11): 1219–23

    Abstract

    A retrospective review was performed of adult and adolescent patients who underwent anterior spinal fusion for thoracolumbar idiopathic scoliosis; radiographic and clinical outcomes were compared.The objective of this study was to compare the efficacy of anterior instrumentation to treat thoracolumbar scoliosis in adults and adolescents by evaluating radiographic and clinical outcomes.Anterior spinal arthrodesis is an effective treatment for idiopathic scoliosis. Deformity characteristics and clinical outcomes of adults versus adolescents have not been compared.A retrospective review of patients undergoing anterior fusion for thoracolumbar scoliosis was performed. Clinical outcomes were assessed using SRS-22. Preoperative and postoperative long films were evaluated independently. Flexibility, curve correction, and clinical outcomes were compared between adult and adolescents.Fifteen adults and 15 adolescents who underwent anterior spinal fusion and instrumentation were evaluated. Mean follow-up was 47 and 46 months, respectively. Flexibility of the major curve in adults (63%) was less than in adolescents (79%) (P < 0.05). Mean preoperative, major curve Cobb angles were 51 degrees and 49 degrees for adults and adolescents, respectively. Mean postoperative Cobb angles improved less for adults (17 degrees ) than for adolescents (10 degrees ) (P < 0.05). The SRS-22 questionnaire revealed no statistical difference between populations.Anterior spinal fusion is an option for both adults and adolescents with flexible, moderate thoracolumbar/lumbar curves. Flexibility significantly decreased with increased age and curve magnitude. This significantly affected curve correction. Adult patients may develop early degeneration at primary curve and compensatory curves. Careful patient selection is critical with this technique.

    View details for DOI 10.1097/BRS.0b013e318170fce0

    View details for PubMedID 18469695

  • Aneurysmal bone cysts of the spine. Neurosurgery clinics of North America Burch, S., Hu, S., Berven, S. 2008; 19 (1): 41–47

    Abstract

    The article reviews aneurysmal bone cysts of the spine and current diagnostic tests approaches and therapeutic interventions are discussed.

    View details for DOI 10.1016/j.nec.2007.09.005

    View details for PubMedID 18156046

  • Spondylolisthesis and spondylolysis. The Journal of bone and joint surgery. American volume Hu, S. S., Tribus, C. B., Diab, M., Ghanayem, A. J. 2008; 90 (3): 656–71

    View details for PubMedID 18326106

  • Biomechanics of the anterior longitudinal ligament during 8 g whiplash simulation following single- and contiguous two-level fusion: a finite element study. Spine Dang, A. B., Hu, S. S., Tay, B. K. 2008; 33 (6): 607–11

    Abstract

    A computational study of anterior longitudinal ligament (ALL) strain in the cervical spine following single- and 2-level fusion during simulated whiplash.To evaluate how cervical fusion alters the peak strain of the ALL in the adjacent motion segments.Although an in vitro study of ALL strain during whiplash has been conducted in healthy cervical spines, no such study has been performed in a cervical spine with fused segments. It has been demonstrated that the loss of motion following fusion results in increased strain in the adjacent motion segments. However, the biomechanics of the adjacent motion segments during high energy acceleration-deceleration simulations have not been widely reported. Accordingly, we investigated the peak strain of the ALL following single- and 2-level fusion during simulated whiplash.A detailed finite element (FE) model of the human body in the driver-occupant position was used to investigate cervical hyperextension injury. The cervical spine was subjected to simulated whiplash at 8 g acceleration and peak ALL strains were computed. The results were validated against published experimental data. This validated FE model was then modified to simulate single- and 2-level fusion and tested under identical loading conditions.The mean increase in peak ALL strain at the motion segment immediately adjacent to the level of fusion was 15.5% for single-level fusion when compared with 40.8% in 2-level contiguous fusion (P = 0.019).Cervical arthrodesis increases peak ALL strain in the adjacent motion segments. Two-level fusion increased ALL strain in the adjacent motion segments, on average, greater than single-level fusion did. Disc arthroplasty and other techniques that provide stability without loss of flexibility may be beneficial in patients undergoing multiple-level fusion. Detailed FE models such as ours can provide strong correlation with experimentally determined data.

    View details for DOI 10.1097/BRS.0b013e318166e01d

    View details for PubMedID 18344853

  • Surgical treatment of spinal stenosis with and without degenerative spondylolisthesis: cost-effectiveness after 2 years. Annals of internal medicine Tosteson, A. N., Lurie, J. D., Tosteson, T. D., Skinner, J. S., Herkowitz, H., Albert, T., Boden, S. D., Bridwell, K., Longley, M., Andersson, G. B., Blood, E. A., Grove, M. R., Weinstein, J. N. 2008; 149 (12): 845–53

    Abstract

    The SPORT (Spine Patient Outcomes Research Trial) reported favorable surgery outcomes over 2 years among patients with stenosis with and without degenerative spondylolisthesis, but the economic value of these surgeries is uncertain.To assess the short-term cost-effectiveness of spine surgery relative to nonoperative care for stenosis alone and for stenosis with spondylolisthesis.Prospective cohort study.Resource utilization, productivity, and EuroQol EQ-5D score measured at 6 weeks and at 3, 6, 12, and 24 months after treatment among SPORT participants.Patients with image-confirmed spinal stenosis, with and without degenerative spondylolisthesis.2 years.Societal.Nonoperative care or surgery (primarily decompressive laminectomy for stenosis and decompressive laminectomy with fusion for stenosis associated with degenerative spondylolisthesis).Cost per quality-adjusted life-year (QALY) gained.Among 634 patients with stenosis, 394 (62%) had surgery, most often decompressive laminectomy (320 of 394 [81%]). Stenosis surgeries improved health to a greater extent than nonoperative care (QALY gain, 0.17 [95% CI, 0.12 to 0.22]) at a cost of $77,600 (CI, $49,600 to $120,000) per QALY gained. Among 601 patients with degenerative spondylolisthesis, 368 (61%) had surgery, most including fusion (344 of 368 [93%]) and most with instrumentation (269 of 344 [78%]). Degenerative spondylolisthesis surgeries significantly improved health versus nonoperative care (QALY gain, 0.23 [CI, 0.19 to 0.27]), at a cost of $115,600 (CI, $90,800 to $144,900) per QALY gained. RESULT OF SENSITIVITY ANALYSIS: Surgery cost markedly affected the value of surgery.The study used self-reported utilization data, 2-year time horizon, and as-treated analysis to address treatment nonadherence among randomly assigned participants.The economic value of spinal stenosis surgery at 2 years compares favorably with many health interventions. Degenerative spondylolisthesis surgery is not highly cost-effective over 2 years but could show value over a longer time horizon.

    View details for DOI 10.7326/0003-4819-149-12-200812160-00003

    View details for PubMedID 19075203

    View details for PubMedCentralID PMC2658642

  • The efficacy of motor evoked potentials in fixed sagittal imbalance deformity correction surgery. Spine Lieberman, J. A., Lyon, R., Feiner, J., Hu, S. S., Berven, S. H. 2008; 33 (13): E414–24

    Abstract

    Retrospective analysis of transcranial motor evoked potential (TcMEP) responses and clinical outcome.To determine the sensitivity and specificity of TcMEPs to detect and predict isolated nerve root injury in selected patients having complex lumbar spine surgery.The surgical correction of fixed sagittal plane deformity involves posterior-based osteotomies and significant changes in the length of and space for the neural elements. The role of transcranial motor-evoked potential (TcMEP) monitoring in osteotomies below the conus has not been established. The purpose of this paper is to describe the relationship between neural complications from surgery and intraoperative TcMEP changes.We retrospectively studied 35 consecutive patients in a single center treated with posterior-based osteotomies for the correction of fixed sagittal plane deformity. Transcranial motor-evoked potentials, free-running and evoked electromyography data were assessed for each case. Analysis includes description of the intraoperative changes observed, and a correlation of changes with postoperative clinical findings.Thirty-five consecutive patients underwent surgery for fixed sagittal plane deformity with complete neuromonitoring data. Twenty-five patients (71%) had an episode of greater than 80% reduction in MEP amplitude to at least 1 muscle. Fifteen of 25 had improvement of TcMEPs after repositioning of the legs (1), additional surgical decompression (4), or volume and pharmacologic resuscitation (10). All 15 of these awoke with no detectable neurologic injury. Ten patients (29%) had reduced TcMEP signals that did not improve despite further decompression and manipulation of the osteotomy site. All 10 had a greater than 67% drop in TcMEPs for at least 1 muscle persisting at the end of the case, and all had a postoperative neurologic deficit. The TcMEP changes in patients who demonstrated nerve injury postoperatively were observed most often during osteotomy closure or sustained dural retraction. 9 patients had weakness involving the iliopsoas or quadriceps; 1 patient had isolated unilateral dorsiflexion weakness. Monitoring TcMEPs in multiple muscle groups was both highly sensitive and specific for predicting injury. Nine patients had recovered motor function completely by discharge, and all but 1 patient (grade 4/5) had a normal motor examination at 6-week follow-up.The use of TcMEPs is sensitive and specific to change in neural function. No patients had a false negative test. The rate of neural deficits is consistent with previous literature, suggesting that TcMEP monitoring may not prevent neural injury. However, there were several cases in which intraoperative intervention resulted in recovery of TcMEPs, and none of these patients sustained any postoperative neural deficit. The severity of neural deficits in this series was minor and the duration was limited. TcMEPs may contribute to calling attention to the need for intraoperative corrections including widening decompressions, improving perfusion, and limiting deformity correction so that more severe neural compromise may be prevented.

    View details for DOI 10.1097/BRS.0b013e318175c292

    View details for PubMedID 18520928

  • Use of C-reactive protein after spinal surgery: comparison with erythrocyte sedimentation rate as predictor of early postoperative infectious complications. Spine Mok, J. M., Pekmezci, M., Piper, S. L., Boyd, E., Berven, S. H., Burch, S., Deviren, V., Tay, B., Hu, S. S. 2008; 33 (4): 415–21

    Abstract

    This is a prospective observational study of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in a cohort of patients undergoing spinal surgery.We sought to characterize the normal kinetics of ESR and CRP after spinal surgery and compare their usefulness as predictors of infectious complications in the early postoperative period.ESR and CRP are nonspecific markers of inflammation used to evaluate postoperative infection. CRP is a quantitative test that exhibits predictable kinetics consisting of a postoperative rise and a peak followed by a decrease toward the normal value. Deviation from normal kinetics may be an indicator of infection.ESR and CRP were collected before surgery and daily after surgery in consecutive patients. All infectious complications were recorded.One hundred forty-nine patients met inclusion criteria. Infectious complications occurred in 20 patients. A postoperative peak, which is necessary to apply the test, was observed in 78% of patients for CRP and 48% for ESR. Multiple linear regression analysis revealed preoperative CRP, number of levels, and lumbar region as significant predictors of greater CRP peak value (r = 0.435, P = 0.001). After the peak, CRP showed an exponential decrease with a half-life of 2.6 days (r = 0.701, P < 0.001). No trend could be determined for ESR. A second rise or failure to decrease as expected had a sensitivity, specificity, positive predictive value, and negative predictive value of 82%, 48%, 41%, and 86% for infectious complications, respectively. Of 8 cases of deep wound infection, 7 exhibited substantial deviations from expected CRP values.CRP is more applicable, predictable, and responsive in the early postoperative period compared with ESR. The postoperative kinetics of CRP derived in this study seems to be conserved regardless of operation, magnitude, or region. Knowledge of the kinetics allows assessment of the degree of difference between actual and expected values. Using a second rise or failure to decrease as expected for CRP is sensitive for infection. A negative test is reassuring that infection is unlikely.

    View details for DOI 10.1097/BRS.0b013e318163f9ee

    View details for PubMedID 18277874

  • Comparison of observer variation in conventional and three digital radiographic methods used in the evaluation of patients with adolescent idiopathic scoliosis. Spine Mok, J. M., Berven, S. H., Diab, M., Hackbarth, M., Hu, S. S., Deviren, V. 2008; 33 (6): 681–86

    Abstract

    This study is a reliability analysis of coronal Cobb angle measurements in adolescent idiopathic scoliosis obtained by multiple observers.We sought to quantify and compare the interobserver reliability of conventional radiographs and 3 methods of digital radiography.The use of digital radiography for the evaluation of adolescent idiopathic scoliosis is being widely adopted. Previous studies comparing manual and computer-based measurements have found excellent intraobserver reliability for both techniques. Interobserver reliability of computer-based measurements on digital radiographs has not been compared with manual measurements on conventional radiographs. Other commonly used forms of output of digital radiography have not been studied.Preoperative standing posteroanterior full-length spine radiographs from 40 patients with adolescent idiopathic scoliosis were examined by 4 observers. Patients were divided into 2 groups of 20 patients. In 1 group, radiographs were obtained by conventional technique. In the other group, radiographs were obtained using a digital radiography system. Three types of output of the identical image obtained by a digital radiography system were examined, including computer-based image, printing of the image fitted onto a single film, or printing of the image onto 2 unstitched films. The Cobb angle, upper vertebra, and lower vertebra of the major curve were measured by each observer. Interobserver reliability for each technique was calculated by intraclass correlation coefficient and interobserver variance.Interobserver reliability as described by intraclass correlation coefficient and interobserver variance was excellent (0.93-0.98) for measurements made on conventional, computer-based, and fitted printed radiographs. The intraclass correlation coefficient was good (0.87) in measurements obtained on radiographs printed on 2 unstitched films.Measurements made on conventional and digital radiographs using manual and computer-based techniques have similar good to excellent interobserver reliability. Interobserver reliability was lower for digital radiographs when printed onto 2 unstitched films. The results suggest that different observers will obtain similar measurements when viewing the same image, but care should be taken when interpreting images printed on 2 unstitched films.

    View details for DOI 10.1097/BRS.0b013e318166aa8d

    View details for PubMedID 18344863

  • Lactic acid and proteoglycans as metabolic markers for discogenic back pain. Spine Keshari, K. R., Lotz, J. C., Link, T. M., Hu, S., Majumdar, S., Kurhanewicz, J. 2008; 33 (3): 312–17

    Abstract

    Disc tissue was removed at surgery from 9 patients with discogenic pain and 9 deformity patients with scoliosis undergoing anterior and posterior spinal fusion. These samples were then analyzed using ex vivo proton high resolution magic angle spinning (HR-MAS) NMR spectroscopy to produce metabolic profiles for comparison between the 2 patient groups.The goal of this study was to use quantitative ex vivo HR-MAS NMR spectroscopy to identify biochemical markers associated with discogenic back pain.Biomarkers of disc degeneration have been previously described using NMR spectroscopy, but the link between discogenic back pain and biomarkers has not been completely understood.HR-MAS NMR spectroscopy was performed on snap frozen samples taken from 9 patients who underwent discectomies for painful disc degeneration. The resulting proton NMR spectrums were compared with those from discs harvested from a reference population consisting of 9 scoliosis patients.Spectral analyses demonstrated significantly lower proteoglycan (PG)/collagen (0.31 +/- 0.22 vs. 0.77 +/- 0.48) and PG/lactate (0.46 +/- 0.24 vs. 2.24 +/- 1.11) ratios, and a higher lactate/collagen (0.77 +/- 0.49 vs. 0.40 +/- 0.21) ratio in specimens obtained from discogenic pain patients when compared with scoliosis patients.Our results suggest that spectroscopic markers of proteoglycan, collagen, and lactate may serve as metabolic markers of discogenic back pain. These results provide a further basis of the potential to develop in vivo MR spectroscopy for the investigation of discogenic back pain.

    View details for DOI 10.1097/BRS.0b013e31816201c3

    View details for PubMedID 18303465

  • Patient preferences and expectations for care: determinants in patients with lumbar intervertebral disc herniation. Spine Lurie, J. D., Berven, S. H., Gibson-Chambers, J., Tosteson, T., Tosteson, A., Hu, S. S., Weinstein, J. N. 2008; 33 (24): 2663–68

    Abstract

    Prospective observational cohort.To describe the baseline characteristics of patients with a diagnosis of intervertebral disc herniation who had different treatment preferences and the relationship of specific expectations with those preferences.Data were gathered from the observational cohort of the Spine Patient Outcomes Research Trial (SPORT). Patients in the observational cohort met eligibility requirements identical to those of the randomized cohort, but declined randomization, receiving instead the treatment of their choice.Baseline preference and expectation data were acquired at the time of enrollment of the patient, before exposure to the informed consent process. Univariate analyses were performed using a t test for continuous variables and chi for categorical variables. Multivariate analyses were also performed with ANCOVA for continuous variables and logistic regression for categorical variables. Multiple logistic regression models were developed in a forward stepwise fashion using blocks of variables.More patients preferred operative care: 67% preferred surgery, 28% preferred nonoperative treatment, and 6% were unsure; 53% of those preferring surgery stated a definite preference, whereas only 18% of those preferring nonoperative care had a definite preference. Patients preferring surgery were younger, had lower levels of education, and higher levels of unemployment/disability. This group also reported higher pain, worse physical and mental functioning, more back pain related disability, a longer duration of symptoms, and more opiate use. Gender, race, comorbidities, and use of other therapies did not differ significantly across preference groups. Patients' expectations regarding improvement with nonoperative care was the strongest predictor of preference.Patient expectations, particularly regarding the benefit of nonoperative treatment, are the primary determinant of surgery preference among patients with lumbar intervertebral disc herniation. Demographic, functional status, and prior treatment experience had significant associations with patients' expectations and preferences.

    View details for DOI 10.1097/BRS.0b013e31818cb0db

    View details for PubMedID 18981962

    View details for PubMedCentralID PMC2768262

  • Surgical strategies and choosing levels for spinal deformity: how high, how low, front and back. Neurosurgery clinics of North America Mok, J. M., Hu, S. S. 2007; 18 (2): 329–37

    Abstract

    The purpose of this article is to describe general strategies in the surgical treatment of adolescent and adult scoliosis, including radiographic evaluation, curve selection, principles guiding the selection of the upper and lower instrumented vertebrae, and indications for anterior surgery. Sagittal plane deformity, including Scheuermann's kyphosis, is discussed. Avoidance and treatment of postoperative flatback deformity is also briefly mentioned. There are multiple and sometimes conflicting considerations that must be reviewed when planning surgical stabilization of spinal deformity. Although there may be significant variation in surgeon decision making, careful adherence to primary principles, such as achieving coronal and sagittal balance in all patients and minimizing fusion levels, particularly in young patients, should be of paramount importance.

    View details for DOI 10.1016/j.nec.2007.01.008

    View details for PubMedID 17556135

  • Intradiscal thermal therapy using interstitial ultrasound: an in vivo investigation in ovine cervical spine. Spine Nau, W. H., Diederich, C. J., Shu, R., Kinsey, A., Bass, E., Lotz, J., Hu, S., Simko, J., Ferrier, W., Sutton, J., Attawia, M., Pellegrino, R. 2007; 32 (5): 503–11

    Abstract

    In vivo investigation of intradiscal ultrasound thermal therapy in ovine cervical spine model.To evaluate the potential of interstitial ultrasound for selective heating of intradiscal tissue in vivo.Application of heat in the spine using resistive wire and radiofrequency current heating devices is currently being used clinically for minimally invasive treatment of discogenic low back pain. Treatment temperatures are representative of those required for thermal necrosis of ingrowing nociceptor nerve fibers and disc cellularity alone, or with coagulation and restructuring of anular collagen in the high temperature case.Two interstitial ultrasound applicator design configurations with directional heating patterns were evaluated in vivo in ovine cervical intervertebral discs (n = 62), with up to 45-day survival periods. Two heating protocols were employed in which the temperature measured 5 mm away from the applicator was controlled to either <54 C (capable of nerve and cellular necrosis) or >70 C (for coagulation of collagen) for a 10-minute treatment period. Transient and steady state temperature maps, calculated thermal doses (t43), and histology were used to assess the thermal treatments.These studies demonstrated the capability to control spatial temperature distributions within selected regions of the in vivo intervertebral disc and anular wall using interstitial ultrasound.Ultrasound energy is capable of penetrating within the highly attenuating disc tissue to produce more extensive radial thermal penetration, lower maximum intradiscal temperature, and shorter treatment times than can be achieved with current clinical intradiscal heating technology. Thus, interstitial ultrasound offers potential as a more precise and faster heating modality for the clinical management of low back pain and studies of thermal effects on disc tissue in animal models.

    View details for DOI 10.1097/01.brs.0000256905.39488.c7

    View details for PubMedID 17334283

  • Review: surgery may be more effective than unstructured nonoperative treatment for chronic low-back pain. The Journal of bone and joint surgery. American volume Hu, S. 2007; 89 (11): 2558

    View details for DOI 10.2106/JBJS.8911.ebo3

    View details for PubMedID 17974909

  • High thoracic spinal infection following upper gastrointestinal work-up. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia Chen, Y., Kim, B. J., Lee, S. H., Hu, S. S. 2007; 14 (11): 1132–35

    Abstract

    Spinal infections originating from the gastrointestinal tract are rare. We report a patient in whom esophageal rupture during endoscopy led to spinal infection with neurological deficit. An 80-year-old Asian man with a history of recent endoscopic gastrointestinal investigation presented to our clinic with the chief complaints of upper thoracic discomfort, chest pain and mild intermittent fever. Progressive weakness and numbness in both lower extremities had developed during the previous two weeks. A thoracic spine MRI showed a space-occupying lesion with involvement of the T2 and T3 vertebral bodies including an epidural abscess. After surgical decompression, the patient gradually recovered power in his lower extremities. Early diagnosis is a key factor to avoid neurologic sequelae in the treatment of patients with spinal infection. Physicians need to be aware of this potential complication following endoscopic gastrointestinal investigation.

    View details for DOI 10.1016/j.jocn.2006.02.023

    View details for PubMedID 17499509

  • Operative management of degenerative scoliosis: an evidence-based approach to surgical strategies based on clinical and radiographic outcomes. Neurosurgery clinics of North America Berven, S. H., Deviren, V., Mitchell, B., Wahba, G., Hu, S. S., Bradford, D. S. 2007; 18 (2): 261–72

    Abstract

    Degenerative scoliosis is a common and important cause of lumbar spine deformity in the adult. The operative management of degenerative scoliosis encompasses a spectrum of approaches, including decompression alone, or fusion that may include posterior or anterior approaches. There exists significant variability in surgical approaches to degenerative scoliosis, and evidence to support a specific approach is limited. Including the structural thoracic spine in fusions to the thoracolumbar junction has a lower rate of revision than fusions with a cephalad segment at T12 or L1. Short fusions to L5 have a low rate of revision at a minimum follow-up of 2 years. Combined anterior and posterior surgery is more effective in improving lordosis than posterior-only surgery without osteotomies. Clinical outcomes of surgery for degenerative scoliosis are variable, andwct 2 self-reported scores for pain improve more reliably than scores for function. Further investigation, including comparison of randomized or matched cohorts and measurement of outcomes related to specific preoperative complaints, will be useful in the development of an evidence-based approach to degenerative scoliosis.

    View details for DOI 10.1016/j.nec.2007.03.003

    View details for PubMedID 17556127

  • Recombinant activated factor VII in spinal surgery: a multicenter, randomized, double-blind, placebo-controlled, dose-escalation trial. Spine Sachs, B., Delacy, D., Green, J., Graham, R. S., Ramsay, J., Kreisler, N., Kruse, P., Khutoryansky, N., Hu, S. S. 2007; 32 (21): 2285–93

    Abstract

    Randomized, placebo-controlled, double-blind, multicenter, Phase IIa study.To assess the safety and efficacy of recombinant-activated Factor VII (rFVIIa) in major spinal surgery.Spinal fusion surgery can cause substantial blood loss and blood product transfusions. Recombinant FVIIa is approved for treatment of bleeding in patients with coagulation abnormalities and has been shown to reduce blood loss and transfusion requirements in surgery in patients with no underlying coagulopathy.Forty-nine patients undergoing fusion of 3 or more vertebral segments were randomized and treated on losing 10% of their estimated blood volume (with total expected surgical blood loss > or = 20%) and received 3 doses (2-hour intervals) of placebo (n = 13) or 30, 60, or 120 microg/kg rFVIIa (n = 12 per group). The primary endpoint was safety. A priori-defined efficacy endpoints included blood loss and transfusion requirements between placebo and each rFVIIa dose group, adjusted for surgery duration, number of segments fused, and estimated blood volume.Serious adverse events did not occur at any greater frequency in any of the treatment groups. One patient (3 x 30 microg/kg rFVIIa) with advanced cerebrovascular disease (undiagnosed, trial exclusion criterion) died 6 days after surgery due to an ischemic stroke. Mean blood loss was as follows: 2270 mL for placebo; 1909, 1262, and 1868 mL for 3 x 30, 3 x 60, and 3 x 120 microg/kg rFVIIa, respectively (differences not statistically significant). Mean adjusted surgical blood loss was as follows: 2536 mL for placebo; 1120, 400, and 823 mL for 3 x 30, 3 x 60, and 3 x 120 microg/kg rFVIIa, respectively (P < or = 0.001). Mean surgical transfusion volume was reduced by 27% to 50% with rFVIIa treatment (not significant). The mean adjusted surgical transfusion volume was reduced by 81% to 95% with rFVIIa treatment (P < or = 0.002).No safety concerns were indicated for the use of rFVIIa in patients at all doses tested; rFVIIa reduced adjusted blood loss and adjusted transfusions during spinal surgery.

    View details for DOI 10.1097/BRS.0b013e3181557d45

    View details for PubMedID 17906567

  • Surgical versus nonsurgical treatment for lumbar degenerative spondylolisthesis. The New England journal of medicine Weinstein, J. N., Lurie, J. D., Tosteson, T. D., Hanscom, B., Tosteson, A. N., Blood, E. A., Birkmeyer, N. J., Hilibrand, A. S., Herkowitz, H., Cammisa, F. P., Albert, T. J., Emery, S. E., Lenke, L. G., Abdu, W. A., Longley, M., Errico, T. J., Hu, S. S. 2007; 356 (22): 2257–70

    Abstract

    Management of degenerative spondylolisthesis with spinal stenosis is controversial. Surgery is widely used, but its effectiveness in comparison with that of nonsurgical treatment has not been demonstrated in controlled trials.Surgical candidates from 13 centers in 11 U.S. states who had at least 12 weeks of symptoms and image-confirmed degenerative spondylolisthesis were offered enrollment in a randomized cohort or an observational cohort. Treatment was standard decompressive laminectomy (with or without fusion) or usual nonsurgical care. The primary outcome measures were the Medical Outcomes Study 36-Item Short-Form General Health Survey (SF-36) bodily pain and physical function scores (100-point scales, with higher scores indicating less severe symptoms) and the modified Oswestry Disability Index (100-point scale, with lower scores indicating less severe symptoms) at 6 weeks, 3 months, 6 months, 1 year, and 2 years.We enrolled 304 patients in the randomized cohort and 303 in the observational cohort. The baseline characteristics of the two cohorts were similar. The one-year crossover rates were high in the randomized cohort (approximately 40% in each direction) but moderate in the observational cohort (17% crossover to surgery and 3% crossover to nonsurgical care). The intention-to-treat analysis for the randomized cohort showed no statistically significant effects for the primary outcomes. The as-treated analysis for both cohorts combined showed a significant advantage for surgery at 3 months that increased at 1 year and diminished only slightly at 2 years. The treatment effects at 2 years were 18.1 for bodily pain (95% confidence interval [CI], 14.5 to 21.7), 18.3 for physical function (95% CI, 14.6 to 21.9), and -16.7 for the Oswestry Disability Index (95% CI, -19.5 to -13.9). There was little evidence of harm from either treatment.In nonrandomized as-treated comparisons with careful control for potentially confounding baseline factors, patients with degenerative spondylolisthesis and spinal stenosis treated surgically showed substantially greater improvement in pain and function during a period of 2 years than patients treated nonsurgically. (ClinicalTrials.gov number, NCT00000409 [ClinicalTrials.gov].).

    View details for DOI 10.1056/NEJMoa070302

    View details for PubMedID 17538085

    View details for PubMedCentralID PMC2553804

  • Visual loss after spinal surgery. Anesthesiology Weiskopf, R. B., Feiner, J., Lieberman, J., Hu, S. S. 2007; 106 (6): 1250–51; author reply 1251–52
  • Preparing the adult deformity patient for spinal surgery. Spine Hu, S. S., Berven, S. H. 2006; 31 (19 Suppl): S126–31

    Abstract

    Review article of preoperative evaluation of surgical patients as relates to adult spine patients.To determine which patients should undergo preoperative evaluation and review options for improved preoperative preparation for these patients.There is increasing attention paid to preoperative preparation for surgical patients to decrease perioperative morbidity. Better preoperative evaluation may lead to decreased complication rates and may improve outcomes.The literature to date, including surgical, hospitalist, and critical care, was reviewed and combined with the authors' experience.Suggestions for preoperative screening questions are summarized.Better recognition of preoperative risk factors may help spine surgeons improve preoperative preparation in their patients, leading to decreased complication rates.

    View details for DOI 10.1097/01.brs.0000234760.69549.79

    View details for PubMedID 16946629

  • Intradiscal thermal therapy does not stimulate biologic remodeling in an in vivo sheep model. Spine Bass, E. C., Nau, W. H., Diederich, C. J., Liebenberg, E., Shu, R., Pellegrino, R., Sutton, J., Attawia, M., Hu, S. S., Ferrier, W. T., Lotz, J. C. 2006; 31 (2): 139–45

    Abstract

    Thermal energy was delivered in vivo to ovine cervical discs and the postheating response was monitored over time.To determine the effects of two distinctly different thermal exposures on biologic remodeling: a "high-dose" regimen intended to produce both cellular necrosis and collagen denaturation and a "low-dose" regimen intended only to kill cells.Thermal therapy is a minimally invasive technique that may ameliorate discogenic back pain. Potential therapeutic mechanisms include shrinkage of collagenous tissues, stimulation of biologic remodeling, and ablation of cytokine-producing cells and nociceptive fibers.Intradiscal heating was performed using directional interstitial ultrasound applicators. Temperature and thermal dose distributions were characterized. The effects of high (>70 C, 10 minutes) and low (52 C-54 C, 10 minutes) temperature treatments on chronic biomechanical and architectural changes were compared with sham-treated and control discs at 7, 45, and 180 days.The high-dose treatment caused both an acute and chronic loss of proteoglycan staining and a degradation of biomechanical properties compared with low-dose and sham groups. Similar amounts of degradation were observed in the low-dose and sham-treated discs relative to the control discs at 180 days after treatment.While a high temperature thermal protocol had a detrimental effect on the disc, the effects of low temperature treatment were relatively minor. Thermal therapy did not stimulate significant biologic remodeling. Future studies should focus on the effects of low-dose therapy on tissue innervation and pro-inflammatory factor production.

    View details for DOI 10.1097/01.brs.0000195344.49747.dd

    View details for PubMedID 16418631

  • Risk factors for infection after spinal surgery. Spine Fang, A., Hu, S. S., Endres, N., Bradford, D. S. 2005; 30 (12): 1460–65

    Abstract

    A retrospective case control analysis of 48 cases of postoperative infection following spinal procedures.Spinal procedures that became infected after surgery were analyzed to identify the significance of preoperative and intraoperative risk factors. Characterization of the nature and timing of the infections was also performed.The rate of postoperative infection following spinal surgery varies widely depending on the nature of the procedure and the patient's diagnosis. Preoperative comorbidities and risk factors also influence the likelihood of infection.A review of 1629 procedures performed on 1095 patients revealed that a postoperative infection developed in 48 patients (4.4%). Data regarding preoperative and intraoperative risk factors were gathered from patient charts for these and a randomly selected control group of 95 uninfected patients. For analysis, these patient groups were further divided into adult and pediatric subgroups, with an age cutoff of 18 years. Preoperative risk factors reviewed included smoking, diabetes, previous surgery, previous infection, steroid use, body mass index, and alcohol abuse. Intraoperative factors reviewed included staging of procedures, estimated blood loss, operating time, and use of allograft or instrumentation.The majority of infections occurred during the early postoperative period (less than 3 months). Age >60 years, smoking, diabetes, previous surgical infection, increased body mass index, and alcohol abuse were statistically significant preoperative risk factors. The most likely procedure to be complicated by an infection was a combined anterior/posterior spinal fusion performed in a staged manner under separate anesthesia. Infections were primarily monomicrobial, although 5 patients had more than 4 organisms identified. The most common organism cultured from the wounds was Staphylococcus aureus. All patients were treated with surgical irrigation and débridement, and appropriate antibiotics to treat the cultured organism.Aggressive treatment of patients undergoing complex or prolonged spinal procedures is essential to prevent and treat infections. Understanding a patient's preoperative risk factors may help the physician to optimize a patient's preoperative condition. Additionally, awareness of critical intraoperative parameters will help to optimize surgical treatment. It may be appropriate to increase the duration of prophylactic antibiotics or implement other measures to decrease the incidence of infection for high risk patients.

    View details for DOI 10.1097/01.brs.0000166532.58227.4f

    View details for PubMedID 15959380

  • Disc arthroplasty design influences intervertebral kinematics and facet forces. The spine journal : official journal of the North American Spine Society Rousseau, M. A., Bradford, D. S., Bertagnoli, R., Hu, S. S., Lotz, J. C. 2005; 6 (3): 258–66

    Abstract

    Total disc replacement is a novel approach for dynamically stabilizing a painful intervertebral segment. While this approach is gaining popularity, and several types of implants are used, the effect of disc arthroplasty on lumbar biomechanics has not been widely reported. Consequently, beneficial or adverse effects of this procedure may not be fully realized, and data for kinematic optimization are unavailable.To characterize kinematic and load transfer modifications at L5/S1 secondary to joint replacement.A human cadaveric biomechanical study in which the facet forces and instant axes of rotation (IAR) were measured for different spinal positions under simulated weightbearing conditions before and after total disc replacement at L5/S1 using semiconstrained (3 degrees of freedom [DOF]; Prodisc) and unconstrained (5 DOF; Charité) articulated implants.Twelve radiographically normal human cadaveric L5/S1 joints (age range 45-64 years) were tested before and after disc replacement using Prodisc II implants (Spine Solutions, Paoli, PA) in six specimens and SB Charité III (Johnson & Johnson, New Brunswick, NJ) in six other specimens. Semiconstrained fixtures in combination with a servo-hydraulic materials testing system subjected the test specimens to a physiologic combination of compression and anterior shear. Multiple intervertebral positions were studied and included up to 6 degrees of flexion, extension, and lateral bending. The IAR was calculated for every 3-degree intervals, and the force through the facet joints was simultaneously measured using flexible intra-articular sensors. Data were analyzed using repeated-measures analysis of variance.During flexion/extension, the average IAR positions and directions were not significantly modified by implantation with the exception that the IAR was higher relative to S1 end plate with the Charité (p=.028). The IAR had a vertically oriented centrode throughout flexion/extension with the Prodisc (p<.001) and the Charité (p<.016). The centrode tended to be greater with the Prodisc. There was a trend that the facet force was decreased throughout flexion/extension for the Prodisc; however, this was statistically significant only at 6 degrees extension (27%, p=.013). In lateral bending, the IAR was significantly modified by Prodisc replacement, with a decreased inclination relative to S1 end plate, (ie, increased coupled axial rotation). While the IAR moved in the horizontal plane toward the side of bending, this effect was more pronounced with the Prodisc. The ipsilateral facet force was significantly increased in 6 degrees lateral bending with the Charité (85%; p=.001).The degree of constraint affects post-implantation kinematics and load transfer. With the Prodisc (3 DOF), the facets were partially unloaded, though the IAR did not match the fixed geometrical center of the UHMWPE. The latter observation suggests joint surface incongruence is developed during movement. With the Charité (5 DOF), the IAR was less variable, yet the facet forces tended to increase, particularly during lateral bending. These results highlight the important role the facets play in guiding movement, and that implant constraint influences facet/implant synergy. The long-term consequences of the differing kinematics on clinically important outcomes such as wear and facet arthritis have yet to be determined.

    View details for DOI 10.1016/j.spinee.2005.07.004

    View details for PubMedID 16651219

  • Pedicle screw fixation of the thoracic spine: an in vitro biomechanical study on different configurations. Spine Deviren, V., Acaroglu, E., Lee, J., Fujita, M., Hu, S., Lenke, L. G., Polly, D., Kuklo, T. R., O'Brien, M., Brumfield, D., Puttlitz, C. M. 2005; 30 (22): 2530–37

    Abstract

    An in vitro biomechanical study of different pedicle screw configuration usage on the thoracic spine using a cadaveric model.To investigate the degree of motion afforded different pedicle screw configurations in the thoracic spine using a cadaveric model with 2 different degrees of intrinsic stability.Recently, thoracic pedicle screws have become an alternative to hook and wire fixation, and have gained popularity. Clinically, pedicle screw use has ranged from application to every segment, to skipping every other level. There exists no clear consensus as to which strategy is most appropriate.The load-displacement behavior of 6 different constructs was determined on 8 fresh frozen cadaver spine specimens (T4-T12). Each construct was evaluated on 2 destabilization models, including minimum destabilization (bilateral facetectomy) and maximum destabilization (facetectomy and annulotomy). Pure moments were applied, and the resultant range of motion for each scenario was determined.Facetectomy did not significantly destabilize the thoracic spine. Annulotomy and facetectomy created gross instability that rendered testing of this destabilization model impossible. All constructs significantly reduced the range of motion compared to intact or facetectomized specimens (P < or = 0.001). When different constructs were compared to each other, a pattern of continuously increasing stability emerged, with the "maximum" construct being the most stable and "minimum" configuration being the least, with varying degrees of statistical significance.Our results suggest that the most important factor for the acute postoperative stability of spinal fixation is the degree of preoperative or iatrogenic destabilization. The minimum amount of pedicle screws provides adequate stability when there is minimal destabilization of the spine. On the other hand, when anterior column release has been performed or instability exists before surgery, segmental pedicle screw fixation may be necessary to achieve adequate stability.

    View details for DOI 10.1097/01.brs.0000186590.45675.ce

    View details for PubMedID 16284591

  • Intervertebral disc replacement maintains cervical spine kinetics. Spine Puttlitz, C. M., Rousseau, M. A., Xu, Z., Hu, S., Tay, B. K., Lotz, J. C. 2004; 29 (24): 2809–14

    Abstract

    An in vitro biomechanical study of C4-C5 intervertebral disc replacement using a cadaveric model.To investigate the degree of motion afforded by a ball-and-socket cervical intervertebral disc prosthesis design.Intervertebral disc prostheses designs attempt to restore or maintain cervical disc motion after anterior cervical discectomy and reduce the likelihood of accelerated degeneration in adjacent discs by maintaining normal motion at the affected disc level. Surprisingly, the actual kinetic and biomechanical effects that cervical disc arthroplasty imparts on the spine have not been widely reported. Accordingly, we investigated what effect implanting a cervical disc prosthesis has on the range of motion at the affected level as well as how it changes the coupled motion patterns at the level of implantation.Six fresh-frozen human cadaveric cervical spines (C2-C7) were used in this study. We evaluated two different spinal conditions: intact and after disc replacement at C4-C5. Compression (using the follower load concept) and pure moment loading were applied to the specimen. Range of motion was measured using an optical tracking system. Statistical differences between the intact and replaced condition range of motion was determined using analysis of variance with post hoc comparisons (alpha = 0.05).The data indicate that the intervertebral disc prosthesis approximated the intact motion in all three rotation planes at the affected level. Finally, changes in cervical coupled rotations, specifically lateral bending during axial rotation loading and axial rotation during lateral bending loading, were not statistically significant between the two tested conditions.Our data demonstrate that a ball-and-socket design can replicate physiologic motion at the affected and adjacent levels. More importantly, the data indicate that motion coupling, which is most dramatic in the cervical spine and plays an important biomechanical role, is maintained.

    View details for DOI 10.1097/01.brs.0000147739.42354.a9

    View details for PubMedID 15599283

  • Blood loss in adult spinal surgery. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society Hu, S. S. 2004; 13 Suppl 1: S3–5

    Abstract

    Spinal surgery in adults can vary from simple to complex and can also have variable anticipated surgical blood loss. There are several factors that can put patients at increased risk for greater intraoperative blood loss. These factors, including a review of the literature, will be discussed.

    View details for DOI 10.1007/s00586-004-0753-x

    View details for PubMedID 15197630

    View details for PubMedCentralID PMC3592187

  • Strategies for managing decreased motor evoked potential signals while distracting the spine during correction of scoliosis. Journal of neurosurgical anesthesiology Lyon, R., Lieberman, J. A., Grabovac, M. T., Hu, S. 2004; 16 (2): 167–70

    Abstract

    Surgical correction of kyphoscoliosis may result in spinal cord injury and neurologic deficits. Monitoring somatosensory evoked potentials (SSEPs) and transcranial motor evoked potentials (MEPs) intraoperatively may allow for early detection and reversal of spinal cord injury. Controlled hypotension and isovolemic hemodilution are often used during these cases to reduce blood loss and transfusion. However, these physiologic parameters may affect the quality of SSEP and MEP signals. Acute reduction or loss of MEP or SSEP signals during spinal distraction presents a crisis for the operative team: should distraction be immediately relieved? The authors describe three patients who showed a decrease in evoked potential signals under hypotensive, hemodiluted conditions at the stage of spinal distraction. Each case illustrates a different strategy for successful management of these patients.

    View details for DOI 10.1097/00008506-200404000-00012

    View details for PubMedID 15021289

  • Burst fracture in the metastatically involved spine: development, validation, and parametric analysis of a three-dimensional poroelastic finite-element model. Spine Whyne, C. M., Hu, S. S., Lotz, J. C. 2003; 28 (7): 652–60

    Abstract

    A finite-element study and in vitro experimental validation was performed for a parametric investigation of features that contribute to burst fracture risk in the metastatically involved spine.To develop and validate a three-dimensional poroelastic model of a metastatically compromised vertebral segment, to evaluate the effect of lytic lesions on vertebral strains and pressures, and to determine the influence of loading and motion segment status (bone density, pedicle involvement, disc degeneration, and tumor size) on the relative risk of burst fracture initiation.Finite-element analysis has been used successfully to predict failure loads and fracture patterns for bone. Although models for vertebra affected with tumors have been presented, these have not been thoroughly validated experimentally. Consequently, their predictive capabilities remain uncertain.A three-dimensional poroelastic finite-element model of the first lumbar vertebra and adjacent intervertebral discs, including a tumor of variable size, was developed. To validate the model, 12 cadaver spinal motion segments were tested in axial compression, in intact condition, and with simulated osteolytic defects. Features of the validated model were parametrically varied to investigate the effects of tumor size, trabecular bone density, pedicle involvement, applied loads, loading rates, and disc degeneration using outcome variables of vertebral bulge and vertebral axial deformation.Consistent trends between the experimental data and model predictions were observed. Overall, the model results suggest that tumor size contributes most toward the risk of initiating burst fracture, followed by the applied load magnitude and bone density.The parametric analysis suggests that the principal factors affecting the initiation of burst fracture in metastatically affected vertebrae are tumor size, magnitude of spinal loading, and bone density. Consequently, patient-specific measures of these factors should be factored into decisions regarding clinical prophylaxis. Pedicle involvement or disc degeneration was less important according to the outcome measures in this study.

    View details for DOI 10.1097/01.BRS.0000051910.97211.BA

    View details for PubMedID 12671351

  • Treatment of thoracic pseudarthrosis in the adult: is combined surgery necessary? Clinical orthopaedics and related research Berven, S., Kao, H., Deviren, V., Hu, S., Bradford, D. 2003: 25–31

    Abstract

    In deformity surgery in adults, pseudarthrosis remains an important cause of progressive deformity and postoperative pain. Revision surgery for pseudarthrosis in the lumbar spine is a difficult challenge with failure rates of as much as 50% using posterior surgery alone. Treatment of pseudarthrosis of the thoracic spine has not been well-described. The purpose of the current study was to review the long-term clinical and radiographic results of posterior-only surgery for the treatment of pseudarthrosis in the thoracic spine. Using a posterior extension osteotomy through the identified pseudarthrosis with reinstrumentation and autogenous bone grafting, an improvement of regional sagittal balance was shown and reliable clinical outcomes were obtained. A single-stage posterior revision surgery with extension osteotomies through the regions of pseudarthrosis coupled with rigid internal fixation and autogenous bone grafting is an effective technique for treatment of pseudarthrosis of the thoracic spine. This technique improves regional sagittal deformity and leads to reliable arthrodesis. Combined anterior and posterior surgery was not necessary for effective treatment of thoracic pseudarthrosis in this series.

    View details for DOI 10.1097/01.blo.0000068183.83581.48

    View details for PubMedID 12782856

  • Lumbar end plate osteotomy in adult patients with scoliosis. Clinical orthopaedics and related research Berven, S. H., Hu, S. S., Deviren, V., Smith, J., Bradford, D. S. 2003: 70–76

    Abstract

    The maintenance of mobile segments in the lumbar spine may prevent complications associated with long fusions to the sacrum and permit improved postoperative patient function and mobility. The purpose of the current study was to describe the technique of end plate osteotomy for surgical treatment of fractional curves in the lumbosacral region. This technique serves to allow the end lumbar vertebra to become horizontal, to reduce lumbosacral fractional curves, and to create a stable end vertebra above the pelvis. A review of long-term clinical and radiographic outcomes in patients treated with the technique have been satisfactory. The authors show that the techniques of end plate osteotomy with concave osteophyte excision is a clinically valuable technique for the treatment of adults with fixed lumbosacral fractional curves.

    View details for DOI 10.1097/01.blo.0000068186.83581.14

    View details for PubMedID 12782861

  • Studies in the modified Scoliosis Research Society Outcomes Instrument in adults: validation, reliability, and discriminatory capacity. Spine Berven, S., Deviren, V., Demir-Deviren, S., Hu, S. S., Bradford, D. S. 2003; 28 (18): 2164–69; discussion 2169

    Abstract

    Observational study of patients with scoliosis and matched controls.To determine the validity and reliability of the modified Scoliosis Research Society Outcomes Instrument (SRS-22) for use in the assessment of deformity in adults. To demonstrate the discriminate validity of the SRS-22 in differentiating between affected and unaffected adults.Spinal deformity has an important impact on the general health status of adults. The magnitude of this impact has been difficult to measure and reported variably in the literature. The development of disease-specific outcomes tools permits improved sensitivity and specificity in measuring the patient's self-assessment of health status. An instrument for measuring disease-specific health status in adults with scoliosis has not been validated.Observational study comparing the health status of adults affected by scoliosis and unaffected controls, matched for age, gender, and socioeconomic status. Pearson correlation analysis was used to determine the relationship of each domain within the SRS-22 and SF-36 with radiographic parameters including sagittal balance, coronal balance, and major curve correction. Discriminate validity of the modified SRS instrument was determined by a comparison of means between affected and unaffected cohorts. The validation of the SRS-22 was determined by criterion validity, using correlation analysis with comparable domains of the SF-36. The reliability of the SRS-22 was demonstrated using test-retest parity and Cronbach's alpha test for internal consistency.One hundred eighty adults were included in the study, 146 with scoliosis and 34 without. Adults with scoliosis scored significantly lower than unaffected controls on every domain of the SRS-22 and the SF-36. The floor and ceiling effect of the SRS-22 were less than observed in the SF-36 instrument. Pearson correlation analysis demonstrated no significant correlation between any radiographic process measure and any specific domain within the SRS-22 or the SF-36 (r < 0.25). Comparison of similar domains in the SRS-22 and the SF-36 demonstrates high correlation between the instruments. Test-retest analysis similarly demonstrates a high degree of reproducibility in each domain (r = 0.83-0.94). Cronbach's alpha test of internal consistency within each domain demonstrates intercorrelation values greater than 0.75 within each domain of the SRS-22.Adult scoliosis has a significant and measurable impact on affected patients compared with controls. There is a poor correlation between radiographic parameters of outcome and patient self-assessment of health status. The SRS-22 is a reliable instrument in adults as demonstrated by a high degree of internal consistency and reproducibility. The SRS-22 is a valid instrument for use in adult deformity as demonstrated by the criterion validity assessment with the SF-36. The study supports the use of the SRS-22 in the adult spinal deformity population.

    View details for DOI 10.1097/01.BRS.0000084666.53553.D6

    View details for PubMedID 14501930

  • Biomechanically derived guideline equations for burst fracture risk prediction in the metastatically involved spine. Journal of spinal disorders & techniques Whyne, C. M., Hu, S. S., Lotz, J. C. 2003; 16 (2): 180–85

    Abstract

    Methods to quantify burst fracture risk and neurologic deficit for patients with spinal metastases have not been well defined. This study aims to develop objective biomechanically based guidelines to quantify metastatic burst fracture risk. An experimentally validated finite element model of a human lumbar motion segment was used to simulate burst fracture. Through parametric analysis, the behavior of metastatically involved vertebrae was quantified and a formula to relate patient-specific variables to burst fracture risk defined. The equation-based guidelines were able to describe the mechanical behavior of the metastatically involved vertebral model (R2 = 0.97) reflecting the risk and mechanism of fracture. Vertebral density was found to influence the mechanism of burst fracture with respect to endplate failure. These analyses provide clinically feasible equation-based guidelines for burst fracture risk assessment in the metastatically involved spine.

    View details for DOI 10.1097/00024720-200304000-00010

    View details for PubMedID 12679673

  • Management of fixed sagittal plane deformity: outcome of combined anterior and posterior surgery. Spine Berven, S. H., Deviren, V., Smith, J. A., Hu, S. H., Bradford, D. S. 2003; 28 (15): 1710–15; discussion 1716

    Abstract

    Retrospective study of consecutive patient series.To review the radiographic and clinical results of patients with preoperative fixed sagittal imbalance treated with combined anterior and posterior arthrodesis, and to determine factors that predict clinical outcome.Combined anterior and posterior arthrodesis of the spine is useful in the management of fixed deformity involving the coronal and sagittal planes. The specific indications for combined surgery in the patient with regional and global imbalance have not been well defined.Retrospective review of 25 consecutive patients treated with combined anterior and posterior spinal arthrodesis. Inclusion criteria included a preoperative global sagittal imbalance of at least 5 cm. Outcome variables included radiographic measures of preoperative, postoperative, and follow-up films, and a clinical assessment using the Modified SRS Outcomes Instrument and a review of postoperative complications.Twenty-five consecutive cases were reviewed. Mean age was 58 years (range 38-77), and mean follow-up was 55 months (range 24-81) for clinical and 44.5 (range 24-81) months for radiographic outcome variables. The mean preoperative sagittal imbalance was 10.5 cm (range 5.2-23.3), which improved to 2.9 cm (range 0-12.6) after surgery, and was maintained as 3.3 cm (range 0-13.5) at follow-up. Mean lumbar lordosis was -23 degrees (range +40 to -47) before surgery, and increased to -42 degrees at follow-up (range -20 degrees to -60 degrees ), an increase of 19 degrees. Patients with preoperative regional hypolordosis in the lumbar spine that was corrected surgically had the highest postoperative scores. The mean score for patient satisfaction with surgical management was 4.45 (range 2.5-5). Correlation analysis of clinical outcome domains demonstrated that patient satisfaction correlated poorly with domains of pain (r = 0.37, P = 0.1) and function (r = 0.4, P = 0.09). Within the domains, self-image showed highest correlation with patient satisfaction (r = 0.65, P = 0.006) and total score (r = 0.89, P = 0.0001).Patients with global sagittal imbalance of the spine were effectively treated with a combined anterior and posterior arthrodesis as measured by radiographic parameters. Patient satisfaction with surgery, and overall clinical outcomes were best in cases that resulted in an increase in lumbar lordosis. The subset of patients with preoperative regional hypolordosis of the lumbar spine has better outcomes than those with preoperative lumbar lordosis in the physiologic range.

    View details for DOI 10.1097/01.BRS.0000083181.25260.D6

    View details for PubMedID 12897497

  • The lumbar zygapophyseal (facet) joints: a role in the pathogenesis of spinal pain syndromes and degenerative spondylolisthesis. Seminars in neurology Berven, S., Tay, B. B., Colman, W., Hu, S. S. 2002; 22 (2): 187–96

    Abstract

    The zygapophyseal joints in the lumbar spine are important structural components contributing to the stability of the lumbar motion segments. Pathology of the zygapophyseal joints in the lumbar spine may be a significant cause of low back pain and segmental instability within the lumbar spine. Management of pathology related to the zygapophyseal joints remains a difficult challenge for the physician caring for patients with spinal disorders. Future investigations with tissue engineering, ligamentous reconstructions, and intervertebral disc replacement or regeneration may have useful applications in the treatment of zygapophyseal joint pathology.

    View details for DOI 10.1055/s-2002-36542

    View details for PubMedID 12524564

  • Use of allograft femoral rings for spinal deformity in adults. Clinical orthopaedics and related research Kleinstueck, F. S., Hu, S. S., Bradford, D. S. 2002: 84–91

    Abstract

    Anterior structural support plays an important role in spinal deformity surgery. Femoral ring allografts have been widely used for this purpose despite numerous alternative implants such as cages. The literature and the authors' experience support the use of femoral ring allograft as a structural and biologic compatible implant to reconstruct anterior column defects. Pseudarthrosis rates and the rate of subsidence and loss of correction are low. No long-term studies exist that show that cages are superior in correction of deformity. Femoral ring allograft remains a viable, cost-effective, and biologic sound alternative.

    View details for DOI 10.1097/00003086-200201000-00010

    View details for PubMedID 11795755

  • Predictors of flexibility and pain patterns in thoracolumbar and lumbar idiopathic scoliosis. Spine Deviren, V., Berven, S., Kleinstueck, F., Antinnes, J., Smith, J. A., Hu, S. S. 2002; 27 (21): 2346–49

    Abstract

    A retrospective evaluation of radiographs in patients with idiopathic scoliosis was undertaken to assess predictors of flexibility.To evaluate potential predictors of flexibility in patients with thoracolumbar and lumbar scoliosis.Curve flexibility is an important consideration in the operative management of idiopathic scoliosis. Flexibility of the major curve is a useful predictor of expected surgical correction, and flexibility of compensatory curves determines whether they are structural or nonstructural. An accurate assessment of curve flexibility has important implications on surgical approaches and planning for deformity correction. The role of age and curve magnitude in predicting curve flexibility has not been well defined. A quantitative assessment of changes in curve flexibility with age and progression of deformity may yield important insight into the change in surgical management options over time.A retrospective review of 75 patients with idiopathic thoracolumbar and lumbar scoliosis (age range 13-78 years) was undertaken. Preoperative standing and side-bending radiographs of thoracolumbar and lumbar curves were evaluated. Cobb angles of structural and fractional curves, curve flexibility, presence of lateral listhesis, and axial and radicular pain were documented. Predictors of structural and fractional curve flexibility were evaluated with correlation and regression analysis. Correlation analysis was used to demonstrate an association between radiographic findings and the clinical presentation.Seventy-five patients had an average major curve magnitude of 56 degrees (range 34-82 degrees ) with flexibility averaging 55% (range 20-93%). Structural curve flexibility was highly inversely correlated with both curve magnitude (r = -0.7; P< 0.001) and with age (r = -0.6; P< 0.001). Lumbar fractional curve (L4-S1) flexibility showed a high inverse correlation with age (r = -0.65; P< 0.001) but did not show correlation with Cobb angle. Thoracic compensatory curves showed a moderate correlation with Cobb angle (r = 0.53). Structural and fractional curve flexibility showed high correlation with each other (r = 0.5-0.66). Regression analysis yielded a formula to predict the flexibility of the structural curve (FSC): FSC = 130 - (Cobb + Age/2). Axial pain was correlated with age (r = 0.63); however, it was not correlated with curve magnitude.We have shown that curve magnitude and patient age are the main predictors of structural flexibility. Every 10 degrees increase in curve magnitude over 40 degrees results in a 10% decrease in flexibility; every 10-year increase in age decreases flexibility of the structural curve by 5% and the lumbosacral fractional curve by 10%. Curve magnitude and age of the patients are significant predictors of curve flexibility. The demonstration of this association offers useful information in estimating how surgical options for deformity correction may change over time.

    View details for DOI 10.1097/00007632-200211010-00007

    View details for PubMedID 12438982

  • Outcome and complications of long fusions to the sacrum in adult spine deformity: luque-galveston, combined iliac and sacral screws, and sacral fixation. Spine Emami, A., Deviren, V., Berven, S., Smith, J. A., Hu, S. S., Bradford, D. S. 2002; 27 (7): 776–86

    Abstract

    A retrospective study of adults with long fusion to the sacrum using three different fixations was performed.To compare the long-term clinical results and complications associated with three methods of lumbosacral fixation for adult spine deformities: Luque-Galveston, combined iliac and sacral screws, and sacral screws.The preferred technique for long fusion to the sacrum is controversial, and surgery for adult deformity is fraught with significant technical difficulties and high complication rates. No clinical study compares the long-term outcome of long fusion to the sacrum using these different methods of lumbosacral fixation.This study included 54 consecutive patients who underwent elective combined anterior and posterior surgical reconstruction for adult spine deformity with a minimum follow-up period of 2 years. The patients were divided into three groups on the basis of the surgical method used for the posterior spine instrumentation. Group 1 consisted of 11 patients with smooth L-rod and segmental sublaminar wire instrumentation (Luque-Galveston technique). Group 2 consisted of 36 patients with posterior Isola segmental instrumentation and combined iliac and sacral screws. Group 3 consisted of 12 patients with Isola segmental instrumentation using bicortical sacral screws. Five patients were revised to another fixation group, giving a total of 59 cases. Radiographic, clinical results, and long-term outcome data were obtained using the modified Scoliosis Research Society (SRS) outcome instrument.There were 26 late complications. Pseudarthrosis developed in 10 patients, requiring revision surgery: 4 (36%) in the Group 1, 5 (14%) in Group 2, and 1 (8.5%) in Group 3. Comparison of the modified SRS outcomes showed no difference among the groups. The average SRS grand total score was 73.4% for Group 1, 70.9% for Group 2, and 62.6% for Group 3. Overall, 76% of the patients were satisfied with their outcome. The presence of perioperative complications or pseudarthrosis significantly correlated with a lower satisfaction score (P = 0.012 and P = 0.048, respectively). Sagittal plane decompensation significantly correlated with a higher pain score (P = 0.035). Patients with prior surgeries scored lower on the self-image questions than patients with no prior surgery (P = 0.007).Attention to sagittal balance is critical in these patients. Revision surgery is as safe and effective as primary surgery. According to the current findings, the Luque-Galveston fixation technique has an unacceptably high rate of pseudarthrosis, and this method is not recommended for adult deformities. Currently, the authors are using bicortical and triangulated sacral screws with an anterior interbody support in patients with good bone stock, but only when the spine balance is restored. Otherwise, they recommend using iliac fixation, although there is a higher rate of painful hardware, requiring removal.

    View details for DOI 10.1097/00007632-200204010-00017

    View details for PubMedID 11923673

  • Advances in Spine Surgery. Surgical technology international Hu, S. S., Bradford, D. S. 1991; I: 401–5

    Abstract

    Technological advances in the field of spine surgery have most often involved instrumentation. In recent years, a great deal of attention has been focused on variable hookscrew-rod systems, the prototype of which is the Cotrel-Dubousset instrumentation (CDI). This French-designed system and similar ones such as the Texas-Scottish Rite (TSRH), or the Isola, provide significantly better fixation and rigidity than has ever been possible, and they allow many patients to be spared the discomfort and inconvenience of post-operative brace or cast support. These features are particularly important for older and chronically ill patients, whose often difficult problems can also be addressed more safely and effectively with this new technology.

    View details for PubMedID 28581625

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