Bio

Bio


Atman Desai, MD, is a Clinical Associate Professor of Neurosurgery at Stanford University Medical Center. Dr. Desai received his medical degree from the University of Cambridge. He completed his residency in Neurological Surgery at Dartmouth-Hitchcock Medical Center and a fellowship in Spinal Oncology and Complex Spinal Reconstruction at Johns Hopkins Hospital. He focuses on the surgical treatment of spinal tumors and spinal deformity. He performed the first robotic-assisted spine surgery at Stanford, and has particular interest in robotic and minimally invasive surgical treatments.

Clinical Focus


  • Robotic Spinal Surgery
  • Spinal Tumors
  • Minimally Invasive Surgery
  • Spinal Degenerative Disease
  • CyberKnife Radiosurgery
  • Neurosurgery

Academic Appointments


Administrative Appointments


  • Director of Neurosurgical Spine Oncology, Stanford University (2015 - Present)
  • Clinical Assistant Professor of Neurosurgery, Stanford University (2014 - Present)
  • Instructor of Neurosurgery, Johns Hopkins Hospital (2013 - 2014)

Honors & Awards


  • Alpha Omega Alpha, Dartmouth College
  • Henry Roy Dean Award, University of Cambridge
  • NREF Post-Residency Clinical Fellowship Award, Neurosurgery Research and Education Foundation

Boards, Advisory Committees, Professional Organizations


  • Member, Stanford Cancer Institute (2016 - Present)
  • Faculty, American Association of Neurological Surgeons Coding and Reimbursement (2015 - Present)
  • Member, Bio-X (2015 - Present)
  • Member, Population Health Sciences (2015 - Present)
  • Committee Member, American Association of Neurological Surgeons (2014 - Present)
  • Member, Congress of Neurological Surgeons (2006 - Present)
  • Member, AO Spine North America (2014 - Present)

Professional Education


  • Fellowship:Johns Hopkins Hospital (2014) MD
  • Residency:Dartmouth Hitchcock Medical Center (2013) NH
  • Internship:Dartmouth Hitchcock Medical Center (2007) NH
  • Medical Education:University of Cambridge School of Clinical Medicine (2005) England
  • MA, University of Cambridge (2006)
  • BA, University of Cambridge (2002)

Research & Scholarship

Current Research and Scholarly Interests


Our laboratory aims to analyze and solve healthcare problems relating to neurosurgical care and spine care on a population level. Through the development of algorithms that can be applied to various large national and state-level healthcare datasets, our goal is to harness big data to:

1. Understand how quality in neurosurgical care and spine care can be defined in both short and long-term measures

2. Develop appropriate measures of quality neurosurgical and spine care

3. Create benchmarks for care in neurosurgery and spine surgery

4. Create multivariate bio-statistical models of pre-operative, peri-operative and post-operative events and long term patient outcomes

5. Understand how existing paradigms in neurosurgical care and spine care can be potentially improved to improve patient outcomes

In addition to our population level research, our laboratory has been a national pioneer in integrating prospective outcomes driven medical informative and database systems into the electronic health record. This allows us to identify pre- and post-operative treatment measures that influence patient outcomes, and in doing so improve patient safety and maximize the efficacy of current treatments for neurosurgical and spine patients.

Publications

All Publications


  • Outpatient spine surgery: defining the outcomes, value, and barriers to implementation. Neurosurgical focus Pendharkar, A. V., Shahin, M. N., Ho, A. L., Sussman, E. S., Purger, D. A., Veeravagu, A., Ratliff, J. K., Desai, A. M. 2018; 44 (5): E11

    Abstract

    Spine surgery is a key target for cost reduction within the United States health care system. One possible strategy involves the transition of inpatient surgeries to the ambulatory setting. Lumbar laminectomy with or without discectomy, lumbar fusion, anterior cervical discectomy and fusion, and cervical disc arthroplasty all represent promising candidates for outpatient surgeries in select populations. In this focused review, the authors clarify the different definitions used in studies describing outpatient spine surgery. They also discuss the body of evidence supporting each of these procedures and summarize the proposed cost savings. Finally, they examine several patient- and surgeon-specific considerations to highlight the barriers in translating outpatient spine surgery into actual practice.

    View details for DOI 10.3171/2018.2.FOCUS17790

    View details for PubMedID 29712520

  • Propensity-matched comparison of outcomes and cost after macroscopic and microscopic lumbar discectomy using a national longitudinal database. Neurosurgical focus Pendharkar, A. V., Rezaii, P. G., Ho, A. L., Sussman, E. S., Purger, D. A., Veeravagu, A., Ratliff, J. K., Desai, A. M. 2018; 44 (5): E12

    Abstract

    OBJECTIVE There has been considerable debate about the utility of the operating microscope in lumbar discectomy and its effect on outcomes and cost. METHODS A commercially available longitudinal database was used to identify patients undergoing discectomy with or without use of a microscope between 2007 and 2015. Propensity matching was performed to normalize differences between demographics and comorbidities in the 2 cohorts. Outcomes, complications, and cost were subsequently analyzed using bivariate analysis. RESULTS A total of 42,025 patients were identified for the "macroscopic" group, while 11,172 patients were identified for the "microscopic" group. For the propensity-matched analysis, the 11,172 patients in the microscopic discectomy group were compared with a group of 22,340 matched patients who underwent macroscopic discectomy. There were no significant differences in postoperative complications between the groups other than a higher proportion of deep vein thrombosis (DVT) in the macroscopic discectomy cohort versus the microscopic discectomy group (0.4% vs 0.2%, matched OR 0.48 [95% CI 0.26-0.82], p = 0.0045). Length of stay was significantly longer in the macroscopic group compared to the microscopic group (mean 2.13 vs 1.83 days, p < 0.0001). Macroscopic discectomy patients had a higher rate of revision surgery when compared to microscopic discectomy patients (OR 0.92 [95% CI 0.84-1.00], p = 0.0366). Hospital charges were higher in the macroscopic discectomy group (mean $19,490 vs $14,921, p < 0.0001). CONCLUSIONS The present study suggests that the use of the operating microscope in lumbar discectomy is associated with decreased length of stay, lower DVT rate, lower reoperation rate, and decreased overall hospital costs.

    View details for DOI 10.3171/2018.1.FOCUS17791

    View details for PubMedID 29712527

  • Preoperative depression, lumbar fusion, and opioid use: an assessment of postoperative prescription, quality, and economic outcomes. Neurosurgical focus O'Connell, C., Azad, T. D., Mittal, V., Vail, D., Johnson, E., Desai, A., Sun, E., Ratliff, J. K., Veeravagu, A. 2018; 44 (1): E5

    Abstract

    OBJECTIVE Preoperative depression has been linked to a variety of adverse outcomes following lumbar fusion, including increased pain, disability, and 30-day readmission rates. The goal of the present study was to determine whether preoperative depression is associated with increased narcotic use following lumbar fusion. Moreover, the authors examined the association between preoperative depression and a variety of secondary quality indicator and economic outcomes, including complications, 30-day readmissions, revision surgeries, likelihood of discharge home, and 1- and 2-year costs. METHODS A retrospective analysis was conducted using a national longitudinal administrative database (MarketScan) containing diagnostic and reimbursement data on patients with a variety of private insurance providers and Medicare for the period from 2007 to 2014. Multivariable logistic and negative binomial regressions were performed to assess the relationship between preoperative depression and the primary postoperative opioid use outcomes while controlling for demographic, comorbidity, and preoperative prescription drug-use variables. Logistic and log-linear regressions were also used to evaluate the association between depression and the secondary outcomes of complications, 30-day readmissions, revisions, likelihood of discharge home, and 1- and 2-year costs. RESULTS The authors identified 60,597 patients who had undergone lumbar fusion and met the study inclusion criteria, 4985 of whom also had a preoperative diagnosis of depression and 21,905 of whom had a diagnosis of spondylolisthesis at the time of surgery. A preoperative depression diagnosis was associated with increased cumulative opioid use (β = 0.25, p < 0.001), an increased risk of chronic use (OR 1.28, 95% CI 1.17-1.40), and a decreased probability of opioid cessation (OR 0.96, 95% CI 0.95-0.98) following lumbar fusion. In terms of secondary outcomes, preoperative depression was also associated with a slightly increased risk of complications (OR 1.14, 95% CI 1.03-1.25), revision fusions (OR 1.15, 95% CI 1.05-1.26), and 30-day readmissions (OR 1.19, 95% CI 1.04-1.36), although it was not significantly associated with the probability of discharge to home (OR 0.92, 95% CI 0.84-1.01). Preoperative depression also resulted in increased costs at 1 (β = 0.06, p < 0.001) and 2 (β = 0.09, p < 0.001) years postoperatively. CONCLUSIONS Although these findings must be interpreted in the context of the limitations inherent to retrospective studies utilizing administrative data, they provide additional evidence for the link between a preoperative diagnosis of depression and adverse outcomes, particularly increased opioid use, following lumbar fusion.

    View details for DOI 10.3171/2017.10.FOCUS17563

    View details for PubMedID 29290135

  • Efficacy and safety of corpus callosotomy after vagal nerve stimulation in patients with drug-resistant epilepsy JOURNAL OF NEUROSURGERY Hong, J., Desai, A., Thadani, V. M., Roberts, D. W. 2018; 128 (1): 277–86

    Abstract

    OBJECTIVE Vagal nerve stimulation (VNS) and corpus callosotomy (CC) have both been shown to be of benefit in the treatment of medically refractory epilepsy. Recent case series have reviewed the efficacy of VNS in patients who have undergone CC, with encouraging results. There are few data, however, on the use of CC following VNS therapy. METHODS The records of all patients at the authors' center who underwent CC following VNS between 1998 and 2015 were reviewed. Patient baseline characteristics, operative details, and postoperative outcomes were analyzed. RESULTS Ten patients met inclusion criteria. The median follow-up was 72 months, with a minimum follow-up of 12 months (range 12-109 months). The mean time between VNS and CC was 53.7 months. The most common reason for CC was progression of seizures after VNS. Seven patients had anterior CC, and 3 patients returned to the operating room for a completion of the procedure. All patients had a decrease in the rate of falls and drop seizures; 7 patients experienced elimination of drop seizures. Nine patients had an Engel Class III outcome, and 1 patient had a Class IV outcome. There were 3 immediate postoperative complications and 1 delayed complication. One patient developed pneumonia, 1 developed transient mutism, and 1 had persistent weakness in the nondominant foot. One patient presented with a wound infection. CONCLUSIONS The authors demonstrate that CC can help reduce seizures in patients with medically refractory epilepsy following VNS, particularly with respect to drop attacks.

    View details for DOI 10.3171/2016.10.JNS161841

    View details for Web of Science ID 000418939300034

    View details for PubMedID 28298036

  • Impact of Inpatient Venous Thromboembolism Continues After Discharge: Retrospective Propensity Scored Analysis in a Longitudinal Database CLINICAL SPINE SURGERY Li, A. Y., Azad, T. D., Veeravagu, A., Bhatti, I., Li, A., Cole, T., Desai, A., Ratliff, J. K. 2017; 30 (10): E1392–E1398
  • Outpatient vs Inpatient Anterior Cervical Discectomy and Fusion: A Population-Level Analysis of Outcomes and Cost. Neurosurgery Purger, D. A., Pendharkar, A. V., Ho, A. L., Sussman, E. S., Yang, L., Desai, M., Veeravagu, A., Ratliff, J. K., Desai, A. 2017

    Abstract

    Outpatient anterior cervical discectomy and fusion (ACDF) is a promising candidate for US healthcare cost reduction as several studies have demonstrated that overall complications are relatively low and early discharge can preserve high patient satisfaction, low morbidity, and minimal readmission.To compare clinical outcomes and associated costs between inpatient and ambulatory setting ACDF.Demographics, comorbidities, emergency department (ED) visits, readmissions, reoperation rates, and 90-d charges were retrospectively analyzed for patients undergoing elective ACDF in California, Florida, and New York from 2009 to 2011 in State Inpatient and Ambulatory Databases.A total of 3135 ambulatory and 46 996 inpatient ACDFs were performed. Mean Charlson comorbidity index, length of stay, and mortality were 0.2, 0.4 d, and 0% in the ambulatory cohort and 0.4, 1.8 d, and 0.04% for inpatients ( P < .0001). Ambulatory patients were younger (48.0 vs 53.1) and more likely to be Caucasian. One hundred sixty-eight ambulatory patients (5.4%) presented to the ED within 30 d (mean 11.3 d), 51 (1.6%) were readmitted, and 5 (0.2%) underwent reoperation. Among inpatient surgeries, 2607 patients (5.5%) presented to the ED within 30 d (mean 9.7 d), 1778 (3.8%) were readmitted (mean 6.3 d), and 200 (0.4%) underwent reoperation. Higher Charlson comorbidity index increased rate of ED visits (ambulatory operating room [OR] 1.285, P < .05; inpatient OR 1.289, P < .0001) and readmission (ambulatory OR 1.746, P < .0001; inpatient OR 1.685, P < .0001). Overall charges were significantly lower for ambulatory ACDFs ($33 362.51 vs $74 667.04; P < .0001).ACDF can be performed in an ambulatory setting with comparable morbidity and readmission rates, and lower costs, to those performed in an inpatient setting.

    View details for DOI 10.1093/neuros/nyx215

    View details for PubMedID 28498922

  • 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

  • The effect of socioeconomic status on gross total resection, radiation therapy and overall survival in patients with gliomas. Journal of neuro-oncology Deb, S., Pendharkar, A. V., Schoen, M. K., Altekruse, S., Ratliff, J., Desai, A. 2017

    Abstract

    Socioeconomic status (SES) is associated with survival in many cancers but the effect of socioeconomic status on survival and access to care for patients with gliomas has not been well studied. This study included 50,170 patients from the Surveillance, Epidemiology, and End Results Program at the National Cancer Institute database diagnosed with gliomas of the brain from 2003 to 2012. Patient SES was divided into tertiles and quintiles. Treatment options included radiation, surgery (gross total resection (GTR)/other surgery), and radiation with surgery. Multivariable logistic regression and Cox proportional hazards model were used to analyze data with SAS v9.4. The results were adjusted for age at diagnosis, race, sex, tumor type, and tumor grade. Kaplan-Meier survival curves were constructed according to SES tertiles and quintiles. Patients from a higher SES tertile were significantly more likely to receive surgery, radiation, GTR, and radiation with surgery (OR 1.092, 1.116, 1.103, 1.150 respectively, all p < 0.0001). This correlation was also true when patients were divided into quintiles (OR 1.054, 1.072, 1.062, 1.089 respectively, all p < 0.0001). Furthermore, the lowest SES tertiles (HR 1.258, 1.146) and the lowest SES quintiles (HR 1.301, 1.273, 1.194, 1.119) were associated with significantly shorter survival times (all p for trend <0.0001). Surgery, radiation therapy, surgery with radiation therapy, and GTR were also found to be associated with improved overall survival in glioma patients (HR 0.553, 0.849, 0.666, 0.491 respectively, all p < 0.0001). The findings from this national study suggest an effect of SES on access to treatment, and survival in patients with gliomas.

    View details for DOI 10.1007/s11060-017-2391-2

    View details for PubMedID 28258423

  • Cervical Osteochondroma Causing Myelopathy in Adults: Management Considerations and Literature Review WORLD NEUROSURGERY Veeravagu, A., Li, A., Shuer, L. M., Desai, A. M. 2017; 97

    Abstract

    Osteochondromas are the most frequent benign bone tumors but only rarely occur along the spinal column and even more rarely induce symptoms from spinal cord compression.We report 2 adult patients, both with a history of hereditary multiple exostoses, who presented with cervical myelopathy secondary to osteochondromas. The first patient is a 22-year-old man with numbness and weakness of his right upper limb and neck pain. Radiologic images showed a bony tumor arising from the C3 lamina with evidence of severe spinal cord compression. The second patient is a 20-year-old woman with weakness of her left upper and lower limbs and progressive numbness of the left hand, as well as neck and back pain. Radiologic images showed a bony tumor arising from the C4 lamina with evidence of significant spinal cord compression and cord signal abnormality. Both patients underwent surgical excision of the epidural mass and pathology confirmed a diagnosis of osteochondroma.We discuss the role of surgical intervention, management, and postoperative follow-up in adult patients with cervical osteochondromas. Recommended management includes radiographic imaging and surgical intervention, particularly when evidence of spinal cord impingement occurs. Consistent postoperative follow-up is necessary to ensure appropriate recovery of neurologic function. Surgical management of cervical osteochondromas typically results in excellent and stable clinical outcomes with rare recurrence.

    View details for DOI 10.1016/j.wneu.2016.10.061

    View details for Web of Science ID 000396449400122

  • Cervical Osteochondroma Causing Myelopathy in Adults: Management Considerations and Literature Review. World neurosurgery Veeravagu, A., Li, A., Shuer, L. M., Desai, A. M. 2016

    Abstract

    Osteochondromas are the most frequent benign bone tumors but only rarely occur along the spinal column and even more rarely induce symptoms from spinal cord compression.We report 2 adult patients, both with a history of hereditary multiple exostoses, who presented with cervical myelopathy secondary to osteochondromas. The first patient is a 22-year-old man with numbness and weakness of his right upper limb and neck pain. Radiologic images showed a bony tumor arising from the C3 lamina with evidence of severe spinal cord compression. The second patient is a 20-year-old woman with weakness of her left upper and lower limbs and progressive numbness of the left hand, as well as neck and back pain. Radiologic images showed a bony tumor arising from the C4 lamina with evidence of significant spinal cord compression and cord signal abnormality. Both patients underwent surgical excision of the epidural mass and pathology confirmed a diagnosis of osteochondroma.We discuss the role of surgical intervention, management, and postoperative follow-up in adult patients with cervical osteochondromas. Recommended management includes radiographic imaging and surgical intervention, particularly when evidence of spinal cord impingement occurs. Consistent postoperative follow-up is necessary to ensure appropriate recovery of neurologic function. Surgical management of cervical osteochondromas typically results in excellent and stable clinical outcomes with rare recurrence.

    View details for DOI 10.1016/j.wneu.2016.10.061

    View details for PubMedID 27777159

  • Impact of Inpatient Venous Thromboembolism Continues After Discharge: Retrospective Propensity Scored Analysis in a Longitudinal Database. Clinical spine surgery Li, A. Y., Azad, T. D., Veeravagu, A., Bhatti, I., Li, A., Cole, T., Desai, A., Ratliff, J. K. 2016: -?

    Abstract

    Propensity score matched retrospective study using a nationwide longitudinal database.To quantify the longitudinal economic impact of venous thromboembolism (VTE) complications in spinal fusion patients.VTE is a rare and serious complication that may occur after spine surgery. The long-term socioeconomic impact understanding of these events has been limited by small sample sizes and a lack of longitudinal follow-up. We provide a comparative economic outcomes analysis of these complications.We identified 204,308 patients undergoing spinal fusion procedures in a national billing claims database (MarketScan) between 2006 and 2010. Cohorts were balanced using 50:1 propensity score matching and outcome measures compared at 6, 12, and 18 months postoperation.A total of 1196 (0.6%) patients developed postoperative VTE, predominantly occurring following lumbar fusion (69.7%). Postoperative VTE patients demonstrated an increase in hospital length of stay (7.8 vs. 3.3 d, P<0.001) and a decreased likelihood of being discharged home (71% vs. 85%, P<0.001). A $26,306 increase in total hospital payments (P<0.001) was observed, with a disproportionate increase seen in hospital payments ($22,103, P<0.001), relative to physician payments ($1766, P=0.001).At 6, 12, and 18 months postfusion, increased rates of readmission and follow-up clinic visits were observed. Delayed readmissions were associated with decreased length of stay (3.6 vs. 4.6 d, P<0.001), but increased total payments, averaging at $21,270 per readmission. VTE patients generated greater cumulative outpatient service payments, costing $8075, $11,134, and $13,202 more at 6, 12, and 18 months (P<0.001).VTEs are associated with longer hospitalizations, a decreased likelihood of being discharged home, and overall increases of hospital resource utilization and cost in inpatient and outpatient settings. VTE patients generate greater charges in the outpatient setting and are more likely to become readmitted at 6, 12, and 18 months after surgery, demonstrating a significant socioeconomic impact long after occurrence.Level III-therapeutic.

    View details for PubMedID 27750270

  • Surgical outcomes of cervical spondylotic myelopathy: an analysis of a national, administrative, longitudinal database. Neurosurgical focus Veeravagu, A., Connolly, I. D., Lamsam, L., Li, A., Swinney, C., Azad, T. D., Desai, A., Ratliff, J. K. 2016; 40 (6): E11-?

    Abstract

    OBJECTIVE The authors performed a population-based analysis of national trends, costs, and outcomes associated with cervical spondylotic myelopathy (CSM) in the United States. They assessed postoperative complications, resource utilization, and predictors of costs, in this surgically treated CSM population. METHODS MarketScan data (2006-2010) were used to retrospectively analyze the complications and costs of different spine surgeries for CSM. The authors determined outcomes following anterior cervical discectomy and fusion (ACDF), posterior fusion, combined anterior/posterior fusion, and laminoplasty procedures. RESULTS The authors identified 35,962 CSM patients, comprising 5154 elderly (age ≥ 65 years) patients (mean 72.2 years, 54.9% male) and 30,808 nonelderly patients (mean 51.1 years, 49.3% male). They found an overall complication rate of 15.6% after ACDF, 29.2% after posterior fusion, 41.1% after combined anterior and posterior fusion, and 22.4% after laminoplasty. Following ACDF and posterior fusion, a significantly higher risk of complication was seen in the elderly compared with the nonelderly (reference group). The fusion level and comorbidity-adjusted ORs with 95% CIs for these groups were 1.54 (1.40-1.68) and 1.25 (1.06-1.46), respectively. In contrast, the elderly population had lower 30-day readmission rates in all 4 surgical cohorts (ACDF, 2.6%; posterior fusion, 5.3%; anterior/posterior fusion, 3.4%; and laminoplasty, 3.6%). The fusion level and comorbidity-adjusted odds ratios for 30-day readmissions for ACDF, posterior fusion, combined anterior and posterior fusion, and laminoplasty were 0.54 (0.44-0.68), 0.32 (0.24-0.44), 0.17 (0.08-0.38), and 0.39 (0.18-0.85), respectively. CONCLUSIONS The authors' analysis of the MarketScan database suggests a higher complication rate in the surgical treatment of CSM than previous national estimates. They found that elderly age (≥ 65 years) significantly increased complication risk following ACDF and posterior fusion. Elderly patients were less likely to experience a readmission within 30 days of surgery. Postoperative complication occurrence, and 30-day readmission were significant drivers of total cost within 90 days of the index surgical procedure.

    View details for DOI 10.3171/2016.3.FOCUS1669

    View details for PubMedID 27246481

  • Cervical Fusion for Absent Pedicle Syndrome Manifesting with Myelopathy WORLD NEUROSURGERY Goodwin, C. R., Desai, A., Khattab, M. H., Elder, B. D., Bydon, A., Wolinsky, J. 2016; 86

    Abstract

    Absent congenital pedicle syndrome is a posterior arch defect characterized by a host of congenital and mechanical abnormalities that result from disconnection of the anterior and posterior columns of the spinal canal. Absent congenital pedicle syndrome is a rare anomaly that is most commonly diagnosed either incidentally, after evaluation of minor trauma, or after complaints of chronic neck pain. To report a case of absent congenital pedicle syndrome who presented with myelopathy and lower extremity weakness and review the literature on the surgical management of this entity.A 32 year old female with a history of systemic lupus erythematous presented to the Neurosurgery Service with progressive weakness in her upper and lower extremities, clonus and hyperreflexia. MRI revealed congenital absence of the pedicles of C2, C3, C4, C5, and C6 with congenitally narrow canal at C4-5. The patient underwent a staged anterior and posterior cervical decompression and fusion. Postoperatively, she was placed in a halo and at one year follow up she was ambulatory with demonstrated improvement in her weakness and fusion of her cervical spine.Absent congenital pedicle syndrome is rare with the majority of reported cases treated conservatively. Surgical management is a treatment option reserved for patients with myelopathy or instability.

    View details for DOI 10.1016/j.wneu.2015.09.017

    View details for Web of Science ID 000369625300105

    View details for PubMedID 26386456

  • Epidural spinal involvement of Erdheim-Chester disease causing myelopathy JOURNAL OF CLINICAL NEUROSCIENCE Hwang, B. Y., Liu, A., Kern, J., Goodwin, C. R., Wolinsky, J. P., Desai, A. 2015; 22 (9): 1532-1536

    Abstract

    We present a 25-year-old woman with Erdheim-Chester disease (ECD) presenting with progressive myelopathy from multiple compressive spinal epidural lesions who required cervicothoracic decompression and fusion, and summarize the literature on epidural spinal involvement of ECD. ECD is a rare non-Langerhans histiocytosis affecting multiple organ systems through infiltration and characteristically causing multifocal osteosclerosis. Central nervous system involvement, particularly of the spine, is rare.

    View details for DOI 10.1016/j.jocn.2015.04.004

    View details for Web of Science ID 000359167600037

    View details for PubMedID 26119978

  • Anterior Versus Posterior Approach for Multilevel Degenerative Cervical Disease: A Retrospective Propensity Score-Matched Study of the MarketScan Database. Spine Cole, T., Veeravagu, A., Zhang, M., Azad, T. D., Desai, A., Ratliff, J. K. 2015; 40 (13): 1033-1038

    Abstract

    Retrospective 2:1 propensity score-matched analysis on a national longitudinal database between 2006 and 2010.To compare rates of adverse events, revisions procedure rates, and payment differences in anterior cervical fusion procedures compared with posterior laminectomy and fusion procedures with at least 3 levels of instrumentation.The comparative benefits of anterior versus posterior approach to multilevel degenerative cervical disease remain controversial. Recent systematic reviews have reached conflicting conclusions. We demonstrate the comparative economic and clinical outcomes of anterior and posterior approaches for multilevel cervical degenerative disk disease.We identified 13,662 patients in a national billing claims database who underwent anterior or posterior cervical fusion procedures with 3 or more levels of instrumentation. Cohorts were balanced using 2:1 propensity score matching and outcomes were compared using bivariate analysis.With the exception of dysphagia (6.4% in anterior and 1.4% in posterior), overall 30-day complication rates were lower in the anterior approach group. The rate of any complication excluding dysphagia with anterior approaches was 12.3%, significantly lower (P < 0.0001) than that of posterior approaches, 17.8%. Anterior approaches resulted in lower hospital ($18,346 vs. $23,638) and total payments ($28,963 vs. $33,526). Patients receiving an anterior surgical approach demonstrated significantly lower rate of 30-day readmission (5.1% vs. 9.9%, P < 0.0001), were less likely to require revision surgery (12.8% vs. 18.1%, P < 0.0001), and had a shorter length of stay by 1.5 nights (P < 0.0001).Anterior approaches in the surgical management of multilevel degenerative cervical disease provide clinical advantages over posterior approaches, including lower overall complication rates, revision procedure rates, and decreased length of stay. Anterior approach procedures are also associated with decreased overall payments. These findings must be interpreted in light of limitations inherent to retrospective longitudinal studies including absence of subjective and radiographical outcomes.3.

    View details for DOI 10.1097/BRS.0000000000000872

    View details for PubMedID 25768690

  • Anterior Versus Posterior Approach for Multilevel Degenerative Cervical Disease A Retrospective Propensity Score-Matched Study of the MarketScan Database SPINE Cole, T., Veeravagu, A., Zhang, M., Azad, T. D., Desai, A., Ratliff, J. K. 2015; 40 (13): 1033-1038

    Abstract

    Retrospective 2:1 propensity score-matched analysis on a national longitudinal database between 2006 and 2010.To compare rates of adverse events, revisions procedure rates, and payment differences in anterior cervical fusion procedures compared with posterior laminectomy and fusion procedures with at least 3 levels of instrumentation.The comparative benefits of anterior versus posterior approach to multilevel degenerative cervical disease remain controversial. Recent systematic reviews have reached conflicting conclusions. We demonstrate the comparative economic and clinical outcomes of anterior and posterior approaches for multilevel cervical degenerative disk disease.We identified 13,662 patients in a national billing claims database who underwent anterior or posterior cervical fusion procedures with 3 or more levels of instrumentation. Cohorts were balanced using 2:1 propensity score matching and outcomes were compared using bivariate analysis.With the exception of dysphagia (6.4% in anterior and 1.4% in posterior), overall 30-day complication rates were lower in the anterior approach group. The rate of any complication excluding dysphagia with anterior approaches was 12.3%, significantly lower (P < 0.0001) than that of posterior approaches, 17.8%. Anterior approaches resulted in lower hospital ($18,346 vs. $23,638) and total payments ($28,963 vs. $33,526). Patients receiving an anterior surgical approach demonstrated significantly lower rate of 30-day readmission (5.1% vs. 9.9%, P < 0.0001), were less likely to require revision surgery (12.8% vs. 18.1%, P < 0.0001), and had a shorter length of stay by 1.5 nights (P < 0.0001).Anterior approaches in the surgical management of multilevel degenerative cervical disease provide clinical advantages over posterior approaches, including lower overall complication rates, revision procedure rates, and decreased length of stay. Anterior approach procedures are also associated with decreased overall payments. These findings must be interpreted in light of limitations inherent to retrospective longitudinal studies including absence of subjective and radiographical outcomes.3.

    View details for DOI 10.1097/BRS.0000000000000872

    View details for Web of Science ID 000357946000009

  • SPORT: Does Incidental Durotomy Affect Longterm Outcomes in Cases of Spinal Stenosis? Neurosurgery Desai, A., Ball, P. A., Bekelis, K., Lurie, J., Mirza, S. K., Tosteson, T. D., Weinstein, J. N. 2015; 76: S57-63

    Abstract

    Incidental durotomy is a familiar encounter during surgery for lumbar spinal stenosis. The impact of durotomy on long-term outcomes remains a matter of debate.To determine the impact of durotomy on the long-term outcomes of patients in the Spine Patient Outcomes Research Trial (SPORT).The SPORT cohort participants with a confirmed diagnosis of spinal stenosis, without associated spondylolisthesis, undergoing standard, first-time, open decompressive laminectomy, with or without fusion, were followed up from baseline at 6 weeks, and 3, 6, and 12 months and yearly thereafter at 13 spine clinics in 11 US states. Patient data from this prospectively gathered database were reviewed. As of May 2009, the mean follow-up among all analyzed patients was 43.8 months.Four hundred nine patients underwent first-time open laminectomy with or without fusion. Thirty-seven of these patients (9%) had an incidental durotomy. No significant differences were observed with or without durotomy in age; sex; race; body mass index; the prevalence of smoking, diabetes mellitus, and hypertension; decompression level; number of levels decompressed; or whether an additional fusion was performed. The durotomy group had significantly increased operative duration, operative blood loss, and inpatient stay. There were, however, no differences in incidence of nerve root injury, mortality, additional surgeries, or primary outcomes (Short Form-36 Bodily Pain or Physical Function scores or Oswestry Disability Index) at yearly follow-ups to 4 years.Incidental durotomy during first-time lumbar laminectomy for spinal stenosis did not impact long-term outcomes in affected patients.SBI, Stenosis Bothersomeness Index; SF-36, Short Form-36; SPORT, Spine Patient Outcomes Research Trial.

    View details for DOI 10.1227/01.neu.0000462078.58454.f4

    View details for PubMedID 25692369

  • Surgical Management of Sacral Chordomas: Illustrative Cases and Current Management Paradigms. Cure¯us Pendharkar, A. V., Ho, A. L., Sussman, E. S., Desai, A. 2015; 7 (8)

    Abstract

    Sacral chordomas represent more than 50% of all sacral tumors. These slow-growing, malignant lesions present insidiously and are often large and intimately involved with sacral neurovascular and pelvic structures. En bloc resection is the only well-established predictor of progression-free survival. Optimal surgical management requires a complex multi-disciplinary approach. Here, we describe two cases of sacral chordoma and review current management paradigms.

    View details for DOI 10.7759/cureus.301

    View details for PubMedID 26430575

  • Utility of Routine Outpatient Cervical Spine Imaging Following Anterior Cervical Corpectomy and Fusion. Cure¯us Desai, A., Pendharkar, A. V., Swienckowski, J. G., Ball, P. A., Lollis, S., Simmons, N. E. 2015; 7 (11)

    Abstract

    Construct failure is an uncommon but well-recognized complication following anterior cervical corpectomy and fusion (ACCF). In order to screen for these complications, many centers routinely image patients at outpatient visits following surgery. There remains, however, little data on the utility of such imaging.The electronic medical record of all patients undergoing anterior cervical corpectomy and fusion at Dartmouth-Hitchcock Medical Center between 2004 and 2009 were reviewed. All patients had routine cervical spine radiographs performed perioperatively. Follow-up visits up to two years postoperatively were analyzed. Sixty-five patients (mean age 52.2) underwent surgery during the time period. Eighteen patients were female. Forty patients had surgery performed for spondylosis, 20 for trauma, three for tumor, and two for infection. Forty-three patients underwent one-level corpectomy, 20 underwent two-level corpectomy, and two underwent three-level corpectomy, using an allograft, autograft, or both. Sixty-two of the fusions were instrumented using a plate and 13 had posterior augmentation. Fifty-seven patients had follow-up with imaging at four to 12 weeks following surgery, 54 with plain radiographs, two with CT scans, and one with an MRI scan. Unexpected findings were noted in six cases. One of those patients, found to have asymptomatic recurrent kyphosis following a two-level corpectomy, had repeat surgery because of those findings. Only one further patient was found to have abnormal imaging up to two years, and this patient required no further intervention.Routine imaging after ACCF can demonstrate asymptomatic occurrences of clinically significant instrument failure. In 43 consecutive single-level ACCF however, routine imaging did not change management, even when an abnormality was discovered. This may suggest a limited role for routine imaging after ACCF in longer constructs involving multiple levels.

    View details for DOI 10.7759/cureus.387

    View details for PubMedID 26719830

    View details for PubMedCentralID PMC4689583

  • Utility of Provocative Discography WORLD NEUROSURGERY Gokaslan, Z. L., Desai, A. 2014; 82 (5): 638-639

    View details for DOI 10.1016/j.wneu.2014.02.013

    View details for Web of Science ID 000347252300058

    View details for PubMedID 24534063

  • Outpatient follow-up of nonoperative cerebral contusion and traumatic subarachnoid hemorrhage: does repeat head CT alter clinical decision-making? JOURNAL OF NEUROSURGERY Rubino, S., Zaman, R. A., Sturge, C. R., Fried, J. G., Desai, A., Simmons, N. E., Lollis, S. S. 2014; 121 (4): 944-949

    Abstract

    Many neurosurgeons obtain repeat head CT at the first clinic follow-up visit for nonoperative cerebral contusion and traumatic subarachnoid hemorrhage (tSAH). The authors undertook a single-center, retrospective study to determine whether outpatient CT altered clinical decision-making.The authors evaluated 173 consecutive adult patients admitted to their institution from April 2006 to August 2012 with an admission diagnosis of cerebral contusion or tSAH and at least 1 clinic follow-up visit with CT. Patients with epidural, subdural, aneurysmal subarachnoid, or intraventricular hemorrhage, and those who underwent craniotomy, were excluded. Patient charts were reviewed for new CT findings, new patient symptoms, and changes in treatment plan. Patients were stratified by neurological symptoms into 3 groups: 1) asymptomatic; 2) mild, nonspecific symptoms; and 3) significant symptoms. Mild, nonspecific symptoms included minor headaches, vertigo, fatigue, and mild difficulties with concentration, short-term memory, or sleep; significant symptoms included moderate to severe headaches, nausea, vomiting, focal neurological complaints, impaired consciousness, or new cognitive impairment evident on routine clinical examination.One hundred seventy-three patients met inclusion criteria, with initial clinic follow-up obtained within approximately 6 weeks. Of the 173 patients, 104 (60.1%) were asymptomatic, 68 patients (39.3%) had mild, nonspecific neurological symptoms, and 1 patient (1.0%) had significant neurological symptoms. Of the asymptomatic patients, 3 patients (2.9%) had new CT findings and 1 of these patients (1.0%) underwent a change in treatment plan because of these findings. This change involved an additional clinic appointment and CT to monitor a 12-mm chronic subdural hematoma that ultimately resolved without treatment. Of the patients with mild, nonspecific neurological symptoms, 6 patients (8.8%) had new CT findings and 3 of these patients (4.4%) underwent a change in treatment plan because of these findings; none of these patients required surgical intervention. The single patient with significant neurological symptoms did not have any new CT findings.Repeat outpatient CT of asymptomatic patients after nonoperative cerebral contusion and tSAH is very unlikely to demonstrate significant new pathology. Given the cost and radiation exposure associated with CT, imaging should be reserved for patients with significant symptoms or focal findings on neurological examination.

    View details for DOI 10.3171/2014.6.JNS132204

    View details for Web of Science ID 000342973300028

    View details for PubMedID 25061865

  • Incidence of Sacral Fractures and In-Hospital Postoperative Complications in the United States An Analysis of 2002-2011 Data SPINE Bydon, M., De la Garza-Ramos, R., Macki, M., Desai, A., Gokaslan, A. K., Bydon, A. 2014; 39 (18): E1103-E1109

    Abstract

    Retrospective study of an administrative database.To estimate the incidence of sacral fractures in the United States and report short-term outcomes after their surgical management.The incidence of sacral fractures in the United States is currently unknown, and these lesions have been associated with significant morbidity after their surgical management.This study used the Nationwide Inpatient Sample database for the years 2002-2011. All patients with a primary discharge diagnosis of a sacral fracture with and without a neurological injury were identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes. Patients with a diagnosis of osteoporosis or pathological fracture were excluded. A stepwise multivariate logistic regression analysis was performed to identify factors associated with an in-hospital complication.During the study period, 10,177 patients with a nonosteoporotic sacral fracture were identified, of whom 1002 patients underwent surgery. Between 2002 and 2011, the estimated incidence of sacral fractures increased from 0.67 per 100,000 persons to 2.09 (P < 0.001). Similarly, the rate of surgical treatment for sacral fractures increased from 0.05 per 100,000 persons in 2002 to 0.24 per 100,000 in 2011 (P < 0.001). Complications occurred in 25.95% of patients and remained steady over time (P = 0.992). Average length of stay significantly decreased from 11.93 days to 9.66 days in the 10-year period (P = 0.023). The independent factors associated with an in-hospital complication were congestive heart failure (odds ratio, 3.65; 95% confidence interval, 1.18-11.26), coagulopathy (odds ratio, 3.58; 95% confidence interval, 1.88-6.81), and electrolyte abnormalities (odds ratio, 3.28; 95% confidence interval, 2.14-5.02).During the examined 10-year period, both the incidence of nonosteoporotic sacral fractures and the surgical treatment of these lesions increased in the United States. Between 2002 and 2011, although patient comorbidity increased, in-hospital complication rates remained stable and length of stay significantly decreased over time.4.

    View details for DOI 10.1097/BRS.0000000000000448

    View details for Web of Science ID 000341018000008

    View details for PubMedID 24875962

  • A predictive model of complications after spine surgery: the National Surgical Quality Improvement Program (NSQIP) 2005-2010 SPINE JOURNAL Bekelis, K., Desai, A., Bakhoum, S. F., Missios, S. 2014; 14 (7): 1247-1255

    Abstract

    There is increasing scrutiny by several regulatory bodies regarding the complications of spine surgery. Precise delineation of the risks contributing to those complications remains a topic of debate.We attempted to create a predictive model of complications in patients undergoing spine surgery.Retrospective cohort study.A total of 13,660 patients registered in the American College of Surgeons National Quality Improvement Project (NSQIP) database.Thirty-day postoperative risks of stroke, myocardial infarction, death, infection, urinary tract infection (UTI), deep vein thrombosis (DVT), pulmonary embolism (PE), and return to the operating room.We performed a retrospective cohort study involving patients who underwent spine surgery between 2005 and 2010 and were registered in NSQIP. A model for outcome prediction based on individual patient characteristics was developed.Of the 13,660 patients, 2,719 underwent anterior approaches (19.9%), 565 corpectomies (4.1%), and 1,757 fusions (12.9%). The respective 30-day postoperative risks were 0.05% for stroke, 0.2% for MI, 0.25% for death, 0.3% for infection, 1.37% for UTI, 0.6% for DVT, 0.29% for PE, and 3.15% for return to the operating room. Multivariate analysis demonstrated that increasing age, more extensive operations (fusion, corpectomy), medical deconditioning (weight loss, dialysis, peripheral vascular disease, coronary artery disease, chronic obstructive pulmonary disease, diabetes), increasing body mass index, non-independent mobilization (preoperative neurologic deficit), and bleeding disorders were independently associated with a more than 3 days' length of stay. A validated model for outcome prediction based on individual patient characteristics was developed. The accuracy of the model was estimated by the area under the receiver operating characteristic curve, which was 0.95, 0.82, 0.87, 0.75, 0.74, 0.78, 0.76, 0.74, and 0.65 for postoperative risk of stroke, myocardial infarction, death, infection, DVT, PE, UTI, length of stay of 3 days or longer, and return to the operating room, respectively.Our model can provide individualized estimates of the risks of postoperative complications based on preoperative conditions, and can potentially be used as an adjunct in decision-making for spine surgery.

    View details for DOI 10.1016/j.spinee.2013.08.009

    View details for Web of Science ID 000338467000026

    View details for PubMedID 24211097

  • Predicting inpatient complications from cerebral aneurysm clipping: the Nationwide Inpatient Sample 2005-2009 JOURNAL OF NEUROSURGERY Bekelis, K., Missios, S., MacKenzie, T. A., Desai, A., Fischer, A., Labropoulos, N., Roberts, D. W. 2014; 120 (3): 591-598

    Abstract

    Precise delineation of individualized risks of morbidity and mortality is crucial in decision making in cerebrovascular neurosurgery. The authors attempted to create a predictive model of complications in patients undergoing cerebral aneurysm clipping (CAC).The authors performed a retrospective cohort study of patients who had undergone CAC in the period from 2005 to 2009 and were registered in the Nationwide Inpatient Sample (NIS) database. A model for outcome prediction based on preoperative individual patient characteristics was developed.Of the 7651 patients in the NIS who underwent CAC, 3682 (48.1%) had presented with unruptured aneurysms and 3969 (51.9%) with subarachnoid hemorrhage. The respective inpatient postoperative risks for death, unfavorable discharge, stroke, treated hydrocephalus, cardiac complications, deep vein thrombosis, pulmonary embolism, and acute renal failure were 0.7%, 15.3%, 5.3%, 1.5%, 1.3%, 0.6%, 2.0%, and 0.1% for those with unruptured aneurysms and 11.5%, 52.8%, 5.5%, 39.2%, 1.7%, 2.8%, 2.7%, and 0.8% for those with ruptured aneurysms. Multivariate analysis identified risk factors independently associated with the above outcomes. A validated model for outcome prediction based on individual patient characteristics was developed. The accuracy of the model was estimated using the area under the receiver operating characteristic curve, and it was found to have good discrimination.The featured model can provide individualized estimates of the risks of postoperative complications based on preoperative conditions and can potentially be used as an adjunct in decision making in cerebrovascular neurosurgery.

    View details for DOI 10.3171/2013.8.JNS13228

    View details for Web of Science ID 000332048800002

    View details for PubMedID 24032701

  • Outcome prediction in intracranial tumor surgery: the National Surgical Quality Improvement Program 2005-2010 JOURNAL OF NEURO-ONCOLOGY Bekelis, K., Bakhoum, S. F., Desai, A., MacKenzie, T. A., Roberts, D. W. 2013; 113 (1): 57-64

    Abstract

    Accurate knowledge of individualized risks is crucial for decision-making in the surgical management of patients with brain tumors. Precise delineation of those risks remains a topic of debate. We attempted to create a predictive model of outcomes in patients undergoing craniotomies for tumor resection (CTR). We performed a retrospective cohort study involving patients who underwent CTR from 2005 to 2010 and were registered in the American College of Surgeons National Quality Improvement Project database. A model for outcome prediction based on individual patient characteristics was developed. Of the 1,834 patients, 457 had meningiomas (24.9 %) and 1377 had non-meningioma tumors (75.1 %). The respective 30-day postoperative risks were 2.1 % for stroke, 1.3 % for MI, 2.7 % for death, 2.4 % for deep surgical site infection, and 6.6 % for return to the OR. Multivariate analysis demonstrated that pre-operative tumor-related neurologic deficit, stroke, altered mental status, and weight loss, were independently associated with most outcomes, including post-operative MI, death, and deep surgical site infection. An additive effect of the variables on the risk of all outcomes was observed. A validated model for outcome prediction based on individual patient characteristics was developed. The accuracy of the model was estimated by the area under the receiver operating characteristic curve, which was 0.687, 0.929, 0.749, 0.746, and 0.679 for postoperative risk of stroke, MI, death, infection, and return to the OR, respectively. Our model can provide individualized estimates of the risks of post-operative complications based on pre-operative conditions, and can potentially be utilized as an adjunct in the decision-making for surgical intervention in brain tumor patients.

    View details for DOI 10.1007/s11060-013-1089-3

    View details for Web of Science ID 000318300700007

    View details for PubMedID 23436132

  • Variation in Outcomes Across Centers After Surgery for Lumbar Stenosis and Degenerative Spondylolisthesis in the Spine Patient Outcomes Research Trial SPINE Desai, A., Bekelis, K., Ball, P. A., Lurie, J., Mirza, S. K., Tosteson, T. D., Zhao, W., Weinstein, J. N. 2013; 38 (8): 678-691

    Abstract

    Retrospective review of a prospectively collected database.To examine whether short- and long-term outcomes after surgery for lumbar stenosis (SPS) and degenerative spondylolisthesis (DS) vary across centers.Surgery has been shown to be of benefit for both SPS and DS. For both conditions, surgery often consists of laminectomy with or without fusion. Potential differences in outcomes of these overlapping procedures across various surgical centers have not yet been investigated.Spine Patient Outcomes Research Trial cohort participants with a confirmed diagnosis of SPS or DS undergoing surgery were followed from baseline at 6 weeks, 3, 6, and 12 months, and yearly thereafter, at 13 spine clinics in 11 US states. Baseline characteristics and short- and long-term outcomes were analyzed.A total of 793 patients underwent surgery. Significant differences were found between centers with regard to patient race, body mass index, treatment preference, neurological deficit, stenosis location, severity, and number of stenotic levels. Significant differences were also found in operative duration and blood loss, the incidence of durotomy, the length of hospital stay, and wound infection. When baseline differences were adjusted for, significant differences were still seen between centers in changes in patient functional outcome (Short Form-36 bodily pain and physical function, and Oswestry Disability Index) at 1 year after surgery. In addition, the cumulative adjusted change in the Oswestry Disability Index Score at 4 years significantly differed among centers, with Short Form-36 scores trending toward significance.There is a broad and statistically significant variation in short- and long-term outcomes after surgery for SPS and DS across various academic centers, when statistically significant baseline differences are adjusted for. The findings suggest that the choice of center affects outcome after these procedures, although further studies are required to investigate which center characteristics are most important.

    View details for DOI 10.1097/BRS.0b013e318278e571

    View details for Web of Science ID 000317565400017

    View details for PubMedID 23080425

  • A Risk Factor-based Predictive Model of Outcomes in Carotid Endarterectomy The National Surgical Quality Improvement Program 2005-2010 STROKE Bekelis, K., Bakhoum, S. F., Desai, A., MacKenzie, T. A., Goodney, P., Labropoulos, N. 2013; 44 (4): 1085-?

    Abstract

    Accurate knowledge of individualized risks and benefits is crucial to the surgical management of patients undergoing carotid endarterectomy (CEA). Although large randomized trials have determined specific cutoffs for the degree of stenosis, precise delineation of patient-level risks remains a topic of debate, especially in real world practice. We attempted to create a risk factor-based predictive model of outcomes in CEA.We performed a retrospective cohort study involving patients who underwent CEAs from 2005 to 2010 and were registered in the American College of Surgeons National Quality Improvement Project database.Of the 35 698 patients, 20 015 were asymptomatic (56.1%) and 15 683 were symptomatic (43.9%). These patients demonstrated a 1.64% risk of stroke, 0.69% risk of myocardial infarction, and 0.75% risk of death within 30 days after CEA. Multivariate analysis demonstrated that increasing age, male sex, history of chronic obstructive pulmonary disease, myocardial infarction, angina, congestive heart failure, peripheral vascular disease, previous stroke or transient ischemic attack, and dialysis were independent risk factors associated with an increased risk of the combined outcome of postoperative stroke, myocardial infarction, or death. A validated model for outcome prediction based on individual patient characteristics was developed. There was a steep effect of age on the risk of myocardial infarction and death.This national study confirms that that risks of CEA vary dramatically based on patient-level characteristics. Because of limited discrimination, it cannot be used for individual patient risk assessment. However, it can be used as a baseline for improvement and development of more accurate predictive models based on other databases or prospective studies.

    View details for DOI 10.1161/STROKEAHA.111.674358

    View details for Web of Science ID 000316673900036

    View details for PubMedID 23412374

  • Indications for treatment of recurrent carotid stenosis BRITISH JOURNAL OF SURGERY Bekelis, K., Moses, Z., Missios, S., Desai, A., Labropoulos, N. 2013; 100 (4): 440-447

    Abstract

    There is significant variation in the indications for intervention in patients with recurrent carotid artery stenosis. The aim of the present study was to describe these indications in a contemporary cohort of patients.This was a systematic review of all peer-reviewed studies reporting on the indications for carotid intervention in patients with recurrent stenosis after carotid endarterectomy (CEA) or carotid artery stenting (CAS) that were published between 1990 and 2012.There were 50 studies reporting on a total of 3524 patients undergoing a carotid procedure; of these, 3478 underwent CEA as the initial intervention. Reintervention was by CEA in 2403 patients and by CAS in 1121. Only 54·7 per cent of the patients were treated for any symptoms and, importantly, just 444 (23·1 per cent of 1926 symptomatic patients) underwent intervention for documented ipsilateral symptoms. None of the studies reported whether the patients were evaluated for other sources of emboli. The remaining 45·3 per cent of patients had asymptomatic restenosis and in the majority of the studies were treated when the degree of stenosis exceeded 80 per cent. The time to repeat intervention was significantly longer in patients with recurrent atherosclerosis, in asymptomatic patients and in patients undergoing CEA.The reported criteria for retreatment of carotid stenosis were not rigorous and there is still significant ambiguity surrounding the indications for intervention.

    View details for DOI 10.1002/bjs.9027

    View details for Web of Science ID 000314657200003

    View details for PubMedID 23288608

  • Interictal PET and ictal subtraction SPECT: Sensitivity in the detection of seizure foci in patients with medically intractable epilepsy EPILEPSIA Desai, A., Bekelis, K., Thadani, V. M., Roberts, D. W., Jobst, B. C., Duhaime, A., Gilbert, K., Darcey, T. M., Studholme, C., Siegel, A. 2013; 54 (2): 341-350

    Abstract

    Interictal positron emission tomography (PET) and ictal subtraction single photon emission computed tomography (SPECT) of the brain have been shown to be valuable tests in the presurgical evaluation of epilepsy. To determine the relative utility of these methods in the localization of seizure foci, we compared interictal PET and ictal subtraction SPECT to subdural and depth electrode recordings in patients with medically intractable epilepsy.Between 2003 and 2009, clinical information on all patients at our institution undergoing intracranial electroencephalography (EEG) monitoring was charted in a prospectively recorded database. Patients who underwent preoperative interictal PET and ictal subtraction SPECT were selected from this database. Patient characteristics and the findings on preoperative interictal PET and ictal subtraction SPECT were analyzed. Sensitivity of detection of seizure foci for each modality, as compared to intracranial EEG monitoring, was calculated.Fifty-three patients underwent intracranial EEG monitoring with preoperative interictal PET and ictal subtraction SPECT scans. The average patient age was 32.7 years (median 32 years, range 1-60 years). Twenty-seven patients had findings of reduced metabolism on interictal PET scan, whereas all 53 patients studied demonstrated a region of relative hyperperfusion on ictal subtraction SPECT suggestive of an epileptogenic zone. Intracranial EEG monitoring identified a single seizure focus in 45 patients, with 39 eventually undergoing resective surgery. Of the 45 patients in whom a seizure focus was localized, PET scan identified the same region in 25 cases (56% sensitivity) and SPECT in 39 cases (87% sensitivity). Intracranial EEG was concordant with at least one study in 41 cases (91%) and both studies in 23 cases (51%). In 16 (80%) of 20 cases where PET did not correlate with intracranial EEG, the SPECT study was concordant. Conversely, PET and intracranial EEG were concordant in two (33%) of the six cases where the SPECT did not demonstrate the seizure focus outlined by intracranial EEG. Thirty-three patients had surgical resection and >2 years of follow-up, and 21 of these (64%) had Engel class 1 outcome. No significant effect of imaging concordance on seizure outcome was seen.Interictal PET and ictal subtraction SPECT studies can provide important information in the preoperative evaluation of medically intractable epilepsy. Of the two studies, ictal subtraction SPECT appears to be the more sensitive. When both studies are used together, however, they can provide complementary information.

    View details for DOI 10.1111/j.1528-1167.2012.03686.x

    View details for Web of Science ID 000314750200018

    View details for PubMedID 23030361

  • Association of a higher density of specialist neuroscience providers with fewer deaths from stroke in the United States population JOURNAL OF NEUROSURGERY Desai, A., Bekelis, K., Zhao, W., Ball, P. A., Erkmen, K. 2013; 118 (2): 431-436

    Abstract

    Stroke is a leading cause of death and disability. Given that neurologists and neurosurgeons have special expertise in this area, the authors hypothesized that the density of neuroscience providers is associated with reduced mortality rates from stroke across US counties.This is a retrospective review of the Area Resource File 2009-2010, a national county-level health information database maintained by the US Department of Health and Human Services. The primary outcome variable was the 3-year (2004-2006) average in cerebrovascular disease deaths per million population for each county. The primary independent variable was the combined density of neurosurgeons and neurologists per million population in the year 2006. Multiple regression analysis was performed, adjusting for density of general practitioners (GPs), urbanicity of the county, and socioeconomic status of the residents of the county.In the 3141 counties analyzed, the median number of annual stroke deaths was 586 (interquartile range [IQR] 449-754), the median number of neuroscience providers was 0 (IQR 0-26), and the median number of GPs was 274 (IQR 175-410) per million population. On multivariate adjusted analysis, each increase of 1 neuroscience provider was associated with 0.38 fewer deaths from stroke per year (p < 0.001) per million population. Rural location (p < 0.001) and increased density of GPs (p < 0.001) were associated with increases in stroke-related mortality.Higher density of specialist neuroscience providers is associated with fewer deaths from stroke. This suggests that the availability of specialists is an important factor in survival after stroke, and underlines the importance of promoting specialist education and practice throughout the country.

    View details for DOI 10.3171/2012.10.JNS12518

    View details for Web of Science ID 000313937900034

    View details for PubMedID 23198833

  • Occipitotemporal hippocampal depth electrodes in intracranial epilepsy monitoring: safety and utility JOURNAL OF NEUROSURGERY Bekelis, K., Desai, A., Kotlyar, A., Thadani, V., Jobst, B. C., Bujarski, K., Darcey, T. M., Roberts, D. W. 2013; 118 (2): 345-352

    Abstract

    Intracranial monitoring for epilepsy has been proven to enhance diagnostic accuracy and provide localizing information for surgical treatment of intractable seizures. The authors investigated the usefulness of hippocampal depth electrodes in the era of more advanced imaging techniques.Between 1988 and 2010, 100 patients underwent occipitotemporal hippocampal depth electrode (OHDE) implantation as part of invasive seizure monitoring, and their charts were retrospectively reviewed. The authors' technique involved the stereotactically guided (using the Leksell model G frame) implantation of a 12-contact depth electrode directed along the long axis of the hippocampus, through an occipital twist drill hole.Of the 100 patients (mean age 35.0 years [range 13-58 years], 51% male) who underwent intracranial investigation, 84 underwent resection of the seizure focus. Magnetic resonance imaging revealed mesial temporal sclerosis (MTS) in 27% of patients, showed abnormal findings without MTS in 55% of patients, and showed normal findings in 18% of patients. One patient developed a small asymptomatic occipital hemorrhage around the electrode tract. The use of OHDEs enabled epilepsy resection in 45.7% of patients who eventually underwent standard or selective temporal lobe resection. The hippocampal formation was spared during surgery because data obtained from the depth electrodes showed no or only secondary involvement in 14% of patients with preoperative temporal localization. The use of OHDEs prevented resections in 12% of patients with radiographic evidence of MTS. Eighty-three percent of patients who underwent resection had Engel Class I (68%) or II (15%) outcome at 2 years of follow-up.The use of OHDEs for intracranial epilepsy monitoring has a favorable risk profile, and in the authors' experience it proved to be a valuable component of intracranial investigation. The use of OHDEs can provide the sole evidence for resection of some epileptogenic foci and can also result in hippocampal sparing or prevent likely unsuccessful resection in other patients.

    View details for DOI 10.3171/2012.9.JNS112221

    View details for Web of Science ID 000313937900018

    View details for PubMedID 23082879

  • Subdural interhemispheric grid electrodes for intracranial epilepsy monitoring: feasibility, safety, and utility Clinical article JOURNAL OF NEUROSURGERY Bekelis, K., Radwan, T. A., Desai, A., Moses, Z. B., Thadani, V. M., Jobst, B. C., Bujarski, K. A., Darcey, T. M., Roberts, D. W. 2012; 117 (6): 1182-1188

    Abstract

    Intracranial monitoring for epilepsy has been proven to enhance diagnostic accuracy and provide localizing information for surgical treatment of intractable seizures. The authors investigated their experience with interhemispheric grid electrodes (IHGEs) to assess the hypothesis that they are feasible, safe, and useful.Between 1992 and 2010, 50 patients underwent IHGE implantation (curvilinear double-sided 2 × 8 or 3 × 8 grids) as part of arrays for invasive seizure monitoring, and their charts were retrospectively reviewed.Of the 50 patients who underwent intracranial investigation with IHGEs, 38 eventually underwent resection of the seizure focus. These 38 patients had a mean age of 30.7 years (range 11-58 years), and 63% were males. Complications as a result of IHGE implantation consisted of transient leg weakness in 1 patient. Of all the patients who underwent resective surgery, 21 (55.3%) had medial frontal resections, 9 of whom (43%) had normal MRI results. Localization in all of these cases was possible only because of data from IHGEs, and the extent of resection was tailored based on these data. Of the 17 patients (44.7%) who underwent other cortical resections, IHGEs were helpful in excluding medial seizure onset. Twelve patients did not undergo resection because of nonlocalizable or multifocal disease; in 2 patients localization to the motor cortex precluded resection. Seventy-one percent of patients who underwent resection had Engel Class I outcome at the 2-year follow-up.The use of IHGEs in intracranial epilepsy monitoring has a favorable risk profile and in the authors' experience proved to be a valuable component of intracranial investigation, providing the sole evidence for resection of some epileptogenic foci.

    View details for DOI 10.3171/2012.8.JNS12258

    View details for Web of Science ID 000311463900028

    View details for PubMedID 23061384

  • Computed tomography angiography: improving diagnostic yield and cost effectiveness in the initial evaluation of spontaneous nonsubarachnoid intracerebral hemorrhage JOURNAL OF NEUROSURGERY Bekelis, K., Desai, A., Zhao, W., Gibson, D., Gologorsky, D., Eskey, C., Erkmen, K. 2012; 117 (4): 761-766

    Abstract

    Computed tomography angiography (CTA) is increasingly used as a screening tool in the investigation of spontaneous intracerebral hemorrhage (ICH). However, CTA carries additional costs and risks, necessitating its judicious use. The authors hypothesized that subsets of patients with nontraumatic, nonsubarachnoid ICH are unlikely to benefit from CTA as part of the diagnostic workup and that particular patient risk factors may be used to increase the yield of CTA in the detection of vascular sources.The authors performed a retrospective analysis of 1376 patients admitted to Dartmouth-Hitchcock Medical Center with ICH over an 8-year period. Patients with subarachnoid hemorrhage, hemorrhagic conversion of ischemic infarcts, trauma, and known prior malignancy were excluded from the analysis, resulting in 257 patients for final analysis. Records were reviewed for medical risk factors, hemorrhage location, and correlation of CTA findings with final diagnosis. Multiple logistic regression analysis was used to investigate the combined effects of baseline variables of interest. Model selection was conducted using the stepwise method with p = 0.10 as the significance level for variable entry and p = 0.05 the significance level for variable retention.Computed tomography angiography studies detected vascular pathology in 34 patients (13.2%). Patient characteristics that were associated with a significantly higher likelihood of identifying a structural vascular lesion as the source of hemorrhage included patient age younger than 65 years (OR = 16.36, p = 0.0039), female sex (OR = 14.9, p = 0.0126), nonsmokers (OR = 103.8, p = 0.0008), patients with intraventricular hemorrhage (OR = 9.42, p = 0.0379), and patients without hypertension (OR = 515.78, p < 0.0001). Patients who were older than 65 years of age, with a history of hypertension, and hemorrhage located in the cerebellum or basal ganglia were never found to have an identified structural source of hemorrhage on CTA.Patient characteristics and risk factors are important considerations when ordering diagnostic tests in the workup of nonsubarachnoid, nontraumatic spontaneous ICH. Although CTA is an accurate diagnostic examination, it can usually be omitted in the workup of patients with the described characteristics. The use of this algorithm has the potential to increase the yield, and thus the safety and cost effectiveness, of this diagnostic tool.

    View details for DOI 10.3171/2012.7.JNS12281

    View details for Web of Science ID 000309485600030

    View details for PubMedID 22880718

  • Spine Patient Outcomes Research Trial: Do Outcomes Vary Across Centers for Surgery for Lumbar Disc Herniation? NEUROSURGERY Desai, A., Bekelis, K., Ball, P. A., Lurie, J., Mirza, S. K., Tosteson, T. D., Zhao, W., Weinstein, J. N. 2012; 71 (4): 833-842

    Abstract

    Lumbar discectomy is the most commonly performed spine procedure. Academic spine centers with potentially differing caseloads and experience may have different outcomes.To determine whether the choice of center in which surgery is performed affects lumbar discectomy outcomes.Spine Patient Outcomes Research Trial participants with a confirmed diagnosis of intervertebral disc herniation undergoing standard first-time open discectomy were followed from baseline at 6 weeks, and 3, 6, and 12 months, and yearly thereafter, at 13 spine clinics in 11 US states. Patient data from this prospective study were reviewed. Enrollment began in March 2000 and ended in November 2004.Seven hundred ninety-two patients underwent first-time lumbar discectomy. Significant differences were found among centers in patient age and race, baseline levels of disability, and treatment preferences. There were no significant differences among the centers in other patient characteristics (eg, sex, body mass index, the prevalence of smoking, diabetes, or hypertension), or disease characteristics (herniation level or type). Some short-term outcomes varied significantly among centers, including operative duration and blood loss, the incidence of durotomy, the length of hospital stay, and reoperation rate. However, there were no differences among the centers in incidence of nerve root injury, postoperative mortality, Short Form 36 scores of body pain or physical function, or Oswestry Disability Index at 4 years.Although mean blood loss, risk of durotomy, length of stay, and rate of reoperation vary among academic spine centers performing lumbar discectomy, there appears to be no difference in long-term functional outcomes.

    View details for DOI 10.1227/NEU.0b013e31826772cb

    View details for Web of Science ID 000309117200034

    View details for PubMedID 22791040

  • Increased population density of neurosurgeons associated with decreased risk of death from motor vehicle accidents in the United States. Journal of neurosurgery Desai, A., Bekelis, K., Zhao, W., Ball, P. A. 2012; 117 (3): 599-603

    Abstract

    Motor vehicle accidents (MVAs) are a leading cause of death and disability in young people. Given that a major cause of death from MVAs is traumatic brain injury, and neurosurgeons hold special expertise in this area relative to other members of a trauma team, the authors hypothesized that neurosurgeon population density would be related to reduced mortality from MVAs across US counties.The Area Resource File (2009-2010), a national health resource information database, was retrospectively analyzed. The primary outcome variable was the 3-year (2004-2006) average in MVA deaths per million population for each county. The primary independent variable was the density of neurosurgeons per million population in the year 2006. Multiple regression analysis was performed, adjusting for population density of general practitioners, urbanicity of the county, and socioeconomic status of the county.The median number of annual MVA deaths per million population, in the 3141 counties analyzed, was 226 (interquartile range [IQR] 151-323). The median number of neurosurgeons per million population was 0 (IQR 0-0), while the median number of general practitioners per million population was 274 (IQR 175-410). Using an unadjusted analysis, each increase of 1 neurosurgeon per million population was associated with 1.90 fewer MVA deaths per million population (p < 0.001). On multivariate adjusted analysis, each increase of 1 neurosurgeon per million population was associated with 1.01 fewer MVA deaths per million population (p < 0.001), with a respective decrease in MVA deaths of 0.03 per million population for an increase in 1 general practitioner (p = 0.007). Rural location, persistent poverty, and low educational level were all associated with significant increases in the rate of MVA deaths.A higher population density of neurosurgeons is associated with a significant reduction in deaths from MVAs, a major cause of death nationally. This suggests that the availability of local neurosurgeons is an important factor in the overall likelihood of survival from an MVA, and therefore indicates the importance of promoting neurosurgical education and practice throughout the country.

    View details for DOI 10.3171/2012.6.JNS111281

    View details for PubMedID 22827590

  • Minimally invasive tubular retractor system for adequate exposure during surgical obliteration of spinal dural arteriovenous fistulas with the aid of indocyanine green intraoperative angiography. Journal of neurosurgery. Spine Desai, A., Bekelis, K., Erkmen, K. 2012; 17 (2): 160-163

    Abstract

    Effective surgical obliteration of spinal dural arteriovenous fistulas (DAVFs) traditionally requires laminectomy or hemilaminectomy to allow intradural exposure and occlusion of the draining vein. The authors present successful treatment of a spinal DAVF by using a tubular retractor system to provide minimally invasive exposure at the L5-S1 level adequate for both microsurgical treatment and intraoperative indocyanine green angiography.

    View details for DOI 10.3171/2012.4.SPINE12152

    View details for PubMedID 22632175

  • Frameless robotically targeted stereotactic brain biopsy: feasibility, diagnostic yield, and safety JOURNAL OF NEUROSURGERY Bekelis, K., Badwan, T. A., Desai, A., Roberts, D. W. 2012; 116 (5): 1002-1006

    Abstract

    Frameless stereotactic brain biopsy has become an established procedure in many neurosurgical centers worldwide. Robotic modifications of image-guided frameless stereotaxy hold promise for making these procedures safer, more effective, and more efficient. The authors hypothesized that robotic brain biopsy is a safe, accurate procedure, with a high diagnostic yield and a safety profile comparable to other stereotactic biopsy methods.This retrospective study included 41 patients undergoing frameless stereotactic brain biopsy of lesions (mean size 2.9 cm) for diagnostic purposes. All patients underwent image-guided, robotic biopsy in which the SurgiScope system was used in conjunction with scalp fiducial markers and a preoperatively selected target and trajectory. Forty-five procedures, with 50 supratentorial targets selected, were performed.The mean operative time was 44.6 minutes for the robotic biopsy procedures. This decreased over the second half of the study by 37%, from 54.7 to 34.5 minutes (p < 0.025). The diagnostic yield was 97.8% per procedure, with a second procedure being diagnostic in the single nondiagnostic case. Complications included one transient worsening of a preexisting deficit (2%) and another deficit that was permanent (2%). There were no infections.Robotic biopsy involving a preselected target and trajectory is safe, accurate, efficient, and comparable to other procedures employing either frame-based stereotaxy or frameless, nonrobotic stereotaxy. It permits biopsy in all patients, including those with small target lesions. Robotic biopsy planning facilitates careful preoperative study and optimization of needle trajectory to avoid sulcal vessels, bridging veins, and ventricular penetration.

    View details for DOI 10.3171/2012.1.JNS111746

    View details for Web of Science ID 000303088800012

    View details for PubMedID 22404667

  • Magnetic resonance imaging/magnetic resonance angiography fusion technique for intraoperative navigation during microsurgical resection of cerebral arteriovenous malformations NEUROSURGICAL FOCUS Bekelis, K., Missios, S., Desai, A., Eskey, C., Erkmen, K. 2012; 32 (5)

    Abstract

    Microsurgical resection of arteriovenous malformations (AVMs) is facilitated by real-time image guidance that demonstrates the precise size and location of the AVM nidus. Magnetic resonance images have routinely been used for intraoperative navigation, but there is no single MRI sequence that can provide all the details needed for characterization of the AVM. Additional information detailing the specific location of the feeding arteries and draining veins would be valuable during surgery, and this detail may be provided by fusing MR images and MR angiography (MRA) sequences. The current study describes the use of a technique that fuses contrast-enhanced MR images and 3D time-of-flight MR angiograms for intraoperative navigation in AVM resection.All patients undergoing microsurgical resection of AVMs at the Dartmouth Cerebrovascular Surgery Program were evaluated from the surgical database. Between 2009 and 2011, 15 patients underwent surgery in which this contrast-enhanced MRI and MRA fusion technique was used, and these patient form the population of the present study.Image fusion was successful in all 15 cases. The additional data manipulation required to fuse the image sets was performed on the morning of surgery with minimal added setup time. The navigation system accurately identified feeding arteries and draining veins during resection in all cases. There was minimal imaging-related artifact produced by embolic materials in AVMs that had been preoperatively embolized. Complete AVM obliteration was demonstrated on intraoperative angiography in all cases.Precise anatomical localization, as well as the ability to differentiate between arteries and veins during AVM microsurgery, is feasible with the aforementioned MRI/MRA fusion technique. The technique provides important information that is beneficial to preoperative planning, intraoperative navigation, and successful AVM resection.

    View details for DOI 10.3171/2012.1.FOCUS127

    View details for Web of Science ID 000303418600008

    View details for PubMedID 22537133

  • Surgery for Lumbar Degenerative Spondylolisthesis in Spine Patient Outcomes Research Trial SPINE Desai, A., Ball, P. A., Bekelis, K., Lurie, J., Mirza, S. K., Tosteson, T. D., Zhao, W., Weinstein, J. N. 2012; 37 (5): 406-413

    Abstract

    Retrospective review of a prospectively collected multi-institutional database.In the present analysis, we investigate the impact of incidental durotomy on outcome in patients undergoing surgery for lumbar degenerative spondylolisthesis.Surgery for lumbar degenerative spondylolisthesis has several potential complications, one of the most common of which is incidental durotomy. The effect of incidental durotomy on outcome, however, remains uncertain.Spine Patient Outcomes Research Trial cohort participants with a confirmed diagnosis of lumbar degenerative spondylolisthesis undergoing standard first-time open decompressive laminectomy, with or without fusion, were followed from baseline at 6 weeks, at 3, 6, 12 months, and yearly thereafter, at 13 spine clinics in 11 US states. Patient data from this prospectively gathered database were reviewed. As of May 2009, the mean (standard deviation [SD]) follow-up among all analyzed degenerative spondylolisthesis patients was 46.6 months (SD = 13.1) (no durotomy: 46.7 vs. had durotomy: 45.2, P = 0.49). The median (range) follow-up time among all analyzed degenerative spondylolisthesis patients was 47.6 months (SD = 2.5-84).A 10.5% incidence of durotomy was detected among the 389 patients undergoing surgery. No significant differences were observed with or without durotomy in age, race, the prevalence of smoking, diabetes and hypertension, decompression level, number of levels, or whether a fusion was performed. There were no differences in incidence of nerve root injury, postoperative mortality, additional surgeries, 36-Item Short Form Health Survey (SF-36) scores of body pain or physical function, or Oswestry Disability Index at 1, 2, 3, and 4 years.Incidental durotomy during first-time surgery for lumbar degenerative spondylolisthesis does not appear to impact outcome in affected patients.

    View details for DOI 10.1097/BRS.0b013e3182349bc5

    View details for Web of Science ID 000300872300021

    View details for PubMedID 21971123

  • Surgical techniques for investigating the role of the insula in epilepsy: a review NEUROSURGICAL FOCUS Desai, A., Bekelis, K., Darcey, T. M., Roberts, D. W. 2012; 32 (3)

    Abstract

    Intracranial electroencephalography monitoring of the insula is an important tool in the investigation of the insula in medically intractable epilepsy and has been shown to be safe and reliable. Several methods of placing electrodes for insular coverage have been reported and include open craniotomy as well as stereotactic orthogonal and stereotactic anterior and posterior oblique trajectories. The authors review each of these techniques with respect to current concepts in insular epilepsy.

    View details for DOI 10.3171/2012.1.FOCUS11325

    View details for Web of Science ID 000301005400007

    View details for PubMedID 22380860

  • SPORT: Does Incidental Durotomy Affect Long-term Outcomes in Cases of Spinal Stenosis? NEUROSURGERY Desai, A., Ball, P. A., Bekelis, K., Lurie, J., Mirza, S. K., Tosteson, T. D., Weinstein, J. N. 2011; 69 (1): 38-44

    Abstract

    Incidental durotomy is a familiar encounter during surgery for lumbar spinal stenosis. The impact of durotomy on long-term outcomes remains a matter of debate.To determine the impact of durotomy on the long-term outcomes of patients in the Spine Patient Outcomes Research Trial (SPORT).The SPORT cohort participants with a confirmed diagnosis of spinal stenosis, without associated spondylolisthesis, undergoing standard, first-time, open decompressive laminectomy, with or without fusion, were followed up from baseline at 6 weeks, and 3, 6, and 12 months and yearly thereafter at 13 spine clinics in 11 US states. Patient data from this prospectively gathered database were reviewed. As of May 2009, the mean follow-up among all analyzed patients was 43.8 months.Four hundred nine patients underwent first-time open laminectomy with or without fusion. Thirty-seven of these patients (9%) had an incidental durotomy. No significant differences were observed with or without durotomy in age; sex; race; body mass index; the prevalence of smoking, diabetes mellitus, and hypertension; decompression level; number of levels decompressed; or whether an additional fusion was performed. The durotomy group had significantly increased operative duration, operative blood loss, and inpatient stay. There were, however, no differences in incidence of nerve root injury, mortality, additional surgeries, or primary outcomes (Short Form-36 Bodily Pain or Physical Function scores or Oswestry Disability Index) at yearly follow-ups to 4 years.Incidental durotomy during first-time lumbar laminectomy for spinal stenosis did not impact long-term outcomes in affected patients.

    View details for DOI 10.1227/NEU.0b013e3182134171

    View details for Web of Science ID 000291344700029

    View details for PubMedID 21358354

  • Outcomes after incidental durotomy during first-time lumbar discectomy JOURNAL OF NEUROSURGERY-SPINE Desai, A., Ball, P. A., Bekelis, K., Lurie, J. D., Mirza, S. K., Tosteson, T. D., Weinstein, J. N. 2011; 14 (5): 647-653

    Abstract

    Incidental durotomy is an infrequent but well-recognized complication during lumbar disc surgery. The effect of a durotomy on long-term outcomes is, however, controversial. The authors sought to examine whether the occurrence of durotomy during surgery impacts long-term clinical outcome.Spine Patient Outcomes Research Trial (SPORT) participants who had a confirmed diagnosis of intervertebral disc herniation and were undergoing standard first-time open discectomy were followed up at 6 weeks and at 3, 6, and 12 months after surgery and annually thereafter at 13 spine clinics in 11 US states. Patient data from this prospectively gathered database were reviewed. As of May 2009, the mean (± SD) duration of follow-up among all of the intervertebral disc herniation patients whose data were analyzed was 41.5 ± 14.5 months (41.4 months in those with no durotomy vs 40.2 months in those with durotomy, p < 0.68). The median duration of follow-up among all of these patients was 47 months (range 1-95 months).A total of 799 patients underwent first-time lumbar discectomy. There was an incidental durotomy in 25 (3.1%) of these cases. There were no significant differences between the durotomy and no-durotomy groups with respect to age, sex, race, body mass index, herniation level or type, or the prevalence of smoking, diabetes, or hypertension. When outcome differences between the groups were analyzed, the durotomy group was found to have significantly increased operative duration, operative blood loss, and length of inpatient stay. However, there were no significant differences in incidence rates for nerve root injury, postoperative mortality, additional surgeries, or SF-36 scores for Bodily Pain or Physical Function, or Oswestry Disability Index scores at 1, 2, 3, or 4 years.Incidental durotomy during first-time lumbar discectomy does not appear to impact long-term outcome in affected patients.

    View details for DOI 10.3171/2011.1.SPINE10426

    View details for Web of Science ID 000289914100015

    View details for PubMedID 21375385

  • Stereotactic depth electrode investigation of the insula in the evaluation of medically intractable epilepsy JOURNAL OF NEUROSURGERY Desai, A., Jobst, B. C., Thadani, V. M., Bujarski, K. A., Gilbert, K., Darcey, T. M., Roberts, D. W. 2011; 114 (4): 1176-1186

    Abstract

    The authors describe their experience with stereotactic implantation of insular depth electrodes in patients with medically intractable epilepsy.Between 2001 and 2009, 20 patients with epilepsy and suspected insular involvement during seizures underwent intracranial electrode array implantation at the authors' institution. All patients had either 1 or 2 insular depth electrodes placed as part of an intracranial array.A total of 29 insular depth electrodes were placed using a frontal oblique trajectory. Eleven patients had a single insular electrode placed and 8 patients had 2 insular electrodes placed unilaterally. One patient had bilateral insular electrodes implanted. Postoperative imaging demonstrated satisfactory placement in all but 1 instance, and there was no associated morbidity or mortality. Fourteen patients underwent a subsequent resection, involving the frontal lobe (9 patients), temporal lobe (4), or frontotemporal lobes (1), and of these, 11 currently have Engel Class I outcome. Two patients (10%) had seizures originating within the insula and another 5 patients (25%) demonstrated early specific insular involvement. Neither patient with an insular seizure focus went on to resection. All 5 of the patients with early specific insular involvement underwent an insula-sparing resective procedure with Engel Class I outcome in all cases.Stereotactic placement of insular electrodes via a frontal oblique approach is a safe and efficient technique for investigating insular involvement in medically intractable epilepsy. The information obtained from insular recording can be valuable for appreciating the degree of insular contribution to seizures, allowing localization to the insula or clearer implication of other sites.

    View details for DOI 10.3171/2010.9.JNS091803

    View details for Web of Science ID 000288725900045

    View details for PubMedID 20950081

  • Akathisia after mild traumatic head injury Case report JOURNAL OF NEUROSURGERY-PEDIATRICS Desai, A., Nierenberg, D. W., Duhaime, A. 2010; 5 (5): 460-464

    Abstract

    The authors describe the case of a 13-year-old boy who exhibited progressive disabling motor restlessness, torticollis, urinary symptoms, and confusion following a fall from a bicycle. The differential diagnosis of this striking symptom complex in this clinical context can be problematic. In this case, the symptoms ultimately appeared most consistent with severe akathisia resulting from a single administration of haloperidol used at an outside hospital to sedate the patient prior to a head CT scan. The literature on akathisia in pediatric patients, and especially in patients following acute head injury, is reviewed, with suggestions for an approach to these symptoms in this clinical setting.

    View details for DOI 10.3171/2009.11.PEDS09389

    View details for Web of Science ID 000277131500008

    View details for PubMedID 20433258

  • How long should cerebrospinal fluid cultures be held to detect shunt infections? JOURNAL OF NEUROSURGERY-PEDIATRICS Desai, A., Lollis, S. S., Missios, S., Radwan, T., Zuaro, D. E., Schwarzman, J. D., Duhaime, A. 2009; 4 (2): 184-189

    Abstract

    Infections of CSF hardware may be indolent, and some patients have received antibiotic treatment for various reasons before CSF is obtained to check for a shunt infection. At present, there are few data in the literature to guide the decision as to how long to hold CSF specimens when attempting to diagnose hardware infections, and institutions vary in the duration at which cultures are considered "final."The authors reviewed the microbiology data from CSF specimens obtained from shunts, ventriculostomies, reservoirs, and lumbar drains at their institution over a 36-month period to discover how long after collection cultures became positive. The authors also sought to discover whether this time was affected by prior treatment with antibiotics.Of 158 positive CSF specimens obtained from hardware, the time to recovery ranged between 1-10 days, with a mean of 3.02 days (SD 2.37 days, 95% CI 2.66-3.38 days). One hundred and twenty-seven positive specimens were associated with clinical infections, and approximately 25% of these grew organisms after > 3 days, with some as long as 10 days after specimens were obtained. The most common organisms grown from individual patients were coagulase-negative Staphylococcus spp (34 cultures), Propionibacterium spp (21), Bacillus spp (6), Pseudomonas aeruginosa (4), and Staphylococcus aureus (4 cultures). Mean and maximum days to recovery were different across species, with S. aureus showing the shortest and Propionibacterium spp showing the longest incubation times. There appeared to be no significant difference in the time to recovery between specimens obtained in patients who had received prior antibiotic treatment versus those who had not.A substantial number of positive CSF specimens obtained in patients with clinical infections grew bacteria after > 3 days, with some requiring as long as 10 days. Thus, a routine 10-day observation period for CSF specimens can be justified.

    View details for DOI 10.3171/2009.4.PEDS08279

    View details for Web of Science ID 000268341400017

    View details for PubMedID 19645555

  • Hepatology outpatient service provision in secondary care: a study of liver disease incidence and resource costs CLINICAL MEDICINE Whalley, S., Puvanachandra, P., Desai, A., Kennedy, H. 2007; 7 (2): 119-124

    Abstract

    This paper discusses the annual incidence of liver disease and resource costs in providing a hepatology service for all new outpatient referrals to a secondary care setting. In a retrospective study, we found that 200 patients (1 in 1,000 of the West Suffolk population) with a mean age of 52 years were referred per year. One-third of patients had cirrhosis (almost half due to alcohol). Annual incidence (per 100,000 population) were as follows: non-alcoholic fatty liver disease (29: of which 23.5 non-cirrhotic and 5.5 cirrhotic), hepatitis C (25), hepatitis B (3), alcohol-related cirrhosis (12.5), primary biliary cirrhosis (3.5), autoimmune hepatitis (3), primary sclerosing cholangitis (2), haemochromatosis (2), hepatocellular carcinoma (1.5) and oesophageal variceal haemorrhage (6.5). Using national indicative tariffs, the total annual hepatology budget was 130K pounds (58K pounds for resources and 72K pounds for clinic attendances). The greatest resource expenditure was on endoscopy (almost half for oesophageal varices) and radiological imaging (one-third of the total budget). These findings will help inform commissioners in hepatology service funding.

    View details for Web of Science ID 000246059500011

    View details for PubMedID 17491498

  • Can Asperger syndrome be diagnosed at 26 months old? A genetic high-risk single-case study JOURNAL OF CHILD NEUROLOGY Baron-Cohen, S., Scott, F., Wheelwright, S., Johnson, M., Bisarya, D., Desai, A., Ahluwalia, J. 2006; 21 (4): 351-356

    Abstract

    Asperger syndrome, a heritable condition entailing empathy deficits together with unusually narrow interests in individuals of normal or even above-average intelligence, was recognized only recently. Here we report the first-ever prospective study of a child born to two adults with a formal diagnosis of Asperger syndrome. The child's parents are both scientists (a mathematician and a chemist). The aim of study 1 was to test if the child also developed Asperger syndrome, given the heritability of the condition, and if Asperger syndrome can be detected at 26 months. At 18 months, the child was given the Checklist for Autism in Toddlers, and at 26 months, she was assessed diagnostically for autism spectrum conditions using the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observational Scale. The child failed the Checklist for Autism in Toddlers at 18 months and met the criteria for Asperger syndrome at 26 months. This single case is consistent with the hypersystemizing, assortative mating theory of autism. This theory requires further testing with large samples. This study also demonstrates that Asperger syndrome can be diagnosed by age 26 months. The aim of study 2 was to test if dyadic eye contact in infancy is intact in a child later diagnosed with Asperger syndrome. The same child's eye contact was measured at three time points (3, 6, and 9 months) over her first year of life and compared with that of age-matched controls. Although the child had low rates of eye contact at 6 months, it was within the normal range at all three points in the first year of life. We conclude that low levels of eye contact are not predictive of later development of Asperger syndrome.

    View details for DOI 10.2310/7010.2006.00072

    View details for Web of Science ID 000238002800019

    View details for PubMedID 16900937

  • Dissociable aspects of performance on the 5-choice serial reaction time task following lesions of the dorsal anterior cingulate, infralimbic and orbitofrontal cortex in the rat: differential effects on selectivity, impulsivity and compulsivity BEHAVIOURAL BRAIN RESEARCH Chudasama, Y., Passetti, F., Rhodes, S. E., Lopian, D., Desai, A., Robbins, T. W. 2003; 146 (1-2): 105-119

    Abstract

    It is becoming increasingly apparent that multiple functions of the frontal cortex such as inhibitory control and executive attention are likely sustained by its functionally distinct and interacting sub-regions but the precise localization of dissociable executive processes has proved difficult and controversial. In the present series of studies, we investigated the behavioural effects of bilateral excitotoxic lesions of different regions of the rat neocortex in the 5-choice serial reaction time task. Whereas lesions of the dorsal anterior cingulate cortex (ACC) impaired performance of the task as revealed by a reduction in discriminative accuracy, lesions made to distinct ventral regions of the frontal cortex showed selective deficits in inhibitory measures of control. Specifically, the infralimbic lesion produced increases in premature responding that was accompanied by fast response latencies. By comparison, the orbitofrontal lesion showed perseverative tendencies particularly when the inter-trial interval was made long and unpredictable, a challenge that would normally promote premature responding instead. These different behavioural effects following dorsal and ventral lesions of the rodent frontal cortex signifies the integrity of the frontal cortex in multiple executive mechanisms that work independently and complementarily by which performance is optimized. Furthermore, these data provide new insights into the functional organization of the rodent frontal cortex with a particular emphasis on localization of function.

    View details for DOI 10.1016/j.bbr.2003.09.020

    View details for Web of Science ID 000187240600011

    View details for PubMedID 14643464