All Publications

  • Iatrogenic carotid-cavernous fistula secondary to endovascular rescue of a left M1 occlusion in the presence of a cavernous carotid aneurysm utilizing a stentriever Interdisciplinary Neurosurgery Alvarez-Pinzon, A. M., Malek, A. R. 2019; 18 (100493): 100493
  • Highly Active Antiretroviral Therapy and Gamma Knife Radiosurgery for the Treatment of AIDS-Related Primary Central Nervous System Lymphoma: A Case Report. World neurosurgery Alvarez-Pinzon, A. M., Valerio, J. E., Swedberg, H. N., Elwasila, S. M., Wolf, A., Alonso Pena, J. R. 2019


    A 66-year-old male presented with acute cephalalgia, disorientation, and lethargy. The patient was evaluated in the ER and admitted with probable hydrocephalus. Brain-MRI revealed multiple nonspecific brain lesions, predominantly involving the right temporal lobe, which on biopsy proved a diagnosis of Primary Central Nervous System Lymphoma (PCNSL). Subsequent laboratory studies demonstrated active HIV infection with a CD4 count of 21 cells/ microliter and HIV viral load (VL) of greater than 400,000 copies/milliliter. The patient was eventually initiated on highly active antiretroviral therapy (HAART). He declined palliative whole-brain radiotherapy (WBRT) but was amenable to Gamma Knife Radiosurgery (GKRS) for treatment of right temporal brain lesions. Three months later, the patient's neurological symptoms improved; similarly, his CD4 count increased to 176 cells/mL and his HIV VL was less than 90 copies/mL. By 12-month follow-up, patient was asymptomatic and at 36-months, Brain MRI demonstrated total remission (CR) without new brain lesions. The gold standard treatment of newly diagnosed PCNSL remains high-dose chemotherapy in conjunction with palliative WBRT, however there may be a role for novel, combined approaches utilizing chemotherapy, HAART, and GKRS to positively impact survival rates of PCNSL related to AIDS.

    View details for PubMedID 30654158

  • A case of chemotherapy-resistant intestinal-type sinonasal adenocarcinoma treated by gamma knife radiosurgery INTERDISCIPLINARY NEUROSURGERY-ADVANCED TECHNIQUES AND CASE MANAGEMENT Alvarez-Pinzon, A. M., Valerio, J. E., Amendola, B. E., Lakhlani, D., Stein, A. A., Coy, S., Wolf, A. L. 2017; 10: 135–37
  • A case report and technical tip of chronic subdural hematoma treated by the placement of a subdural peritoneal shunt. Trauma case reports Alvarez-Pinzon, A. M., Valerio, J. E., Barkley, K. A., Swedberg, H. N., Wolf, A. L. 2017; 7: 7–10


    Chronic subdural hematomas (CSDH) tend to occur most commonly in the elderly population, usually resulting from minor or insignificant head trauma. The pathophysiology behind CSDH is often directly associated with cerebral atrophy, and other causes of cerebral atrophy such as alcoholism or dementia. Other predisposing factors include diabetes, coagulopathy, use of anticoagulants (including aspirin), seizure disorders, and CSF shunts. Considerable evidence supporting the use of external drainage after evacuation of primary CSDH is readily available in the literature.We report the case of a 72 year-old male with a history of recurrent left subdural hematoma presenting to the neurosurgical clinic with a two-day history of personality changes, difficulty speaking, urinary incontinence, and headaches. Burr hole evacuation was performed with the placement of a subdural peritoneal shunt. At the one-month follow-up appointment, the patient had complete resolution of symptoms and CT scan showed no new recurrence of the subdural hematoma.Although several treatment options are available for the management of CSDH, recurrence of hematoma is a major and very common complication that may result in re-injury due to mass effect caused by chronic hematoma. However, placement of subdural peritoneal shunt for the treatment of CSDH can reduce the recurrence rate of CSDH and therefore, reduce the risk of brain re-injury.

    View details for DOI 10.1016/j.tcr.2017.01.005

    View details for PubMedID 30014025

    View details for PubMedCentralID PMC6024109

  • Comparison of Percutaneous Retrogasserian Balloon Compression and Gamma Knife Radiosurgery for the Treatment of Trigeminal Neuralgia in Multiple Sclerosis WORLD NEUROSURGERY Alvarez-Pinzon, A. M., Wolf, A. L., Swedberg, H. N., Barkley, K. A., Cucalon, J., Curia, L., Valerio, J. E. 2017; 97: 590–94


    We compared and evaluated percutaneous retrogasserian balloon compression (PBC) and Gamma Knife radiosurgery (GKRS) for treatment of trigeminal neuralgia (TN) in patients with multiple sclerosis (MS).In this single-center, retrospective comparative study, 202 patients with MS and concomitant TN were evaluated. A minimum follow-up of 24 months was required. Patients with a history of microvascular decompression or previous intervention were excluded. Between February 2009 and December 2013, 78 PBC procedures and 124 first-dosage GKRS procedures were performed. PBC procedures were successfully completed in all cases. The 2 groups were compared with regard to initial effect, duration of effect, and complications including type and severity.Immediate pain relief occurred in 87% of patients treated with PBC and in 23% of patients treated with GKRS. Kaplan-Meier plots for the 2 treatment modalities were similar. The 50% recurrence rate was at 12 months for the PBC group and 18 months for the GKRS group. Complication (excluding numbness) rates were 3% for GKRS and 21% for PBC. The difference was statistically significant (χ2 test, P = 0.03).PBC and GKRS are effective techniques for treatment of TN in patients with MS. Fewer complications and superior long-term relief were associated with GKRS. We consider GKRS as the first option for the treatment of TN in patients with MS, reserving PBC for patients with acute, intractable pain.

    View details for DOI 10.1016/j.wneu.2016.10.028

    View details for Web of Science ID 000396449400080

    View details for PubMedID 27756676

  • Failure Rate and Clinical Outcomes of Anterior Cruciate Ligament Reconstruction Using Autograft Hamstring Versus a Hybrid Graft ARTHROSCOPY-THE JOURNAL OF ARTHROSCOPIC AND RELATED SURGERY Leo, B. M., Krill, M., Barksdale, L., Alvarez-Pinzon, A. M. 2016; 32 (11): 2357–63


    To compare the revision rate and subjective outcome measures of autograft hamstring versus a soft tissue hybrid graft combining both autograft hamstring and tibialis allograft for isolated anterior cruciate ligament (ACL) reconstruction.A single-center retrospective, nonrandomized, comparative study of isolated ACL reconstruction revision rates for subjects who underwent arthroscopic reconstruction of the ACL using autograft hamstring or a soft tissue hybrid graft using both autograft hamstring and tibialis allograft was performed. Patients with isolated ACL tears were included and underwent anatomic single-bundle reconstruction using an independent tunnel drilling technique and a minimum of 24 months' follow-up. The primary outcome assessed was the presence or absence of ACL rerupture. Secondary clinical outcomes consisted of the International Knee Documentation Committee, University of California at Los Angeles (UCLA) ACL quality of life assessment, and the visual analog pain scale.Between February 2010 and April 2013, 95 patients with isolated ACL tears between ages 18 and 40 met the inclusion criteria and were enrolled. Seventy-one autograft hamstring and 24 soft tissue hybrid graft ACL reconstructions were performed during the course of this study. The follow-up period was 24 to 32 months (mean 26.9 months). There were no statistically significant differences in patient demographics or Outerbridge classification. No statistically significant differences in ACL retears (5.6% auto, 4.2% hybrid; P = .57) were found between groups. Clinical International Knee Documentation Committee and UCLA ACL quality of life assessment improvement scores revealed no statistically significant differences in autograft and hybrid graft reconstructions (41 ± 11, 43 ± 13; P = .65) (38 ± 11, 40 ± 10; P = .23). The mean pain level decreased from 8.1 to 2.8 in the autograft group and 7.9 to 2.5 in the hybrid group (P = .18).The use of a hybrid soft tissue graft has a comparable rerupture rate and clinical outcome to ACL reconstruction using autograft hamstring.Level III, retrospective comparative study.

    View details for DOI 10.1016/j.arthro.2016.04.016

    View details for Web of Science ID 000389519200030

    View details for PubMedID 27286700

  • Primary Central Nervous System Lymphoma (PCNSL): Analysis of Treatment by Gamma Knife Radiosurgery and Chemotherapy in a Prospective, Observational Study CUREUS Alvarez-Pinzon, A. M., Wolf, A. L., Swedberg, H., Coy, S. R., Valerio, J. E. 2016; 8 (7): e697


    Primary central nervous system lymphoma (PCNSL) is a rare cancer accounting for less than 3% of primary brain and central nervous system (CNS) tumors. Tissues involved include the brain parenchyma, leptomeninges, eyes, and spinal cord. High-dose methotrexate (MTX) is the gold standard for newly diagnosed PCNSL. However, Gamma Knife radiosurgery (GKRS) may be efficacious as a co-adjuvant treatment. The purpose of this prospective observational cohort study is to determine the effectiveness of MTX in combination with GKRS in the treatment of PCNSL.This is a prospective, observational cohort study evaluating the treatment of histologically confirmed PCNSL with MTX as a single agent in a dose of 8 g/m2 (control) and treatment with MTX, plus GKRS. Strict inclusion and exclusion criteria were employed. Primary outcomes were measured by survival rate. Secondary outcomes were assessed by the tumor's responsiveness to treatment and reduction in size as noted on imaging.Between January 2007 and January 2012, 128 charts were evaluated. Included in this evaluation were 73 chemotherapy (control) and 55 chemotherapy, plus GKRS, patients (variable). The follow-up period was 24 to 49 months (mean: 36.9 months). There were no statistically significant differences in patient demographics or histology diagnosis. Patients were treated with GK doses ranging from 11 Gy to 16 Gy (median: 11 Gy). The median survival rate from initial diagnosis was 26.8 months in the chemotherapy group and 47.6 in the chemotherapy, plus GKRS, group (p-value: 0.0034). All lesions showed a complete response after GKRS when evaluated using magnetic resonance imaging after three to eight weeks (mean range: 6.3 weeks).The use of GKRS is non-invasive, safe, and shows rapid success, improving the prognosis of the patient. This noninvasive treatment modality should be considered as an option for patients with PCNSL. In our study, GKRS as a co-adjuvant therapy to high-dose methotrexate was statistically significant for greater tumor control, enhanced overall survival period, and a lesser number of complications.

    View details for DOI 10.7759/cureus.697

    View details for Web of Science ID 000453614100033

    View details for PubMedID 27570717

    View details for PubMedCentralID PMC4996544

  • Is Subdural Peritoneal Shunt Placement an Effective Tool for the Management of Recurrent/Chronic Subdural Hematoma? CUREUS Alvarez-Pinzon, A. M., Stein, A. A., Valerio, J. E., Delgado, V., Escalante, J. A., Lopez, N., Wolf, A. L. 2016; 8 (5): e613


    OBJECTIVE : To describe a surgical technique and to report using a retrospective study the efficacy of peritoneal shunts for the treatment of recurrent/chronic subdural hematoma (CSDH). We describe the considerations, complications, and outcomes related to this technique. METHODS : In a retrospective cohort study, 125 charts with a diagnosis of subacute/chronic subdural hematoma were assigned for evaluation. Of the charts reviewed, 18 charts were found from subjects with a diagnosis of recurrent sub-acute or chronic subdural hematoma. All patients had undergone initial surgical treatment of their condition followed by peritoneal shunt placement to help alleviate intracranial pressure. Factors including the age, size of subdural hematoma, number of previous events, BMI, complications, survival, and clinical course were analyzed. RESULTS : After subdural peritoneal shunt placement all patients had full neurological recovery with no complaints of headaches, lethargy, weakness, confusion or seizures. None of the cases had new subdural hematoma episodes after placement for a minimum of a two-year period (mean 26.1 months) (range 24.3-48.6 months). No postoperative complications were reported. The rates of postoperative hemorrhage, infection, distal catheter revision, and perioperative seizures was found to be zero percent. Shunt drainage was successful in all cases, draining 85% of the blood in the first 48 hours. There was no significant relationship between complications and the use of anticoagulants four weeks after surgery.Peritoneal shunts, though rarely used, are a viable option in the treatment of sub-acute/chronic subdural hematomas. When pursuing this treatment, this technique is recommended to mitigate the risks of repeat surgical intervention and lessen perioperative time in high-risk patients.

    View details for DOI 10.7759/cureus.613

    View details for Web of Science ID 000453612100019

    View details for PubMedID 27335718

    View details for PubMedCentralID PMC4914066

  • The incidence of radiographic aseptic loosening of the humeral component in reverse total shoulder arthroplasty JOURNAL OF SHOULDER AND ELBOW SURGERY Gilot, G., Alvarez-Pinzon, A. M., Wright, T. W., Flurin, P., Krill, M., Routman, H. D., Zuckerman, J. D. 2015; 24 (10): 1555–59


    The reverse total shoulder arthroplasty (RTSA) has been used in the treatment of complex shoulder problems. The incidence of aseptic loosening of the humeral component has not been previously reported.This is a multicenter, retrospective, blinded, case-control radiographic review of 292 patients to determine the rate of humeral stem loosening. There were 177 cemented and 115 press-fit humeral components. Radiographs were critiqued for radiolucent lines adjacent to the humeral stem based on the method described by Gruen et al.The overall rate of loosening was 0.74%. No radiographic loosening occurred in the press-fit group (115 stems). In the cemented group (177 stems), 2 shoulders (1.18%) were identified with radiographically loose stems. No loosening occurred in the press-fit group. No statistically significant difference was found in humeral stem loosening when the press-fit group and the cemented group were compared (P = .198).Our study indicates the cemented or press-fit RTSA system will result in a low incidence of radiolucent lines and radiographic loosening. Compared with historical survivorship of conventional anatomic total shoulder arthroplasty, RTSA shows a lower rate of radiographic stem loosening at a mean of 38.46 months.The RTSA has a low incidence of humeral stem loosening at midterm. These results underscore the importance of careful selection of patients to provide the benefits of this surgical technique. Press-fit fixation may provide a lower risk to stem loosening.

    View details for DOI 10.1016/j.jse.2015.02.007

    View details for Web of Science ID 000361571600012

    View details for PubMedID 25958209

  • Outcome of Large to Massive Rotator Cuff Tears Repaired With and Without Extracellular Matrix Augmentation: A Prospective Comparative Study ARTHROSCOPY-THE JOURNAL OF ARTHROSCOPIC AND RELATED SURGERY Gilot, G. J., Alvarez-Pinzon, A. M., Barcksdale, L., Westerdahl, D., Krill, M., Peck, E. 2015; 31 (8): 1459–65


    To compare the results of arthroscopic repair of large to massive rotator cuff tears (RCTs) with or without augmentation using an extracellular matrix (ECM) graft and to present ECM graft augmentation as a valuable surgical alternative used for biomechanical reinforcement in any RCT repair.We performed a prospective, blinded, single-center, comparative study of patients who underwent arthroscopic repair of a large to massive RCT with or without augmentation with ECM graft. The primary outcome was assessed by the presence or absence of a retear of the previously repaired rotator cuff, as noted on ultrasound examination. The secondary outcomes were patient satisfaction evaluated preoperatively and postoperatively using the 12-item Short Form Health Survey, the American Shoulder and Elbow Surgeons shoulder outcome score, a visual analog scale score, the Western Ontario Rotator Cuff index, and a shoulder activity level survey.We enrolled 35 patients in the study: 20 in the ECM-augmented rotator cuff repair group and 15 in the control group. The follow-up period ranged from 22 to 26 months, with a mean of 24.9 months. There was a significant difference between the groups in terms of the incidence of retears: 26% (4 retears) in the control group and 10% (2 retears) in the ECM graft group (P = .0483). The mean pain level decreased from 6.9 to 4.1 in the control group and from 6.8 to 0.9 in the ECM graft group (P = .024). The American Shoulder and Elbow Surgeons score improved from 62.1 to 72.6 points in the control group and from 63.8 to 88.9 points (P = .02) in the treatment group. The mean Short Form 12 scores improved in the 2 groups, with a statistically significant difference favoring graft augmentation (P = .031), and correspondingly, the Western Ontario Rotator Cuff index scores improved in both arms, favoring the treatment group (P = .0412).The use of ECM for augmentation of arthroscopic repairs of large to massive RCTs reduces the incidence of retears, improves patient outcome scores, and is a viable option during complicated cases in which a significant failure rate is anticipated.Level III, prospective, blinded, nonrandomized, comparative study.

    View details for DOI 10.1016/j.arthro.2015.02.032

    View details for Web of Science ID 000360936400011

    View details for PubMedID 25891222

  • Hybrid Graft Anterior Cruciate Ligament Reconstruction: A Predictable Graft for Knee Stabilization ORTHOPEDICS Alvarez-Pinzon, A. M., Barksdale, L., Krill, M. K., Leo, B. M. 2015; 38 (6): E473–E476


    Trauma to the anterior cruciate ligament (ACL) is a season-ending injury and involves months of activity modification and rehabilitation. The annual incidence of ACL tears in the United States is approximately 200,000, which allows for a broad range of individualized treatment options. Various surgical techniques, including transtibial and independent tunnel drilling, allograft and autograft tissue, and various implants, have been described in the literature. This article describes the indications and technique for a hybrid soft tissue graft for ACL reconstruction. Autologous grafts eliminate the risk of disease transmission and have recently been shown to have a lower rerupture rate, particularly in younger, active patients; however, the harvesting of autologous hamstring grafts carries a risk of donor-site morbidity, iatrogenic injury of the graft, and inadequate graft size. In contrast to a traditional autologous soft tissue graft, the hybrid graft allows for graft size customization for a desired reconstruction, especially in cases where autograft hamstrings may be iatrogenically damaged or of inadequate size when harvested. The goal of a hybrid graft ACL reconstruction is to provide a favorable-sized graft with clinical outcomes comparable with autologous soft tissue grafts. In contrast to a traditional autologous soft tissue graft, this technique provides another option in the event of unforeseen deficiencies or complications associated with harvesting and preparation of the autologous gracilis and semitendinosis soft tissue graft.

    View details for DOI 10.3928/01477447-20150603-54

    View details for Web of Science ID 000358548000005

    View details for PubMedID 26091219