Faculty Bibliography

OBJECT/OBJECTIVE:Minimally invasive (MI) transforaminal lumbar interbody fusion (TLIF) has been demonstrated in previous studies to offer improvement in pain and function comparable to those provided by the open surgical approach. However, comparative studies in the obese population are scarce, and it is possible that obese patients may respond differently to these two approaches. In this study, the authors compared the clinical benefit of open and MI TLIF in obese patients. METHODS:The authors conducted a retrospective cohort study based on review of electronic medical records at a single institution. Eligible patients had a body mass index (BMI) ≥ 30 kg/m(2), were ≥ 18 years of age, underwent single-level TLIF between 2007 and 2011, and outcome was assessed at a minimum 6 months postoperatively. The authors categorized patients according to surgical approach (open vs MI TLIF). Outcome measures included postoperative improvement in visual analog scale (VAS), Oswestry Disability Index (ODI), estimated blood loss (EBL), and hospital length of stay (LOS). RESULTS:A total 74 patients (21 open and 53 MI TLIF) were studied. Groups had similar baseline characteristics. The median BMI was 34.4 kg/m(2) (interquartile range 31.6-37.5 kg/m(2)). The mean follow-up time was 30 months (range 6.5-77 months). The mean improvement in VAS score was 2.8 (95% CI 1.9-3.8) for the open group (n = 21) and 2.4 (95% CI 1.8-3.1) for the MI group (n = 53), which did not significantly differ (unadjusted, p = 0.49; adjusted, p = 0.51). The mean improvement in ODI scores was 13 (95% CI 3-23) for the open group (n = 14) and 15 (95% CI 8-22) for the MI group (n = 45), with no significant difference according to approach (unadjusted, p = 0.82; adjusted, p = 0.68). After stratifying by BMI (< 35 kg/m(2) and ≥ 35 kg/m(2)), there was still no difference in either VAS or ODI improvement between the approaches (both unadjusted and adjusted, p > 0.05). Complications and EBL were greater for the open group than for the MI group (p < 0.05). CONCLUSIONS:Obese patients experienced clinically and statistically significant improvement in both pain and function after undergoing either open or MI TLIF. Patients achieved similar clinical benefit whether they underwent an open or MI approach. However, patients in the MI group experienced significantly decreased operative blood loss and complications than their counterparts in the open group.

A major goal of the Section on Tumors of the American Association of Neurological Surgery (AANS) and Congress of Neurological Surgeons (CNS) since it was founded in 1984 has been to foster both education and research in the field of brain tumor treatment and development. In support of this goal, the Section sponsors a number of awards, named lectures, and fellowships at the annual meetings of the AANS and CNS. In this article, we describe the awards given by the AANS/CNS Section on Tumors since its foundation, the recipients of the awards, and their philanthropic donors. The subsequent history of awardees and their work is briefly examined. Specifically for the Preuss and Mahaley Awards, this article also examines the rates of publication among the award-winning abstracts and achievement of grant funding by awardees.

Stereotactic frame placement for radiosurgery is assumed to be an uncomfortable experience. We developed angled anterior posts for the Leksell frame to avoid pin penetration of the temporalis muscle. This study aimed to determine the frequency of angled post requirement and quantify the patient pain experience from frame placement. We prospectively enrolled 63 patients undergoing radiosurgery. Angled posts were used when conventional post trajectory was posterior or within 3mm of the superior temporal line to avoid temporalis muscle penetration. Pain scores (0 to 10) were collected prior to frame placement, immediately after frame placement, before radiosurgery, after radiosurgery, and a day after radiosurgery. A total of 63 patients were enrolled: 33 (48%) patients required angled posts. Women were significantly more likely to require angled posts than men (60.0% versus 33.3%, respectively; p=0.034). Mean pain scores were very low, ranging from 0.33 to 2.23. There were no significant differences in pain outcomes between both groups at all time points. Stereotactic frame placement is not perceived to be a painful procedure. This information may be useful when counseling patients about the pain experience with frame application and the option of using angled anterior posts.

Malignant peripheral nerve sheath tumors (MPNSTs) are rare, affecting only a small portion of the general population. In many cases, MPNSTs occur in association with neurofibromatosis Type 1 and at times arise secondary to previous radiation therapy (RT). These tumors can be found essentially anywhere a peripheral nerve is present, but they rarely originate primarily from the spinal nerve or cauda equina and cause leptomeningeal spread. This report describes the treatment course of a 43-year-old man with a history of testicular seminoma treated with RT a decade before, who was found to have a large sacral MPNST. The patient underwent complete sacrectomy for gross-total resection. Despite this effort, he was eventually found to have metastatic lesions throughout the spine and brain, ultimately resulting in acute hydrocephalus and death. Biopsy results of these metastatic lesions proved to be characteristic of his original MPNST. The literature is also reviewed and the diagnostic modalities, management strategies, and prognosis of MPNST are discussed.

STUDY DESIGN/METHODS:Systematic review of literature. OBJECTIVE:To perform a comprehensive English language systematic literature review of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF), concentrating on incidence, risk factors, health related quality of life impact, prevention strategy, and classification systems. SUMMARY OF BACKGROUND DATA/BACKGROUND:PJK and PJF are well described clinical pathologies and are a frequent cause of revision surgery. The development of a PJK classification that correlates with clinical outcomes and guides treatment decisions and possible prevention strategies would be of significant benefit to patients and surgeons. METHODS:The phrases "proximal junctional," "proximal junctional kyphosis," and "proximal junctional failure" were used as search terms in PubMed for all years up to 2014 to identify all articles that included at least one of these terms. RESULTS:Fifty-three articles were identified overall. Eighteen articles assessed for risk factors. Eight studies specifically reviewed prevention strategies. There were no randomized prospective studies. There were 3 published studies that have attempted to classify PJK. The reported incidence of PJK ranged widely, from 5% to 46% in patients undergoing spinal instrumentation and fusion for adult spinal deformity. It is reported that 66% of PJK occurs within 3 months and 80% within 18 months after surgery. The reported revision rates due to PJK range from 13% to 55%. Modifiable and nonmodifiable risk factors for PJK have been characterized. CONCLUSION/CONCLUSIONS:PJK and PJF affect many patients after long segment instrumentation after the correction of adult spinal deformity. The epidemiology and risk factors for the disease are well defined. A PJK and PJF scoring system may help describe the severity of disease and guide the need for revision surgery. The development and prospective validation of a PJK classification system is important considering the prevalence of the problem and its clinical and economic impact. LEVEL OF EVIDENCE/METHODS:N/A.

Comparative studies evaluating efficacy and safety of minimally invasive spinal fusion between patients with significant obesity (body mass index [BMI]≥35 kg/m(2)) and those of normal weight are scarce. We examined complication rates and outcomes for minimally invasive transforaminal lumbar interbody fusion (MITLIF) in patients with significant obesity and those of normal weight undergoing treatment for symptomatic spondylolisthesis. Patients with a BMI≥35 kg/m(2) or <25 kg/m(2) undergoing elective MITLIF for symptomatic spondylolisthesis for the period 2006-09 were identified. Of the 16 patients identified, nine patients with a mean BMI of 37.4 kg/m(2) were included in the obese group, while seven patients with a mean BMI of 23.4 kg/m(2) comprised the normal weight group. Estimated blood loss (EBL), operative time, complication rate, length of hospital stay, and clinical outcomes were assessed. Outcome measures included patient-reported visual analog scale (VAS) score for pain and the Oswestry Disability Index (ODI) questionnaire completed by the patient. No significant differences were found in blood loss (p=0.436), hospital stay (p=0.606), or number of surgical complications (p=0.920) between the two groups. Mean follow-up intervals were 15.0 months for patients with obesity, and 18.6 months for those of normal weight. Both groups had significant improvements in VAS (obese, p=0.003; normal, p=0.016) and ODI (obese, p=0.020; normal, p=0.034) scores. There were no statistically significant differences between normal weight and obese groups in postoperative VAS (p=0.728) and ODI (p=0.886) scores. Patients with significant obesity experienced clinical improvement similar to that of patients with normal weight, suggesting that obesity does not impact MITLIF outcomes. In addition, both groups experienced similar complication rates, operative times, EBL, and length of hospital stay.

STUDY DESIGN/METHODS:Retrospective case series. OBJECTIVE:To compare perioperative end points and outcomes of single-level versus multilevel corpectomy performed using a modified costotransversectomy approach. SUMMARY OF BACKGROUND DATA/BACKGROUND:Single-level corpectomy via posterolateral approach has been shown to be an effective alternative to the traditional anterior thoracotomy approach. However, there is a paucity of studies that have examined multilevel thoracic corpectomy via posterolateral approach. METHODS:Using electronic medical records, we identified a consecutive population of adult patients who underwent modified costotransversectomy corpectomy in the thoracic region between 2006 and 2009. Patients were stratified by number of corpectomies performed into either a single-level or multilevel group. With the use of baseline descriptive statistics and multivariate analysis, perioperative parameters and follow-up outcomes were assessed between the 2 groups. RESULTS:A total of 40 patients were included in the final analysis, with 25 patients in the single-level group and 15 patients in the multilevel group. Mean follow-up was 16.1 months. Overall complication rate was 37.5%. Between the 2 groups, there were no significant differences in operative time, blood loss, transfusion rate, quantity of blood transfused, length of hospital stay, or complication rates. Also, there were no significant differences in repeat surgery rate, Medical Research Council strength, Nurick score, or pain at most recent follow-up, and all groups gained a comparable magnitude of benefit from surgery. CONCLUSION/CONCLUSIONS:Multilevel corpectomy via modified costotransversectomy approach in the thoracic region is a feasible and effective option that does not seem to be associated with significantly increased morbidity. The degree of clinical improvement also seems comparable with single-level corpectomy.

OBJECT/OBJECTIVE:The surgical Apgar score (SAS) reliably predicts postoperative death and complications and has been validated in a large cohort of general and vascular surgery patients. However, there has been limited study of the utility of the score in the neurosurgical population. The authors tested the hypothesis that the SAS would predict postoperative complications and length of stay after neurosurgical procedures. METHODS:A cohort of 918 intracranial and spine surgery patients treated over a 3-year period were retrospectively evaluated. The 10-point SAS was calculated and postoperative 30-day mortality and complications rates, intensive care unit (ICU) stay, and hospital stay were assessed by 2 independent raters. Univariate analysis and multivariate logistic regression were performed. RESULTS:There were 145 patients (15.8%) with at least 1 complication and 24 patients (2.6%) who died within 30 days of surgery. Surgical Apgar scores were significantly associated with the likelihood of postoperative complications (p < 0.001) and death (p = 0.002); scores varied inversely with postoperative complication and mortality risk in a multivariate analysis. Low SASs also predicted prolonged ICU and hospital stay. Patients with scores of 0-2 stayed a mean of 18.9 days (p < 0.001) and patients with scores of 3-4 stayed an average of 14.3 days (p < 0.001) compared with 4.1 days in patients with scores of 9-10. CONCLUSIONS:The application of the surgical Apgar score to a neurosurgical cohort predicted 30-day postoperative mortality and complication rates as well as extended ICU and hospital stay. This readily calculated score may help neurosurgical teams efficiently direct postoperative care to those at highest risk of death and complications.

Paragangliomas are relatively rare tumors, accounting for only about 0.3% of all neoplasms. Most paragangliomas are defined as benign in nature, but 10-20% possess metastatic potential. There have been scattered reports of metastatic paraganglioma in the literature, but in rare circumstances, paragangliomas can metastasize to the spinal column causing destruction or compression of the spinal cord, clinically manifesting as pain or neurological deficit. We report a case of metastatic paraganglioma in which a 47-year-old man had spinal metastasis from a primary abdominal paraganglioma and was found to be positive for SDHB mutation, portraying negative implications for prognosis. Long-term follow-up is reported. In addition, we review the literature on the topic of metastatic paraganglioma, management of paragangliomas involving spine, and touch on the importance of the presence of SDHB mutations in these cases.

BACKGROUND:Mesh cages have commonly been used for reconstruction after corpectomy. Recently, expandable cages have become a popular alternative. Regardless of cage type, subsidence is a concern following cage placement. OBJECTIVE:To assess whether subsidence rates differ between static and expandable cages, and identify independent risk factors for subsidence and extent of subsidence when present. METHODS:A consecutive population of patients who underwent corpectomy between 2006 and 2009 was identified. Subsidence was assessed via x-ray at 1-month and 1-year follow-ups. In addition to cage type, demographic, medical, and cage-related covariates were recorded. Multivariate models were used to assess independent associations with rate, odds, and extent of subsidence. RESULTS:Of 91 patients, 44.0% had expandable cages and 56.0% had static cages. One-month subsidence rate was 36.3%, and the 1-year subsidence rate was 51.6%. Expandable cages were independently associated with higher rates and odds of subsidence in comparison with static cages. Infection, trauma, and footplate-to-vertebral body endplate ratio of less than 0.5 were independent risk factors for subsidence. The presence of prongs on cages and posterior fusion 2 or more levels above and below corpectomy level had lower rates and odds of subsidence. Infection and cage placement in the thoracic or lumbar region had greater extent of subsidence when subsidence was present. CONCLUSION/CONCLUSIONS:Expandable cages had higher rates and risk of subsidence in comparison with static cages. When subsidence was present, expandable cages had greater magnitudes of subsidence. Other factors including footplate-to-vertebral body endplate ratio, prongs, extent of supplemental posterior fusion, spinal region, and diagnosis also impacted subsidence.