Faculty Bibliography

Background: Salvage surgery for progressive symptoms or recurrent growth of vestibular schwannoma (VS) after stereotactic radiosurgery (SRS) is uncommon. It has been reported to be more difficult, the same or easier than expected compared with microsurgical resection (MS) of treatment-naive VS, with variable facial nerve outcomes. We conducted a matched cohort analysis to evaluate facial nerve outcomes for patients undergoing MS for progressive symptoms or recurrent growth of VS after SRS compared with MS for treatment-naive VS. Methods: We evaluated the records of 365 non-NF2 VS patients treated with MS from 2001 to 2014. All patients who had postoperative notes were considered to have "adequate follow-up" and included in the study. Nine patients underwent resection for VS after prior SRS (MS-POST SRS) with no prior intervention, 7 of which had adequate follow-up, and 331 patients that underwent MS for treatment naive VS (MS-NO SRS), 317 of which had adequate follow-up. From this dataset, we created propensity score matched cohorts to retrospectively compare facial nerve preservation and clinical outcomes. The propensity score model incorporated age at surgery, tumor size, and pre-operative HB grade, and cases were matched at a ratio of 4:1 MS-NO SRS to MS-POST SRS cases. Results: The MS-POST SRS (n = 7) and MS-NO SRS (n = 28) groups differed only in preoperative hearing status (p < 0.01). Preoperative HB grades were similar between MS-POST SRS and MS-NO SRS groups (p>0.3). The average time-to-intervention after SRS in the MS-POST SRS group was 44.4 months. The indication for MS after SRS was symptom progression with tumor growth in 4 cases, and only tumor growth in the remaining 3. Postoperatively, 3 cases in the MS-POST SRS group demonstrated improvement in HB grade and none became worse whereas 3 of 28 cases in the MS-NO SRS group demonstrated improvement and 12 cases had decrement in HB grade relative to baseline (p < 0.05). There was no significant difference in the extent of resection with both cohorts (MS-POST SRS and MS-NO SRS) attaining gross total resection in 85.7% of cases. Subsequent intervention was not required for any case in the MS-POST SRS group and 2 cases in the MS-NO SRS group, although this difference was not significant. Both cases requiring subsequent intervention in the MS-POST SRS group were gross total resections via the translabyrinthine approach, with subsequent intervention required at 62 and 48 months. There were no significant differences in the complication rate for individual complications or the overall complication rate between cohorts. Conclusions: At a center with high clinical volume, microsurgical resection of VS after prior SRS was associated with good postoperative facial nerve preservation and low morbidity, comparable to those observed in resection of treatment-naive VS. In addition there were similar outcomes in terms of extent of resection between the two groups. The good outcomes reported here may reflect a confluence of factors which include patient selection, the experience of the attending surgeons, the use of more contemporary SRS dosing protocols during initial treatment for these patients, and divergent goals of therapy between cohorts

Objective: Cerebral venous sinus thrombosis (CVST) is a rare but potentially dangerous complication following craniotomies involving the posterior fossa, the skull base, and craniotomies involving the superior sagittal sinus. Surgical manipulation of the sinuses has been shown to cause sinus thromboses of varying degrees. This phenomenon is often clinically silent, with only a small number of patients becoming symptomatic. Recent advances in neuroimaging provide higher resolution evaluation of cerebral sinuses pre and postoperatively, often revealing clinically silent filling defects. Although sinus thrombosis can be a major cause of morbidity and mortality, its incidence and factors that contribute to its formation in the postoperative population remain unclear. In addition, current guidelines advise to anticoagulate with Heparin upon diagnosis, which can be contraindicated for immediate post craniotomy patients. The goal of this study is to evaluate retrospective data of patient outcomes and factors that might contribute to sinus thrombus formation. Methods: A retrospective chart review was conducted at NYU Langone Medical Center. Ninety-seven patients were included who underwent either a retrosigmoid/translabrynthine/suboccipital resection of a posterior fossa tumor or a supratentorial craniotomy for resection of parasagittal/falcine tumor between July 1, 2014 and July 1, 2015. Pre operative Magnetic Resonance Venography (MRV) was obtained per the attending surgeon's discretion. Based on intraoperative findings, clinical symptoms, and surgeon's preference, a postoperative MRV was obtained. Decision to treat a thrombosis was made based on the results of the MRV and clinical symptoms. Treatments included observation, intravenous fluids (IVF) alone, anti-platelet therapy with Aspirin alone, or a combination of the two. Results: A total of 7 of 97 patients (7.22%) had postoperative sinus thrombosis. Of those patients, 5 had occlusion of the venous sinuses. In the occlusion group, 4 had preoperative imaging documenting patency of the sinuses. An additional 2 patients had postoperative MRVs revealing partial thrombosis of the sinus, 1 that was new and 1 that did not have a preoperative MRV for comparison. Compared with the cohort of patients without postoperative thromboses, there was no significant difference in age, BMI, length of surgery, or surgical approach. Of the 5 patients with postoperative thrombotic occlusion, 4 underwent intervention (1 with IVF alone, 2 with IVF and aspirin, and 1 with aspirin alone). Two patients with thromboses also developed CSF leaks requiring lumbar drainage and operative repair. One patient had a persistent CSF leak requiring a shunt. Of the 2 patients with partial thrombosis, 1 was placed on IVF and aspirin. At 3 months follow up, 1 out of 5 patients in the occlusion group had recanalization of the previously thrombosed sinus. Conclusions: MRV is a non-invasive method to evaluate the caliber and patency of dural venous sinuses in post craniotomy patients. Symptomatic thrombosis is rare and can be managed either conservatively or with IVF and/or anti platelet therapy, both which are safer than anticoagulation with heparin in post craniotomy patients. A larger prospective trial is necessary to further characterize the incidence of postoperative venous sinus thrombosis, identify risk factors, and to devise recommendations for therapy

We describe the first patient, to our knowledge, with anaplastic pleomorphic xanthoastrocytoma (PXA) with spinal leptomeningeal spread at the time of diagnosis and present a review of the literature. PXA is a tumor that typically has an indolent course but occasionally, when anaplastic features are present, behaves in a more aggressive manner. We found that PXA with spinal leptomeningeal spread at the time of diagnosis confers a worse prognosis. Craniospinal imaging should be obtained at time of diagnosis of PXA and the presence of leptomeningeal spread may be indicative of a more aggressive disease process.

Spinal fixation in the osteoporotic patient can be challenging due to the poor trabecular bone quality of the vertebral body. Patients with osteoporotic vertebral body compression fractures are at risk for future compression fractures at adjacent levels, especially after cement augmentation. The purpose of this technical report is to describe the utilization of a cortical screw trajectory along with kyphoplasty for a patient with an osteoporotic compression fracture as well as degenerative spinal disease. This trajectory allows for the possibility of percutaneous pedicle access in the event of future compression fractures. Our patient underwent a decompressive laminectomy and kyphoplasty at the level of an osteoporotic compression fracture. The fracture was stabilized with cortical screw instrumentation and fusion at a level above and a level below the fracture. Subsequently the patient developed an adjacent level fracture within the fusion construct. Due to the utilization of a cortical screw trajectory for the initial fusion, the traditional pedicle trajectory was still accessible. As a result, the new fracture was treated with a percutaneous kyphoplasty through a standard pedicle trajectory. In conclusion, the use of a cortical screw trajectory for stabilization of osteoporotic compression fractures provides for a stronger bone screw interface and avoids osteoporotic trabecular vertebral body bone. At the same time this trajectory allows for future percutaneous pedicular access in the event that the patient suffers future compression fractures.

OBJECTIVE: Wound infections are one of the most common and potentially devastating complications of spinal surgery. Intra-wound application of vancomycin powder has been shown to lower the infection risk following posterior instrumented fusion, but little evidence supports use in other spinal operations. The goal of this study is to assess the efficacy of vancomycin powder for lumbar laminectomy and fusion, both instrumented and non-instrumented. METHODS: All cases of lumbar laminectomy and posterior fusion (with or without pedicle screw fixation) by a single surgeon were reviewed from 2007 to 2011. Routine application of 1g vancomycin powder was started in August 2009. Baseline characteristics and operative data were compared between untreated patients and those who received vancomycin powder. Rates of wound infection were compared for all fusions, and then separately for instrumented and non-instrumented cases. RESULTS: 253 patients underwent lumbar laminectomy and fusion between 2007 and 2011. Baseline and operative variables were similar between untreated patients (n=97) and those who received vancomycin powder (n=156). Patients were followed for at least one year. The infection rate fell significantly following introduction of vancomycin powder (from 11% to 0%, p=0.000018). Subgroup analysis revealed significant infection reduction for both instrumented cases (from 12% to 0%, p=0.000806) and non-instrumented cases (from 10% to 0%, p=0.0496). No complications attributable to vancomycin powder were identified. CONCLUSION: Local vancomycin powder appears to lower the risk of wound infection following lumbar laminectomy and fusion, both instrumented and non-instrumented. Further studies are needed to optimize dosing of vancomycin powder, assess long-term safety and efficacy, and evaluate use in other spinal operations.

ABSTRACT: Study Design. A retrospective cohort study.Objective. To assess the ability of local vancomycin powder to prevent wound infection after posterior cervical fusionSummary of Background Data. Wound infections are a significant source of morbidity and cost associated with spine surgery. Intraoperative application of vancomycin powder to the wound edges has been shown to lower the infection risk after posterior instrumented thoracolumbar fusion. There is little data on the efficacy and safety of local vancomycin powder in cervical spine surgery.Methods. All cases of posterior cervical fusion by a single surgeon were reviewed from 2007 to 2011. Routine application of 1 gram vancomycin powder was started in August 2009. Baseline characteristics, operative details, and rates of wound infection and pseudarthrosis were compared between untreated patients and those who received vancomycin powder.Results. 171 patients underwent posterior cervical fusion between 2007 and 2011. Baseline and operative variables were similar between untreated patients (n = 92) and those who received vancomycin powder (n = 79). Patients were followed for a minimum of one year (range 1.1 to 5.7 years). The infection rate fell from 10.9% to 2.5% (p = 0.0384) following the introduction of vancomycin powder. The untreated and treated groups had similar rates of pseudarthrosis (5.4% versus 5.1%). No complications attributable to vancomycin powder were identified.Conclusion. Routine local application of vancomycin powder is a low-cost, effective strategy for preventing wound infection after posterior cervical fusion. Further studies are needed to optimize dosing, assess long-term safety, and evaluate use in other spinal operations.

Object Surgery is increasingly used to treat children with refractory epilepsy. Before surgery, the authors routinely evaluated the coagulation profile to identify coagulation abnormalities not established by personal and family history, physical examination, and routine screening tests. Methods Thirty-nine consecutive children undergoing testing prior to epilepsy surgery were prospectively evaluated. The authors evaluated a detailed hematological history and an elaborative hematological panel including complete blood count, hepatic panel, anticoagulant levels, coagulation profile (prothrombin time, partial thromboplastin time, international normalized ratio, fibrinogen, thrombin time, von Willebrand antigen, ristocetin cofactor, factor VIII, and individual factor assays when indicated) and platelet aggregation studies (in the presence of adenosine diphosphate, epinephrine, collagen, and ristocetin). Patient variables included tuberous sclerosis complex (TSC), age at epilepsy onset, age at surgery, seizure frequency, number and type of antiepileptic drugs, recent or present ketogenic diet, and use of selective serotonin reuptake inhibitors. Results Ten children (25.6%) had either coagulation or platelet function abnormalities. Abnormal coagulation was identified in 5 children, and abnormal platelet function was discovered in 6. A diagnosis of TSC was associated with a platelet function abnormality (p = 0.012), whereas children without TSC had a higher rate of coagulopathy (p = 0.041). None of the other characteristics reached statistical significance. In 2 patients (5.1%) with TSC and platelet aggregation abnormalities, the authors noted normal standard screening laboratory studies and an uneventful detailed personal and family history. One of these 2 patients developed a significant intraoperative bleeding complication. Conclusions A preoperative screening with standard laboratory studies and detailed history may not be adequate to fully examine underlying coagulation abnormalities in children with refractory epilepsy. Platelet aggregation studies should be considered in patients with TSC