Faculty Bibliography

BACKGROUND AND PURPOSE: Preoperative localization of the pituitary gland with imaging in patients with macroadenomas has been inadequately explored. The pituitary gland enhancing more avidly than a macroadenoma has been described in the literature. Taking advantage of this differential enhancement pattern, our aim was to evaluate the role of high-resolution dynamic MR imaging with golden-angle radial sparse parallel reconstruction in localizing the pituitary gland in patients undergoing trans-sphenoidal resection of a macroadenoma. MATERIALS AND METHODS: A retrospective study was performed in 17 patients who underwent trans-sphenoidal surgery for pituitary macroadenoma. Radial volumetric interpolated brain examination sequences with golden-angle radial sparse parallel technique were obtained. Using an ROI-based method to obtain signal-time curves and permeability measures, 3 separate readers identified the normal pituitary gland distinct from the macroadenoma. The readers' localizations were then compared with the intraoperative location of the gland. Statistical analyses were performed to assess the interobserver agreement and correlation with operative findings. RESULTS: The normal pituitary gland was found to have steeper enhancement-time curves as well as higher peak enhancement values compared with the macroadenoma (P < .001). Interobserver agreement was almost perfect in all 3 planes (kappa = 0.89). In the 14 cases in which the gland was clearly identified intraoperatively, the correlation between the readers' localization and the true location derived from surgery was also nearly perfect (kappa = 0.95). CONCLUSIONS: This study confirms our ability to consistently and accurately identify the normal pituitary gland in patients with macroadenomas with the golden-angle radial sparse parallel technique with quantitative permeability measurements and enhancement-time curves.

H3K27 downregulates gene transcription. When H3K27 is trimethylated, it is tightly associated with inactive gene promoters. In malignant gliomas, the loss of histone H3K27 trimethylation is strongly associated with underlying K27M mutation; however the role of H3K27 in meningiomas has not been completely elucidated. Atypical and anaplastic meningiomas (WHO Grade II and III) are associated with higher risk of recurrence following gross total resection; however the molecular biology of anaplastic progression is not completely understood. We performed histological and molecular analysis of 14 WHO Grade II and III meningiomas and compared them with 6 locally invasive WHO Grade I meningiomas. Grade and atypical features were correlated with expression of histone H3K27 trimethylation by immunohistochemistry. Staining intensity (none, weak, moderate, strong) and extent of staining (0-100% of the tumor) were evaluated semi-quantitatively. We also tested the tumors for K27M mutation by mutation specific antibody. Out of 14 high grade meningiomas, 10 showed a complete loss of K27 trimethyl staining and 4 tumors showed small foci of preserved trimethyl staining, mostly in areas close to the dura; however staining intensity was weak. In contrary, all 6 (100%) WHO Grade I tumors showed preserved multifocal trimethyl mark expression in 25-50% of the tumor cells, with moderate (5) or strong (1) staining intensity. All tumors were negative for histone H3K27M mutation by immunohistochemistry. Atypical and anaplastic meningiomas show almost uniform loss of histone H3K27 trimethylation staining. However this loss of trimethylation is not caused by histone H3K27M mutation. Loss of histone H3K27 trimethylation leads to dysregulation of the PRC2 complex, which is involved in repression of non-cell-type specific promoters and may contribute to aggressive behavior. Clinically, loss of histone H3K27 trimethylation can be used as a diagnostic marker for a high grade meningiomaswhen histological features are inconclusive

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

BACKGROUND: In this article, we report on the technique of placing fat in between a sellar or parasellar neoplasm and the optic chiasm to possibly protect the optic chiasm from sequelae of radiation. METHODS: A review was performed on three patients, each of whom had planned subtotal resection with fat placed near their optic chiasm to facilitate future radiosurgery. RESULTS: Follow-up on our three patients varied from 6 months to 3 years post-stereotactic radiosurgery. The fat remained stable and in place. The tumors either remained stable or reduced in size. No infections, postoperative marker dependent neurological complications or unusual symptoms were encountered. CONCLUSIONS: Placement of fat between a parasellar neoplasm and the optic chiasm appears to be a safe approach to help define the tumor chiasm space, helping to facilitate radiosurgery. Future experience is warranted to determine the efficacy of this technique.

A petroclival meningioma represents a challenging tumor to resect in the cerebellopontine angle and ventral to the brain stem. Multiple cranial nerves and blood vessels may be intimately involved with the tumor. A partial labyrinthectomy presigmoid transpetrosal approach can facilitate resection while preserving hearing. This approach allows for a direct line of sight along the petrous bone while sealing the canals can preserve hearing. In this video operative manuscript, we demonstrate a step-by-step illustration of a partial labyrinthectomy presigmoid transpetrosal resection of a petroclival meningioma. This approach affords the best chance of hearing preservation and an opportunity for maximum tumor resection. The video can be found here: http://youtu.be/29I4KEXz1vY .