Faculty Bibliography

OBJECTIVE:A) To describe an improved methodology for continuously monitoring the functional integrity of facial nerve by eliciting facial corticobulbar motor-evoked potentials (FCoMEP) and B) To establish the prognosis of facial nerve function based on changes in FCoMEP during skull base surgery. METHODS:Intraoperative monitoring of FCoMEP performed in 100 patients. Previously published methodology has been improved upon by a) doing preoperative mapping of the facial nerve, b) facilitating the corticobulbar tract (CBT) by continuous transcranial electrical stimulation (TES) at 2 Hz repetition rate, c) recording from multiple facial nerve innervated muscles, and d) eliciting blink reflex (BR). We analyzed changes in FCoMEP, comparing them with the clinical facial nerve outcome scored with the House-Brackman (HB) scale. RESULTS:The monitorability rate was 100%. Out of 100 patients, nine presented a new facial deficit after surgery. Eight of these showed significant changes in FCoMEP. In four patients FCoMEPs were lost; they presented a complete facial paralysis from which they did not recover. To discriminate the prognosis of patients, ROC analysis identified a cut-off at 65% for FCoMEPs amplitude decrease with a sensitivity of 89% and specificity of 99%. In four patients FCoMEP showed a decrease in amplitude greater than 65%, and they presented mild/moderate facial paresis that was transient. One patient did not present changes in FCoMEP but had a mild facial paresis from which the patient recovered. CONCLUSIONS:The improved methodology allows the maximum rate of monitorability and minimizes false positive and false negative results. This study shows that prognosis of facial nerve may be reliably established based on FCoMEP parameters. SIGNIFICANCE/CONCLUSIONS:We improved the previously described methodology for continuously monitoring the functional integrity of the facial nerve by increasing the monitorability rate, and we describe the impact of FCoMEP intraoperative management of facial nerve. This method may permit establishing the short-term and long-term prognosis of facial nerve function in skull base surgery.

BACKGROUND AND PURPOSE/OBJECTIVE:Skull base tumors are commonly supplied by dural branches of the meningohypophyseal and inferolateral trunks. Embolization through these arteries is often avoided due to technical challenges and inherent risks; however, successful embolization can be a valuable surgical adjunct. We aimed to review the success and complications in our series of tumor embolizations through the meningohypophyseal and inferolateral trunks. MATERIALS AND METHODS/METHODS:We performed a retrospective review of patients with tumor treated with preoperative embolization at our institution between 2010 and 2020. We reviewed the following data: patients' demographics, tumor characteristics, endovascular embolization variables, and surgical results including estimated blood loss, the need for transfusion, and operative time. RESULTS:= 4) trunk. In this group of patients, on average, 79% of tumors were embolized. No mortality or morbidity from the embolization procedure was observed in this subgroup of patients. The average estimated blood loss in the operation was 395 mL (range, 200-750 mL). None of the patients required a transfusion, and the average operative time was 7.3 hours. CONCLUSIONS:Some skull base tumors necessitate embolization through ICA branches such as the meningohypophyseal and inferolateral trunks. Our series demonstrates that an effective and safe embolization may be performed through these routes.

Soon after the World Health Organization declared the severe acute respiratory syndrome coronavirus 2 a global health emergency on January 30, 2020, New York City was plagued by the virus and its health system and economy pushed to their limits. The majority of the limited neurosurgical data in relation to COVID-19 is anecdotal and the higher theoretical risk of transmission of the virus among skull base aerosol generating (SBAG) cases has not been investigated or discussed in a neurosurgical population. We discuss a series of 13 patients who underwent 15 SBAG surgical procedures during the peak of COVID-19 in our hospital system and the protocols use perioperatively for their procedures. Our data support that with proper preoperative testing, a well-delineated surgical algorithm, and appropriate personal protective equipment, emergent/urgent cases can be done safely in hospitals that are currently experiencing high volumes of COVID-19 cases as we did in March to May of 2020.

The prognostic value of mutations in G-protein genes GNAQ and GNA11 in patients with intracranial and orbital melanocytomas is unknown. The authors present a case of GNA11 mutation (GNA11Q209L) in a 32-year-old male suffering from a meningeal melanocytoma with orbital involvement and ipsilateral Nevus of Ota. The patient underwent gamma knife stereotactic radiosurgery without biopsy and later partial transcranial resection of the melanocytic tumor that was subject to immunohistochemical and molecular analysis. A 50-gene next-generation sequencing panel revealed a 626A>T mutation in the GNA11 gene. One year later, intracranial extension of the melanocytoma necessitated a ventriculoperitoneal shunt and immunotherapy. Future work is needed to determine how GNA11 mutations in melanocytomas influence prognosis and monitoring strategies.

PURPOSE:), whereas no molecularly based stratification exists for the broad spectrum of patients with low- and intermediate-risk meningioma. METHODS:DNA methylation data and copy-number information were generated for 3,031 meningiomas (2,868 patients), and mutation data for 858 samples. DNA methylation subgroups, copy-number variations (CNVs), mutations, and WHO grading were analyzed. Prediction power for outcome was assessed in a retrospective cohort of 514 patients, validated on a retrospective cohort of 184, and on a prospective cohort of 287 multicenter cases. RESULTS:= .005). Besides the overall stratification advantage, the integrated score separates more precisely for risk of progression at the diagnostically challenging interface of WHO grade 1 and grade 2 tumors (hazard ratio 4.34 [2.48-7.57] and 3.34 [1.28-8.72] retrospective and prospective validation cohorts, respectively). CONCLUSION:Merging these layers of histologic and molecular data into an integrated, three-tiered score significantly improves the precision in meningioma stratification. Implementation into diagnostic routine informs clinical decision making for patients with meningioma on the basis of robust outcome prediction.

OBJECTIVE:Pituitary carcinoma is a rare tumor, defined as a tumor of adenohypophyseal cells with systemic or craniospinal metastasis. We present a case of a growth hormone (GH)-secreting pituitary carcinoma with a review of literature to better characterize this disease. DESIGN:Case report and literature review of 25 cases of GH-secreting pituitary carcinomas RESULTS: The age of diagnosis of GH-secreting carcinomas ranged 24-69 years old with a mean age of 44.4 with 52% of cases present in females. Mean latency period between diagnosis of acromegaly and transition to pituitary carcinoma was 11.4 years with mean survival being 3.4 years. CONCLUSION:Growth hormone (GH)-secreting pituitary carcinomas are rare and hard to distinguish from aggressive pituitary adenomas. From review of literature, treatment options include debulking surgery, radiotherapy, or chemotherapy with dismal outcomes. There are no diagnostic markers or features which can predict metastatic progression of these tumors. Future studies with genomic landscapes and relevant tumor markers are needed to identify pituitary tumors most likely to metastasize.

Inhibition of mTORC1 signaling has been shown to diminish growth of meningiomas and schwannomas in preclinical studies, and clinical data suggest that everolimus, an orally administered mTORC1 inhibitor, may slow tumor progression in a subset of NF2 patients with vestibular schwannoma (VS). To assess the pharmacokinetics, pharmacodynamics and potential mechanisms of treatment resistance, we performed a pre-surgical (phase 0) clinical trial of everolimus in patients undergoing elective surgery for VS or meningiomas. Eligible patients with meningioma or VS requiring tumor resection enrolled on study received everolimus 10 mg daily for 10 days immediately prior to surgery. Everolimus blood levels were determined immediately prior to and after surgery. Tumor samples were collected intraoperatively. Ten patients completed protocol therapy. Median pre- and post-operative blood levels of everolimus were found to be in a high therapeutic range (17.4 ng/ml and 9.4 ng/ml, respectively). Median tumor tissue drug concentration determined by mass spectrometry was 24.3 pg/mg (range 9.2-169.2). We observed only partial inhibition of phospho-S6 in the treated tumors, indicating incomplete target inhibition compared to control tissues from untreated patients (p=0.025). Everolimus led to incomplete inhibition of mTORC1 and downstream signaling. These data may explain the limited anti-tumor effect of everolimus observed in clinical studies for NF2 patients and will inform the design of future pre-clinical and clinical studies targeting mTORC1 in meningiomas and schwannomas.

OBJECTIVE:Meningiomas that arise primarily within the cavernous sinus are often believed to be more indolent in their growth pattern. Despite this perceived growth pattern, disabling symptoms can arise even with small tumors. While research has been done on cavernous sinus meningiomas (CSMs) and their treatment, very little is known about their natural growth rates. With a better understanding of the growth rate of CSM, patient treatment and guidance can be can optimized and individualized. The goal of this study was to determine volumetric growth rates of untreated CSMs. METHODS:Thirty-seven patients with 166 MR images obtained between May 2004 and September 2019 were reviewed, with a range of 2-13 MR images per patient (average of 4.5 MR images per patient). These scans were obtained over an average follow-up period of 45.9 months (median 33.8, range 2.8-136.9 months). All imaging prior to any intervention was included in this analysis. Volumetric measurements were performed and assessed over time. RESULTS:The estimated volumetric growth rate was 23.3% per year (95% CI 10.2%-38.0%, p < 0.001), which is equivalent to an estimated volume doubling time (VDT) of 3.3 years (95% CI 2.1-7.1 years). There was no significant relationship between growth rate and patient age (p = 0.09) or between growth rate and patient sex (p = 0.78). The median absolute growth rate was 41% with a range of -1% to 1793%. With a definition of "growth" as an increase of greater than 20% during the observed period, 65% of tumors demonstrated growth within their observation interval. Growth rates for each tumor were calculated and tumors were segmented based on growth rate. Of 37 patients, 22% (8) demonstrated no growth (< 5% annual growth, equivalent to a VDT > 13.9 years), 32% (12) were designated as slow growth (annual growth rate 5%-20%, VDT 3.5-13.9 years), 38% (14) were found to have medium growth (annual growth rate 20%-100%, VDT 0.7-3.5 years), and 8% were considered fast growing (annual growth rate > 100%, VDT < 0.7 years). CONCLUSIONS:This study evaluated CSM volumetric growth rates. A deeper understanding of the natural history of untreated CSMs allows for better counseling and management of patients.

Inflammatory orbital lesions include a broad list of diagnoses, many of them with overlapping clinical and radiographic features. They often present a diagnostic conundrum, even to the most experienced orbital specialist, thus placing considerable weight on surgical biopsy and histopathological analysis. However, histopathological diagnosis is also inherently challenging due to the rarity of these lesions and the overlaps in histologic appearance among distinct disease entities. We herein present the case of an adolescent male with a subacutely progressive orbital mass that generated a significant diagnostic dilemma. Early orbital biopsy was consistent with a benign fibro-inflammatory lesion, but corticosteroid therapy was ineffective in halting disease progression. After an initial substantial surgical debulking, histopathological analysis revealed several key features consistent with IgG4-related disease (IgG4-RD), a systemic fibro-inflammatory process typically accompanied by multifocal tumor-like lesions. Surprisingly, within months, there was clear evidence of clinical and radiographic disease progression despite second-line rituximab treatment, prompting a second surgical debulking. This final specimen displayed distinctive features of Rosai-Dorfman disease (RDD), a systemic inflammatory disease characterized by uncontrolled histiocytic proliferation. Interestingly, certain features of this re-excision specimen were still reminiscent of IgG4-RD, which not only reflects the difficulty in differentiating RDD from IgG4-RD in select cases, but also illustrates that these diagnoses may exist along a spectrum that likely reflects a common underlying pathogenetic mechanism. This case emphasizes the importance of surgical biopsy or resection and histopathological analysis in diagnosing-and, ultimately, treating-rare, systemic inflammatory diseases involving the orbit, and, furthermore, highlights the shared histopathological features between RDD and IgG4-RD.