Faculty Bibliography

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: 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

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 .

Cervical radiculopathy secondary to compression from congenital anomalous vertebral arteries (VAs) is a known entity. Patients present with a variety of symptoms ranging from upper-extremity numbness to true occipital neuralgia. Treatment options for extracranial tortuous VAs include conservative management or some form of surgical microvascular decompression (MVD). The authors report on a patient with a congenital anomalous VA loop causing cervical nerve root compression. Successful MVD was conducted with relief of the patient's symptoms. A novel sling technique was used for mobilization of the VA. To the authors' knowledge, this is the first MVD described utilizing this technique.

There is evidence that primary hemifacial spasm (HFS) in the majority of patients is related to a vascular compression of the facial nerve at its root exit zone (REZ). As a consequence, the hyperexcitability of facial nerve generates spasms of the facial muscles. Microvascular decompression (MVD) of the facial nerve near its REZ has been established as an effective treatment of HFS. Intra-operative disappearance of abnormal muscle responses (lateral spread) elicited by stimulating one of the facial nerve branches has been used as a method to predict MVD effectiveness. Other neurophysiologic techniques, such as facial F-wave, blink reflex and facial corticobulbar motor evoked potentials (FCoMEP), are feasible to intra-operatively study changes in excitability of the facial nerve and its nucleus during MVDs. Intra-operative neuromonitoring with the mentioned techniques allows a better understanding of HFS pathophysiology and helps to optimise the MVD.

OBJECTIVE:Conventional surgical treatment of bilateral ophthalmic aneurysms would require bilateral craniotomies and bilateral neck dissections for proximal control of the cervical internal carotid artery (ICA). We present a semiemergent case where bilateral ophthalmic artery aneurysms were clipped using a unilateral mini-pterional craniotomy and contralateral proximal cervical ICA control while employing the Sugita head frame. CLINICAL PRESENTATION/METHODS:A 37-year-old female presented with progressive right retro-orbital headaches. MRI/A revealed a right carotid-ophthalmic aneurysm as well as a small aneurysm on the left carotid-ophthalmic segment. Given the young age and medial orientation of the right aneurysm, direct surgical clipping was planned. It was our thought that a contralateral approach would afford us the best chance to clip the right medially pointing aneurysm fully without optic nerve retraction while having proximal control via exposure of contralateral cervical ICA. METHODS:After gaining proximal ICA control from right neck dissection, the Sugita frame was rotated to allow for a left pterional craniotomy. The right medially pointing ophthalmic aneurysm was clipped without optic nerve retraction. After dissection of the distal dural ring and gaining proximal control, the left aneurysm was clipped. Postoperatively, the patient remained intact without any visual complaints, and both aneurysms were obliterated on angiography. CONCLUSION/CONCLUSIONS:Our case illustrates safety and control while clipping bilateral ophthalmic artery aneurysms via a unilateral mini-pterional approach and utility of the Sugita head frame.

BACKGROUND: An intracranial posterior circulation revascularization procedure in the form of a side-to-side in situ posterior inferior cerebellar artery (PICA)-PICA bypass operation was introduced in 1991. This elegant and apparently low-risk operation is performed infrequently. Thus, the operative nuances used in this procedure have not been well reported, limiting the scope of treatment modalities of vertebral artery-PICA aneurysms and vertebral dissections. OBJECTIVE: To repair an incidental right-sided PICA aneurysm noted in a 51-year-old woman in magnetic resonance imaging and subsequent angiography. METHODS: The patient underwent side-to-side in situ PICA-PICA bypass surgery. RESULTS: Immediate indocyanine green angiography suggested that the PICA distal to the aneurysms was filling in a retrograde fashion through the bypass. On the following day, the patient was taken for coil embolization of the aneurysm. However, angiography images revealed that the aneurysm was spontaneously thrombosed, the proximal PICA was patent, and the PICA distal to the aneurysms was filling in a retrograde fashion, as suspected in intraoperative indocyanine green angiography. No further treatments were done. The patient recovered fully. CONCLUSION: We describe in detail the preoperative evaluation, decision process, and operative techniques for a side-to-side in situ PICA-PICA bypass operation, which is a relatively safe and elegant posterior circulation bypass procedure

OBJECT: Chordomas are rare malignant neoplasms arising predominantly at the sacrum and skull base. They are uniformly lethal unless treated with aggressive resection and proton beam irradiation. The authors present results of the surgical management of a large number of patients with clivus chordomas. Factors that influence the surgeon's ability to achieve radical tumor resection are also evaluated. METHODS: Between 1991 and 2005, 71 patients with clivus chordomas underwent surgery. The average follow-up was 66 months (median 60 months, range 3-189 months). Sixty-five patients had complete records that were analyzed in the present report. Thirty-five percent of them had undergone surgery before being treated by the authors. They were evaluated with MR imaging and CT scanning and underwent surgery utilizing a variety of skull base techniques aimed at achieving radical excision. Many also underwent postoperative radiation, usually in the form of proton beam therapy. The patients were followed up with serial imaging at regular intervals as well as with neurological evaluation. RESULTS: Radical tumor resection was achieved in 58% of the group. The overall 5-year survival rate was 75%. Radical resection had a positive impact on survival. The ability to achieve radical resection was dependent on the preoperative tumor volume and the number of anatomical areas involved by the tumor. Cranial nerve impairment and CSF leakage were the most frequent postoperative complications. CONCLUSIONS: Radical excision is the ideal surgical goal in the treatment of clival chordomas and can be achieved with reasonable risks. Several different surgical approaches may be necessary to accomplish this