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Omar Choudhri and Michael T. Lawton

The middle tentorial incisural space, located lateral to the midbrain and medial to the temporal lobe, contains the ambient cistern through which courses the third, fourth, and fifth cranial nerves, posterior cerebral artery (PCA), superior cerebellar artery, and the choroidal arteries. Arteriovenous malformations (AVMs) in this compartment are supplied by the thalamogeniculate and posterior temporal branches of the PCA, and drain into tributaries of the basal vein of Rosenthal. We present a case of an AVM in this middle tentorial incisural space that persisted after embolization and radiosurgery, and was microsurgically resected through a subtemporal approach. This case demonstrates the anatomy of the middle incisural space and technical aspects in microsurgical resection of these rare AVMs.

The video can be found here: https://youtu.be/V-dIWh8ys3E.

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Omar Choudhri and Steven D. Chang

Craniopharyngiomas are benign, partly cystic epithelial tumors that can rarely occur in a retrochiasmatic location with involvement of the third ventricle. The lamina terminalis is an important neurosurgical corridor to these craniopharyngiomas in the anterior portion of the third ventricle. We present a video case of a large midline suprasellar and third ventricular craniopharyngioma in a 32-year-old male with visual disturbances. The tumor was approached with a subfrontal translamina terminalis exposure, and a gross-total resection of the tumor was achieved. This surgery involved working through a lamina terminalis fenestration around the optic nerve, optic chiasm, optic tracts, and the anterior communicating artery complex. This video illustrates the techniques employed in performing a transbasal anterior skull base approach to the third ventricle and demonstrates vivid surgical anatomy of neurovascular structures around the lamina terminalis.

The video can be found here: https://youtu.be/fCYMgx8SnKs.

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Omar Choudhri and Steven D. Chang

Pinealoblastomas are WHO grade IV tumors of the pineal region and comprise up to 50% of all pineal parenchymal tumors. They are highly aggressive tumors that spread along the craniospinal axis and are most commonly seen in children. The standard of care involves maximal surgical resection and chemoradiation following tissue diagnosis. We present the rare case of a large pinealoblastoma in an 18-year-old girl who presented with headaches and Parinaud's syndrome from tectal compression. An attempt was made at endoscopic transventricular biopsy of the tumor at an outside hospital, but it was aborted given bleeding at the biopsy site. We performed a supracerebellar infratentorial approach in a sitting position to achieve a gross-total resection of the tumor. This video case illustrates techniques for setting up a sitting craniotomy and approaching a previously biopsied hemorrhagic pinealoblastoma. The venous conglomerate at the tentorial incisura was found to be enveloped by the tumor and a thickened arachnoid scar. Surgical anatomy of the third ventricle and the pineal region is illustrated in this case through the process of surgical dissection and tumor resection.

The video can be found here: https://youtu.be/CzB0lFQ7AyI.

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Kimon Bekelis, Ian D. Connolly, Huy M. Do and Omar Choudhri

OBJECTIVE

The impact of procedural volume on the outcomes of cerebrovascular surgery in children has not been determined. In this study, the authors investigated the association of operative volume on the outcomes of cerebrovascular neurosurgery in pediatric patients.

METHODS

The authors performed a cohort study of all pediatric patients who underwent a cerebrovascular procedure between 2003 and 2012 and were registered in the Kids' Inpatient Database (KID). To control for confounding, the authors used multivariable regression models, propensity-score conditioning, and mixed-effects analysis to account for clustering at the hospital level.

RESULTS

During the study period, 1875 pediatric patients in the KID underwent cerebrovascular neurosurgery and met the inclusion criteria for the study; 204 patients (10.9%) underwent aneurysm clipping, 446 (23.8%) underwent coil insertion for an aneurysm, 827 (44.1%) underwent craniotomy for arteriovenous malformation resection, and 398 (21.2%) underwent bypass surgery for moyamoya disease. Mixed-effects multivariable regression analysis revealed that higher procedural volume was associated with fewer inpatient deaths (OR 0.58; 95% CI 0.40–0.85), a lower rate of discharges to a facility (OR 0.87; 95% CI 0.82–0.92), and shorter length of stay (adjusted difference −0.22; 95% CI −0.32 to −0.12). The results in propensity-adjusted multivariable models were robust.

CONCLUSIONS

In a national all-payer cohort of pediatric patients who underwent a cerebrovascular procedure, the authors found that higher procedural volume was associated with fewer deaths, a lower rate of discharges to a facility, and decreased lengths of stay. Regionalization initiatives should include directing children with such rare pathologies to a center of excellence.

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Omar Choudhri and Michael P. Marks

Tentorial dural arteriovenous fistulae are rare intracranial fistulae, in which the fistula pocket is present within the leaves of tentorium cerebelli. These tentorial fistulae can be rarely present near the galenic complex, where they can engorge the deep venous system and cause symptoms of venous hypertension. We present an interesting case of endovascular treatment of a galenic tentorial dural arteriovenous fistula in a patient with headaches and imbalance. The fistula was accessed through the artery of Davidoff and Schecter from the posterior cerebral artery supplying the fistula. The fistula was completely embolized using Onyx and with preservation of vein of Galen.

The video can be found here: http://youtu.be/igX2X5tfvrg.

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Omar Choudhri and Gary K. Steinberg

Tentorial dural arteriovenous fistulae (TDAVFs) are complex lesions with the arteriovenous fistula located between the leaves of the tentorium cerebelli. While a large portion of dural arteriovenous fistulae are treated endovascularly, TDAVF may require additional microsurgical treatment given their high risk of hemorrhage and multitude of feeders. We describe the case of a 65-year-old male who presented with hemorrhage from a straight sinus and galenic TDAVF. The straight sinus portion of the fistula was obliterated by 3 endovascular treatments and 1 microsurgical treatment. The galenic component of the TDAVF persisted and was approached via a posterior interhemispheric approach in a lateral position. This video demonstrates surgical technique and anatomy associated with this rarely seen dural arteriovenous fistula.

The video can be found here: https://youtu.be/iOLzWOabLZ0.

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Stanley Hoang, Omar Choudhri, Michael Edwards and Raphael Guzman

A vein of Galen malformation is a rare intracranial vascular lesion affecting the pediatric population. Its poor prognosis has been significantly improved with the development of endovascular embolization. In this paper the authors review the developmental mechanisms, clinical pathophysiology, and the available data on the management and outcome of the disease.

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Aatman Shah, Omar Choudhri, Henry Jung and Gordon Li

In this review paper the authors analyze new therapeutic options for the embolization of meningiomas, as well as the future of meningioma treatment through recent relevant cohorts and articles. They investigate various embolic materials, types of meningiomas amenable to embolization, imaging techniques, and potential imaging biomarkers that could aid in the delivery of embolic materials. They also analyze perfusion status, complications, and new technical aspects of endovascular preoperative embolization of meningiomas. A literature search was performed in PubMed using the terms “meningioma” and “embolization” to investigate recent therapeutic options involving embolization in the treatment of meningioma. The authors looked at various cohorts, complications, materials, and timings of meningioma treatment. Liquid embolic materials are preferable to particle agents because particle embolization carries a higher risk of hemorrhage. Liquid agents maximize the effect of devascularization because of deeper penetration into the trunk and distal tumor vessels. The 3 main imaging techniques, MRI, CT, and angiography, can all be used in a complementary fashion to aid in analyzing and treating meningiomas. Intraarterial perfusion MRI and a new imaging modality for identifying biomarkers, susceptibility-weighted principles of echo shifting with a train of observations (SW-PRESTO), can relay information about perfusion status and degrees of ischemia in embolized meningiomas, and they could be very useful in the realm of therapeutics with embolic material delivery. Direct puncture is yet another therapeutic technique that would allow for more accurate embolization and less blood loss during resection.

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Rohaid Ali, Maged Goubran, Omar Choudhri and Michael M. Zeineh

The goal of this paper was to review the effectiveness of using 7-T MRI to study neuroimaging biomarkers for Alzheimer’s disease (AD). The authors reviewed the literature for articles published to date on the use of 7-T MRI to study AD. Thus far, there are 3 neuroimaging biomarkers for AD that have been studied using 7-T MRI in AD tissue: 1) neuroanatomical atrophy; 2) molecular characterization of hypointensities; and 3) microinfarcts.

Seven-Tesla MRI has had mixed results when used to study the 3 aforementioned neuroimaging biomarkers for AD.

First, in the detection of neuroanatomical atrophy, 7-T MRI has exciting potential. Historically, noninvasive imaging of neuroanatomical atrophy during AD has been limited by suboptimal resolution. However, now there is compelling evidence that the high resolution of 7-T MRI may help overcome this hurdle. Second, in detecting the characterization of hypointensities, 7-T MRI has had varied success. PET scans will most likely continue to lead in the noninvasive imaging of amyloid plaques; however, there is emerging evidence that 7-T MRI can accurately detect iron deposits within activated microglia, which may help shed light on the role of the immune system in AD pathogenesis. Finally, in the detection of microinfarcts, 7-T MRI may also play a promising role, which may help further elucidate the relationship between cerebrovascular health and AD progression.

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Omar Choudhri, Aatman Shah, Jennifer Basarab-Tung, Richard A. Jaffe and Gary K. Steinberg

The authors describe the case of a 51-year-old man with bilateral moyamoya disease and prior strokes who developed an asystolic cardiac arrest while undergoing revascularization surgery under mild hypothermia. The patient was successfully treated with venoarterial (VA) extracorporeal membrane oxygenation (ECMO) after manual cardiopulmonary resuscitation (CPR) was unsuccessful for 45 minutes. ECMO is a cardiopulmonary support system that is indicated for respiratory failure in pediatric and adult patients. It is increasingly being used as an extension to mechanical CPR for patients who have suffered cardiac arrest if the underlying cause of cardiac arrest is thought to be reversible. Identifying which patients should be placed on emergency ECMO after cardiac arrest is controversial given its high morbidity and mortality. ECMO in neurosurgical settings has associated risks of intracranial hemorrhage and neurological compromise, while resource utilization is paramount given the high costs of this treatment. This paper is significant because it describes the use of ECMO in an unindicated setting. Limited data are available for ECMO usage after cardiac arrest with baseline cerebral ischemia. Furthermore, this paper raises important considerations for extracorporeal CPR use in a patient who had recently undergone craniotomy. The patient in this report remained on ECMO for 48 hours, after which he was successfully weaned. He developed a pericardial effusion and compartment syndrome from the ECMO but made a complete neurological recovery. Use of ECMO emergently in an appropriately chosen neurosurgical patient is safe, even in the setting of baseline cerebral ischemia and recent craniotomy.