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M. Yashar S. Kalani and Joseph M. Zabramski

Object

The threat of symptomatic hemorrhage from cerebral cavernous malformations (CCMs) during pregnancy remains poorly understood. The authors undertook this study to better define the risk of pregnancy-related hemorrhage in this population.

Methods

The records of female patients with sporadic (isolated lesions and negative family history) and familial forms of CCM, which were collected as part of the Barrow Neurological Institute CCM natural history study, were examined. Clinical data related to pregnancy, including type of delivery (vaginal or cesarean section) and any change in neurological status, were obtained from chart reviews and patient interviews.

Results

There were 168 pregnancies among 64 female patients with CCM (28 sporadic and 36 familial). Assuming an average of 46 weeks per pregnancy (40 weeks of gestation and 6 weeks of puerperium), patients were at risk for hemorrhage for a total of 148.6 years. Symptomatic hemorrhage (defined as new-onset or exacerbation of seizure activity or any change in neurological status) occurred during 5 pregnancies, with the most common symptom being seizures (4 cases). The overall risk for symptomatic hemorrhage was 3% per pregnancy; the risk was 1.8% per pregnancy in the sporadic group and 3.6% per pregnancy in the familial patients.

There were 19 deliveries by cesarean section: 5 for obstetrical reasons, 8 for fear of possible hemorrhage, and 6 for unknown reasons. Vaginal delivery was performed without complications for the remaining 149 pregnancies.

Conclusions

The authors' experience suggests that the risk of symptomatic hemorrhage from a CCM during pregnancy is not increased and that a history of CCM is not a contraindication to pregnancy or vaginal delivery.

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Craig Kilburg, Philipp Taussky, M. Yashar S. Kalani and Min S. Park

The use of flow-diverting stents for intracranial aneurysms has become more prevalent, and flow diverters are now routinely used beyond their initial scope of approval at the proximal internal carotid artery. Although flow diversion for the treatment of cerebral aneurysms is becoming more commonplace, there have been no reports of its use to treat flow-related cerebral aneurysms associated with arteriovenous malformations (AVMs). The authors report the cases of 2 patients whose AVM-associated aneurysms were managed with flow diversion. A 40-year-old woman presented with a history of headaches that led to the identification of an unruptured Spetzler-Martin Grade V, right parietooccipital AVM associated with 3 aneurysms of the ipsilateral internal carotid artery. Initial attempts at balloon-assisted coil embolization of the aneurysms were unsuccessful. The patient underwent placement of a flow-diverting stent across the diseased vessel; a 6-month follow-up angiogram demonstrated complete occlusion of the aneurysms. In the second case, a 57-year-old man presented with new-onset seizures, and an unruptured Spetzler-Martin Grade V, right frontal AVM associated with an irregular, wide-necked anterior communicating artery aneurysm was identified. The patient underwent placement of a flow-diverting stent, and complete occlusion of the aneurysm was observed on a 7-month follow-up angiogram. These 2 cases illustrate the potential for use of flow diversion as a treatment strategy for feeding artery aneurysms associated with AVMs. Because of the need for dual antiplatelet medications after flow diversion in this patient population, however, this strategy should be used judiciously.

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M. Yashar S. Kalani, Kaan Yağmurlu and Robert F. Spetzler

The authors describe the interpeduncular fossa safe entry zone as a route for resection of ventromedial midbrain lesions. To illustrate the utility of this novel safe entry zone, the authors provide clinical data from 2 patients who underwent contralateral orbitozygomatic transinterpeduncular fossa approaches to deep cavernous malformations located medial to the oculomotor nerve (cranial nerve [CN] III). These cases are supplemented by anatomical information from 6 formalin-fixed adult human brainstems and 4 silicone-injected adult human cadaveric heads on which the fiber dissection technique was used.

The interpeduncular fossa may be incised to resect anteriorly located lesions that are medial to the oculomotor nerve and can serve as an alternative to the anterior mesencephalic safe entry zone (i.e., perioculomotor safe entry zone) for resection of ventromedial midbrain lesions. The interpeduncular fossa safe entry zone is best approached using a modified orbitozygomatic craniotomy and uses the space between the mammillary bodies and the top of the basilar artery to gain access to ventromedial lesions located in the ventral mesencephalon and medial to the oculomotor nerve.

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Parham Yashar, Gabriel Zada, Brianna Harris and Steven L. Giannotta

Object

Vestibular schwannomas (VSs) are benign tumors of the eighth cranial nerve sheath, representing approximately 6%–8% of all newly diagnosed brain tumors, with an annual incidence of 2000–2500 cases in the US. Although most of these lesions are solid, cystic vestibular schwannomas (CVSs) compose 4%–20% of all VSs and are commonly larger at the time of presentation. The authors present their experience with the operative management of CVSs, including surgical approach, extent of resection, and postoperative facial nerve outcomes. The literature pertaining to clinical and histopathological differences between CVSs and their solid counterparts is reviewed.

Methods

The University of Southern California Department of Neurosurgery database was retrospectively reviewed to identify patients who had undergone resection of a VS between 2000 and 2010. One hundred seventy-nine patients with VS were identified. Patients with CVSs were the subject of the present analysis. Diagnosis of a CVS was made based on MRI findings. Clinical and neuroimaging data, including pre- and postoperative assessments and operative notes, were collected and reviewed.

Results

Twenty-three patients, 14 men (61%) and 9 women (39%), underwent 24 operations for CVSs. These patients composed 12.8% of all cases of VS. Patient ages ranged from 28 to 78 years (mean 55 years), and the mean maximal tumor diameter was 3.6 cm (range 2.0–4.0 cm). Patients most frequently presented with headache, hearing loss, vertigo, and dizziness. Preoperative facial numbness was reported in 44% of patients. Among the 24 cases, 13 were treated with retrosigmoid craniotomy and 11 via a translabyrinthine approach. Complete resection was achieved in 11 patients (48%), subtotal resection (STR) in 8 patients (35%), and near-total resection (NTR) in 4 patients (17%). Facial nerve outcomes were available in all except one case. Good facial nerve outcomes (House-Brackmann [HB] Grades I–III) were achieved in 82% of the patients who had undergone either NTR or STR, as compared with 73% of patients who had undergone gross-total resection (GTR; p > 0.05, Fisher exact test). In comparison, 83% of patients with solid VSs had a good HB grade (p = 0.38, Fisher exact test), although this finding did not reach statistical significance. Complications included wound infection (2 patients), delayed CSF leakage (1 patient), and a delayed temporal encephalocele following a translabyrinthine approach and requiring surgical repair (1 patient).

Conclusions

Cystic vestibular schwannoma represents a clinical and surgical entity separate from its solid counterpart, as demonstrated by its more rapid clinical course and early surgical outcomes. Facial nerve grades may correlate with the degree of tumor resection, trending toward poorer grades with more significant resections. Although GTR is recommended whenever possible, performing an STR when facial nerve preservation is in jeopardy to improve facial nerve outcomes is the preferred strategy at the authors' institution.

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M. Yashar S. Kalani, Sudarshan Iyer, Stephen W. Coons and Kris A. Smith

Intradural spinal teratomas are rare tumors of the spinal cord that are infrequently encountered in children. Although the mechanistic basis for the formation of these tumors is unclear, several lines of evidence suggest that a dysembryogenic process in the embryo results in their formation. The authors present a case of spinal intradural teratoma in an 18-year-old, previously healthy man and review the literature linking the development of these tumors to defects in neurulation and embryogenesis.

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Mark E. Oppenlander, M. Yashar S. Kalani and Curtis A. Dickman

Cavernous malformations (CMs) are found throughout the CNS but are relatively uncommon in the spine. In this report, the authors describe a giant CM with the imaging appearance of an aggressive, invasive, expansive tumor in the cervical spine. The intradural extramedullary portion of the tumor originated from a cervical nerve root; histologically, the lesion was identified as an intraneural CM. Most of the tumor extended into the paraspinal tissues. The tumor was also epidural, intraosseous, and osteolytic and had completely encased cervical nerve roots, peripheral nerves, branches of the brachial plexus, and the vertebral artery on the right side. It became symptomatic during the puerperal period. Gross-total resection was achieved using staged operative procedures, complex dural reconstruction, spinal fixation, and fusion. Clinical, radiographic, and histological details, as well as a discussion of the relevant literature, are provided.

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R. Loch Macdonald

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Daniel M. S. Raper, Nasser Mohammed, M. Yashar S. Kalani and Min S. Park

The preferred method for treating complex dural arteriovenous fistulae of the transverse and sigmoid sinuses is via endovascular, transarterial embolization using liquid embolysate. However, this treatment approach mandates access to distal dural feeding arteries that can be technically challenging by standard endovascular approaches. This video describes a left temporal craniotomy for direct stick microcatheterization of an endovascularly inaccessible distal posterior division of the middle meningeal artery for embolization of a complex left temporal dural arteriovenous fistula. The case was performed in the hybrid operative suite with biplane intraoperative angiography. Technical considerations, operative nuances, and outcomes are reviewed.

The video can be found here: https://youtu.be/Dnd4yHgaKcQ.

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M. Yashar S. Kalani, Peter Nakaji, Joseph M. Zabramski and Robert F. Spetzler

Posterior circulation aneurysms are commonly treated with endovascular techniques. In select cases, microsurgery remains an essential tool for treating these lesions. We present a case of a ruptured posterior inferior cerebellar artery (PICA) aneurysm approached via a craniotomy. Given the labyrinth of neurovascular bundles present in the posterior fossa, surgical exposure of PICA aneurysms can be challenging. This video demonstrates the steps of the craniotomy, subarachnoid dissection, mobilization of the vertebral artery and lower cranial nerves, and clipping of the aneurysm.

The video can be found here: http://youtu.be/fQSxQj7oL0U.

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Nicholas Theodore, M. Yashar S. Kalani and Volker K. H. Sonntag