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M. Yashar S. Kalani and Joseph M. Zabramski


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.


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.


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.


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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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:

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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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R. Loch Macdonald

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

Dorsal pons lesions at the facial colliculus level can be accessed with a suboccipital telovelar (SOTV) approach using the superior fovea safe entry zone. Opening the telovelar junction allows visualization of the dorsal pons and lateral entry at the level of the fourth ventricle floor. Typically, a lateral entry into the floor of the fourth ventricle is better tolerated than a midline opening. This video demonstrates the use of the SOTV approach to remove a cavernous malformation at the level of the facial colliculus. This case is particularly interesting because of a large venous anomaly and several telangiectasias in the pons. Dissections in the video are reproduced with permission from the Rhoton Collection (

The video can be found here:

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Kaan Yagmurlu, M. Yashar S. Kalani, Mark C. Preul, and Robert F. Spetzler

The authors describe a safe entry zone, the superior fovea triangle, on the floor of the fourth ventricle for resection of deep dorsal pontine lesions at the level of the facial colliculus. Clinical data from a patient undergoing a suboccipital telovelar transsuperior fovea triangle approach to a deep pontine cavernous malformation were reviewed and supplemented with 6 formalin-fixed adult human brainstem and 2 silicone-injected adult human cadaveric heads using the fiber dissection technique to illustrate the utility of this novel safe entry zone. The superior fovea has a triangular shape that is an important landmark for the motor nucleus of the trigeminal, abducens, and facial nerves. The inferior half of the superior fovea triangle may be incised to remove deep dorsal pontine lesions through the floor of the fourth ventricle. The superior fovea triangle may be used as a safe entry zone for dorsally located lesions at the level of the facial colliculus.

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M. Yashar S. Kalani, Nikolay L. Martirosyan, Peter Nakaji, and Robert F. Spetzler

The supracerebellar infratentorial approach provides access to the dorsal midbrain, pineal region, and tentorial incisura. This approach can be used with the patient in a sitting, prone, park-bench, or supine position. For a patient with a supple neck and favorable anatomy, we prefer the supine position. The ipsilateral shoulder is elevated, the head turned to the contralateral side, the chin is tucked, and the neck extended toward the floor to open the craniocervical angle for added working room. Care must be taken to place the craniotomy laterally to make use of the ascending angle of the tentorium for ease of access to deep-seated lesions.

The video can be found here: