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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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R. Loch Macdonald

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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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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, Maziyar A. Kalani, Ryder Gwinn, Bart Keogh and Victor C. K. Tse

The human insular cortex, or the lobus insularis, is considered the developmentally most primitive lobe of the telencephalon. Covered by an overlying cortical lid, the insula has functions that are distinct from yet related to those of the adjacent temporal lobe and deep limbic structures. In the first part of this paper the authors outline the development of the human insula, including the cellular heterogeneity comprising the various parts of the insular lobe. Using the understanding gained from the development of the insula they then address implications of insular development for cortical development and connection as well as for tumorigenesis and tumor spread from the insula to other cortical structures, most notably the temporal lobe. An understanding of cortico-insular development and interconnection allows for both a better understanding of insular pathology and also facilitates planning of resection of cortico-insular gliomas to avoid damage to eloquent structures.

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Michael Karsy, Andrea Brock, Jian Guan, Phillip Taussky, M. Yashar S. Kalani and Min S. Park

Stroke is a leading cause of disability in the US. Although there has been significant progress in the area of medical and surgical thrombolytic technologies, neuroprotective agents to prevent secondary cerebral injury and to minimize disability remain limited. Only limited success has been reported in preclinical and clinical trials evaluating a variety of compounds. In this review, the authors discuss the most up-to-date information regarding the underlying molecular biology of stroke as well as strategies that aim to mitigate this complex signaling cascade. Results of historical research trials involving N-methyl-d-aspartate and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor antagonists, clomethiazole, antioxidants, citicoline, nitric oxide, and immune regulators have laid the groundwork for current progress. In addition, more recent studies involving therapeutic hypothermia, magnesium, albumin, glyburide, uric acid, and a variety of other treatments have provided more options. The use of neuroprotective agents in combination or with existing thrombolytic treatments may be one of many exciting areas of further development. Although past trials of neuroprotective agents in ischemic stroke have been limited, significant insights into mechanisms of stroke, animal models, and trial design have incrementally improved approaches for future therapies.

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Nam K. Yoon, Al-Wala Awad, M. Yashar S. Kalani, Philipp Taussky and Min S. Park

Atherosclerotic disease of the cerebral vasculature is a major cause of stroke worldwide. Atherosclerosis that is refractory to best medical management may require revascularization. In these instances, endovascular treatment provides a popular and safe alternative to open surgical techniques. The authors provide an overview of stent technology in the treatment of ischemic stroke, discussing the major studies evaluating stenting for extracranial carotid artery, vertebral artery, and intracranial atherosclerotic disease. The authors describe the commonly used stents with respect to their individual characteristics and technical limitations. Current and future developments in stent technology are also discussed, with areas for further innovation and clinical research.

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Aristotelis S. Filippidis, M. Yashar S. Kalani, Peter Nakaji and Harold L. Rekate

Object

Negative-pressure and low-pressure hydrocephalus are rare clinical entities that are frequently misdiagnosed. They are characterized by recurrent episodes of shunt failure because the intracranial pressure is lower than the opening pressure of the valve. In this report the authors discuss iatrogenic CSF leaks as a cause of low- or negative-pressure hydrocephalus after approaches to the cranial base.

Methods

The authors retrospectively reviewed cases of low-pressure or negative-pressure hydrocephalus presenting after cranial approaches complicated with a CSF leak at their institution.

Results

Three patients were identified. Symptoms of high intracranial pressure and ventriculomegaly were present, although the measured pressures were low or negative. A blocked communication between the ventricles and the subarachnoid space was documented in 2 of the cases and presumed in the third. Shunt revisions failed repeatedly. In all cases, temporary clinical and radiographic improvement resulted from external ventricular drainage at subatmospheric pressures. The CSF leaks were sealed and CSF communication was reestablished operatively. In 1 case, neck wrapping was used with temporary success.

Conclusions

Negative-pressure or low-pressure hydrocephalus associated with CSF leaks, especially after cranial base approaches, is difficult to treat. The solution often requires the utilization of subatmospheric external ventricular drains to establish a lower ventricular drainage pressure than the drainage pressure created in the subarachnoid space, where the pressure is artificially lowered by the CSF leak. Treatment involves correction of the CSF leak, neck wrapping to increase brain turgor and allow the pressure in the ventricles to rise to the level of the opening pressure of the valve, and reestablishing the CSF route.

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M. Yashar S. Kalani, Nikolay L. Martirosyan, Andrew S. Little, Udaya K. Kakarla and Nicholas Theodore

The authors describe a rare case of tumoral calcinosis (TC) of the thoracic spine in a 13-year-old boy with thoracic scoliosis. The patient presented with a 2-year history of back pain. He had no personal or family history of bone disease, deformity, or malignancy. Magnetic resonance imaging revealed a heterogeneously enhancing mass involving the T-7 vertebral body and the left pedicle. Computed tomography findings suggested that the mass was calcified and that this had resulted in scalloping of the vertebral body. The lesion was resected completely by using a left T-7 costotransversectomy and corpectomy. The deformity was corrected with placement of a vertebral body cage and pedicle screw fixation from T-5 to T-9. Pathological analysis of the mass demonstrated dystrophic calcification with marked hypercellularity and immunostaining consistent with TC. This represents the third reported case of vertebral TC in the pediatric population. Pediatric neurosurgeons should be familiar with lesions such as TC, which may be encountered in the elderly and in hemodialysis-dependent populations, and may not always require aggressive resection.

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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.