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André Beer-Furlan, Hormuzdiyar H. Dasenbrock, Krishna C. Joshi and Michael Chen

Acute basilar artery occlusion is one of the most devastating subtypes of ischemic stroke with an extremely high morbidity and mortality rate. The most common causes include embolism, large-artery atherosclerosis, penetrating small-artery disease, and arterial dissection. The heart and vertebral arteries are the main source of emboli in embolic basilar occlusions. The authors present an uncommon acute basilar occlusion secondary to a fusiform aneurysm with intraluminal thrombus. The patient underwent a mechanical thrombectomy with successful recanalization, but persistent intraluminal thrombus. The authors discuss the management dilemma and describe their choice for placement of flow diverter stents.

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

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André Beer-Furlan, Hormuzdiyar H. Dasenbrock, Krishna C. Joshi and Michael Chen

Tentorial dural arteriovenous fistulas (DAVFs) are uncommon, complex fistulas located between the leaves of the tentorium cerebelli with a specific anatomic and clinical presentation characterized by high hemorrhagic risk. They have an extensive arterial supply and complex venous drainages, making them difficult to treat. There is recent literature favoring treatment through an endovascular transarterial route. The authors present an uncommon tentorial/ambient cistern region DAVF with feeders arising from the external and internal carotid arteries. The patient underwent a combined transarterial and transvenous approach with successful obliteration of the DAVF. The authors discuss the management challenges faced in this case.

The video can be found here: https://youtu.be/VXDD8zUvsSQ.

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André Beer-Furlan, Krishna C. Joshi, Hormuzdiyar H. Dasenbrock and Michael Chen

Superior sagittal sinus (SSS) dural arteriovenous fistulas (DAVFs) are rare and present unique challenges to treatment. Complex, often bilateral, arterial supply and involvement of large volumes of eloquent cortical venous drainage may necessitate multimodality therapy such as endovascular, microsurgical, and stereotactic radiosurgery techniques. The authors present a complex SSS DAVF associated with an occluded/severely stenotic SSS. The patient underwent a successful endovascular transvenous approach with complete obliteration of the SSS. The authors discuss the management challenges faced on this case.

The video can be found here: https://youtu.be/-rztg0_cBXY.

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Michael Zhang, Yi-Ren Chen, Steven D. Chang and Anand Veeravagu

OBJECTIVE

Symptomatic vertebral hemangiomas (SVHs) are a very rare pathology that can present with persistent pain or neurological deficits that warrant surgical intervention. Given the relative rarity and difficulty in assessment, the authors sought to present a dedicated series of SVHs treated using stereotactic radiosurgery (SRS) to provide insight into clinical decision making.

METHODS

A retrospective review of a single institution's experience with hypofractionated radiosurgery for SVH from 2004 to 2011 was conducted to determine the clinical and radiographic outcomes following SRS treatment. The authors report and analyze the treatment course of 5 patients with 7 lesions, 2 of which were treated primarily by SRS.

RESULTS

Of the 5 patients studied, 4 presented with a chief complaint of pain refractory to conservative measures. Three patients reported dysesthesias, and 2 reported upper-extremity weakness. Following radiosurgery, 4 of 5 patients exhibited improvement in their primary symptoms (3 for pain and 1 for weakness), achieving a clinical response after a mean period of 1 year. In 2 cases there was 20%–40% reduction in lesion size in the most responsive dimension as noted on images. All treatments were well tolerated.

CONCLUSIONS

SRS for SVH is a safe and feasible treatment strategy, comparable to prior radiotherapy studies, and in select cases may successfully confer delayed decompressive effects. Additional investigation will determine future patient selection and how conformal SRS treatment can best be administered.

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Michael L. Chen, J. Gordon McComb and Mark D. Krieger

Object

Atypical teratoid/rhabdoid tumors (ATRTs) represent a relatively newly categorized neoplastic entity. They commonly present in childhood, and have a rapidly progressive clinical course with a survival time of less than 1 year. Treatment regimens have been nonuniform. In this retrospective review of patients with ATRTs who were treated at the authors' institution according to a uniform protocol, the goal was to assess the efficacy of the treatment and its outcome.

Methods

Over a 7-year period, ATRT was diagnosed in 11 patients (six boys and five girls). The median age of the patients was 61 months, and their ages ranged from 3 months to 17 years. Signs and symptoms began, on average, a little more than 1 month before diagnosis and included the following: headache (36%), nausea and vomiting (46%), lethargy (18%), seizures (27%), cranial nerve findings (46%), ataxia (18%), long tract findings (18%), and hydrocephalus (46%). Tumor location was cortical in four patients, in the pineal region in four, in the posterior fossa in two, and spinal in one. In one patient disseminated disease was revealed on the initial imaging study; seven patients had disseminated tumor subsequently. Treatment consisted of chemotherapy in 11 patients, chemotherapy and local radiation in five, and chemotherapy and craniospinal radiation in three. Six patients are alive, three have died, and two were lost to follow-up review. The mean time to death was 24 months, and ranged from 2 to 67 months. Among the surviving patients the mean duration of follow up is 18.5 months and ranges from 2 to 37 months. The median time to progression was 3.5 months.

Conclusions

Atypical teratoid/rhabdoid tumors are malignant lesions with rapid progression. Further study is necessary to determine the efficacy of therapy.

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Michael L. Levy, Thomas C. Chen and Martin H. Weiss

✓ A case report of monostotic fibrous dysplasia of the clivus in a postadolescent woman is described. Although fibrous dysplasia of craniofacial structures is well documented, involvement of the clivus has not been reported. Diagnosis by clinical, radiographic, and histopathological features is detailed. Implications for the role of surgery and management are discussed.

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Joshua G. Kouri, Michael Y. Chen, Joseph C. Watson and Edward H. Oldfield

✓ Generally accepted contraindications to using a transsphenoidal approach for resection of tumors that arise in or extend into the suprasellar region include a normal-sized sella turcica, normal pituitary function, and adherence of tumor to vital intracranial structures. Thus, the transsphenoidal approach has traditionally been restricted to the removal of tumors involving the pituitary fossa and, occasionally, to suprasellar extensions of such tumors if the sella is enlarged. However, conventional transcranial approaches to the suprasellar region require significant brain retraction and offer limited visualization of contralateral tumor extension and the interface between the tumor and adjacent structures, such as the hypothalamus, third ventricle, optic apparatus, and major arteries. In this paper the authors describe successful removal of suprasellar tumors by using a modified transsphenoidal approach that circumvents some of the traditional contraindications to transsphenoidal surgery, while avoiding some of the disadvantages of transcranial surgery.

Four patients harbored tumors (two craniopharyngiomas and two hemangioblastomas) that arose in the suprasellar region and were located either entirely (three patients) or primarily (one patient) within the suprasellar space. All patients had a normal-sized sella turcica. Preoperatively, three of the four patients had significant endocrinological deficits signifying involvement of the hypothalamus, pituitary stalk, or pituitary gland. Two patients exhibited preoperative visual field defects. For tumor excision, a recently described modification of the traditional transsphenoidal approach was used. Using this modification, one removes the posterior portion of the planum sphenoidale, allowing access to the suprasellar region. Total resection of tumor was achieved (including absence of residual tumor on follow-up imaging) in three of the four patients. In the remaining patient, total removal was not possible because of adherence of tumor to the hypothalamus and midbrain. One postoperative cerebrospinal fluid leak occurred. Postoperative endocrinological function was worse than preoperative function in one patient. No other new postoperative endocrinological or neurological deficits were encountered.

This study demonstrates the feasibility of using a modified transsphenoidal approach for resection of certain suprasellar, nonpituitary tumors.

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Joseph C. T. Chen, Michael L. Levy, Ziv Corber and Murwarid Mura Assifi

Applications of endoscopic technique neurosurgery are becoming increasingly popular as greater evidence of the safety and efficacy of these techniques is reported. Nevertheless, significant technical limitations need to be solved before neuroendoscopy can achieve widespread popularity. One limitation is the surgeon's difficulties in becoming anatomically oriented in a two-dimensional (2-D) environment. The lack of appropriate visual cues to orient oneself in three-dimensional (3-D) space makes relatively simple anatomical regions difficult to navigate. The authors describe an endoscopy system that allows for stereoscopic visualization during minimally invasive procedures and that acts as an adjunct to conventional open craniotomies. Four cases are described in which stereoendoscopy was used as either a primary means of visualization or as an adjunct to the operating microscope in conventional open neurosurgical procedures. The authors believe that stereoendoscopic vision is a significant advance in endoscope technology and will play a large role in the popularization of minimally invasive techniques in neurosurgery.

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Edward H. Oldfield, Andrew Bennett III, Michael Y. Chen and John L. Doppman

✓ Spinal dural arteriovenous fistulas (AVFs) frequently cause progressive myelopathy. When they are localized by imaging studies, surgery can be safely performed by simply interrupting the vein draining the fistula intradurally, and the results will be excellent and lasting. In some patients with clinical features of a spinal dural AVF and in whom magnetic resonance imaging and/or myelography findings are consistent with a diagnosis of a spinal dural AVF, however, spinal arteriography demonstrates no such results. The authors used a simple strategy based on knowledge of the epidemiology, pathophysiology, and anatomy of spinal dural AVFs to manage these cases successfully. In two patients, atherosclerotic occlusion was the primary cause for the failure of arteriography to visualize the dural AVF. The presence of an aortic aneurysm was an additional contributing factor preventing arteriographic visualization in one of these patients. In a third patient, massive obesity, and aortic atheroslerosis and tortuosity contributed to the absence of findings on three spinal arteriograms before surgical exploration lead to a more focused arteriographic examination that was successful.

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Joseph C. T. Chen, Javad Rahimian, Michael R. Girvigian and Michael J. Miller

✓ Radiosurgery has emerged as an indispensable component of the multidisciplinary approach to neoplastic, functional, and vascular diseases of the central nervous system. In recent years, a number of newly developed integrated systems have been introduced for radiosurgery and fractionated stereotactic radiotherapy treatments. These modern systems extend the flexibility of radiosurgical treatment in allowing the use of frameless image-guided radiation delivery as well as high-precision fractionated treatments. The Novalis linear accelerator system demonstrates adequate precision and reliability for cranial and extracranial radiosurgery, including functional treatments utilizing either frame-based or frameless image-guided methods.