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Introduction. The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR)

Gregory J. Zipfel

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Introduction. The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR)

Gregory J. Zipfel

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Editorial: Ultra-early surgery for aneurysmal subarachnoid hemorrhage

Gregory J. Zipfel

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Update on the management of unruptured intracranial aneurysms

Gregory J. Zipfel and Ralph G. Dacey

Over the past decade, several factors have led to a dramatic change in the manner in which patients with unruptured intracranial aneurysms are diagnosed and treated. These factors include the increased use of noninvasive imaging modalities for the diagnosis of intracranial aneurysms, publication of new natural history data detailing the hemorrhage risks associated with unruptured intracranial aneurysms, and the broad application of endovascular therapy for their treatment. With these new technologies and new natural history data has come considerable uncertainty about the optimal treatment strategy for patients with unruptured intracranial aneurysms. In this light, it seems prudent to review periodically and examine critically all recent data pertaining to the natural history and treatment of unruptured intracranial aneurysms, in an effort to provide a scientific update on which management recommendations can be based. This review article represents the authors' attempt at such an update, and it is their hope that members of the community of neurovascular surgeons might find this information helpful during their continuing efforts to provide optimal care for their patients with unruptured intracranial aneurysms.

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High flow EC–IC bypass for a giant left MCA aneurysm

Eric J. Arias and Gregory J. Zipfel

Giant cerebral aneurysms may be treated through a variety of options, including aneurysm trapping with concurrent bypass. This video describes the case of a large, recurrent, left middle cerebral artery aneurysm that was treated using a high flow, radial artery bypass graft, from the external carotid artery to the left temporal M2 branch. A step-by-step operative description, with emphasis on proper microsurgical technique, is included.

The video can be found here: http://youtu.be/9xTMC6InivQ.

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Letter to the Editor: Dural arteriovenous fistula: a clinical model of thalamic dementia?

Rodrigo Carrasco and José M. Pascual

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Intracranial hemorrhage from dural arteriovenous fistulas: clinical features and outcome

David J. Daniels, Ananth K. Vellimana, Gregory J. Zipfel, and Giuseppe Lanzino

Object

In this paper the authors' goal was to review the clinical features and outcome of patients with intracranial dural arteriovenous fistulas (DAVFs) who presented with hemorrhage.

Methods

A retrospective study of 28 patients with DAVFs who presented with intracranial hemorrhage to 2 separate institutions was performed. The information reviewed included clinical presentation, location and size of hemorrhage, angiographic features, treatment, and clinical and radiologically documented outcomes. Clinical and radiological follow-up were available in 27 of 28 patients (mean follow-up 17 months).

Results

The vast majority of patients were male (86%), and the most common presenting symptom was sudden-onset headache. All DAVFs had cortical venous drainage, and about one-third were associated with a venous varix. The most common location was tentorial (75%). Treatment ranged from endovascular (71%), surgical (43%), Gamma Knife surgery (4%), or a combination of modalities. The majority of fistulas (75%) were completely obliterated, and most patients experienced excellent clinical outcome (71%, modified Rankin Scale score of 0 or 1). There were no complications in this series.

Conclusions

Case series, including the current one, suggest that the vast majority of patients who present with intracranial hemorrhage from a DAVF are male. The most common location for DAVFs presenting with hemorrhage is tentorial. Excellent outcomes are achieved with individualized treatment, which includes various therapeutic strategies alone or in combination. Despite the hemorrhagic presentation, almost two-thirds of patients experience a full recovery with no or minimal residual symptoms.

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Do the morphological characteristics of arteriovenous malformations affect the results of radiosurgery?

Gregory J. Zipfel, Patrick Bradshaw, Frank J. Bova, and William A. Friedman

Object. The authors sought to determine which morphological features of arteriovenous malformations (AVMs) are statistically predictive of preradiosurgical hemorrhage, postradiosurgical hemorrhage, and neuroimaging-defined failure of radiosurgical treatment. In addition, correlation between computerized tomography (CT) scanning and angiography for the identification of AVM structures was investigated.

Methods. Archived CT dosimetry and available angiographic and clinical data for 268 patients in whom AVMs were treated with linear accelerator radiosurgery were retrospectively reviewed. Many of the morphological features of AVMs, including location, volume, compact or diffuse nidus, neovascularity, ease of nidus identification, number of feeding arteries, location (deep or superficial) of feeding arteries, number of draining veins, deep or superficial venous drainage, venous stenoses, venous ectasias, and the presence of intranidal aneurysms, were analyzed. In addition, a number of patient and treatment factors, including patient age, presenting symptoms, radiation dose, repeated treatment, and radiological outcome, were subjected to multivariate analyses.

Two hundred twenty-seven patients were treated with radiosurgery for the first time and 41 patients underwent repeated radiosurgery. Eighty-one patients presented with a history of AVM hemorrhage and 91 patients had AVMs in a periventricular location. Twenty-six patients (10%) experienced a hemorrhage following radiosurgery. Of the 268 patients, 81 (30%) experienced angiographically defined cures, and 37 (14%) experienced MR imaging-defined cures. Eighty-six patients (32%) experienced neuroimaging-defined treatment failure, and 64 underwent insufficiently long follow up.

A larger AVM volume (odds ratio [OR] 0.349; p = 0.004) was associated with a decreased rate of pretreatment hemorrhage, whereas periventricular location (OR 6.358; p = 0.000) was associated with an increased rate of pretreatment hemorrhage. None of the analyzed factors was predictive of hemorrhage following radiosurgery. A higher radiosurgical dose was strongly correlated with neuroimaging-defined success (OR 3.743; p = 0.006), whereas a diffuse nidus structure (OR 0.246; p = 0.008) and associated neovascularity (OR 0.428; p = 0.048) were each associated with a lower neuroimaging-defined cure rate. A strong correlation between CT scanning and angiography was noted for both nidus structure (p = 0.000; Fisher exact test) and neovascularity (p = 0.002; Fisher exact test).

Conclusions. Patients presenting with AVMs that are small or periventricular were at higher risk for experiencing hemorrhage. A higher radiosurgical dose correlated strongly with neuroimaging-defined success. Patients in whom the AVM had a diffuse structure or associated neovascularity were at higher risk for neuroimaging-defined failure of radiosurgery. A strong correlation between CT scanning and angiography in the assessment of AVM structure was demonstrated.

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Job negotiation for neurosurgeon-scientists

John D. Rolston, Gregory J. Zipfel, and Dario J. Englot

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Update on the natural history of cavernous malformations and factors predicting aggressive clinical presentation

Chad W. Washington, Kathleen E. McCoy, and Gregory J. Zipfel

Cavernous malformations (CMs) are angiographically occult, low-pressure neurovascular lesions with distinct imaging and clinical characteristics. They present with seizure, neurological compromise due to lesion hemorrhage or expansion, or as incidental findings on neuroimaging studies. Treatment options include conservative therapy, medical management of seizures, surgical intervention for lesion resection, and in select cases stereotactic radiosurgery. Optimal management requires a thorough understanding of the natural history of CMs including consideration of issues such as mode of presentation, lesion location, and genetics that may impact the associated neurological risk. Over the past 2 decades, multiple studies have been published, shedding valuable light on the clinical characteristics and natural history of these malformations. The purpose of this review is to provide the reader with a concise consolidation of this published material such that they may better understand the risks associated with CMs and their implications on patient treatment.