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Ricky Medel, R. Webster Crowley and Aaron S. Dumont

Endovascular cerebral revascularization is becoming a frequently used alternative to surgery for the treatment of atherosclerotic disease, especially in the intracranial circulation where options are limited. Recent literature regarding the equivalent efficacy of carotid artery stenting and carotid endarterectomy in certain patient populations, as well as the recognition of the significant risk for recurrent stroke posed by intracranial lesions, will only serve to amplify this trend. Hyperperfusion syndrome has been well documented in the setting of carotid endarterectomy; however, a paucity of literature exists regarding the incidence, pathophysiology, and management as it relates to percutaneous interventions. The purpose of this review is to outline the current state of knowledge, with particular attention to the distinct attributes of endovascular treatment that would be expected to modify the course of hyperperfusion syndrome.

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Ricky Medel, R. Webster Crowley and Aaron S. Dumont

Spinal vascular malformations represent a complex group of entities whose treatment paradigm continually evolves. Given the ever-increasing role of endovascular therapy, it is the goal of the authors to review the current literature regarding this therapeutic tool and to provide recommendations guiding management. A thorough literature search was conducted using Medline, with subsequent articles being identified through cross-referencing. The analysis revealed that, since its introduction in the 1960s, endovascular therapy has been used to manage the entire spectrum of spinal vascular malformations, during which period it has undergone considerable technological and technical evolution. As such, embolization has proved of growing therapeutic utility, largely resulting from the mounting evidence supporting its safety and efficacy, in addition to the inherent minimally invasive nature. This alternative to surgical intervention will be increasingly used as first-line therapy in spinal vascular malformations.

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R. Webster Crowley, Ricky Medel and Aaron S. Dumont

✓As a leading cause of death and disability in patients across the world, stroke is a problem that plagues both neurosurgeons and neurologists alike. Whether a result of atherosclerosis, moyamoya disease, or a complication in the treatment of a complex intracranial aneurysm, cerebrovascular occlusion can have devastating effects on patients. For nearly half a century neurosurgeons have searched for safer, more effective ways to increase the amount of blood flow to ischemic brain tissue. From the first extracranial–intracranial bypasses to the recent technological advancements seen with endovascular therapy, cerebral revascularization techniques have been constantly evolving. Over the years cerebral ischemia has gone from a condition that was previously considered surgically untreatable, to a condition with several viable options for prevention and treatment. In this paper the authors discuss the historical evolution of treatment for cerebrovascular occlusive disease.

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R. Webster Crowley, Ricky Medel and Aaron S. Dumont

Occipital artery to posterior inferior cerebellar artery bypasses remain an important tool for cerebrovascular neurosurgeons, particularly in the management of complex aneurysms of the posterior inferior cerebellar artery requiring proximal occlusion or trapping. The procedure requires meticulous technique and attention to detail. The authors outline their technique for accomplishing this bypass emphasizing nuances for complication avoidance.

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R. Webster Crowley, Nader Pouratian and Jason P. Sheehan

✓ Despite the implementation of increasingly aggressive surgery, chemotherapy, and fractionated radiotherapy for the treatment of glioblastoma multiforme (GBM), most therapeutic regimens have resulted in only modest improvements in patient survival. Gamma knife surgery (GKS) has become an indispensable tool in the primary and adjuvant management of many intracranial pathologies, including meningiomas, pituitary tumors, and arteriovenous malformations. Although it would seem that radiosurgical techniques, which produce steep radiation dose fall-off around the target, would not be well suited to treat these infiltrative lesions, a limited number of institutional series suggest that GKS might provide a survival benefit when used as part of the comprehensive management of GBM. This may largely be attributed to the observation that tumors typically recur within a 2-cm margin of the tumor resection cavity. Despite these encouraging results, enthusiasm for radiosurgery as a primary treatment for GBM is significantly tempered by the failure of the only randomized trial that has been conducted to yield any benefit for patients with GBM who were treated with radiosurgery. In this paper, the authors review the pathophysiological mechanisms of GKS and its applications for GBM management.

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R. Webster Crowley, Ricky Medel and Aaron S. Dumont

Penetrating injuries to the neck can result in a number of abnormalities that are of interest to neurosurgeons and interventional neuroradiologists. Gunshot or stab wounds may cause damage to the cervical spinal cord, the adjacent osseous and ligamentous structures, and the peripheral or cranial nerves. In addition, a significant percentage of penetrating wounds to this location result in vascular injury. These may present insidiously or acutely and with a variety of symptoms. The authors present the case of a patient in whom an occipital lobe infarction developed roughly 2 months after the patient was struck in the neck by a bullet. He was found to have a complete transection of the left vertebral artery, with an associated vertebral-venous fistula. The fistula was eventually treated endovascularly with a combination of platinum coils and Amplatzer Vascular Plugs. The management is discussed, with specific emphasis on the technical aspects of the case.

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Robert M. Starke, Dale Ding, Christopher R. Durst, R. Webster Crowley and Kenneth C. Liu

Dissecting vertebral artery (VA) aneurysms are difficult to obliterate when the parent artery cannot be safely occluded. In this video, we demonstrate a combined microsurgical and endovascular treatment technique for a ruptured, dissecting VA aneurysm incorporating the origin of the posterior inferior cerebellar artery (PICA). We first performed a PICA-PICA side-to-side bypass to preserve flow through the right PICA. An endovascular approach was then utilized to embolize the proximal portion of the aneurysm from the right VA and the distal portion of the aneurysm from the left VA.

The video can be found here: http://youtu.be/dkkKsX2BiJI.

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Dale Ding, Robert M. Starke, Christopher R. Durst, R. Webster Crowley and Kenneth C. Liu

Increasing evidence supports dural venous sinus stenosis as the patho-etiology of pseudotumor cerebri (PTC) in a subset of affected patients. In this video, we demonstrate our technique for 1) diagnostic venous manometry to identify a flow-limiting stenosis of the transverse sinus in a PTC patient; and 2) successful treatment of the patient with venous stenting across the structural and physiological stricture in the dural sinus. The pressure gradient decreased from 20 mmHg pre-stent to 3 mmHg post-stent. In order to further quantify the effect of our intervention, concurrent intracranial pressure monitoring was performed.

The video can be found here: http://youtu.be/auxRg17F8yI.

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Ricky Medel, R. Webster Crowley, D. Kojo Hamilton and Aaron S. Dumont

Pseudoaneurysms are rare lesions with a multitude of causes, including infectious, traumatic, and iatrogenic origins. In addition, there are a number of potential treatment options, all of which require consideration to determine the most appropriate management. Historically, surgical intervention has been the method of choice, but because the histopathological features of these lesions make them largely unsuitable for clipping, trapping or excision is often required. More recently endovascular methods have been used, including coil embolization, stent reconstruction, or parent artery occlusion. Although these methods are often successful, situations arise in which they are not technically feasible. The authors describe such a case in a pediatric patient with an iatrogenic pseudoaneurysm. Onyx was used to embolize the lesion and the results were excellent.