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Christopher F. Dowd, Van V. Halbach and Randall T. Higashida

The field of interventional neuroradiology has experienced remarkable technological developments in microcatheters and embolic materials during the past two decades. The realm of meningioma therapy has benefited handsomely from the combination of these technical improvements and the knowledge of experienced practitioners in this field. Transarterial embolization has become a standard procedure in the preoperative management of meningiomas. The authors describe the indications, pretreatment evaluation, techniques, and outcomes when preoperative angiography and embolization are performed in the treatment of these tumors.

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Perry P. Ng, Randall T. Higashida, Sean Cullen, Reza Malek, Van V. Halbach and Christopher F. Dowd

Interventional neuroradiology is a less invasive modality than open neurosurgery for the treatment of a wide range of neurovascular disorders. Refinements in technique and improvements in the design of microcatheters, guide wires, and embolic materials have yielded superior clinical outcomes and provided an impetus to treat more of these lesions endovascularly rather than surgically. Endovascular therapy is the standard of care for direct and indirect carotid artery cavernous sinus fistulas and may also be curative for dural arteriovenous fistulas (AVFs) in other locations.

The authors provide review of the clinical features, pathophysiology, and management of intracranial AVFs focusing on contemporary endovascular treatment options.

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Cameron G. McDougall, Van V. Halbach, Christopher F. Dowd, Randall T. Higashida, Donald W. Larsen and Grant B. Hieshima

✓ Preliminary experience using electrolytically detachable coils to treat basilar tip aneurysms in 33 patients is described. The most frequent presentation was subarachnoid hemorrhage (SAH) in 23 patients. All patients were referred after neurosurgical assessment and exclusion as candidates for surgical clipping of their aneurysms. At the time of initial treatment complete aneurysm occlusion was achieved in seven (21.2%) of 33 patients. In 17 of the patients (51.5%), greater than 90% but less than 100% aneurysm occlusion was achieved. Angiographic follow up (mean 11.7 months) was available in 19 patients. At follow-up angiography four (21%) of 19 aneurysms were 100% occluded and 12 (63.2%) of 19 were more than 90% but less than 100% occluded.

The mean clinical follow-up time in treated patients surviving beyond the initial treatment period is 15 months. One patient suffered major permanent morbidity from thrombosis of the basilar tip region a few hours after coil placement. One patient treated following SAH experienced further hemorrhage 6 months later. No other patient suffered direct or indirect permanent morbidity as a consequence of this method of treatment.

The authors believe that this technique is a reasonable alternative for patients who are not candidates for conventional surgical treatment or in whom such treatment has failed. This study's follow-up period is brief and greater experience with long-term follow-up study is mandatory.

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Van V. Halbach, Christopher F. Dowd, Randall T. Higashida, Peter A. Balousek, Samuel F. Ciricillo and Michael S. B. Edwards

Object. In this study the authors report on the results of endovascular treatment for mural-type vein of Galen malformations (VGMs) in a group of infants.

Methods. Eight children (six infants and two neonates) who suffered from symptoms caused by a mural-type VGM were treated by means of endovascular therapy. Their age at the time of treatment ranged from 13 days to 19 months (mean 7.6 months). Two neonates and three infants who presented with hydrocephalus and increased head circumference, one of whom was stabilized with a shunt, underwent elective closure of the malformations 3, 4, 6, 6, and 13 months later, respectively. Two patients presented with hemorrhage; one had an intraventricular hemorrhage (IVH) on the 1st day of life and one, a 5-month-old infant, suffered a large parenchymal hemorrhage and an IVH; both patients were immediately cured by means of endovascular techniques. One child presented with a seizure and cortical venous drainage that were treated immediately. Eleven separate treatment sessions were conducted; eight via transarterial femoral access and the remaining three via a transvenous approach. Two patients were treated by using transfemoral transvenous embolization with fibered coils, and one patient required a transtorcular transvenous approach to permit complete closure of the fistula with electrolytically detachable coils. The embolic devices used included silk suture emboli (three patients), electrolytically detachable coils (three patients), and fibered platinum coils (seven patients). In seven patients, complete closure was demonstrated on postembolization arteriographic studies. The eighth patient had stagnant flow in a giant 6-cm varix treated with arterial and venous coils but has not yet undergone follow-up studies. Late follow-up arteriography was performed in four patients at times ranging from 11 to 24 months postprocedure. In one patient, thrombosis of the malformation and shrinkage of the varix were confirmed on follow-up computerized tomography scanning. The remaining three patients have not yet undergone follow-up angiographic examination. Two asymptomatic complications occurred, including separation of the distal catheter, which was removed with a snare device, and a single platinum coil that embolized to the lung, producing no symptoms in 101 months of clinical follow up. The follow-up period ranged from 3 to 105 months, with a mean of 52 months.

Conclusions. Endovascular therapy is the treatment of choice for mural-type VGMs and offers a high rate of cure with low morbidity.

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Adel M. Malek, Van V. Halbach, Stephen Holmes, Constantine C. Phatouros, Philip M. Meyers, Christopher F. Dowd and Randall T. Higashida

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Randall T. Higashida, Wade Smith, Daryl Gress, Ross Urwin, Christopher F. Dowd, Peter A. Balousek and Van V. Halbach

✓ The authors demonstrate the technical feasibility of using intravascular stents in conjunction with electrolytically detachable coils (Guglielmi detachable coils [GDCs]) for treatment of fusiform, broad-based, acutely ruptured intracranial aneurysms and review the literature on endovascular approaches to ruptured aneurysms and cerebral stent placement. A 77-year-old man presented with an acute subarachnoid hemorrhage of the posterior fossa. A fusiform aneurysm with a broad-based neck measuring 12 mm and involving the distal vertebral artery (VA) and proximal third of the basilar artery (BA) was demonstrated on cerebral angiography. The aneurysm was judged to be inoperable. Six days later a repeated hemorrhage occurred. A 15-mm-long intravascular stent was placed across the base of the aneurysm in the BA and expanded to 4 mm to act as a bridging scaffold to create a neck. A microcatheter was then guided through the interstices of the stent into the body and dome of the aneurysm, and GDCs were deposited for occlusion.

The arteriogram obtained after stent placement demonstrated occlusion of the main dome and body of the aneurysm. The coils were stably positioned and held in place by the stent across the distal VA and BA fusiform aneurysm. Excellent blood flow to the distal BA and posterior cerebral artery was maintained through the stent. There were no new brainstem ischemic events attributable to the procedure. No rebleeding from the aneurysm had occurred by the 10.5-month follow-up evaluation, and the patient has experienced significant neurological improvement.

Certain types of intracranial fusiform aneurysms may now be treated by combining intravascular stent and GDC placement for aneurysm occlusion via an endovascular approach. This is the first known clinical application of this novel approach in a ruptured cerebral aneurysm.

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Randall T. Higashida, Fong Y. Tsai, Van V. Halbach, Christopher F. Dowd, Tony Smith, Kenneth Fraser and Grant B. Hieshima

✓ Transluminal angioplasty for hemodynamically significant stenosis (> 70%) involving the posterior cerebral circulation is now being performed by the authors in selected cases. A total of 42 lesions affecting the vertebral or basilar artery have been successfully treated by percutaneous transluminal angioplasty techniques in 41 patients. The lesions involved the proximal vertebral artery in 34 cases, the distal vertebral artery in five, and the basilar artery in three. Patients were examined clinically at 1 to 3 and 6 to 12 months after angioplasty. Three (7.1%) permanent complications occurred, consisting of stroke in two cases and vessel rupture in one. There were four (9.5%) transient complications (< 30 minutes): two cases of vessel spasm and two of cerebral ischemia. Clinical follow-up examination demonstrated improvement of symptoms in 39 cases (92.9%). Radiographic follow-up studies demonstrated three cases (7.1 %) of restenosis involving the proximal vertebral artery; two were treated by repeat angioplasty without complication, and the third is being followed clinically while the patient remains asymptomatic.

In patients with significant atherosclerotic stenosis involving the vertebral or basilar artery territories, transluminal angioplasty may be of significant benefit in alleviating symptoms and improving blood flow to the posterior cerebral circulation.

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Stanley L. Barnwell, Van V. Halbach, Christopher F. Dowd, Randall T. Higashida, Grant B. Hieshima and Charles B. Wilson

✓ Dural arteriovenous (AV) fistulas are thought to be acquired lesions that form in an area of thrombosis within a sinus. If the sinus remains completely thrombosed, venous drainage from these lesions occurs through cortical veins, or, if the sinus is open, venous drainage is usually into the involved sinus. Among 105 patients with dural A V fistulas evaluated over the the past 5 years, seven had a unique type of dural AV fistula in the superior sagittal, transverse, or straight sinus in which only cortical venous drainage occurred despite a patent involved sinus; the fistula was located within the wall of a patent dural sinus, but outflow was not into the involved sinus. This variant of dural AV fistulas puts the patient at serious risk for hemorrhage or neurological dysfunction caused by venous hypertension. Three patients presented with hemorrhage, one with progressive neurological dysfunction, one with seizures, and two with bruit and headaches. A combination of surgical and endovascular techniques was used to close the fistula while preserving flow through the sinus.

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Cameron G. McDougall, Van V. Halbach, Christopher F. Dowd, Randall T. Higashida, Donald W. Larsen and Grant B. Hieshima

Object. The purpose of this review is to describe the incidence, causes, management, and outcome of aneurysmal hemorrhage that occurred in patients during endovascular treatment with the Guglielmi detachable coil (GDC) system.

Methods. At the authors' institution between September 1991 and August 1995, more than 200 patients were treated using GDCs for intracranial aneurysms. The first 200 patients treated in this fashion were reviewed and all who experienced new subarachnoid hemorrhage (SAH) during the procedure were identified. Angiographic studies were also reviewed and patients were contacted for longer-term follow up when possible.

Four patients who experienced intraprocedural SAH were identified. The causes of hemorrhage were believed to be perforation of the aneurysm by the guidewire in one patient, perforation by the microcatheter in a second, and perforation by the delivery wire in a third. The fourth patient had a hemorrhage during injection of contrast material for control angiographic studies after placement of the final coil. One patient died, but the other three experienced no neurological symptoms or recovered without acquiring additional deficits. Overall a procedural hemorrhage rate of 2% was seen, with permanent morbidity and mortality rates of 0% and 0.5%, respectively.

Conclusions. Although SAH during endovascular treatment of intracranial aneurysms remains a significant risk, its incidence is low and a majority of patients can survive without serious sequelae.