Clinical characteristics of vertebrobasilar artery dissection.
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Sixteen patients with the diagnosis of vertebral or basilar artery dissection who were admitted at the Seoul National University Hospital from 1972 to 1996 are described. During the same period, we encountered 76 patients with posterior circulation aneurysms, so the vertebrobasilar artery dissection was 21% of posterior circulation aneurysms. The mean age was 44 years, and male predominated. Nine patients presented with subarachnoid hemorrhage (SAH) and seven with ischemic symptoms. The characteristic angiographic finding of patients with SAH was aneurysmal dilatation (pseudoaneurysm) in eight of nine cases. In cases of ischemic symptoms, only one case had aneurysmal dilatation. Some other angiographic findings were demonstrated such as string sign, tapered narrowing, complete occlusion, or double lumen. Clinical course of SAH group was much different from that of ischemic group. Rebleeding occurred in three patients of SAH group; immediately after the rebleeding all patients became comatose, but after extraventricular drainage, all patients with rebleeding recovered rapidly. In SAH group, four of nine cases died but there was no mortality in the ischemic group. These four patients showed signs of stem failure, when computed tomography (CT) demonstrated no evidence of additional bleeding and follow-up CT showed the infarction at a part of stem and/or cerebellum. Vasospasm or sudden extensive extension of dissection could be the cause of death. Surgical management was performed in three patients, endovascular intervention in four, and conservative management in two. The patients with incomplete embolization or conservative management had poor outcome. In ischemic group, all underwent conservative management including anticoagulation and/or antiplatelet therapy. On follow-up, most of the patients with ischemic symptoms made complete or very good recoveries. (+info)
Angioarchitecture related to hemorrhage in cerebral arteriovenous malformations.
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A retrospective study was conducted to determine the angioarchitecture related to hemorrhage in patients with cerebral arteriovenous malformations (AVMs), who underwent conservative treatment and long-term follow-up. The average observation period was 9.3 years, and the annual bleeding rate was estimated at 3.6%. In all cases angiographic findings were reviewed in detail. The average AVM grade by Spetzler-Martin was 3.5. Higher bleeding rate was observed in large AVM (5.4%) compared with small (2.1%) or medium AVM (2.9%). Deep venous drainage (8.6%/year) was strongly correlated to hemorrhage. Concerning location of nidus, hemorrhage was frequently found in insular, callosal, and cerebellar AVMs. Venous ectasia, feeder aneurysm, and external carotid supply were commonly demonstrated on angiograms. Comparison of annual bleeding rate revealed that AVMs with intranidal aneurysm (8.5%) and venous stenosis (5.5%) had a high propensity to hemorrhage. Therapeutic strategy should be focused on these potentially hazardous lesions by the use of endovascular embolization or stereotactic radiosurgery, even if surgical resection is not indicated. (+info)
Multidisciplinary approach to arteriovenous malformations.
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The treatment of arteriovenous malformations (AVMs) depends on the efforts of a multidisciplinary team whose ultimate goal is to achieve better results when compared to the natural history of the pathology. The role of adjuvant treatment modalities such as radiosurgery and endovascular embolization is discussed. Treatment strategies and surgical results from a personal series of 344 patients operated in a 10-year period are reviewed. The Spetzler and Martin classification was modified to include subgroups IIIA (large size grade III AVMs) and IIIB (small grade III AVMs in eloquent areas) to assist the surgical resection criteria. The treatment strategy followed was surgery for grades I and II, embolization plus surgery for grade IIIA, radiosurgery for grade IIIB, and conservative for grades IV and V. According to the new proposed classification 45 (13%) patients were grade I, 96 (28%) were grade II, 44 (13%) grade IIIA, 97 (28%) grade IIIB, 45 (13%) grade IV, and 17 (5%) were grade V. As for surgical results 85.8% of the patients had a good outcome (no additional neurological deficit), 12.5% had a fair outcome (minor neurological deficit), 0.6% had a bad outcome (major neurological deficit), and 1.2% died. These figures indicate that the treatment of AVMs can achieve better results compared to the natural history if managed by a well trained group of specialists led by an experienced neurosurgeon. (+info)
Embolization of cerebral arteriovenous malformations (AVMs)--material selection, improved technique, and tactics in the initial therapy of cerebral AVMs.
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Successful embolization can be achieved only when the following three factors are correct and in co-operation: catheter tip position, flow control, and the setting time of normal-butyl cyanoacrylate (NBCA). Otherwise, the procedure may end with unsatisfactory results or complications. The current principle of safe and efficient embolization of cerebral arteriovenous malformation (AVM) is based on superselective cannulation of every strategically important feeding pedicle and injection of liquid embolic material under flow control. This study was based upon our experiences of embolizing 92 cases with cerebral AVM performed under the above conditions at our department. Results showed very encouraging new observations with implications for further procedures: total removal of the AVM nidus after embolization was achieved in 90% of the cases, preradiosurgical embolization achieved 52% volume reduction and successfully maneuvered all cases into the gamma knife focal spot. Recently improved microcatheters with increased flexibility and minimal friction made it possible to place the tip of the microcatheter into the nidus with a higher success rate and better safety factors. In order to obliterate a substantial amount of the AVM nidus and prevent penetration into the draining veins, the creation of optimal flow status, and optimal setting time of NBCA have paramount importance. (+info)
Microsurgical resection of incompletely obliterated intracranial arteriovenous malformations following stereotactic radiosurgery.
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Radiosurgery is effective in obliterating small arteriovenous malformations (AVMs), but less successful in thrombosing larger AVMs. This study reviewed patients who underwent surgical resection of their large AVMs following failed radiosurgical obliteration. AVMs from 36 patients (aged 7 to 64 years, mean 29.9) were surgically resected 1 to 11 years after radiosurgery. Initial AVM volumes were 0.7 to 117 cm3 (mean 21.6 cm3), and radiosurgical doses ranged from 4.6 to 45 Gray equivalent (GyE) (mean 21.1 GyE). Thirty AVMs (83%) were located in eloquent tissue. Venous drainage was deep (14), superficial (13), or both (9). Spetzler grades were II (2), III (12), IV (18), and V (4). Nine patients suffered rehemorrhage after radiosurgery but prior to surgery, while three patients developed radiation necrosis. Twenty-seven patients underwent endovascular embolization prior to surgery. During microsurgical resection, the AVMs were found to be significantly less vascular and more easily resected, compared to AVMs in patients who had not received radiosurgery. Histology showed endothelial proliferation with hyaline and mineralization in vessel walls. Partial or complete thrombosis of some AVM vessels, and evidence of vessel and brain necrosis were noted in many cases. Clinical outcome was excellent or good in 34 cases, with two patients dying of rebleeding from residual AVM. Five patients were neurologically worse following microsurgical resection. Final outcome was largely related to the pretreatment grade. Radiosurgery several years prior to surgical resection appears useful in treating unusually large and complex AVMs. (+info)
Management of pericentral arteriovenous malformations.
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Pericentral arteriovenous malformations (AVMs) have more often been deemed inoperable lesions because of their complexity, owing to their critical locations and dismal outcome. This study discusses the management of this group of patients with a variety of treatments which includes surgery, nidus embolization, and radiosurgery. Out of 89 patients treated for AVMs in our institute over a period of 30 months (1992 through May 1995), we present a case series of 34 patients who had AVMs located in the pericentral region. All the treated AVMs were Spetzler and Martin grade III (6 patients), grade IV (13 patients), and grade V (15 patients). The neurological outcome remained, normal or improved from baseline in 68% of patients following treatments; of the remaining 32%, 19% remained in the same condition (with continuing preoperative deficits) and 10% showed some deterioration from their pretreatment condition. Thus 87% were unchanged or improved after the treatment regime. There was a 3% mortality (one patient who died as result of initial hemorrhage) in the series. Our multimodality treatment for this group of AVMs confirms the efficacy of the practiced strategies for their management. The results derived from the experience with this selected group of patients with AVMs lead us to recommend treating these patients with multimodality regimen rather than awaiting the natural history of the disease in the best interest of the patients. (+info)
Surgical techniques for arteriovenous malformations in functional areas: focus on the superior temporal gyrus.
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Direct surgical intervention of arteriorvenous malformations (AVMs) in functional areas has been accepted as a standard mode of treatment. However, safe and successful intervention requires that such factors as exact location, size, vascular supply, and drainage be considered. Importantly, surgical techniques must be individualized to each patient, based on hemodynamic anatomy of the AVM. This paper discusses AVMs in the superior temporal lobe, which have a complex neuronal anatomy and circulatory system; the authors present 22 patients with AVMs of various sizes and describe the surgical techniques specific for the indicated location. Surgical procedures adhered to the following principles: 1) avoid brain tissue removal; 2) preserve microcirculation; 3) maintain circulation of the isolated major draining vein to access the AVM core; 4) compartmental isolation; and 5) preservation of functional area cortex covering the AVM. All patients underwent total resection except one, who had a subtotal resection. Neurological and occupational recovery was remarkable except for partial hemianesthesia in one patient; two patients are still in rehabilitation. This is the first description of a direct surgical approach to AVMs in the superior temporal gyrus, where management is challenging because the lesions may extend elsewhere, such as to Broca's and Wernicke's areas. The results suggest that the procedure is promising. (+info)
Surgery for deeply seated arteriovenous malformation: with special reference to thalamic and striatal arteriovenous malformation.
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Surgery for deeply seated arteriovenous malformation (AVM) is controversial because stereotactic irradiation is applicable to the lesion. We have, however, experienced 30 deeply seated AVMs treated by direct surgery and/or endovascular treatment. The present study shows profiles of those patients and results of surgery. They include AVM in the thalamus in 12 cases, striatum in four cases, paraventricular area in five cases, medial temporal lobe in three cases, intraventricular area in three cases, and other regions in three cases. They were treated by surgery alone in 23 cases, embolization followed by surgery in four cases, and embolization alone in three cases. AVM in the mediodorsal thalamus and fornix (5 cases) was best treated by transcallosal approach. Venous aneurysm was commonly found in the AVM of this region and was a good navigator to the AVM. Pulvinar AVM was accessible through posterior interhemispheric approach (2 cases). None of these cases had additional neurological deficits. Cadaver dissection was useful for acquisition of surgical approach. Striatal AVM was approached through hematoma cavity with minimal manipulation to the surrounding structures, yet two of four cases showed progression of their weakness. The present study indicates that thalamic AVM can be approached surgically with careful selection of the approach. On the other hand, striatal AVM is not a good candidate for direct surgery and better treated by stereotactic irradiation. (+info)