1/180. Embolization of cerebral arteriovenous malformations with cellulose acetate polymer: a clinical, radiological, and histological study.OBJECTIVE: A cellulose acetate polymer (CAP) solution was hypothesized to be useful for the embolization of arteriovenous malformations (AVMs). To investigate this possibility, we analyzed the clinical, radiological, and histological results of patients with AVMs embolized by using a CAP solution. methods: We reviewed the cases of 11 patients with AVMs treated by embolization before surgical resection. We used two types of CAP solutions, CAP-M and CAP-L, which are mixtures of 250 mg of solid CAP and 1800 or 2250 mg of bismuth trioxide dissolved in 5.5 or 7.0 ml of dimethyl sulfoxide, respectively. After the embolization procedure, percent reduction of the nidus volume was measured, and thereafter, the clinical course and computed tomographic scans and/or magnetic resonance imaging scans were evaluated. All patients underwent surgical resection 1 to 51 days after embolization. Resected specimens were stained for light microscopic examination. RESULTS: Thirty-nine feeding vessels were embolized. The reduction rate of the nidus volume ranged from 20% to nearly 100%. Transient and persistent ischemic deficits occurred in three patients and one patient, respectively, and there were no hemorrhagic complications. All AVMs but one were completely resected by surgery. The embolized AVMs were soft enough to be easily cut and retracted. The histological examinations disclosed no or mild inflammatory reactions within 2 weeks after embolization. The internal elastic lamina was preserved in every case. Recanalization through the cast of the CAP mass was not observed until 51 days after embolization. CONCLUSION: CAP solution is a safe and useful embolic agent for AVMs.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
2/180. Dural arteriovenous malformation in the anterior cranial fossa.Two cases of dural arteriovenous malformation (AVM) at the base of the anterior cranial fossa are described. In both cases an intracerebral hematoma following the rupture of the AVM was the first indication of the disease. In one case, the malformation was supplied both by the anterior ethmoidal artery and frontopolar artery draining into the superior sagittal sinus. In the second case, the right anterior ethmoidal artery with draining veins into the superior sagittal sinus and sphenoparietal sinus was the feeding vessel. Surgical evacuation of the hematoma and excision of the malformation was performed on both patients. The typical clinical signs and radiological findings are described. A review of the pertinent literature is given.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
3/180. Endoscopic procedures for resection of arteriovenous malformations.BACKGROUND: Resection of arteriovenous malformations (AVMs), particularly those located in functional areas, requires precision. To enhance that precision, endoscope-assisted microsurgery has been employed at loma Linda University. methods: Twenty-five consecutive cases of AVM were treated microsurgically with endoscopic assistance. patients were divided into two groups: (1) those having AVMs in functional areas, and (2) those whose AVMs extended into the ventricle, either in the trigonal area or the capsulocaudatothalamic area. The endoscope was inserted into the subarachnoid space to interrupt communicating venules around the major draining vein and into the cleavage developed between the AVM venous loops and surrounding brain tissue as shunting arterioles and communicating venules were interrupted. For surgery of intraventricular AVMs, the curved endoscope was inserted into the ventricle, providing visualization of the AVM core, which was dissected from the ventricular side. RESULTS: AVMs were totally resected in all cases except for two patients with capsulocaudatothalamic AVMs, which were decreased in size sufficiently to receive radiosurgery. CONCLUSION: Endoscope-assisted microsurgery enhances magnification, illumination, and technical precision while the surgeon is dissecting the AVM core vessels and while operating on AVMs extending into the ventricle.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
4/180. Microdroplet tracking using biplane digital subtraction angiography for cerebral arteriovenous malformation blood flow path and velocity determinations.High-speed biplane angiography is used to determine the path and velocity of microdroplets of contrast material in three dimensions. By allowing more accurate determination of detailed blood flow in feeding vessels and draining veins of cerebral arteriovenous malformations than available with standard angiography, the new method offers the potential for more accurate treatment and further study of neurovascular/cerebrovascular hemodynamics. The first study of the method is presented.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
5/180. An adult case of recurrent arteriovenous malformation after "complete" surgical excision: a case report.BACKGROUND: Complete surgical excision of arteriovenous malformations (AVM) documented by postoperative angiography is considered a cure. However, recent reports have shown that AVMs in children may recur after negative postoperative angiograms, and some suggest that it may reflect the immaturity of their cerebrovasculature. This case report demonstrates that AVM in adults may also recur, despite postoperative angiograms confirming complete removal. CASE DESCRIPTION: This 28-year-old man presented in 1994 with a focal motor seizure and was found to have an AVM in the right frontal lobe. He underwent surgical excision of the AVM; postoperative angiograms taken immediately after surgery and 15 days later showed no residual AVM. He remained free of symptoms after surgery and it was considered that a complete removal had been achieved. In 1998 he developed a subarachnoid hemorrhage, and subsequent angiograms revealed a small AVM in an adjacent location. CONCLUSION: This is the oldest patient reported in the literature with a recurrence of AVM, despite postoperative angiograms confirming complete removal. Angiographically invisible immature vessels, which might have been left in the surgical field, might have formed a new malformation later. We still believe that such recurrence must be very rare after AVM surgery, but we now recommend follow-up angiography at yearly intervals to our patients.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
6/180. Intraventricular contrast medium leakage during ethanol embolization of an arteriovenous malformation.We report the unusual phenomenon of abrupt intraventricular contrast medium leakage from the choroid plexus occurring during ethanol embolization of a periventricular arteriovenous malformation. There was no evidence of any associated intraventricular hemorrhage to suggest that leakage arose from a vessel perforation, as was first suspected. Intraventricular contrast medium leakage has been reported previously in the setting of ependymitis, and it is likely that similar pathogenetic mechanisms apply in this case. To our knowledge, this is the first reported case of intraventricular contrast medium leakage occurring during an embolization procedure.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
7/180. Carotid rete mirabile presenting subarachnoid haemorrhage. Report Of two cases.Carotid rete mirabile (CRM) consists of arterial channels between the internal and external carotid arteries in some lower mammals. It is a very rare pathological condition in humans. We report two patients who presented with clinical signs of subarachnoid haemorrhage (SAH). Their sudden-onset SAH was thought to have been due to rupture of cerebral aneurysms, however, angiograms revealed an abnormal vascular network around the cavernous sinus. To our knowledge, 2 of 7 reported patients with CRM presented with SAH, however, only one of these patients had a probable cerebral aneurysm. We suggest that in patients with CRM, the rupture of anastomosing vessels be a probable cause of SAH.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
8/180. Radiographic evidence and surgical confirmation of a saccular aneurysm on a hypoplastic duplicated A1 segment of the anterior cerebral artery: case report.OBJECTIVE AND IMPORTANCE: True duplication of the A1 segment of the anterior cerebral artery is extremely rare, as is finding a true A1 segment saccular aneurysm. We report the angiographic and surgical findings of such a case with the additional association of a hypoplastic ipsilateral M1 segment of the middle cerebral artery. CLINICAL PRESENTATION: A 68-year-old man presented with a Hunt and Hess Grade II subarachnoid hemorrhage and symptoms of headache, nuchal rigidity, and facial paresis. INTERVENTION: Angiographic evaluation with superselective exploration revealed a small ruptured aneurysm located on a duplicated hypoplastic A1 segment of the left anterior cerebral artery with associated middle cerebral artery stenosis and secondary early moyamoya changes. Surgical clipping of the aneurysm was performed successfully while sparing the hypoplastic A1 segment. CONCLUSION: A1 aneurysms occurring on a duplicated anterior cerebral artery segment probably develop from a congenital weakness of the parent vessel and increased local shear stress. Superselective angiography was helpful in the preoperative planning and facilitated the decision to treat with surgical clipping instead of embolization.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
9/180. Management of residual dysplastic vessels after cerebral arteriovenous malformation resection: implications for postoperative angiography.OBJECTIVE: The verification of surgical resection of cerebral arteriovenous malformations (AVMs) relies on angiography. Abnormal vasculature often is identified after removal of the AVM. Differentiation of dysplastic feeding vessels that resemble the neovascularity of moyamoya disease, as distinct from residual AVM, is crucial for preserving critical brain areas. We review a large experience with immediate postoperative angiography after AVM resection and discuss the implications for management of abnormal dysplastic vessels discovered after AVM resection. methods: Beginning in 1992, 86 consecutive patients with AVMs underwent operations by standard protocol for immediate postoperative angiography under the same general anesthetic. Angiographic interpretation dictated admission to the intensive care unit or return to the operating room for further resection. RESULTS: In 78 patients, the angiogram revealed complete resection. Two patients were returned to the operating room, one for residual malformation with an early draining vein, and one for resection of residual dysplastic vessels. There was one postoperative hemorrhage in a patient whose postoperative angiogram was falsely negative for AVM. Six patients with residual dysplastic vessels mimicking residual AVM, but without an early draining vein, were managed conservatively. Delayed follow-up angiography demonstrated spontaneous involution of these abnormal vessels in all of these patients. CONCLUSION: Residual dysplastic feeding vessels resembling the neovascularity of moyamoya disease but not associated with an early draining vein do not necessarily represent residual malformation after AVM resection. The abnormal vessels will proceed to complete spontaneous resolution. Given the difficulty of interpreting intraoperative angiography, immediate postoperative angiography may be a viable alternative after AVM resection.- - - - - - - - - - ranking = 11keywords = vessel (Clic here for more details about this article) |
10/180. Vascular structure of arteriovenous malformations.Cerebral arteriovenous malformations (AVMs) are classified angiographically into two types: the arteriovenous fistula (AVF) type and the plexiform type. However, the differences in vascular structure of these two types have not been clarified. The purpose of the present study is to elucidate the vascular structure of plexiform AVMs and to discuss the clinical significance of this classification of AVMs. Specimens of AVMs resected in 8 cases and identified by cerebral angiography as plexiform AVMs were examined. Immediately after their removal, microdissection of the terminal arterial feeder, the nidus, and the venous drainer was performed under a microscope. A histological examination of each element was then conducted. microdissection of a portion of the vascular mass that formed the nidus made it possible to separate individual vessels of the mass from each other. Many of these individual vessels connected with the feeder on one side, while the other side anastomosed with the drainer, thus exhibiting the morphology of an AVF. From our examination of the AVMs in the present study, we inferred that the plexiform type is fundamentally a conglomeration of AVFs. It is therefore suggested that the vascular structure of this type of AVM is not fundamentally different from that of the AVF type.- - - - - - - - - - ranking = 2keywords = vessel (Clic here for more details about this article) |
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