91/1441. Surgical management of cerebral arteriovenous malformations with intraoperative digital subtraction angiography. Complete excision of cerebral arteriovenous malformations (AVMs) is requisite to improving the outcome of patients with AVMs. Five patients with a small or medium cerebral AVM underwent surgery with an intraoperative digital subtraction angiography (DSA) unit. There were no residual AVMs and no complications in the examination of intraoperative DSA. The findings of postoperative angiography were consistent with those of intraoperative DSA. Intraoperative DSA provided the benefits of not only identification of a feeding artery, but also recognition of the complete excision during surgery. ( info) |
92/1441. Combination of intraoperative embolisation with surgical resection for treatment of giant cerebral arteriovenous malformations. Objective: To reduce the risk of surgical resection of giant arteriovenous malformation (AVM) and prevent normal perfusion pressure breakthrough (NPPB) and thus to lower postoperative mortality.methods: During the operation, which was carried out under general anaesthesia, the proximal ends of the feeding arteries were first ligated and 0.5 ml IBCA mixed with 0.5 ml of 5% glucose was injected into the vessels towards the AVM, then the malformed vessels were totally resected. Postoperative digital subtraction angiography (DSA) of the four vessels was performed in all patients.Results: Fifty patients with giant AVMs survived after operation, only 6 (12.0%) had transient neurological dysfunction and 44 (88.0%) recovered after a follow-up of 6-36 months. No patient suffered from NPPB.Conclusions: The embolisation could block the arteriovenous shunts sufficiently to decrease the blood flow away from the normal areas of the brain so as to prevent the incidence of intra- and post-operative rebleeding, especially in NPPB. Therefore, the combination of intraoperative embolisation with surgical resection is an effective strategy in the treatment of giant cerebral AVMs, which makes it possible to operate on patients who used to be regarded as inoperable cases. ( info) |
93/1441. Haemorrhagic complication after total extirpation of huge arteriovenous malformations. Two cases with huge arteriovenous malformations (AVMs) who developed haemorrhagic complications after surgery are described. The cause of the postoperative haemorrhage was considered to be the normal perfusion pressure breakthrough phenomenon and/or occlusive hyperaemia. These two haemodynamic insults possibly occur simultaneously and induce life-threatening haemorrhage. It was concluded that a huge high-flow AVM with a large venous ampulla in its deep drainers has a high risk of a postoperative intravenous thrombosis, resulting in haemorrhage together with normal perfusion pressure breakthrough phenomenon. ( info) |
94/1441. Strategic embolisation for successful resection of a large cerebral arteriovenous malformation. The risks accompanied by the treatment of cerebral arteriovenous malformation (AVM) are still cumulative despite recent progress in available treatment options. Pre-operative embolisation is one such option, however, it seldom makes the surgical resection difficult. The excessive embolised nidus makes the surgical resection difficult because it cannot be compressed during the resection surgery and embolised nidus as a 'glue ball' with marginal hypervascular territory is most difficult to remove. The aim of pre-operative embolisation for successful surgical resection is to put glue into the marginal part of the nidus so as to make a cleavage between the surrounding normal tissues. Remaining feedings via the dilatated leptomeningeal anastomoses from surrounding normal cortical arteries do not interfere with the resection and can be eliminated easily by coagulating the pia matter around the nidus. Strategic planning with regard to the systemic course of treatment, including the manner of resection, is important for effective pre-operative embolisation. ( info) |
95/1441. Surgical resection of cerebral arteriovenous malformation combined with pre-operative embolisation. To assess the importance of pre-operative embolisation, 27 cases of cerebral artriovenous malformation (AVM) treated in this institute between July 1994 and October 1998 were analysed. The patients' ages ranged from 3 to 70 years (average 36.9) with a follow-up period of 1-41 months (average 19.2). The patient presented with haemorrhage in 21 cases and seizure in five. In 21 of 27 cases, surgical resection of a nidus was performed, gamma knife therapy was applied in three and conservative therapy was chosen in three. Of 21 cases treated surgically, total removal was achieved in 19 cases and a residual nidus was seen in one (a large basal ganglia AVM). In the remaining case, postoperative angiography was not available. Pre-operative embolisation followed by surgical resection of the nidus was performed in seven cases in which there was a large AVM. A volume index was calculated to indicate the size of the nidus using X x Y x Z, where X is the maximum diameter (cm) of the nidus on the lateral angiogram, Y is the diameter (cm) perpendicular to X and Z is the maximum diameter (cm) on the anteroposter or angiogram. The index averaged 45.9 for the cases in which pre-operative embolisation was performed, while it was 5.6 in the cases without embolisation. Pre-operative embolisation was performed to reduce the nidus flow as much as possible, to prevent overload to the surrounding structures. At surgery, the nidus was resected from the surrounding tissue and care was taken not to enter the nidus. Postoperatively, the systolic blood pressure was maintained at 90-100 mmHg for several days in the intensive care unit. The results were excellent in 15 cases, good in three (hemiparesis due to the initial haemorrhage remained in all three), fair in one (a patient with a severe subarachnoid haemorrhage). Two patients died (acute pulmonary oedema and severe meningitis). Minor postoperative bleeding or oozing was seen in three cases. In conclusion, reducing the shunt flow through a nidus in a step-wise fashion with pre-operative embolisation of a large AVM seems to be quite helpful in preventing postoperative haemodynamic overload to the surrounding brain. It is also important not to enter the nidus when it is removed at surgery. This helps to prevent intraoperative and/or postoperative bleeding, and led to successful total removal of the nidus with a good postoperative course. ( info) |
96/1441. Unilateral proptosis and chemosis caused by dural arteriovenous malformation of the superior sagittal sinus. We describe a patient with unilateral proptosis and chemosis resulting from a dural arteriovenous malformation (AVM) of the superior sagittal sinus (SSS) fed mainly by branches of both external carotid arteries. The symptoms may have been caused by increased SSS pressure and disturbance of venous flow by the dural AVM. ( info) |
97/1441. The rationale and technique of staged-volume arteriovenous malformation radiosurgery. PURPOSE: Stereotactic radiosurgery is an effective management strategy for properly selected arteriovenous malformation (AVM) patients. However, the risk of postradiosurgical radiation-related injury generally limits this procedure to patients with AVMs of an average diameter of 3 cm or less. radiosurgery of large AVMs in a planned staged fashion was undertaken to limit the radiation exposure to the surrounding normal brain. methods AND MATERIALS: Between April 1997 and December 1999, 10 patients with a median AVM volume of 17.4 cm(3) (range, 7.4-53.3 cm(3)) underwent staged-volume radiosurgery (23 procedures). At the first radiosurgical procedure, the total volume of the AVM is estimated and a dose plan calculated that covers 10 cm(3)-15 cm(3), or one-half the nidus volume if the AVM is critically located (brainstem, thalamus, or basal ganglia). At 6-month intervals thereafter, radiosurgery was repeated to different portions of the AVM with the previous dose plan(s) being re-created utilizing intracranial landmarks to minimize radiation overlap. Radiosurgical procedures were continued until the entire malformation has been irradiated. RESULTS: The radiation dosimetry of staged-volume AVM radiosurgery was compared to hypothetical single-session procedures for the 10 patients. Staged-volume radiosurgery decreased the 12-Gy volume by an average of 11.1% (range, 4.9-21%) (p < 0.001). The non-AVM 12-Gy volume was reduced by an average of 27.2% (range, 12.5-51.3%) (p < 0.001). DISCUSSION: Staged-volume radiosurgery of large AVMs results in less radiation exposure to the adjacent brain. Further follow-up is needed to determine whether this technique provides a high rate of AVM obliteration while maintaining an acceptable rate of radiation-related complications. ( info) |
98/1441. Parietal lipoma associated with cortical dysplasia and abnormal vasculature: case report and review of the literature. We present the case of an unusually located intracranial lipoma in a 17-year-old patient with partial epilepsy who was being controlled with medication. The lipoma was located deep in the left sylvian fissure, in the inferior parietal lobule, associated with cortical dysplasia of the surrounding supramarginal gyrus. Abnormal vasculature was detected adjacent to and within the adipose mass. The findings of the imaging studies that included CT, MR imaging, and MR angiography, are described along with a brief review of the literature. ( info) |
99/1441. Occlusive hyperemia: a radiosurgical phenomenon? OBJECTIVE: Causes of neurological deficits after arteriovenous malformation (AVM) radiosurgery, including hemorrhage, radiation injury, and delayed cyst formation, are described. CONCEPT: Occlusive hyperemia has been described as a reason for neurological deterioration after AVM resection. thrombosis of draining veins or dural sinuses is thought to cause postoperative bleeding or neurological deficits secondary to venous hypertension. In a similar manner, local hemodynamic changes can occur in the brain adjacent to an AVM after radiosurgery if venous outflow is obstructed. Two patients are presented whose cases demonstrate this phenomenon. CONCLUSION: patients can experience clinical worsening after AVM radiosurgery from premature thrombosis of draining veins. Local hemodynamic changes could explain why imaging changes thought to be radiation related occur more frequently after radiosurgery of AVMs than of tumors. ( info) |
100/1441. Cerebral arteriovenous malformation presenting as visual deterioration in a child. A rare case of visual loss as the presenting feature of a central arteriovenous malformation involving the vein of Galen is reported. A 5-year-old girl with a history of deteriorating vision for the past 6 months was examined. Ocular examination showed a left hemianopia, left optic atrophy, and dilated vessels of the right optic disc. MRI revealed a massive deep-seated central arteriovenous malformation involving the vein of Galen. The mechanism of visual loss is likely to be a combination of ischaemic optic atrophy associated with a steal phenomenon and direct compression of the right optic radiation. ( info) |