Abstract
Surgical problems of large high-flow AVMs were studied based on our own experiences with 5 patients undergoing staged operations. All patients had supratentorial large AVMs of Spetzler's grade IV. Three patients had histories of intracerebral hemorrhage and 2 complained of headache and general seizures. The ages of the patients ranged from 31 to 50 years. All but one patient (Case 4) underwent staged surgical treatment including feeder clipping, embolization or partial excision of the nidus. The AVMs were totally excised in 4 patients (Case 1, 2, 3, 4). Postoperative hemorrhagic complication occurred in 2 patients (Case 4, 5) following one-stage excision of the nidus and clipping of the main feeding vessels, respectively. In these two patients, preoperative angiographical steal was more remarkable and the sum of the diameters of the feeding vessels was larger than those in other patients without postoperative hemorrhage. The feeders were clipped adjacent to the nidus at 45% of the sum of the diameters of all feeding vessels on preoperative angiogram in Case 5. This resulted in severe intracerebral hemorrhage. The feeder clipping near the nidus and obliteration of a large amount of blood flow through feeding vessels thus carries a risk of hemorrhagic complication. Staged operation is preferable for large high-flow AVMs but careful selection of the feeders to be clipped and their sites is quite important to prevent hemorrhagic complication when AVMs have marked preoperative angiographical steal and large feeding vessels.
