Dural arteriovenous fistula of the posterior fossa developing after surgical occlusion of the sigmoid sinus

Five cases of dural arteriovenous fistula (AVF) which developed in the affected sigmoid-transverse sinus 3 to 6 after sacrifice of the sigmoid sinus because of tumor involvement are presented. The original tumor was meningioma in two patients, and neurinoma, glomus jugulare tumor and ameloblastoma in one patient each. The involved sigmoid sinus was resected with the tumor and ligated at the normal edge. The resected sigmoid sinus remained as a small stump on the retrosigmoid portion in all cases. Serial angiography performed before and after the tumor surgery demonstrated no abnormal arteriovenous communications showing dural AVF in any of our cases. Although many reports have suggested that sinus thrombosis in a precipitating factor in the pathogenesis of dural AVFʹs, there are only a few cases in which serial angiography was performed before the new development of dural AVFʹs. In all of our cases, surgical resection of dural AVF was performed and histological examination was carried out. Subintimal fibrous thickening was marked, and the sinus wall contained many dural vessels. Organized thrombosis with neovascularization was seen in only two patients. Our cases demonstrate that subintimal fibrous thickening and a hypertrophied sinus wall secondary to increased intrasinus pressure or sinus thrombosis occurring after the sinus occlusion can provoke dural AVFʹs in the course of a lifetime, and suggest that maintenance of intrasinus blood flow may be very important to prevent this late postoperative complication.