[Epidemiology and etiology of dural arteriovenous fistula]

Dural arteriovenous fistula (DAVF) is generally recognized as an acquired lesion; however, its epidemiology, etiology, and natural history are yet to be completely elucidated. Recently, an epidemiological survey of the detected DAVF cases in Japan between 1998 and 2002 was conducted. The detection rate of DAVF per 100,000 adults per year is 0.29 for DAVF. Furthermore, unlike Europe and North America where cases of transverse-sigmoid sinus DAVF are predominantly detected, in Japan, a higher number of cases of cavernous sinus lesions are detected, indicating racial difference in the presentation of DAVF. Our study indicates that dural sinus thrombosis, which is generally considered as a causative factor of DAVF, is less likely to precede the detection of DAVF. A possible mechanism underlying the formation of DAVF is as follows: subtle changes, including minor trauma, cause the formation of an abnormal arteriovenous shunt in the dura and promote progressive steno-occlusive change in its venous drainage.