부산대학교 도서관

No multi-institutional studies on radiosurgery for cerebral arteriovenous malformations (AVMs) have been published. We analyzed the results of >3 years' follow-up in 885 patients with AVMs, who underwent gamma knife (GK) radiosurgery between May/1991 and March/1994 at one of Japan's 11 gamma knife centers. Postradiosurgically, 681 (77%) of the 885 patients were periodically examined by angiography. Complete nidus obliteration was angiographically confirmed in 443 patients (50%), subtotal obliteration in 114 (13%), shrinkage in 99 (11%) and no significant change in the remaining 25 (3%). These rates correspond to 65%, 17%, 15% and 4%, respectively, of the 681 patients who had follow-up angiography. Hemorrhages occurred during the postradiosurgical latency period, ranging from 1 to 48 months, in 41 patients (4.6%). The annual rates were 2.4% during the first postradiosurgical year, 0.9% during the second, 0.8% during the third, and 0.3% during the fourth. Although 14 (34%) of the 41 patients showed full recovery, 13 (32%) died and the other 14 (34%) have persistent deficits. Radiation-related aggravation of clinical symptoms was seen in 24 (2.7%) of the 885 patients between the 5th and 36th post-radiosurgical months. Steroid treatment was required in all 24 patients, 16 of whom recovered completely while the other eight had persistent deficits. The herein-reported overall obliteration rate seems relatively low as compared with those reported previously. However, the annual incidence of (re-) bleeding during the latency period was low as compared with those reported for untreated AVMs.