一定の治療方針に基づいたhigh grade AVMの治療成績 : 外科的治療の意義(<特集>High grade AVMの治療)  [in Japanese] Management of Spetzler and Martin Grade III to V Arteriovenous Malformations : Usefulness of Surgical Extirpation(<Topics>Treatment Strategy for High Grade AVMs)  [in Japanese]

We analyzed the outcome when high-grade arteriovenous malformations (AVMs), i.e., Spetzler and Martin Grades III, IV, and V, were managed by multimodal therapy to clarify the appropriate treatment for these patients. Seventy-six patients with high-grade AVM were enrolled for this study and followed for a mean of 3.1 years. Initially, surgical treatment was recommended for all patients if it would not cause or worsen a neurological deficit. Fifteen patients were treated conservatively, while 41 patients underwent surgery, and the remaining 20 patients were treated with stereotactic radiosurgery. (1) Conservative management: Seven episodes of bleeding occurred during the follow-up period, and the hemorrhage rate was 6.39%/year. (2) Surgical treatment: To prevent neurological complications, techniques such as preoperative embolization of the feeding artery, strict blood pressure control, brain function mapping, and intraoperative angiography were employed during surgery and perioperatively. None of the patients developed a permanent neurological deficit after surgery. A poor outcome (i.e., a modified Rankin scale score >2) was seen in older patients (more than 65 years old), patients with bleeding episodes, patients with large lesions (diameter >3 cm), and patients with deep or posterior fossa lesions. (3) Stereotactic radiosurgery: MRA showed more than 80% obliteration of the AVM in 14 patients at 6 months later. During the follow-up period, there were 3 complications (hemorrhage, brain tumor, and middle cerebral artery stenosis). If surgery is unlikely to cause or worsen neurological symptoms, surgical resection is an appropriate treatment for high-grade AVM.