Surgical treatment of spinal arteriovenous malformations: vascular anatomy and surgical outcome.

BACKGROUND AND PURPOSE Spinal arteriovenous malformations (AVMs) are rare but debilitating lesions of the central nervous system. This study evaluated the outcome in patients with spinal AVMs treated surgically, and the relationship between outcome and the vascular anatomy of the lesions. METHODS These AVMs were classified into four types: dural AVM (type I), glomus AVM (type II), juvenile AVM (type III), and intradural direct arteriovenous fistula (type IV). Either interruption of the feeding vessels or excision of the AVMs was performed in all patients. RESULTS Intradural AVMs manifested as subarachnoid or intramedullary hemorrhages, whereas dural AVM manifested as epidural hemorrhage in two patients, and as an episode of subarachnoid hemorrhage in one patient. The nidus in five of the six dural AVMs was below the mid-thoracic level. In six of the seven patients with intradural AVMs, the nidus was located in the cervical region. The prognosis of patients with dural AVMs was generally good, but in patients with intradural AVMs, motor recovery was worse and resection was more difficult. CONCLUSIONS Correct diagnosis and classification of spinal AVMs are the key prerequisites for successful treatment. The surgical outcome is closely related to the vascular anatomy of the lesion. For dural AVMs, only surgical interruption of the arteriovenous shunting at the dural sleeve of the nerve is required and good surgical results are often obtained. Intradural direct arteriovenous fistula responded well to surgery, whereas combined endovascular and microsurgical techniques can minimize the chance of rebleeding in intramedullary AVMs.