Determinants of neurological outcome after surgery for brain arteriovenousmalformation

Background and Purpose-We sought to define determinants of neurological def icit after surgery for brain arteriovenous malformation (AVM). Methods-One hundred twenty-four prospective patients (48% women, mean age 3 3 years) underwent microsurgical brain AVM resection. Patients were examine d by 3 study neurologists immediately before surgery, postoperatively in-ho spital, by in-person long-term follow-up, and with a structured telephone f ollow-up. They were classified according to the 5-point Spetzler-Martin gra ding system, with its 3 elements: size, venous drainage pattern, and locati on. The functional neurological status was classified with the modified Ran kin scale. Multivariate logistic regression models were applied to test the effect of patient age, gender, and the 3 Spetzler-Martin elements on early and long-term postoperative neurological complications. Results-Twelve patients (10%) were classified as Spetzler-Martin grade 1; 3 6 (29%) as grade 2; 47 (38%) as grade 3; 26 (21%) as grade 4; and 3 (2%) as grade 5. Postoperatively, in-hospital, 51 patients (41%) showed new neurol ogical deficits (15% disabling [ie, Rankin scale score >2] and 26% nondisab ling [ie, Rankin 1 or 2]). At long-term follow-up (mean follow-up time 12 m onths), 47 patients (38%) revealed surgery-related neurological deficits (6 % disabling; 32% nondisabling), The rate of neurological complications incr eased by Spetzler-Martin grade. Female gender, AVM size, and deep venous dr ainage were significantly associated with neurological deficits at in-hospi tal and long-term evaluation, For patient age and AVM location, no signific ant association was found. Conclusions-The findings suggest that female gender, AVM size, and AVM drai nage into the deep venous system may be determinants of neurological defici t after microsurgical AVM resection.