Microsurgical resection of brain arteriovenous malformations in the elderly: outcomes analysis and risk stratification

OBJECTIVE Few outcomes studies have been published on microsurgical resection of arteriovenous malformations (AVMs) in elderly patients, and most are limited by a small sample size and the heterogeneous application of treatment modalities. This study aimed to determine whether functional outcomes at last follow-up (LFU) in patients 60 years or older differed when stratified by age. METHODS Patients 60 years or older (n = 104) who had undergone microsurgical AVM resection (total, n = 72; 60-65 years, n = 35; and > 65 years, n = 37) or observation (n = 32) were identified from a prospective database. Age, sex, Spetzler-Martin (SM) grade, supplemented SM grade, clinical presentation, AVM location, AVM-associated aneurysms, and functional outcome measured using the modified Rankin Scale (mRS score 0-2 [favorable] vs mRS score > 2 [unfavorable]) at LFU were analyzed. RESULTS AVM patients undergoing microsurgical resection were younger, had lower AVM grades, and were more likely to present with rupture. Overall outcome in the surgical group was favorable in 71% of the patients and was statistically significantly better in patients 60-65 years old (p = 0.039). In patients older than 65 years, outcome was dependent on SM grade and level of preexisting functional dependence. Patients with supplemented SM grades of greater than 6 points had favorable outcomes that were age dependent (p = 0.029). This difference was not observed in patients with lower supplemented SM grades or in those with low or high preoperative SM grades (SM grade = 2 and grade = 4, respectively). CONCLUSIONS This study demonstrates that favorable outcomes can be achieved with microsurgical resection of AVMs in elderly patients, with careful patient selection. Outcomes in more elderly patients (> 65 years of age) are more dependent on preoperative SM and supplemented SM grading than those in younger cohorts.