Long-term outcomes of Spetzler-Martin grade IV and V arteriovenous malformations: a single-center experience

Abstract

OBJECTIVE This study aimed to explore whether intervention can benefit Spetzler-Martin (SM) grade IV–V arteriovenous malformations (AVMs). METHODS Eighty-two patients with SM grade IV–V AVMs were retrospectively reviewed from 2015 to 2018. Patients were divided into two groups: those who received conservative management (22 cases [26.8%]) and intervention (60 cases [73.2%], including 21 cases of microsurgery, 19 embolization, and 20 hybrid surgery). Neurofunctional outcomes were assessed with the modified Rankin Scale (mRS). The primary outcome was long-term neurofunctional status, and the secondary outcomes were short-term neurofunctional status, long-term obliteration rate, seizure control, and risk of subsequent hemorrhage. RESULTS Regarding the primary outcome, after an average of 4.7 years of clinical follow-up, long-term neurofunctional outcomes were similar after conservative management or intervention (absolute difference −0.4 [95% CI −1.5 to 0.7], OR 0.709 [95% CI 0.461–1.090], p = 0.106), whereas intervention had an advantage over conservative management for avoidance of severe disability (defined as mRS score > 3) (1.7% vs 18.2%, absolute difference 16.5% [95% CI −23.6% to 56.6%], OR 0.076 [95% CI 0.008–0.727], p = 0.025). Regarding the secondary outcomes, intervention was conducive to better seizure control (Engel class I–II) (70.0% vs 0.0%, absolute difference 70.0% [95% CI 8.6%–131.4%], p = 0.010) and avoidance of subsequent hemorrhage (1.4% vs 6.0%, absolute difference 4.6% [95% CI −0.4% to 9.6%], p = 0.030). In the subgroup analysis based on different intervention modalities, microsurgery and hybrid surgery achieved higher complete obliteration rates than embolization (p < 0.001), and hybrid surgery resulted in significantly less intraoperative blood loss than microsurgery (p = 0.041). CONCLUSIONS Intervention is reasonable for properly indicated SM grade IV–V AVMs because it provides satisfactory seizure control with decreased risks of severe disability and subsequent hemorrhage than conservative management. Clinical trial registration no.: NCT04572568 (ClinicalTrials.gov)