Microsurgical Resection of Unruptured Brain Arteriovenous Malformations: A 12-Year Single-Center Experience

Background and Objectives: The management of unruptured brain arteriovenous malformations (ubAVMs) remains controversial, particularly following the ARUBA trial, which favored conservative management. However, concerns regarding the validity of its findings persist. This study aimed to evaluate the outcomes of microsurgical resection of ubAVMs in a high-volume neurosurgical center. Materials and Methods: This is a retrospective single-center study that analyzed 52 patients treated by microsurgical resection at the Cerebrovascular Department, University Clinical Center of Serbia, between January 2010 and January 2022. All patients were classified according to the supplementary Spetzler-Martin (suppl-SM) grading system and stratified into low-risk (suppl-SM ≤ 6) and high-risk (suppl-SM > 6) groups. Functional outcomes were assessed using the modified Rankin Scale (mRS) at discharge and 9-month follow-up. Results: The mean patient age was 38.8 years, with equal gender distribution. Epileptic seizure was the most common presenting symptom (80.4%). In the low-risk group, there were no deaths, and poor outcomes were rare (6.8% at discharge; 2.3% at 9 months). Conversely, the high-risk group demonstrated significantly worse outcomes (62.5% poor outcome at discharge, 28.6% at 9 months). The overall hemorrhagic stroke rate was 5.8%, with one fatality (12.5%) in the high-risk subgroup. Absence of superficial venous drainage and presence of combined/deep venous drainage were strongly associated with poor outcomes. Conclusions: Microsurgical resection of ubAVMs is a safe and effective treatment strategy for low-grade lesions, yielding excellent functional outcomes and minimal morbidity. Our findings, supported by other large series, reinforce microsurgery as the gold standard for low-grade ubAVMs in appropriately selected patients.