Preoperative Embolization in Surgical Treatment of Arteriovenous Malformations in Critical location: A Multicenter Study with Propensity-Score Matching

Introduction: Brain arteriovenous malformations (AVMs) are congenital vascular abnormalities that can lead to severe neurological outcomes if left untreated. Preoperative embolization is commonly used as an adjunct therapy to microsurgical resection, though its impact on outcomes remains uncertain. Particularly concering the risk of complications of embolization added to surgical resection of AVMs in critical locations. This study aimed to compare the safety and efficacy of microsurgical resection with and without preoperative embolization on critical location AVMs.

Methods: We conducted a multicenter retrospective analysis from the MISTA consortium, including adult patients who underwent microsurgical resection of AVMs in critical location brain areas between January 2010 and December 2023. Patients were divided into two groups: those who had microsurgical resection alone and those who underwent preoperative embolization followed by microsurgical resection. Propensity score matching (PSM) was used to control for potential confounders. Outcomes assessed included functional status (modified Rankin Scale [mRS]), angiographic obliteration, and procedural complications.

Results: A total of 216 patients were included, with a median age of 41 years (IQR, 26-58). After matching, 57 patients in each group were compared. Independent long-term functional outcomes (defined as mRS 0-2) were similar between the groups (85% vs. 86%; P = 0.97). Complete obliteration rates at the last imaging follow-up were 96% in the embolization group and 89% in the surgery-only group (P = 0.16). Complication rates (26% vs. 21%; P = 0.51), and mortality rates (3.5% vs. 1.8%; P > 0.99) were comparable in both groups.

Conclusion : Preoperative embolization did not significantly improve functional outcomes, obliteration rates, or reduce the incidence of complications when compared to microsurgical resection alone. However, no additional risk was identified with the use of preoperative embolization for AVMs in critical locations. These findings suggest that concerns regarding the increased risk associated with preoperative embolization in such regions may not be well-founded. Thus, its use should be considered on a case-by-case basis, taking into account the specific characteristics of the AVM and the surgeon’s expertise and comfort with the procedure.