Long-Term Outcomes of Stereotactic Radiosurgery Focused Treatment of Brain Arteriovenous Malformations Based on Rupture Status: A Systematic Review and Meta-Analysis.

Abstract

Stereotactic radiosurgery (SRS) is a non-invasive treatment option for brain arteriovenous malformations (bAVMs). However, SRS cures are delayed, making it less favorable for higher risk ruptured bAVMs (rbAVMs) than unruptured (ubAVMs). This systematic review and meta-analysis explores the long-term outcomes of SRS-focused protocols for rbAVMs and ubAVMs. This study adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Literature search was conducted using PubMed, Ovid Medline, Scopus, and hand-search on January 30th, 2025. The inclusion criteria encompassed studies: distinguishing cohorts by rupture status, reporting post-SRS outcomes, and without overlapping series. Pooled analysis was performed from 24 articles using DerSimonian-Laird random effects models. Subgroup and meta-regression analyses were also conducted. All analyses were performed using R. For rbAVMs, the pooled rupture, obliteration, and mortality rates were 7.14% (95% CI: 5.76%-8.64%), 65.0% (95% CI: 57.2%-72.4%), and 0.87% (95% CI: 0.00%-5.14%), respectively, and for ubAVMs, 6.13% (95% CI: 4.71%-7.69%), 59.5% (95% CI: 51.3%-67.3%), and 0.89% (95% CI: 0.00%-3.82%), respectively. Subgroup meta-analyses of rupture rates and obliteration rates showed no significant differences based on prior treatments (Q = 2.47, p = 0.48; Q = 4.34, p = 0.23; respectively) or volume-staging protocols (Q = 4.90, p = 0.18; Q = 1.12, p = 0.77, respectively). Meta-regression analysis for rbAVMs demonstrated a positive correlation between intranidal aneurysms and rupture rate (p < 0.05, R² = 100%), an inverse correlation between Spetzler-Martin (SM) grade I-II bAVMs and obliteration rate (p < 0.05, R² = 68.6%), and a positive correlation between SM grade III-V bAVMs and obliteration rate (p < 0.05, R² = 68.0%). Meta-regression analysis for ubAVMs demonstrated an inverse correlation between eloquent-region lesions and rupture rate (p < 0.05, R² = 31.3%), and surprisingly a positive correlation between mean age and obliteration rate (p < 0.05, R² = 23.8%). SRS-focused studies show similar long-term outcomes regardless of rupture status, but presence of underlying factors indicates the need for individualized risk-benefit analysis.