Standalone Stereotactic Radiosurgery (SRS) versus Pre-SRS Embolization for Treatment of Cerebral Arteriovenous Malformations: A Systematic Review and Meta-analysis

Introduction: Although the first-line treatment for most cerebral arteriovenous malformations (AVMs) is microsurgery, stereotactic radiosurgery (SRS) can play an important role in treating small-to-moderate size (< 3 cm) AVMs that are located deep, making them microsurgically inaccessible. In fact, both SRS and endovascular techniques (namely embolization) have both become common microsurgical adjuncts used to treat AVMs—which can be among the most dangerous and complicated brain lesions to treat. Smaller lesions are preferred because they are easier to target with precise, high-dose SRS. The risk for radiation necrosis can be minimized for small AVMs but becomes magnified when dealing with larger lesions. Here, pre-SRS embolization could play a role in reducing AVMs' size and flow rate before SRS. Nonetheless, embolization has contrarily been found to decrease post-SRS AVM obliteration rates, providing no identifiable advantages over standalone SRS. In the present study, we compare the safety and efficacy of SRS for AVMs performed with versus without embolization.

Methods: We queried three databases in accordance with PRISMA guidelines to identify all studies comparing SRS with versus without embolization as adjuncts to microsurgical resection of AVMs. Meta-analysis focused on AVM obliteration rate (for rates reported at a minimum 2-year follow-up date) and the rate of subsequent AVM hemorrhage as the primary outcomes of interest. Other relevant outcomes included the incidence of neurological deficits secondary to radiation-induced damage and associated mortality. P-values < 0.05 were regarded as indicators of statistical significance.

Results: Thirty studies consisting of 5,023 patients, 1,399 (27.8%) and 3,624 (72.15%) of whom received embolization prior to SRS and stand-alone SRS, respectively, met the criteria for inclusion in the present meta-analysis. This inclusion hinged upon the availability of radiographic obliteration rates at a minimum 2-year follow-up. Ultimately, across the 30 studies, the difference in obliteration rates between the SRS with embolization and SRS-only groups was negligible (OR: 0.889 [95% CI: 0.660–1.196, I ² = 65%, p = 0.44). Furthermore, there was no statistically significant difference in the odds of hemorrhage between the groups (OR: 1.084 [95% CI: 0.837–1.405, I ² = 0%, p = 0.54). This trend continued throughout the remaining analyses and subanalyses, as there was no significant difference in the odds of severe neurological deficits (Group A subanalysis) or posttreatment mortality (Group B subanalysis) between groups.

Conclusion: There is no significant difference in rates of obliteration, hemorrhage, neurological deficits, or mortality associated with SRS alone versus SRS with embolization. These findings differ from previous studies, which found that performing embolization prior to SRS may reduce AVM obliteration rates. Given the high risk for publication bias evident throughout our analysis, this discordant finding indicates that further investigation is required to delineate whether performing embolization prior to SRS for cerebral AVMs confers any significant benefits.

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Artikel online veröffentlicht:
07. Februar 2025