Exploring the Potential of Low-Dose Gamma Knife Radiosurgery for Brain AVMs: A Study of Efficacy and Patient Characteristics

ObjectiveTo assess the safety and efficacy of low-dose gamma knife radiosurgery (SRS) in treating brain arteriovenous malformations (AVMs) using a nationwide multicenter cohort. Specifically, we aim to evaluate the outcomes of AVM obliteration, hemorrhagic stroke risk, and neurological status post-SRS, comparing the efficacy and safety of lower radiation doses with traditional high-dose SRS protocols.MethodsThis observational prospective cohort study utilized registry data from the Multimodality Treatment for Brain AVMs in Mainland China (MATCH study), analyzing patients treated with gamma knife between August 2011 and December 2021. The cohort comprised 677 patients, stratified by treatment approach (combined embolization and SRS, combined surgical resection and SRS, and SRS alone). Baseline characteristics, including age, sex, AVM location, and nidus complexity, were recorded, and clinical outcomes were followed for up to 20 years.ResultsOf the 677 patients, 340 (50.2%) achieved AVM obliteration, with an annual post-SRS hemorrhagic stroke risk of 0.92%. Significant predictors of obliteration included younger age, smaller lesion diameter (<3 cm), and lower Spetzler-Martin grades. The cumulative post-SRS hemorrhagic stroke risk was highest in the first 5 years (2.56% annually). Multivariable analysis revealed that deep venous drainage was significant protective factor of AVM obliteration and flow-related aneurysm was significant predictors of failure to achieve obliteration. Additionally, pre-treatment AVM rupture was associated with a lower risk of post-SRS hemorrhagic stroke.ConclusionsLow-dose gamma knife treatment could be effective for AVM obliteration, with a favorable risk profile, particularly in younger patients with smaller, less complex lesions. The findings emphasize the importance of individualized SRS strategies and highlight the lower incidence of complications with low-dose protocols. Further studies with longer follow-up and larger sample sizes are needed to validate these results and refine treatment strategies.