Predictors for long-term incomplete nidus obliteration following stereotactic radiosurgery for brain arteriovenous malformations: a systematic review and meta-analysis

Introduction: This study aimed to identify predictive factors for long-term incomplete nidus obliteration following stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs). Material and methods: A systematic search across the PubMed, Web of Science, and Scopus databases identified observational studies reporting such factors. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The study protocol was registered through PROSPERO. Each eligible study's quality was assessed using the modified Newcastle-Ottawa Scale. Odds ratios (ORs) were calculated for dichotomous parameters. Results: Two high-quality prospective cohort and three high-quality retrospective cohort studies were included, covering patients with complete (n = 638) and incomplete (n = 297) nidus obliteration. The mean age of the patients was 25.54 +/- 12.81 years and the mean follow-up time was 95.98 +/- 27.64 months. Predictors for incomplete obliteration of nidus included: AVM classified as Spetzler-Martin (SM) grade >= IV (odds ratio (OR) 10.57, 95% confidence interval (CI) 2.00-55.96, p = 0.006), the presence of multiple (> 1) feeding arteries (OR 6.47, 95% CI 2.20-19.10, p = 0.0007), nidus volume > 10 mL (OR 5.08, 95% CI 1.68-15.33, p = 0.004), and the occurrence of intranidal aneurysm (OR 3.33, 95% CI 1.10-10.08, p = 0.03). No statistically significant difference in proportions of patients with incomplete nidus obliteration was found between paediatric (<= 18 years) and adult (> 18) patient cohorts (p = 0.95). Conclusions: The following factors were found to be predictive for long-term incomplete nidus obliteration post-SRS for brain AVMs: SM grade equal to or higher than IV; the presence of multiple feeding arteries; AVM nidus volume exceeding 10 mL; and the occurrence of intranidal aneurysm. These findings will be beneficial in refining patient selection for radiosurgical treatment.