Factors Associated with Clinical Outcomes of Repeat Gamma Knife Radiosurgery for Cerebral Arteriovenous Malformations
Year: 2026
Type: article
Study design: Observational Study
Abstract: OBJECTIVE: Gamma knife radiosurgery (GKRS) is an established treatment for cerebral arteriovenous malformations (AVMs). However, incomplete obliteration after initial GKRS continues to pose a risk of hemorrhage. Although repeat GKRS is used as a salvage treatment, specific guidelines and safety profiles remain to be fully defined. By analyzing the clinical outcomes of repeat GKRS in 60 patients with incompletely obliterated AVMs, this study aims to test the hypothesis that optimizing treatment-related variables, particularly the timing of retreatment, may improve the safety and efficacy of repeat GKRS for residual AVMs. METHODS: This retrospective study included 60 patients with AVMs who underwent repeat GKRS between 1992 and 2024. Clinical charts, radiologic imaging, and treatment parameters were analyzed to assess complete obliteration, hemorrhage after repeat GKRS, and adverse radiation effects (AREs). Kaplan-Meier survival analysis was performed to estimate obliteration and hemorrhage rates. Univariate and multivariate analyses were conducted to identify factors associated with complete obliteration, hemorrhage, and AREs. RESULTS: Complete obliteration was achieved in 40 patients (66.7%). The actuarial obliteration rates were 1.7%, 22.5%, 53.5%, and 73.9% at 1, 3, 5, and 10 years, respectively. A target volume reduction rate >50% (p=0.004; hazard ratio [HR], 3.002; 95% confidence interval [CI], 1.414-6.374) and lower initial Spetzler-Martin (SM) grade (p=0.008; HR, 0.608; 95% CI, 0.420-0.879) were independently associated with complete obliteration. Six patients (10%) experienced hemorrhage after repeat GKRS, corresponding to an annual hemorrhage rate of 2.3%. AVMs located in the posterior fossa (p=0.005; HR, 80.958; 95% CI, 3.891-1684.629) and hemorrhage prior to repeat GKRS (p=0.020; HR, 19.075; 95% CI, 1.576-230.805) were independently associated with hemorrhage. Seven patients (11.7%) experienced AREs after repeat GKRS. Larger repeat target volume (p=0.042; odds ratio [OR], 3.170; 95% CI, 1.044-9.626) and a shorter interval of months between initial and repeat treatment (p=0.040; OR, 0.823; 95% CI, 0.683-0.991) were independently associated with AREs. CONCLUSION: Repeat GKRS for incompletely obliterated AVMs may provide favorable obliteration rates. Adequate volume response after initial GKRS and lower SM grades may predict successful complete obliteration. Patients with prior hemorrhage and AVMs located in the posterior fossa may be at greater risk of hemorrhage after repeat GKRS. Larger treatment volume and shorter intervals between initial and repeat GKRS were associated with AREs. Extending the interval between initial and repeat GKRS may reduce the risk of AREs and provide a safer approach for treating incompletely obliterated AVMs.
Institutions: Kyung Hee University, Kyung Hee University Medical Center
Language: English
Subfield: Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $300
OpenAlex ID: W7125759349
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