Characterization of Pediatric Infratentorial Arteriovenous Malformations: A Retrospective, Multicenter Cohort Study

BACKGROUND AND OBJECTIVES: Infratentorial arteriovenous malformations (AVMs) harbor different characteristics compared with supratentorial AVMs. This study aims to explore the unique characteristics of pediatric infratentorial AVMs and their response to single session stereotactic radiosurgery (SRS). METHODS: The International Radiosurgery Research Foundation database of pediatric patients with AVM (age <18 years) who underwent SRS was retrospectively reviewed. Baseline demographics, AVM characteristics, outcomes, and complications post-SRS were compared between infratentorial and supratentorial pediatric AVMs. Unfavorable outcome was defined as the absence of AVM obliteration, post-SRS hemorrhage, or permanent radiation-induced changes at last follow-up. RESULTS: A total of 535 pediatric AVMs managed with SRS with a median follow-up of 67 months (IQR 29.0-130.6) were included, with 69 being infratentorial and 466 supratentorial. The infratentorial group had a higher proportion of deep location (58.4% vs 30.3%, P = <.001), deep venous drainage (79.8% vs 61.8%, P = .004), and prior embolization (26.1% vs 15.7%, P = .032). There was a higher proportion of hemorrhagic presentation in the infratentorial group (79.7% vs 71.3%, P = .146). There was no statistically significant difference in the odds of an unfavorable outcome (odds ratio [OR] = 1.36 [0.82-2.28]), AVM obliteration (OR = 0.85 [0.5-1.43]), post-SRS hemorrhage (OR = 0.83 [0.31-2.18]), or radiologic radiation-induced changes (OR = 1.08 [0.63-1.84]) between both cohorts. No statistically significant difference on the rates of outcomes of interest and complications were found in the adjusted model. CONCLUSION: Despite baseline differences between infratentorial and supratentorial pediatric AVMs, SRS outcomes, including AVM obliteration and post-SRS hemorrhage rates, were comparable amongst both groups. SRS appears to have a similar risk profile and therapeutic benefit to infratentorial pediatric AVMs as it does for those with a supratentorial location.