Stereotactic radiosurgery treatment of pediatric arteriovenous malformations: a PRISMA systematic review and meta-analysis.

Background: Stereotactic radiosurgery (SRS) is considered a safe definitive treatment for pediatric arteriovenous malformations (AVMs) upon indicated presentations. There are no published guidelines by the International Stereotactic Radiosurgery Society (ISRS) detailed with indications or characteristics that warrant SRS, other than the guideline that SRS is a safe and efficacious treatment for pediatric AVMs. SRS is performed using either Gamma Knife (GK) or Linear Accelerator (LINAC). This systematic review aims to uncover treatment, differences in GK and LINAC outcomes, and AVM characteristics that lead to high obliteration rates and suggest future studies to determine treatment decisions, raise obliteration rates, and lower complication rates in SRS treatment of pediatric AVMs.

Methods: We performed a systematic review according to PRISMA guidelines across PubMed, Embase, and SCOPUS utilizing search terms related to pediatric patients, AVMS, and SRS. We collected data from the 32 full-text studies and 4 abstracts that met inclusion criteria. Subsequent pooled analysis was performed on GK vs LINAC obliteration rates, followed by sub-cohort analysis of all SRS patients with hemorrhagic presentation, Spetzler-Martin (SM) Grade, and prior procedure and their effect on obliteration rates.

Results: The 36 studies reported 3425 patients, with a slight male preponderance (1662 patients, 48.5%). The obliteration analysis included 2834 patients that met follow-up criteria and contained obliteration data. The weighted mean age was 12.63 years. Pooled cohort analysis found no significant difference in obliteration proportions when comparing GK to LINAC (P = 0.7449), with an overall obliteration rate of 63% in patients with at least 1 year follow-up. The sub-cohort analysis of all patients treated with SRS revealed that presentation with AVM hemorrhage was associated with increased obliteration (CE: RR = 1.22 [95%CI = 1.09-1.35; RE: RR = 1.22, 95%CI = 10.6-1.40; prediction interval = 1.07-1.38) with low heterogeneity (I² = 17.1%, τ² < 0.0001, p = 0.2902). Smaller SM grade was not statistically associated with increased obliteration (CE: RR = 1.25 [95%CI = 0.87-1.81]; RE: RR = 1.84 [95%CI = 0.97-3.50]; prediction interval = 0.38-8.86) and moderate levels of heterogeneity were detected (I² = 45.2%, τ² = 0.2668, p = 0.1042). Procedure prior to SRS also had higher obliteration rates than no prior procedure (CE: RR = 0.77 [95%CI = 0.61-0.86]; RE: RR = 0.71 [95%CI = 0.54-0.92]; prediction interval = 0.36-1.39) with low to moderate heterogeneity (I² = 27.6%, τ² = 0.0.0264, p = 0.2466).

Conclusion: SRS is a safe and effective treatment for pediatric AVMs. This study suggests that there are no differences in obliteration between GK and LINAC, with increased obliteration in patients with hemorrhage at presentation and procedures prior to SRS treatment. Further multicenter, prospective studies are necessary to dictate future treatment decisions.