Outcomes in children receiving single-fraction Gamma Knife radiosurgery for arteriovenous malformation.

INTRODUCTION

Stereotactic radiosurgery (SRS) is used for arteriovenous malformations (AVM), but the risk for secondary malignancy (SM), radiation necrosis (RN), obliteration rates (ObR), and late neurologic toxicities in pediatric patients is not well defined. To address this, we reviewed our two-decade-long institutional experience treating pediatric AVMs with SRS.

METHODS

Retrospective review of patients receiving single-fraction SRS for AVM between 1/2006 and 12/2023. ObR and RN were determined on neuroimaging, and toxicities by clinical evaluation. Overall follow-up was 56 months (range 6-193); 59 patients had follow-up > 36 months (median 85 months).

RESULTS

Eighty-nine patients/101 AVMs were treated at average age of 12.9 years (range 2.36-20.1). Median follow-up was 56 months (range 6-193); 59 patients (66.3%) had > 36 months of follow-up (median 85 months). Average AVM volume was 2.85 cm3 (range 0.034-24.95 cm3), and 80.4% were < 3 cm. Eloquent areas were involved in 65.3%; 56.4% had deep venous drainage. Most had Spetzler-Martin (SM) grade 2 or 3 (39.6 and 36.6); SM grade 1 (12.9%), 4 (8.9%), and unknown (2.0%) were also treated. Most had pre-SRS hemorrhage (70.8%), neurologic deficit (37.1%), or seizure (21.3%); few were incidental (12.4%). Before SRS, 13.5% were embolized, 7.9% resected, and 6.7% both; most (71.9%) had no intervention. Radiographic obliteration by imaging was 55.0% at 3 years, 73.1% at 4 years, and 83.0% at 5 years. In patients with long-term follow-up, ObR after SRS alone was 90.6%. Eight AVMs (7.9%) failed to obliterate by 3 years and were retreated: five with SRS, two with embolization, and one with resection. Obliteration was achieved in 7/8 (87.5%) of these residual AVMs; overall ObR was 97.6%. No patients developed SM, hemorrhage, or died post-SRS, but 13% had residual seizures, 14.6% had persistent headaches, and 39% had neurologic deficits. Seven (8.5%) developed symptomatic RN.

CONCLUSION

Single-fraction SRS for AVMs is effective, with a high obliteration rate and low radionecrosis rates. No secondary malignancies, hemorrhages, or deaths occurred.