Outcomes of Gamma Knife Radiosurgery in Intracranial Arteriovenous Malformations

To evaluate the outcomes of intracranial arteriovenous malformations (AVMs) after single-session treatment with gamma knife radiosurgery (GKRS) and factors influencing the outcomes.

Single-center retrospective study, including patients undergoing GKRS for intracranial AVMs. Demography, treatment profiles, and follow-ups were collected from the medical records. Obliteration rates, adverse radiation events (AREs), and clinical outcomes were noted, and factors influencing the same were evaluated.

A total of 313 patients with a mean age of 27 years (8-66 years) were included in the study. While Spetzler-Martin (SM) grade 2 (46.3%) or SM grade 3 (37.4%) AVMs were common, SM grade 1 and SM grade 4 accounted for 10.9% and 5.4% of cases. The mean modified Pollock-Flickinger (PF) score was 1.02 (0.18-2.23), whereas the mean AVM volume was 3.75 cc (0.04-16 cc). The mean marginal dose was 23 Gy with 95% coverage. A total of 253 (80%) patients came for follow-up, but only 196 (62.6%) patients had adequate follow-up, out of which 148 (75.5%) had complete obliteration. AVM volume was the single most significant factor influencing the obliteration rates in AVM. Clinical outcomes were dependent on the AVM volume and modified PF score. Of 107 patients with seizures, 69% (75) were seizure-free. Twenty-two (8.7%) had complications, of which only seven had permanent neurological deficits (five hemiparesis and three visual field defects). The rebleed rate was 5.5% (14 patients).

GKRS remains a safe and effective treatment modality for intracranial AVMs. The AVM volume was the most important factor affecting the obliteration rates and AREs. The AVM volume and modified PF scores were significant factors affecting the clinical outcomes.