Author: Madeleine Arbogast, David Dorndos, Denise E Foltz, Justin Fraser, Damodar Pokhrel, William St Clair 👨🔬
Affiliation: University of Kentucky, Department of Radiation Medicine, University of Kentucky, Department of Neurosurgery, University of Kentucky, Radiation Medicine 🌍
Purpose: For stereotactic radiosurgery (SRS) treatments of intracranial arteriovenous malformations (AVM) and fistulas (AVF), same-day Leksell Gamma Knife (GK) is the preferred modality. Long-term clinical outcomes are presented to provide insight into patient responses to treatment via GammaPlan SRS on GK PerfexionTM for AVM and AVF.
Methods: In total, 112 patients previously treated for AVM or AVF in 2010-2024 via GK-SRS were selected for this IRB-approved, single-institutional, retrospective study. Utilizing contrast-enhanced angiograms for nidus size delineation, highly conformal SRS plans were generated either manually or via Lightning Dose Optimizer using high-resolution MRI images. Target size was 7.6+/-13.6(0.20–68.3) cc; marginal prescription dose to nidus was 19.3+/-2.6 (14.0–24.0) Gy. Maximum dose to brainstem and optic pathway and normal brain receiving V8Gy–V14Gy were evaluated. Patient-reported treatment and toxicity responses were obtained from clinical follow-up reports in 6-month intervals.
Results: 70 of 112 patients–36 (51.4%) female and 34 (48.6%) males; median age of 45±17(7–83) years–had fully reported clinical outcomes. Mean follow-up interval was 63+/-40 (6–183) months. Overall, 57 (81.4%) were treated for AVM, 11 (15.7%) for AVF, and 2 (2.6%) for both anomalies. Average Paddick conformity and gradient indices were 0.63+/-0.11 and 2.8+/-0.3. Symptomatic response to GK-SRS was reported in 54(77.1%) patients; 16(22.9%) had no response. Normal brain radionecrosis was reported in 11(15.5%) AVM patients. Of these 11 patients, 10(90.9%) were female, 5 had relatively large AVM (7.6–41.5cc), 4 staged-AVM, 3 had Spetzler-Martin (SM) grade IV-V, and 6 didn't respond to GK-SRS. Radionecrosis patients were managed with steroids, pentoxifylline, Vitamin E or intra-arterial Avastin.
Conclusion: Results demonstrate same-day GK-SRS is highly effective in treating AVM/AVF with few radiation-induced adverse effects. Normal brain radionecrosis had higher reported incidence among female AVM patients having larger nidus size and higher SM-grade. These clinical findings indicate further dose optimization is necessary for female patients with large AVM anomalies.