Development of a model to predict permanent symptomatic postradiosurgery injury for arteriovenous malformation patients

Purpose: To better predict permanent complications from arteriovenous malformation (AVM) radiosurgery. Methods and Materials: Data from 85 AVM patients who developed symptomatic complications following gamma knife radiosurgery and 337 control patients with no complications were evaluated as part of a multiinstitutional study. Of the 85 patients with complications, 38 patients were classified as having permanent symptomatic sequelae (necrosis), AVM marginal doses varied from 10-35 Gy and treatment volumes from 0.26-47.9 cc, Median follow-up for patients without complications was 45 months (range: 24-92), Results: Multivariate analysis of the effects of AVM location and the volume of tissue receiving 12 Gy or more (12-Gy-Volume) allowed construction of a significant postradiosurgery injury expression (SPIE) score. AVM locations in order of increasing risk and SPIE score (from 0-10) were: frontal, temporal, intraventricular, parietal, cerebellar, corpus callosum, occipital, medulla, thalamus, basal ganglia, and pons/midbrain. The final statistical model predicts risks of permanent symptomatic sequelae from SPIE scores and Id-Gy-Volumes. Prior hemorrhage, marginal dose, and Marginal-12-Gy-Volume (target volume excluded) did not significantly improve the risk-prediction model for permanent sequelae (p greater than or equal to 0.39), Conclusion: The risks of developing permanent symptomatic sequelae from AVM radiosurgery vary dramatically with location and, to a lesser eh-tent, volume. These risks can be predicted according to the SPIE location-risk score and the 12-Gy-Volume. (C) 2000 Elsevier Science Inc.