Gamma Knife Radiosurgery for Hemorrhagic Brainstem Cavernomas.

AIM Effectiveness and safety of gamma knife radiosurgery (GKRS) for hemorrhagic brainstem cavernous malformations (BSCM) is still an unresolved problem. The purpose of this study was to assess treatment results of GKRS for hemorrhagic BSCMs. MATERIAL AND METHODS A retrospective review was performed of patients with hemorrhagic BSCMs who were treated at the Acıbadem Kozyatağı Hospital GKRS unit from May 2007 to October 2015. RESULTS In total 82 patients were identified. All patients had experienced at least one hemorrhagic event (range 1-3) and all of them presented radiological evidence of hemorrhage. The median target volume was 0,3 mL, and the median marginal radiation dose was 12 Gy. The mean durations before and after surgery were 25,5 (range 1-204) months and 50,3 (range 13-113) months respectively. Pretreatment hemorrhage rates were calculated from the date of first hemorrhage to the date of radiosurgery. There were 97 bleeds over 174.4 patient-years during the observation period, with an annual hemorrhage rate of 55.7 %. If the first bleed is excluded, the annual hemorrhage rate was 8.6%. Only three patients demonstrated rebleeding, which occurred at 3,12 and 79 months after radiosurgery. Over a total follow up time of 344 patient-years the annual rebleeding rate was therefore 0,87 %, indicating that the risk of BSCM hemorrhage was significantly decreased by radiosurgery. CONCLUSION In this study GKRS was a safe and effective treatment for symptomatic low volume BSCMs when using a low marginal dose. A randomized controlled trial is needed that compares GKRS to observation if we are to establish the true efficacy of this treatment.