Appropriate management of hemorrhage after Gamma Knife surgery (GKS) for arteriovenous malformations (AVMs) of the brain is poorly understood, although a certain proportion of patients suffer from hemorrhage.
Among 500 patients observed for 1 to 183 months (median 70 months) after GKS, 32 patients (6.4%) suffered a hemorrhage. Hemorrhage developed even after angiographically documented obliteration of the AVM in five (2%) of 250 patients followed for 1 to 133 months (median 75 months) post-GKS. These patients had been treated according to their pathological condition. Treatment of these patients and their outcomes were retrospectively reviewed. As a management strategy in patients with preobliteration hemorrhage, the intracerebral hematoma and the AVM nidus were removed in four patients, and chronic encapsulated hematoma was removed in three. Among 11 patients who were conservatively treated, AVMs were ultimately obliterated in five, including three patients who underwent repeated GKS. Intracerebral hematoma from angiographically documented obliterated AVMs was radically resected in two patients, including one who also underwent aspiration of an accompanying symptomatic cyst. Intraoperative bleeding was easily controlled in these patients. Outcomes after hemorrhage, measured with the modified Rankin Scale, were significantly better in patients with postobliteration hemorrhage than in those with preobliteration hemorrhage (p < 0.05).
Various types of hemorrhagic complications after GKS for AVMs can be properly managed based on an understanding of each pathological condition. Although a small risk of bleeding remains after angiographically demonstrated obliteration, surgery for such AVMs is safe, and the patient outcomes are more favorable. Radical resection to prevent further hemorrhage is recommended for ruptured AVMs after obliteration because such AVMs can cause repeated hemorrhages.