A case of subarachnoid hemorrhage following repeated gamma knife radiosurgery for recurrent trigeminal neuralgia

This report describes the case of a 78-year-old female who presented with subarachnoid hemorrhage and had a history of two gamma knife radiosurgery (GKS) treatments for right trigeminal neuralgia. Computed tomography angiography on admission revealed a 3-mm aneurysm at the bifurcation of the common trunk of the right anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery. The patient underwent surgical trapping of the right AICA and was subsequently discharged (with a modified Rankin Scale score of 1). The aneurysm was located adjacent to the GKS treatment field and was considered to have been a result of radiation exposure during the treatments. GKS-related aneurysms are often pseudoaneurysms and carry a high risk of rupture, even when their size is small. Careful planning is therefore essential to ensure that critical vessels are not included in the radiation field. Moreover, most GKS-related aneurysms that require trapping of the parent artery are associated with a risk of ischemic complications, and careful consideration is required to decide whether endovascular or direct surgery would be the safer and more secure approach. (author)