Delayed Development of Aneurysms Following Gamma Knife Surgery for Trigeminal Neuralgia: Report of 2 Cases.

Abstract

Delayed development of intracranial aneurysms is an extremely rare complication of gamma knife surgery (GKS), with only 6 cases been reported to date. There are no reported cases after GKS performed to treat trigeminal neuralgia (TN). Of the 6 aforementioned cases, none referred to the natural history or pathophysiology of GKS-related intracranial aneurysm formation. We treated 2 patients with subarachnoid hemorrhage (SAH) resulting from rupture of an intracranial aneurysm that developed long after GKS. Case 1 involved a 77-year-old man who had undergone GKS to treat recurrent TN after microvascular decompression surgery. At 13 years after the GSK, he developed SAH from a ruptured left anterior inferior cerebellar artery in close vicinity to the left trigeminal nerve. He died from a premature rupture before intervention could be instituted. Case 2 involved a 72-year-old woman who developed SAH at 9 years after undergoing GKS for TN. A ruptured left superior cerebellar artery aneurysm was treated successfully with endovascular occlusion of the parent artery. She recovered well after the surgery, and was discharged to the rehabilitation hospital with a modified Rankin Scale score of 2. Long-term observations are necessary after GKS performed for TN owing to the possibility of formation of intracranial aneurysms near the irradiated region.