title: Delayed Development of Aneurysms Following Gamma Knife Surgery for Trigeminal Neuralgia: Report of 2 Cases.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  Long-term observations are necessary after GKS performed for TN owing to the possibility of formation of intracranial aneurysms near the irradiated region.
authors.affiliation: Division of Neurosurgery, Saiseikai Kumamoto Hospital, Kumamoto, Japan. Electronic address: h.uchikawa.1223@gmail.com.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Uchikawa
authors.affiliation: Division of Neurosurgery, Saiseikai Kumamoto Hospital, Kumamoto, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nishi
authors.affiliation: Department of Neurosurgery, Kumamoto University Hospital, Kumamoto, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kaku
authors.affiliation: Division of Neurosurgery, Saiseikai Kumamoto Hospital, Kumamoto, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Goto
authors.affiliation: Department of Neurosurgery, Kumamoto University Hospital, Kumamoto, Japan.
authors.forename: Jun-Ichi
authors.initials: JI
authors.lastname: Kuratsu
authors.affiliation: Department of Neurosurgery, Kumamoto University Hospital, Kumamoto, Japan.
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Yano
mesh_terms: D000368:Aged; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging / Q000209:etiology*; D002531:Cerebellum / Q000098:blood supply; D002533:Cerebral Angiography; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000209:etiology*; D018810:Magnetic Resonance Angiography; D008297:Male; D061145:Microvascular Decompression Surgery; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000209:etiology*; D016634:Radiosurgery / Q000009:adverse effects*; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000209:etiology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014277:Trigeminal Neuralgia / Q000532:radiotherapy*
keywords: Aneurysm; Gamma knife; Trigeminal neuralgia