title: Considerations in the surgical treatment of superior-wall type aneurysm at the proximal (M1) segment of the middle cerebral artery.
abstract: OBJECTIVE
  To present our experience and analyze the risks of neck clipping for superior-wall type aneurysms of the proximal segment of the middle cerebral artery (M1-Sup aneurysm).
  
  
  METHODS
  Of 14 patients with M1-Sup aneurysms, 4 suffered postoperative infarctions in the territory of the lenticulostriate arteries (LSA) or fronto-orbital arteries. We re-examined our intraoperative findings and clinical records in an effort to identify possible causes.
  
  
  RESULTS
  The patency of the LSA was confirmed at the end of surgery in all 14 cases. We posit that temporary occlusion of the LSA by a permanent clip resulted in delayed obstruction of the LSA in 3 patients. Other possibilities we considered were relatively long temporary occlusion of the M1, slipping of the clips and twisting of the clip blades after release of the brain retractors.
  
  
  CONCLUSIONS
  M1-Sup aneurysms are some of the most complicated aneurysms; they carry the risk of perforator injury during neck clipping. Surgical considerations to avoid perforator injury are discussed.
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan. tiwama@cc.gifu-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Iwama
authors.forename: S
authors.initials: S
authors.lastname: Yoshimura
authors.forename: Y
authors.initials: Y
authors.lastname: Kaku
authors.forename: N
authors.initials: N
authors.lastname: Sakai
mesh_terms: D000328:Adult; D000368:Aged; D001479:Basal Ganglia / Q000098:blood supply; D020520:Brain Infarction / Q000209:etiology; D002536:Cerebral Arteries / Q000473:pathology*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000473:pathology; D012189:Retrospective Studies; D012307:Risk Factors; D013525:Surgical Instruments