title: Re-exploration of the craniotomy after surgical treatment of unruptured intracranial aneurysms.
abstract: BACKGROUND
  Unplanned re-exploration of the craniotomy after surgical treatment of unruptured intracranial aneurysms (UIAs) is sometimes required, but the underlying causes and rates of these procedures are seldom reported. This study retrospectively analyzed the causes of such re-explorations to identify methods for decreasing their necessity.
  
  
  METHODS
  From January 2000 to December 2011, 1,720 patients with a total of 1,938 UIAs underwent surgical treatment at our institution. From this cohort, 26 patients (1.5 %) with 38 UIAs required re-exploration. Clinical data, aneurysm characteristics, treatment methods, and the incidence and causes of re-exploration of the craniotomy were analyzed for these 26 patients.
  
  
  RESULTS
  Several causes of re-exploration were identified: compromised distal blood flow (eight patients, 0.47 %), hemorrhagic venous infarction (four patients, 0.23 %), brain retraction injury (three patients, 0.17 %), newly identified aneurysms (three patients, 0.17 %), bleeding from an incompletely clipped aneurysm (two patients, 0.12 %), epidural hematoma (two patients, 0.12 %), failed aneurysm clipping (two patients, 0.12 %) and other causes (two patients, 0.12 %). Annual re-exploration incidence rates ranged from 0 to 3.1 %. Annual incidence rates gradually decreased following the introduction of several intraoperative monitoring systems.
  
  
  CONCLUSIONS
  Precise surgical planning and careful operative techniques can reduce the incidence of unplanned re-exploration of the craniotomy. The introduction of various intraoperative monitoring systems can also contribute to a reduction in this incidence.
authors.affiliation: Department of Neurosurgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Korea.
authors.forename: Wonhyoung
authors.initials: W
authors.lastname: Park
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Ahn
authors.forename: Jung Cheol
authors.initials: JC
authors.lastname: Park
authors.forename: Do Hoon
authors.initials: DH
authors.lastname: Kwon
authors.forename: Byung Duk
authors.initials: BD
authors.lastname: Kwun
authors.forename: Chang Jin
authors.initials: CJ
authors.lastname: Kim
mesh_terms: D000368:Aged; D003399:Craniotomy / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D002532:Intracranial Aneurysm / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology / Q000601:surgery; D012086:Reoperation / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000009:adverse effects / Q000592:standards / Q000706:statistics & numerical data