title: The keyhole concept in aneurysm surgery: results of the past 20 years.
abstract: BACKGROUND
  Improvements in preoperative imaging and intraoperative visualization have led to a refinement in surgical techniques.
  
  
  OBJECTIVE
  Report of a 20-year experience with application of the keyhole technique as a contribution to the ongoing debate on the impact of limited craniotomies in aneurysm surgery.
  
  
  METHODS
  Over a 20-year period, 1000 consecutive patients with 1297 aneurysms were surgically treated in 1062 operations: 651 in the acute stage after SAH and 411 with unruptured aneurysms. The outcome was assessed with the modified Rankin scale and approach-related complications.
  
  
  RESULTS
  The majority of the cases were treated by 4 different keyhole approaches: The supraorbital approach was used in 793 patients for 989 aneurysms, the subtemporal in 48 patients for 50 aneurysms, the interhemispheric in 46 patients for 51 aneurysms, and the retromastoidal in 55 patients for 55 aneurysms. In 120 patients, the classic pterional approach was applied to treat 152 aneurysms. The results of unruptured aneurysms were good (modified Rankin scale ≤ 2) in 96.52%. The complication rates of the keyhole approaches were less than in the pterional group, although the difference did not reach statistical significance.
  
  
  CONCLUSIONS
  The overall outcome, rate of retreatment, and approach-related complications with keyhole approaches for the management of ruptured and unruptured aneurysms are comparable to recently published conventional surgical aneurysm series. In addition to the common benefits of limited-exposure approaches, this series demonstrates appropriate safety and applicability of the keyhole technique in aneurysm surgery.
authors.affiliation: Department of Neurosurgery, Johannes Gutenberg-University, Mainz, Germany. gerrit.fischer@gmx.de
authors.forename: Gerrit
authors.initials: G
authors.lastname: Fischer
authors.forename: Axel
authors.initials: A
authors.lastname: Stadie
authors.forename: Robert
authors.initials: R
authors.lastname: Reisch
authors.forename: Nikolai J
authors.initials: NJ
authors.lastname: Hopf
authors.forename: Georg
authors.initials: G
authors.lastname: Fries
authors.forename: Hans
authors.initials: H
authors.lastname: Böcher-Schwarz
authors.forename: Erik
authors.initials: E
authors.lastname: van Lindert
authors.forename: Karl
authors.initials: K
authors.lastname: Ungersböck
authors.forename: Engelbert
authors.initials: E
authors.lastname: Knosp
authors.forename: Joachim
authors.initials: J
authors.lastname: Oertel
authors.forename: Axel
authors.initials: A
authors.lastname: Perneczky
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000379:methods; D003399:Craniotomy / Q000379:methods*; D005260:Female; D005625:Frontal Lobe / Q000601:surgery; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis / Q000601:surgery*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult