title: Frameless optical computer-aided tracking of a microscope for otorhinology and skull base surgery.
abstract: OBJECTIVE
  To integrate a digitally controlled operating microscope without a laser autofocus system into a frameless optical computer-aided surgery system and to test the accuracy and usability of this system in otorhinological surgery.
  
  
  METHODS
  Experimental study and case series.
  
  
  METHODS
  Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Inselspital, and the Maurice E. Müller Institute for Biomechanics, University of Bern, Bern, Switzerland.
  
  
  METHODS
  Eight computer-aided microscopic surgical procedures were performed between January and October 2000 on patients with various diseases of the anterior and lateral skull base.
  
  
  RESULTS
  The practical accuracy of the navigated microscope on the lateral side of a cadaver skull was 2.27 +/- 0.25 mm and on the anterior side of the same skull was 2.07 +/- 0.35 mm. In all 8 cases of computer-aided microscopic surgery, no complications occurred. Clinical inaccuracy was 2 to 3 mm.
  
  
  CONCLUSIONS
  Integration of a low-cost, non-laser autofocus microscope into our computer-aided surgery system was successfully performed and offers surgeons the ability to combine the precise optics of the operating microscope with the localization power of a computer-aided system.
authors.affiliation: Department of Oto-Rhino-Laryngology, Head and Neck Surgery, University Hospital, Freiburgstrasse, CH-3010 Bern, Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Zheng
authors.forename: M
authors.initials: M
authors.lastname: Caversaccio
authors.forename: R
authors.initials: R
authors.lastname: Bächler
authors.forename: F
authors.initials: F
authors.lastname: Langlotz
authors.forename: L P
authors.initials: LP
authors.lastname: Nolte
authors.forename: R
authors.initials: R
authors.lastname: Häusler
mesh_terms: D002102:Cadaver; D006801:Humans; D008866:Microsurgery / Q000295:instrumentation* / Q000379:methods; D013517:Otorhinolaryngologic Surgical Procedures / Q000295:instrumentation* / Q000379:methods; D019291:Skull Base / Q000601:surgery*; D013813:Therapy, Computer-Assisted / Q000295:instrumentation* / Q000379:methods