title: [Surgery of the skull base and paranasal sinuses assisted by a computerized navigation system without external orientation support].
abstract: OBJECTIVE
  To present a new concept in computer-assisted surgery for the base of the skull and paranasal sinuses using a frameless navigation system.
  
  
  METHODS
  This system is based on computer tomography images, which are displayed online on a workstation monitor. Using specially mounted infrared instruments, the patient's anatomic landmarks are visualized on the monitor. This system does not require invasive markers because it uses a reference system fixed to the patient with a silicone maxillary splint.
  
  
  METHODS
  From March 1997 to February 1998 we operated on 44 patients with this innovative system.
  
  
  RESULTS
  The clinical accuracy of this system was 0.5 to 2 mm for surgery of the anterior skull base and 1 to 2.5 mm for the lateral skull base. There were no intraoperative complications.
  
  
  CONCLUSIONS
  This computer-assisted surgical aid made it possible to carry out complex and difficult skull-base surgery with reasonable intraoperative safety. It also allowed development of new minimally invasive surgical approaches.
authors.affiliation: Clínica Universitaria de Otorrinolaringología, Cirugía de Cabeza y Cuello, Inselspital Berna, Suiza.
authors.forename: M
authors.initials: M
authors.lastname: Caversaccio
authors.forename: M
authors.initials: M
authors.lastname: Nuyens
authors.forename: R
authors.initials: R
authors.lastname: Bächler
authors.forename: K
authors.initials: K
authors.lastname: Lädrach
authors.forename: G
authors.initials: G
authors.lastname: Schroth
authors.forename: L
authors.initials: L
authors.lastname: Nolte
authors.forename: R
authors.initials: R
authors.lastname: Häusler
mesh_terms: D002812:Chondroma / Q000601:surgery*; D004724:Endoscopy / Q000379:methods; D004867:Equipment Design; D005918:Glomus Tumor / Q000601:surgery*; D006801:Humans; D009298:Nasal Polyps / Q000601:surgery*; D010255:Paranasal Sinus Neoplasms / Q000601:surgery*; D010256:Paranasal Sinuses / Q000601:surgery*; D012008:Recurrence; D012189:Retrospective Studies; D019291:Skull Base / Q000601:surgery*; D013813:Therapy, Computer-Assisted / Q000295:instrumentation*