title: Three-dimensional analysis of the accuracy of optic and electromagnetic navigation systems using surface registration in live endoscopic sinus surgery.
abstract: This study presents the first report in the same patients on the time efficiency of surface registration as well as the navigational accuracy using optic and electromagnetic tracking systems.
  
  
  
  Thirty patients with bilateral chronic paranasal pansinusitis underwent endoscopic sinus surgery. After surface registration, the surgeries were performed on one side using optic navigation guidance and on the other side using electromagnetic navigation guidance. The intraoperative measurements performed included the time taken for the surface registration and surgical procedure on each side, as well as the navigation errors at the different locations.
  
  
  
  The time for surface registration was significantly longer in the optic navigation group than the electromagnetic group. A comparison of the navigation errors along the 3 axes showed that the deviation in the medial-lateral direction was significantly less than that in the anterior-posterior and cranial-caudal directions in the optic navigation group as well as the electromagnetic group.
  
  
  
  The procedure for surface registration in both optic and electromagnetic guidance is efficient and convenient. The accuracy of both navigation systems is comparable and within acceptable ranges for clinical use. In addition, the best accuracy was measured in the medial-lateral direction compared with the other two axes.
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Chang
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Fu-Shan
authors.initials: FS
authors.lastname: Jaw
authors.affiliation: Department of Otolaryngology, Far Eastern Memorial Hospital, Taipei, Taiwan.
authors.forename: Wu-Chia
authors.initials: WC
authors.lastname: Lo
authors.affiliation: Department of Otolaryngology, Far Eastern Memorial Hospital, Taipei, Taiwan.
authors.forename: Kai-Min
authors.initials: KM
authors.lastname: Fang
authors.affiliation: Department of Otolaryngology, Far Eastern Memorial Hospital, Taipei, Taiwan.
authors.forename: Po-Wen
authors.initials: PW
authors.lastname: Cheng
mesh_terms: D000328:Adult; D004574:Electromagnetic Fields; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D057605:Natural Orifice Endoscopic Surgery / Q000379:methods*; D061848:Optical Imaging; D010865:Pilot Projects; D012852:Sinusitis / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D055815:Young Adult