title: Three-dimensional analysis of the surface registration accuracy of electromagnetic navigation systems in live endoscopic sinus surgery.
abstract: Studies on the performance of surface registration with electromagnetic tracking systems are lacking in both live surgery and the laboratory setting. This study presents the efficiency in time of the system preparation as well as the navigational accuracy of surface registration using electromagnetic tracking systems.
  
  
  
  Forty patients with bilateral chronic paranasal pansinusitis underwent endoscopic sinus surgery after undergoing sinus computed tomography scans. The surgeries were performed under electromagnetic navigation guidance after the surface registration had been carried out on all of the patients. The intraoperative measurements indicate the time taken for equipment set-up, surface registration and surgical procedure, as well as the degree of navigation error along 3 axes.
  
  
  
  The time taken for equipment set-up, surface registration and the surgical procedure was 179 +- 23 seconds, 39 +- 4.8 seconds and 114 +- 36 minutes, respectively. A comparison of the navigation error 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.
  
  
  
  The procedures of equipment set-up and surface registration in electromagnetic navigation tracking are efficient, convenient and easy to manipulate. The system accuracy is within the acceptable ranges, especially on the medial-lateral axis.
authors.forename: C M
authors.initials: CM
authors.lastname: Chang
authors.forename: K M
authors.initials: KM
authors.lastname: Fang
authors.forename: T W
authors.initials: TW
authors.lastname: Huang
authors.forename: C T
authors.initials: CT
authors.lastname: Wang
authors.forename: P W
authors.initials: PW
authors.lastname: Cheng
mesh_terms: D015331:Cohort Studies; D055590:Electromagnetic Phenomena; D004724:Endoscopy / Q000295:instrumentation*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012852:Sinusitis / Q000000981:diagnostic imaging / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome