title: Comparison of laser versus surface-touch registration for image-guided sinus surgery.
abstract: BACKGROUND
  Use of image-guidance systems has become more popular in endoscopic sinus surgery. The laser registration technique has been used previously; however, a less expensive surface-touch registration technique recently has been developed. We compared the accuracy and speed of laser and surface-touch registration techniques.
  
  
  METHODS
  Localization accuracy after laser and surface-touch registration was examined after 15 endoscopic sinonasal procedures between July and September 2004. Compared anatomic locations included the nasofrontal angle, nasolabial angle, posterior maxillary wall, skull base, and posterior vomer. For each localization point, the degree of error (in millimeters) was measured in superior-inferior (SI), anterior-posterior (AP), and right-left (RL) dimensions. The length of time for each registration procedure was recorded for both techniques.
  
  
  RESULTS
  Laser registration was significantly faster (mean, 20 seconds) than surface-touch registration (mean, 20 seconds versus 63 seconds, respectively; p < 0.05). Laser registration was accurate within 0.3 mm in the SI direction, 0.4 mm in the AP direction, and 0.4 mm in the RL direction. Surface-touch registration was accurate within 0.3 mm in the SI direction, 0.4 mm in the AP direction, and 0.3 mm in the RL direction. There was no significant difference between techniques for any anatomic point. In 97.7% of all points, accuracy was within 2 mm or less for both the laser and surface-touch registration.
  
  
  CONCLUSIONS
  Surface-touch registration is significantly slower than laser registration but has virtually no difference in accuracy. Both techniques compare very favorably to the accuracy of other systems reported in the literature.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina Hospital, Charleston 29425, USA.
authors.forename: Bradford A
authors.initials: BA
authors.lastname: Woodworth
authors.forename: Gavin W
authors.initials: GW
authors.lastname: Davis
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Schlosser
mesh_terms: D004724:Endoscopy / Q000379:methods*; D006801:Humans; D007834:Lasers; D010256:Paranasal Sinuses / Q000601:surgery*