title: [LED autoregistration in navigated endonasal sinus surgery].
abstract: BACKGROUND
  In endonasal sinus surgery, computer aided surgery (CAS) is a generally accepted method. Applying CAS, there are basic problems with the constancy of accuracy at a free mobile patient head as well as with extended referencing time. The navigation system manufacturer Stryker-Leibinger invented together with our working group a non-invasive, frameless, automatic patient registration and simultaneous tracking system for navigated endonasal sinus surgery. With this new user-friendly system it concerns an active, LED-based, self-adhesive on the surface of splanchnocranium autoregistration mask.
  
  
  METHODS
  The LED autoregistration mask was tested in an anatomic cadaver study and an ongoing clinical patient study regarding manageability, applicability and accuracy. Accuracy measurements were accomplished on different control points of the head in the cadaver study. The determination of accuracy was calculated with the metric Euclidean distance. Further we report on our experiences with a total of 20 patients applying the new mask. To control the accuracy, anatomic landmarks of the patients were adducted. Goal of our study was to determine the accuracy of the LED mask and to compare it with titanium screw markers, the valid reference gold standard.
  
  
  RESULTS
  The LED autoregistration mask convinced by a high precision with relatively simple useability. Total accuracy amounted to 2.22 +/- 0.91 mm. The LED system proved to be a valuable orientation guide mainly at revision surgeries with modified anatomy.
  
  
  CONCLUSIONS
  LED surface autoregistration is especially suitable for endonasal sinus surgery and represents a very helpful tool for the rhinosurgeon. Our accuracy studies have shown that the LED autoregistration mask is comparable to the gold standard titanium screw markers and, in addition, very reliable.
authors.affiliation: Universitätsklinik für Hals-, Nasen- und Ohrenheilkunde und Poliklinik, Universitätsklinikum Freiburg. arapakis@hno.ukl.uni-freiburg.de
authors.forename: I
authors.initials: I
authors.lastname: Arapakis
authors.forename: U
authors.initials: U
authors.lastname: Hubbe
authors.forename: W
authors.initials: W
authors.lastname: Maier
authors.forename: R
authors.initials: R
authors.lastname: Laszig
authors.forename: J
authors.initials: J
authors.lastname: Schipper
mesh_terms: D003196:Computer Graphics; D003625:Data Collection / Q000295:instrumentation*; D004724:Endoscopy; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D010254:Paranasal Sinus Diseases / Q000601:surgery*; D010256:Paranasal Sinuses / Q000473:pathology / Q000601:surgery*; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed