title: Workspace and pivot point for robot-assisted endoscope guidance in functional endonasal sinus surgery (FESS).
abstract: BACKGROUND
  For the further development of robot-assisted endoscope guidance in functional endoscopic sinus surgery (FESS), ground data about the workspaces and endoscope movements in conventional FESS are needed.
  
  
  METHODS
  Applying a self-developed marker-based tracking system, we collected the pose data (position and orientation) of the endoscope and all other instruments used in five real sinus surgeries.
  
  
  RESULTS
  The automated segmentation of the endoscope poses shows the shape of a hourglass, with a pivot region or pivot point at the 'waistline' of the hourglass, close to the nasal entrance in the nasal dome.
  
  
  CONCLUSIONS
  We were able to identify a pivot point at the waistline of the segmented endoscope poses. The size of the pivot point corresponds with the diameter of the 4 mm endoscope. Because of the reduction to four degrees of freedom for endoscope motions (three rotations and one translation), easier and safer robot-assisted endoscope guidance becomes feasible.
authors.affiliation: Department of Otorhinolaryngology, University Hospital Bonn, Bonn, Germany.
authors.forename: Klaus Wolfgang
authors.initials: KW
authors.lastname: Eichhorn
authors.forename: Ralf
authors.initials: R
authors.lastname: Westphal
authors.forename: Carsten
authors.initials: C
authors.lastname: Last
authors.forename: Markus
authors.initials: M
authors.lastname: Rilk
authors.forename: Friedrich
authors.initials: F
authors.lastname: Bootz
authors.forename: Friedrich M
authors.initials: FM
authors.lastname: Wahl
authors.forename: Mark
authors.initials: M
authors.lastname: Jakob
mesh_terms: D019723:Endoscopes; D004724:Endoscopy / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D010256:Paranasal Sinuses / Q000473:pathology / Q000601:surgery*; D065287:Robotic Surgical Procedures / Q000295:instrumentation / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods
keywords: 3D navigation; CAS; anterior skull base; computer-assisted surgery; intra-operative navigation; pivot point