title: Real-time tracking and virtual endoscopy in cone-beam CT-guided surgery of the sinuses and skull base in a cadaver model.
abstract: BACKGROUND
  Custom software was developed to integrate intraoperative cone-beam computed tomography (CBCT) images with endoscopic video for surgical navigation and guidance. A cadaveric head was used to assess the accuracy and potential clinical utility of the following functionality: (1) real-time tracking of the endoscope in intraoperative 3-dimensional (3D) CBCT; (2) projecting an orthogonal reconstructed CBCT image, at or beyond the endoscope, which is parallel to the tip of the endoscope corresponding to the surgical plane; (3) virtual reality fusion of endoscopic video and 3D CBCT surface rendering; and (4) overlay of preoperatively defined contours of anatomical structures of interest.
  
  
  METHODS
  Anatomical landmarks were contoured in CBCT of a cadaveric head. An experienced endoscopic surgeon was oriented to the software and asked to rate the utility of the navigation software in carrying out predefined surgical tasks. Utility was evaluated using a rating scale for: (1) safely completing the task; and (2) potential for surgical training. Surgical tasks included: (1) uncinectomy; (2) ethmoidectomy; (3) sphenoidectomy/pituitary resection; and (4) clival resection. CBCT images were updated following each ablative task.
  
  
  RESULTS
  As a teaching tool, the software was evaluated as "very useful" for all surgical tasks. Regarding safety and task completion, the software was evaluated as "no advantage" for task (1), "minimal" for task (2), and "very useful" for tasks (3) and (4). Landmark identification for structures behind bone was "very useful" for both categories.
  
  
  CONCLUSIONS
  The software increased surgical confidence in safely completing challenging ablative tasks by presenting real-time image guidance for highly complex ablative procedures. In addition, such technology offers a valuable teaching aid to surgeons in training.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Eitan
authors.initials: E
authors.lastname: Prisman
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Daly
authors.forename: Harley
authors.initials: H
authors.lastname: Chan
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Siewerdsen
authors.forename: Allan
authors.initials: A
authors.lastname: Vescan
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Irish
mesh_terms: D002102:Cadaver; D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography / Q000379:methods; D004724:Endoscopy / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D021621:Imaging, Three-Dimensional; D007396:Internship and Residency; D007430:Intraoperative Care / Q000379:methods; D010256:Paranasal Sinuses / Q000000981:diagnostic imaging / Q000601:surgery*; D015641:Radiography, Interventional / Q000379:methods; D012225:Rhinoplasty / Q000193:education; D019291:Skull Base / Q000000981:diagnostic imaging / Q000601:surgery*; D012984:Software; D013664:Teaching Materials; D020535:Video-Assisted Surgery / Q000379:methods