title: Intraoperative IGS/CT updates for complex endoscopic frontal sinus surgery.
abstract: BACKGROUND
  Computer-aided surgery (CAS) systems integrate endoscopic visualization with real-time localization based on preoperative imaging. One short-coming of the current systems is the lack of real-time, radiographic assessment of surgical changes. We describe the potential applications of xCAT, a new intraoperative mobile volume CT scanner and its utility in providing surgical navigation updates in the operating room.
  
  
  METHODS
  A case report is presented describing how intraoperative CT updates were used in a complicated, revision endoscopic frontal sinus surgery.
  
  
  RESULTS
  A 53-year-old male with Samter's triad and a history of multiple previous endoscopic sinus surgeries presented with recurrent, symptomatic nasal polyposis and right-sided frontal headaches. Preoperative CT scans showed a large type III frontal recess cell obstructing the frontal sinus. He underwent revision endoscopic surgery with the use of CAS and the xCAT intraoperative CT scanner. Use of the intraoperative CT scanner to update preoperative images was extremely helpful in the endoscopic dissection of the frontal recess cell and in assessing completeness of dissection along the anterior skull base.
  
  
  CONCLUSIONS
  The xCAT intraoperative mobile volume CT scanner shows promise in providing real-time updates to surgical navigation. This may prove to be a valuable tool in endoscopic sinus surgery, especially in complex revision and frontal sinus cases.
authors.affiliation: Division of Rhinology, Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pa., USA.
authors.forename: Sri Kiran
authors.initials: SK
authors.lastname: Chennupati
authors.forename: Bradford A
authors.initials: BA
authors.lastname: Woodworth
authors.forename: James N
authors.initials: JN
authors.lastname: Palmer
authors.forename: Noam A
authors.initials: NA
authors.lastname: Cohen
authors.forename: David W
authors.initials: DW
authors.lastname: Kennedy
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Chiu
mesh_terms: D003937:Diagnosis, Differential; D004724:Endoscopy / Q000379:methods*; D005626:Frontal Sinus / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D013517:Otorhinolaryngologic Surgical Procedures / Q000379:methods*; D010254:Paranasal Sinus Diseases / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed / Q000379:methods*