title: Computer-assisted resection of benign sinonasal tumors with skull base and orbital extension.
abstract: OBJECTIVE
  To use freehand, real-time, intraoperative, 3-dimensional computed tomography (3-D CT) localization to assist with resection of sinonasal lesions with skull-base and/or orbital extension.
  
  
  METHODS
  The 3-D CT is computer-assisted technology using the preoperative CT scan as a road map for resection of lesions. Previous technology, while resulting in little intraoperative error, required use of a somewhat cumbersome rigid articulated arm and attached probe, limiting mobility and requiring rigid fixation of the head to maintain system reference. A new freehand version of this technology, eliminating these limitations, has been used for resection of benign sinonasal lesions with skull-base and/or orbital extension.
  
  
  METHODS
  Tertiary care, university-based practice.
  
  
  METHODS
  Seven patients prospectively selected with benign lesions involving the sinonasal cavity and orbit and/or skull base.
  
  
  METHODS
  All patients underwent surgical resection of their tumors using endoscopic, open, or combined procedures with the assistance of freehand 3-D CT localization. MAIN OUTCOME ASSESSMENTS: Surgeon assessment of usefulness.
  
  
  RESULTS
  In several cases, the device assisted the operator in determining the exact location of a displaced optic nerve, ensuring vision preservation, while in other cases, the location and depth of skull-base penetration was clearly determined, allowing resection via a transnasal endoscopic approach. In addition, the device was useful for determining the depth of necessary resection for optimal cosmetic result. In all cases, system accuracy was within less than 2 mm at the operative site. System limitations included need for an additional preoperative CT and time required at the beginning of the case for system setup and registration.
  
  
  CONCLUSIONS
  Freehand 3-D CT, while still with limitations, offers the advantage of increased surgical safety, aiding anatomic understanding in distorted surgical fields for resection of benign sinonasal tumors with orbital and skull-base extension.
authors.affiliation: Department of Otorhinolaryngology/Head and Neck Surgery, University of Pennsylvania Medical Center, Philadelphia, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Senior
authors.forename: D C
authors.initials: DC
authors.lastname: Lanza
authors.forename: D W
authors.initials: DW
authors.lastname: Kennedy
authors.forename: G S
authors.initials: GS
authors.lastname: Weinstein
mesh_terms: D000293:Adolescent; D000328:Adult; D006801:Humans; D008297:Male; D009078:Mucocele / Q000000981:diagnostic imaging / Q000601:surgery; D009669:Nose Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D009915:Orbit / Q000000981:diagnostic imaging / Q000601:surgery; D009918:Orbital Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D010255:Paranasal Sinus Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D011446:Prospective Studies; D015641:Radiography, Interventional / Q000295:instrumentation / Q000379:methods; D019291:Skull Base / Q000000981:diagnostic imaging / Q000601:surgery; D019292:Skull Base Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D013813:Therapy, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods