title: Intra-operative virtual endoscopy for image guided endonasal transsphenoidal pituitary surgery.
abstract: OBJECTIVE
  Virtual endoscopy has already proven its benefit for pre-operative planning of endoscopic pituitary surgery. The translation of such a system into the operating room is a logical consequence, but only a few general intra-operative image guided systems providing virtual endoscopic images have been proposed so far. A discussion of related visualization and interaction problems occurring during sinus and pituitary surgery is still missing.
  
  
  METHODS
  This paper aims at filling this gap and proposes a system that integrates an existing virtual endoscopy system originally designed for pre-operative planning of pituitary surgery with a professional intra-operative navigation system. Visualization and interaction possibilities of the pre-operative planning system have been extended to fulfill the special requirements to the system if used for intra-operative navigation of endonasal transsphenoidal pituitary surgery.
  
  
  RESULTS
  The feasibility of the system has been successfully tested on 1 cadaver and 12 patients. The virtual endoscopic images were found useful (1) during the endonasal transsphenoidal approach in cases of anatomic variations and for the individually tailored opening of the sellar floor, and (2) during tumor resection for respecting the internal carotid artery. The visualization of hidden anatomical structures behind the bony walls of the sphenoid sinus during the sellar phase of the surgery has been found most beneficial.
  
  
  CONCLUSIONS
  According to our data, intra-operative virtual endoscopy provides additional anatomical information to the surgeon. By depicting individual anatomical variations in advance, it may add to the safety of this frequent neurosurgical procedure.
authors.affiliation: VRVis Research Center for Virtual Reality and Visualization, Ltd., Donau-City-Strasse 1, 1220, Vienna, Austria. fschulze@vrvis.at
authors.forename: Florian
authors.initials: F
authors.lastname: Schulze
authors.forename: Katja
authors.initials: K
authors.lastname: Bühler
authors.forename: André
authors.initials: A
authors.lastname: Neubauer
authors.forename: Armin
authors.initials: A
authors.lastname: Kanitsar
authors.forename: Leslie
authors.initials: L
authors.lastname: Holton
authors.forename: Stefan
authors.initials: S
authors.lastname: Wolfsberger
mesh_terms: D004724:Endoscopy / Q000379:methods*; D006801:Humans; D007432:Intraoperative Period; D019635:Neurosurgical Procedures / Q000379:methods*; D010902:Pituitary Gland / Q000601:surgery*; D010911:Pituitary Neoplasms / Q000601:surgery*; D013100:Sphenoid Bone / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014584:User-Computer Interface