title: Three-dimensional anatomical landmarks of the sphenoid ostium for a safer transsphenoidal approach.
abstract: OBJECTIVE
  The sphenoid ostium (SO) is an anatomical reference in transsphenoidal approach surgery.
  
  
  METHODS
  The morphological features of the SO were studied in 352 skull base by 3D-Doctor Demo version.
  
  
  RESULTS
  The mean diameters of the SO were measured as 5.8 ± 1.3 mm (right) and 5.9 ± 1.2 mm (left), respectively. The mean distance from the SO to the midline was measured as 2.3 ± 1.1 mm (right) and 1.8 ± 0.9 mm (left), respectively. 8 bones had SO on one side, whilst 4 bones had no SO. In 5 bones there was a double SO structure on one side. 74.4% of ovoid SO specimens have the largest perimeter, therefore, allow the highest degree of surgical success. It was noted that they were not symmetrical (21.8%). Openings were found to be at different distances from the midline, some at different distances from the floor; in addition, differently shaped openings, as well as those with an opening absent on one side or with double openings, were observed.
  
  
  CONCLUSIONS
  Separate coordinates and safe routes must be calculated for right and left openings. The SO analysis could eliminate some of standardization measurements of an exposed surgical area.
authors.affiliation: Ege University, Faculty of Medicine, Department of Anatomy, Izmir, Turkey.
authors.forename: Figen
authors.initials: F
authors.lastname: Govsa
authors.forename: Mehmet Asim
authors.initials: MA
authors.lastname: Ozer
mesh_terms: D000328:Adult; D006801:Humans; D019635:Neurosurgical Procedures / Q000379:methods; D013100:Sphenoid Bone / Q000033:anatomy & histology*; D013101:Sphenoid Sinus / Q000033:anatomy & histology*