title: Evaluation of surgical freedom for microscopic and endoscopic transsphenoidal approaches to the sella.
abstract: BACKGROUND
  Microscopic and endoscopic transsphenoidal approaches to the sellar are well established. Surgical freedom is an important skull base principle that can be measured objectively and used to compare approaches.
  
  
  OBJECTIVE
  To compare the surgical freedom of 4 transsphenoidal approaches to the sella turcica to aid in surgical approach selection.
  
  
  METHODS
  Four transsphenoidal approaches to the sella were performed on 8 silicon-injected cadaveric heads. Surgical freedom was determined with stereotactic image guidance using previously established techniques. The results are presented as the area of surgical freedom and angular surgical freedom (angle of attack) in the axial and sagittal planes.
  
  
  RESULTS
  Mean total exposed area surgical freedom for the microscopic sublabial, endoscopic binostril, endoscopic uninostril, and microscopic endonasal approaches were 102 ± 13, 89 ± 6, 81 ± 4, and 69 ± 10 cm2, respectively. The endoscopic binostril approach had the greatest surgical freedom at the pituitary gland and ipsilateral and contralateral internal carotid arteries (25.7 ± 5.4, 28.0 ± 4.0, and 23.0 ± 3.0 cm2) compared with the microscopic sublabial (21.8 ± 3.5, 21.3 ± 2.4, and 19.5 ± 6.3 cm2), microscopic endonasal (14.2 ± 2.7, 14.1 ± 3.2, and 16.3 ± 4.0 cm2), and endoscopic uninostril (19.7 ± 4.8, 22.4 ± 2.3, and 19.5 ± 2.9 cm2) approaches. Axial angle of attack was greatest for the microscopic sublabial approach to the same targets (14.7 ± 1.3°, 11.0 ± 1.5°, and 11.8 ± 1.1°). For the sagittal angle of attack, the endoscopic binostril approach was superior for all 3 targets (16.6 ± 1.7°, 17.2 ± 0.70°, and 15.5 ± 1.2°).
  
  
  CONCLUSIONS
  Microscopic sublabial and endoscopic binostril approaches provided superior surgical freedom compared with the endonasal microscopic and uninostril endoscopic approaches. This work provides objective baseline values for the quantification and evaluation of future refinements in surgical technique or instrumentation.
authors.affiliation: *Division of Neurological Surgery and ‡Division of Neurosurgery Research, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona.
authors.forename: Ali M
authors.initials: AM
authors.lastname: Elhadi
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Hardesty
authors.forename: Hasan A
authors.initials: HA
authors.lastname: Zaidi
authors.forename: M Yashar S
authors.initials: MY
authors.lastname: Kalani
authors.forename: Peter
authors.initials: P
authors.lastname: Nakaji
authors.forename: William L
authors.initials: WL
authors.lastname: White
authors.forename: Mark C
authors.initials: MC
authors.lastname: Preul
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Little
mesh_terms: D002102:Cadaver; D006801:Humans; D044583:Neuroendoscopy / Q000379:methods*; D009666:Nose; D010902:Pituitary Gland / Q000601:surgery; D012658:Sella Turcica / Q000601:surgery*