title: Comparison of endoscopic transnasal and transoral approaches to the craniovertebral junction.
abstract: OBJECTIVE
  The study compared the endoscopic anatomy of the transnasal and transoral approaches to the craniovertebral junction (CVJ).
  
  
  METHODS
  Structures examined and compared with both the straight and angled telescopes in 10 cadaveric specimens included the pharyngeal walls and adjacent musculature, resected anterior arch of the axis and odontoid, cruciform, axial, and apical ligaments, clival and dural openings, and the intradural exposure.
  
  
  RESULTS
  There is considerable overlap at the pharyngeal level in the structures that can be viewed by the transoral and transnasal routes. The transoral approach provides a wider corridor with less restricted manipulation of instruments than the transnasal approach, but the transnasal approach provides a better view of the clivus, upper part of the CVJ, and the structures posterior to the removed odontoid and anterior arch of C1. Combining the two approaches provides significantly better access to the midline anterior CVJ than either approach alone, allows the scopes to be advanced in one cavity and the surgical instruments in the other cavity, and reduces the need to split the palate, tongue, or mandible in order to reach the target area. The transnasal approach also allows access to the superior part of the occipital condyles, paraclival areas, and hypoglossal canals without removal of the condyles, but these structures can be exposed by the transoral route only after at least partial removal of the condyles.
  
  
  CONCLUSIONS
  The endoscopic transoral and transnasal approaches to the CVJ should be viewed as complementary routes as opposed to strict alternatives.
authors.affiliation: Department of Neurological Surgery, University of Florida, Gainesville, Florida, USA.
authors.forename: Askin
authors.initials: A
authors.lastname: Seker
authors.forename: Kohei
authors.initials: K
authors.lastname: Inoue
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Osawa
authors.forename: Akin
authors.initials: A
authors.lastname: Akakin
authors.forename: Turker
authors.initials: T
authors.lastname: Kilic
authors.forename: Albert L
authors.initials: AL
authors.lastname: Rhoton
mesh_terms: D000328:Adult; D002102:Cadaver; D065634:Cerebrospinal Fluid Leak; D002559:Cerebrospinal Fluid Rhinorrhea / Q000601:surgery; D003388:Cranial Fossa, Posterior / Q000033:anatomy & histology / Q000601:surgery*; D004388:Dura Mater / Q000033:anatomy & histology / Q000601:surgery; D004724:Endoscopy / Q000379:methods*; D005539:Foramen Magnum / Q000033:anatomy & histology / Q000601:surgery; D006801:Humans; D008022:Ligaments / Q000033:anatomy & histology / Q000601:surgery; D009296:Nasal Cavity / Q000033:anatomy & histology / Q000601:surgery; D019635:Neurosurgical Procedures / Q000379:methods*; D009809:Odontoid Process / Q000033:anatomy & histology / Q000601:surgery; D010614:Pharynx / Q000033:anatomy & histology / Q000601:surgery