title: Anterior video-assisted approach to the craniovertebral junction: transnasal or transoral? A cadaver study.
abstract: BACKGROUND
  Endoscopy represents both an alternative and useful complement to the standard microsurgical approach to the anterior craniovertebral junction (CVJ). Nevertheless, few studies provide an experimental comparison between transnasal and transoral endoscopic control on CVJ. We compared the surgical exposition angle and the working channel volume of both the transnasal and transoral approaches in the cadaver.
  
  
  METHODS
  Eleven fresh non-perfused cadavers were studied. Transnasal and transoral linear and angled exposure of the CVJ were evaluated by means of X-ray and CT scan both in sagittal and lateral planes.
  
  
  RESULTS
  The transoral endoscopic surgical exposition was wider compared with the transnasal in anterior and lateral projections:(1)in the sagittal plane, both in vertical exposition (transnasal inferior to transoral from 5.89 % to 76.48 %, average 35.89 %) and in vertical surgical angle (from 22 % to 77.42 %, average 56.53 %); (2)in the coronal plane, both in coronal exposition (transnasal inferior to transoral from 50.77 % to 83.88 %, average 70.34 %) and in coronal surgical angle (from 65.58 % to 86.71 %, average 76.70 %). The sagittal surgical domain was found to spanning from the inferior third of the clivus to C3 with the transoral and from the middle third of the clivus to the nasopalatal line (NPL) with the transnasal approach. The overlapping surgical domain area was found to be the inferior third of the clivus.
  
  
  CONCLUSIONS
  The endoscope assisted transoral approach allows a better surgical control of the CVJ. It provides a better CVJ exposure, in sagittal and transverse planes, providing a larger working channel and an easier manoeuvrability. The transnasal approach is limited in caudal direction down to the NPL, otherwise the transoral approach is limited in the rostral direction with a maximum to the foramen magnum in normal specimen. In every individual case, pros and cons of the appropriate approach have to be taken into account as well as the choice of a combined transnasal and transoral approaches strategy.
authors.affiliation: Institute of Neurosurgery, Catholic University of Rome, Largo Gemelli, 8, 00168, Rome, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Visocchi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: La Rocca
authors.forename: Giuseppe Maria
authors.initials: GM
authors.lastname: Della Pepa
authors.forename: Egidio
authors.initials: E
authors.lastname: Stigliano
authors.forename: Alessandro
authors.initials: A
authors.lastname: Costantini
authors.forename: Francesco
authors.initials: F
authors.lastname: Di Nardo
authors.forename: Giulio
authors.initials: G
authors.lastname: Maira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D003388:Cranial Fossa, Posterior / Q000601:surgery*; D004724:Endoscopy; D005260:Female; D005539:Foramen Magnum / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000295:instrumentation*