title: Evolution from microscopic transoral to endoscopic endonasal odontoidectomy.
abstract: OBJECTIVE
  The goal of this study was to compare the indications, benefits, and complications between the endoscopic endonasal approach (EEA) and the microscopic transoral approach to perform an odontoidectomy. Transoral approaches have been standard for odontoidectomy procedures; however, the potential benefits of the EEA might be demonstrated to be a more innocuous technique. The authors present their experience with 12 consecutive cases that required odontoidectomy and posterior instrumentation.
  
  
  METHODS
  Twelve consecutive cases of craniovertebral junction instability with or without basilar invagination were diagnosed at the National Institute of Neurology and Neurosurgery in Mexico City, Mexico, between January 2009 and January 2013. The EEA was used for 5 cases in which the odontoid process was above the nasopalatine line, and was compared with 7 cases in which the odontoid process was beneath the nasopalatine line; these were treated using the transoral microscopic approach (TMA). Odontoidectomy was performed after occipital-cervical or cervical posterior augmentation with lateral mass and translaminar screws. One case was previously fused (Oc-C4 fusion). The senior author performed all surgeries. American Spinal Injury Association scores were documented before surgical treatment and after at least 6 months of follow-up.
  
  
  RESULTS
  Neurological improvement after odontoidectomy was similar for both groups. From the transoral group, 2 patients had postoperative dysphonia, 1 patient presented with dysphagia, and 1 patient had intraoperative CSF leakage. The endoscopic procedure required longer surgical time, less time to extubation and oral feeding, a shorter hospital stay, and no complications in this series.
  
  
  CONCLUSIONS
  Endoscopic endonasal odontoidectomy is a feasible, safe, and well-tolerated procedure. In this small series there was no difference in the outcome between the EEA and the TMA; however, fewer complications were documented with the endonasal technique.
authors.affiliation: Departments of Neurological Surgery, National Institute of Neurology and Neurosurgery "Manuel Velasco Suarez," Mexico City, Mexico.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Ponce-Gómez
authors.forename: Luis Alberto
authors.initials: LA
authors.lastname: Ortega-Porcayo
authors.forename: Hector Enrique
authors.initials: HE
authors.lastname: Soriano-Barón
authors.forename: Arturo
authors.initials: A
authors.lastname: Sotomayor-González
authors.forename: Nicasio
authors.initials: N
authors.lastname: Arriada-Mendicoa
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Gómez-Amador
authors.forename: Marité
authors.initials: M
authors.lastname: Palma-Díaz
authors.forename: Juan
authors.initials: J
authors.lastname: Barges-Coll
mesh_terms: D000293:Adolescent; D000328:Adult; D001268:Atlanto-Axial Joint / Q000601:surgery*; D004724:Endoscopy / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009666:Nose / Q000601:surgery*; D009809:Odontoid Process / Q000601:surgery*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014741:Video Recording; D055815:Young Adult
keywords: AAS = atlantoaxial subluxation; ASIA = American Spinal Injury Association; BI = basilar invagination; CTA = CT angiography; CVJ = craniovertebral junction; EEA = endoscopic endonasal approach; EEO = endoscopic endonasal odontoidectomy; TMA = transoral microscopic approach; TMO = transoral microscopic odontoidectomy; VPI = velopharyngeal insufficiency; craniovertebral junction; endoscopic endonasal approach; odontoidectomy; transoral microscopic approach