title: C1 anterior arch preservation in transnasal odontoidectomy using three-dimensional endoscope: A case report.
abstract: BACKGROUND
  The transoral ventral corridor is the most common approach used to reach the craniovertebral junction (CVJ). Over the last decade, many case reports have demonstrated the transnasal corridor to the odontoid peg represents a practicable route to remove the tip of the odontoid process. The biomechanical consequences of the traditional odontoidectomy led to the necessity of a cervical spine stabilization. Preserving the inferior portion of the C1 anterior arch should prevent instability.
  
  
  METHODS
  This is the first report in which the technique to remove the tip of the odontoid while preserving the C1 anterior arch is described by means of a three-dimensional (3D) endoscope. A 53-year-old man underwent a transnasal 3D endoscopic approach because of a complex CVJ malformation. The upper-medial portion of the C1 anterior arch was removed preserving its continuity, and the odontoidectomy was performed. After surgery, a dynamic X-ray scan showed no difference in CVJ motility in comparison with the preoperative one.
  
  
  CONCLUSIONS
  The stereoscopic perception augmented the precision of the surgical gesture in the deep field. The importance of a 3D view relates to the depth of field, which a two-dimensional endoscopy cannot provide. This affects the preservation of the C1 anterior arch because of the presence of critical structures that are exposed to potential damage if not displayed.
authors.affiliation: Department of Neurosciences, Molinette University Hospital, Via Cherasco 15, 10126 Torino, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Zenga
authors.affiliation: Department of Neurosciences, Molinette University Hospital, Via Cherasco 15, 10126 Torino, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Marengo
authors.affiliation: Department of Neurosciences, Molinette University Hospital, Via Cherasco 15, 10126 Torino, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pacca
authors.affiliation: Department of Surgical Sciences, First ENT Division, Molinette University Hospital, Via Genova 3, 10126 Torino, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Pecorari
authors.affiliation: Department of Neurosciences, Molinette University Hospital, Via Cherasco 15, 10126 Torino, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ducati
keywords: C1 anterior arch preservation; craniovertebral junction stability; three-dimensional endoscope; transnasal odontoidectomy