title: A clinical case of endoscopically assisted anterior screw fixation for the type II odontoid fracture.
abstract: METHODS
  A clinical case using a new surgical technique is reported.
  
  
  OBJECTIVE
  To report for the first time an endoscopically assisted anterior screw fixation for the Type II odontoid fracture.
  
  
  BACKGROUND
  Recently, many endoscopically assisted surgeries have been performed for various spinal surgery because of its minimally invasive character. However, the anterior retropharyngeal approach to the upper cervical spine using endoscopy has not been reported.
  
  
  METHODS
  A 76-year-old man was operatively managed for a Type II odontoid fracture. The operation was performed under immobilization of cervical spine using a halo vest apparatus. A skin incision 2 cm long was made on the medial border of the right sternocleidomastoid muscle at the C5-C6 intervertebral level. Blunt dissection between the neurovascular bundle laterally and the trachea and esophagus medially was performed. A processed polyethylene syringe (volume, 10 mL) was used as the tubular retractor. This retractor kept the minimum but sufficient space for the screw fixation and avoided esophageal complication. Using a cannulated screw system, a cancellous screw was inserted from the anteroinferior edge of the C2 vertebral body to the tip of the odontoid process. The drilling and the screwing process was monitored by a two-dimensional image intensifier. The entry point was monitored by endoscopy to avoid soft tissue involvement as well.
  
  
  RESULTS
  The operation was completed without any soft tissue complications such as esophageal injury. The blood loss was 30 mL. The procedure resulted in nonunion, partially because of patient's old age or an entry point 2 mm above the anterior caudal margin of the C2 body retrospectively.
  
  
  CONCLUSIONS
  Although the reported odontoid fracture ended in nonunion, the authors believe their modification of the approach using an endoscope made anterior screw fixation for the odontoid fracture safer and less invasive than the original anterior retropharyngeal approach.
authors.affiliation: Department of Orthopaedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama City, Wakayama, Japan. hashizum@wakayama-med.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hashizume
authors.forename: Mamoru
authors.initials: M
authors.lastname: Kawakami
authors.forename: Masaki
authors.initials: M
authors.lastname: Kawai
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tamaki
mesh_terms: D000368:Aged; D001863:Bone Screws; D004724:Endoscopy / Q000379:methods*; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008297:Male; D009809:Odontoid Process / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D011859:Radiography; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome