title: Ventral cancellous bone augmentation of the dens and temporary instrumentation C1/C2 as a function-preserving option in the treatment of dens pseudarthrosis.
abstract: METHODS
  An innovative function preserving technique for the treatment of odontoid nonunion via ventral cancellous bone augmentation of the dens is described. A retrospective clinical study of 17 patients, thus treated by this technique is reported.
  
  
  OBJECTIVE
  Assessment of a new method, which preserves the rotational mobility of the C1/C2 joint.
  
  
  BACKGROUND
  Nonunion after odontoid fractures are usually treated by posterior fusion of C1/C2. Although there are reports of good clinical results, restriction of rotational mobility is inevitable.
  
  
  METHODS
  Seventeen patients with dens pseudarthrosis or delayed healing were operated on between the year 1991 and 2005. A hole was drilled in the dens and packed with autologous bone graft. Temporary Instrumentation C1/C2 (anteriorly or posteriorly) was performed for 3 to 4 months. Patients were evaluated clinically and radiographically, rotation computed tomography or magnetic resonance imaging studies were conducted.
  
  
  RESULTS
  Fifteen patients were available for follow-up. Nine patients demonstrated healing of the pseudarthrosis with preservation of C1/C2 joint mobility (confirmed by rotation-computed tomgraphy or rotation -magnetic resonance imaging in 7 cases, average segmental rotation 37.3 degrees). Four patients showed persistent pseudarthrosis (2 were fused by posterior C1/C2 fixation) and 2 patients demonstrated spontaneous C1-C2 fusion.
  
  
  CONCLUSIONS
  Ventral cancellous bone augmentation of the dens and temporary instrumentation C1/C2 is a function-preserving option in the treatment of dens pseudarthrosis.
authors.affiliation: Center for Orthopedics and Traumatology, Zentralklinikum Suhl, Germany. michael.ruf@zs.srh.de
authors.forename: Michael
authors.initials: M
authors.lastname: Ruf
authors.forename: Thomas
authors.initials: T
authors.lastname: Welk
authors.forename: Matthias
authors.initials: M
authors.lastname: Müller
authors.forename: Harry R
authors.initials: HR
authors.lastname: Merk
authors.forename: Jürgen
authors.initials: J
authors.lastname: Harms
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D002648:Child; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011542:Pseudarthrosis / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome