title: Risk factors for non-union in the non-operative management of type II  dens fractures.
abstract: BACKGROUND
  Despite the publication of numerous studies, there remains controversy regarding the non-operative treatment of type II dens fractures. The halo-thoracic vest (HTV) and rigid cervical collar are the most commonly used. We sought to compare the outcomes of patients managed with these devices in terms of risk factors for non-union and complication rates.
  
  
  METHODS
  This study was a retrospective review of adult patients with type II dens fractures treated non-operatively at a Level 1 Trauma Centre between 2001 and 2007. Patient medical records and imaging studies were reviewed. Union was defined as stable fibrous union or bony union at 3 months.
  
  
  RESULTS
  Sixty-seven patients were included – 35 treated using a HTV and 32 with a collar. Non-union was associated with increased time in HTV or collar (P = 0.011), a mechanism of injury involving a low fall (P = 0.008), or low velocity injuries (P = 0.04). The proportion of patients with stable union at 3 months was 60% for the HTV group versus 35% for the cervical collar group (P = 0.10). There were trends to support increased risk of non-union with age ≥65 years (P = 0.13) or with fracture displacement ≥2 mm (P = 0.17) at the time of presentation. Clinically significant complications of the HTV were more common than those experienced with collar. Of HTV patients, 60% suffered one or more complications compared with 6% for collar.
  
  
  CONCLUSIONS
  We were unable to demonstrate any statistically significant advantage or disadvantage of either device. Further investigation of mortality and morbidity would be beneficial.
authors.affiliation: Department of Orthopaedic Surgery, The Alfred Hospital, Victoria, Australia. ms_emma_lewis@yahoo.com
authors.forename: Emma
authors.initials: E
authors.lastname: Lewis
authors.forename: Susan
authors.initials: S
authors.lastname: Liew
authors.forename: Adam
authors.initials: A
authors.lastname: Dowrick
mesh_terms: D000328:Adult; D005260:Female; D005599:Fractures, Ununited / Q000453:epidemiology* / Q000517:prevention & control; D006801:Humans; D008297:Male; D009809:Odontoid Process / Q000293:injuries*; D009989:Orthotic Devices; D012189:Retrospective Studies; D012307:Risk Factors; D016103:Spinal Fractures / Q000145:classification / Q000628:therapy*