Background: Non-surgical immobilization strategies for type 2 odontoid fractures vary considerably, with some surgeons preferring rigid collars, halothoracic bracing or the Minerva brace. Choice of device should be informed by the effectiveness in achieving union, whilst minimizing mortality and complications. Objectives: Perform a systematic review evaluating the efficacy of non-surgical interventions for type 2 odontoid fractures. Data Sources: MEDLINE (OvidSP), EMBASE (OvidSP) and The Cochrane Library, ClinicalTrials.gov, Current Controlled Trials. Methods: We conducted a systematic review of studies directly comparing the halothoracic brace and cervical collars or the Minerva brace for union, mortality and complications. Studies were appraised for quality and bias, and results were pooled for analysis. Results: Our search identified 1794 citations, 13 of which met inclusion criteria. There were no randomized or prospective studies. All studies were small, retrospective and observational. Our results demonstrate a greater likelihood of developing stable union (osseous and fibrous); relative risk (RR) 1.27 (95 confidence intervals (CI) 1.03 to 1.57; P = 0.03); and airway complications; RR 7.52 (95 CI 1.39 to 40.83; P = 0.02) with halothoracic bracing compared with cervical collar. In patients >65, there was a greater risk of airway complications; RR 7.50 (0.96-58.36; P = 0.05). No other significant differences were identified. Conclusion: Evidence to support selection of non-surgical immobilization in type 2 odontoid fractures is poor. Osseous union has traditionally been the benchmark for successful treatment; however, evidence of association between union and improved outcomes is lacking. We highlight the need for a randomized study to promote evidence-based decision-making in the non-surgical management of this injury. ? 2013 Royal Australasian College of Surgeons.