External Immobilization of Odontoid Fractures: A Systematic Review to Compare the Halo and Hard Collar

Background The aim of this systematic review was to compare the halo and hard collar in the management of adult odontoid fractures. Methods Systematic and independent searches on MEDLINE (PubMed) and the Cochrane Database of Systematic Reviews. Inclusion criteria included studies 1) with clinical outcomes, 2) in adults (18 years of age or order), 3) with odontoid fractures, 4) with patients immobilized using a halo or hard collar, and 5) in multiple (more than 5) patients. Treatment failure rates were calculated as the proportion requiring operative intervention. Results There were 714 cases included, who were managed in a halo (60%) or collar (40%). The mean age was 66 years (range, 18–96 years). Type 2 odontoid fractures were the most common (83%). There was no significant difference in failure rates between the halo and collar in patients with type 2 odontoid fractures (P = 0.111). This was also true in elderly (older than 65 years of age) patients (P = 0.802). The collar had a higher failure rate in type 3 odontoid fractures, though numbers were small (P = 0.035). Fibrous malunion occurred in 56 patients, and only 7% failed. There was only 1 case of neurological deterioration. Although mortality rates were similar between the collar and halo (P = 0.173), the halo was associated with a significantly higher complication rate (P < 0.001). Conclusions For the most common clinical scenario, the halo and collar have similar failure rates, such that the higher morbidity associated with the halo may not be justified, especially in elderly patients. Malunion usually represents a stable clinical outcome, and surgery is rarely required. Prospective randomized studies are needed to more definitively compare the devices.