Favorable prognosis with nonsurgical management of type III acute odontoid fractures: a consecutive series of 212 patients.

Background Context: The recommended primary treatment for type III odontoid fractures (OFx) is external immobilization, except for patients having major displacement of the odontoid fragment. The bony fusion rate of type III OFx has been reported to be >85%. High compliance to treatment recommendations is favorable only if the treatment leads to a good outcome.

Purpose: The primary aim of this study was to determine the long-term outcome after conservative and surgical treatment of type III OFx and to reaffirm that primary external immobilization is the best treatment for most type III fractures.

Study Design/setting: Retrospective study based on a prospective database.

Patient Sample: Two hundred twelve consecutive patients with type III OFx treated at Oslo University Hospital over an 8-year period (2009-2017).

Outcome Measures: Long-term rates of bony fusion, crossover from primary conservative treatment to surgical fixation, new onset spinal cord injury (SCI), severe persistent neck pain (visual analogue scale - VAS), and persistent disability measured with Neck Disability index (NDI).

Methods: The present study was based on data extracted from our quality control database for acute cervical spine fractures from a general population. During the years 2018 to 2019 long-term follow-up of alive patients was performed (median follow-up time was 38.0 months; range 3.0-108.0 months). The follow-up included neurological examination, radiological examination and scoring of bony fusion status, crossover from primary conservative treatment to surgical fixation, new onset SCI, neck pain, and Neck Disability Index (NDI score).

Results: In this consecutive series of 212 patients with type III acute OFx, median patient age was 72 years, 56% had severe preinjury comorbidities (ASA score ≥3) and 22% lived dependently. Severe comorbidities and dependent living were significantly associated with increasing age (p<.001). The trauma mechanism was fall injury in 82%. The median age of patients injured by falls was significantly higher than in patients with a nonfall injury (p<.001). At the time of diagnosis, 4% had an OFx related SCI. Primary treatment was external immobilization alone in 95.3% and open surgical fixation in 4.7%. Patients treated with primary external immobilization alone presented with significantly less translation of the odontoid fragment (p<.001) and less angulation of the odontoid fragment (p=.025) than patients treated with primary surgery. Subsequent crossover to surgical fixation was performed in 5.4%. At long-term follow-up, 95.7% of patients had bony fusion of the OFx, 80.5% had minimal/no neck pain, and none developed new onset SCI. There was no significant difference in long-term follow-up VAS (p=.444) or NDI (p=.562) between the primary external immobilization group and the primary surgical group.

Conclusion: This study reaffirms that nonsurgical treatment remains the preferable option in the majority of patients with type III OFx.