Surgical Management of Unstable Atlas Fractures: A Single Institutional Retrospective Review with Comparison of Occipitocervical and Atlantoaxial Fusion Outcomes.

Background: Atlas fractures represent 25% of craniocervical injuries, most common in elders. Unstable C1 fractures with lateral mass displacement require surgical fixation. Options include atlantoaxial fusion (AAF) or occiput-cervical fusion (OCF), each have their respective merits and detractors. Here, we compare the clinical and neurological outcomes of patients with unstable atlas fractures treated with AAF and OCF.

Methods: Retrospective review of patients with unstable atlas fractures that underwent either AAF or OCF between 2005-2023 was performed. Demographics, clinical characteristics, radiographic parameters, and outcomes were collected. Cervical sagittal balance was measured by O-C2 angle, C2-7 lordosis, and C2-7 sagittal vertical axis (SVA).

Results: 44 patients with unstable atlas fractures were included (25 underwent AAF and 19 OCF). Median age was 73 years, 52% were male. Demographics, mechanism of injury, and other clinical characteristics were similar. Landell's Type 2 atlas fractures and lateral mass displacement were significantly in OCF group. Median number of levels was significantly greater in the OCF group (3 versus 2 in AAF, p=<.001). C2-7 lordosis was less in OCF vs. AAF (p=.045). SVA was less in the AAF group vs. OCF (p=.044). Cervical SVA was decreased 4.5 mm in average in the AAF group vs. 5.2 mm increase in OCF (p=0.040). There were no significant differences in the rates of postoperative complication, surgical revision, or neurologic function.

Conclusions: OCF results in significant loss of lordosis and increase in cervical SVA relative to AAF, which may impact long-term quality of life and disability not directly measured in this study.