Atypical Hangman's Fractures: An Institutional Study of 51 Patients With Atypical Traumatic Spondylolisthesis of C2.

Study Design: Retrospective cohort study.

Objectives: Atypical hangman's fractures are associated with increased risk for neurologic injury due to involvement of the posterior cortex of the axis body. We present the largest single-center cohort of atypical hangman's fractures with the goal of guiding treatment decisions and outcomes based on fracture classification.

Methods: We performed a retrospective analysis of all patients with atypical hangman's fractures treated at a single Level I trauma center between January 2010 and September 2023. 51 patients met inclusion criteria and demographic, treatment, and radiographic data were recorded and compared across the Type I and II fracture groups.

Results: Final treatment modalities varied significantly between the groups ( < 0.01), with hard cervical collar and invasive halo immobilization being the most prevalent treatments for fracture Types I and II respectively. One Type I fracture patient and four Type II fracture patients failed non-operative treatment, requiring surgery. Across both groups, posterior cervical fusion (73%) was the most common surgical approach. Median length of stay varied significantly between the two fracture groups (2.0 (1.0-7.0) vs 5.0 (3.0-8.0) days; = 0.01). Irrespective of fracture type, longer hospital length of stay was associated with increased patient age (IRR = 1.02; < 0.01), non-white race (IRR = 2.47; = 0.01), injury caused by MVC (IRR = 1.93; < 0.01), and the presence of non-spine orthopedic injuries (IRR = 1.72; = 0.03).

Conclusions: While atypical Type I hangman's fractures may be managed effectively non-operatively with a hard cervical collar, atypical Type II fractures managed with a hard cervical collar are at greater risk of requiring subsequent surgical intervention.