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

Abstract

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 ( P < 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; P = 0.01). Irrespective of fracture type, longer hospital length of stay was associated with increased patient age (IRR = 1.02; P < 0.01), non-white race (IRR = 2.47; P = 0.01), injury caused by MVC (IRR = 1.93; P < 0.01), and the presence of non-spine orthopedic injuries (IRR = 1.72; P = 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.