A Propensity-Matched Analysis of the Impact of Sternal Fractures on Outcomes in Concurrent Thoracic Spine Fractures: The Fourth Column of the Spine

BACKGROUND: The thoracic vertebrae, ribs, and sternum, provide structural and protective support for the upper body. The unique framework of the region suggests that fractures involving both the thoracic spine and sternum occur with notable spinal instability. Despite their clinical relevance, the short-term medical and surgical outcomes of combined sternal and thoracic spinal fractures remain poorly understood compared with thoracic fractures alone. This study aims to compare the 90-day complication rates and surgical intervention requirements in patients with concomitant sternal and thoracic vertebral fractures with those with isolated thoracic vertebral fractures. METHODS: Patients presenting with acute sternal and thoracic spine fractures in the same admission were identified using the PearlDiver database. Patients with sternal and vertebral fractures were propensity matched in a 1:1 ratio with a control group by age and Elixhauser comorbidity index. Medical complications, rate of spinal cord injury, and rates of surgical intervention were assessed at 90 days. RESULTS: A total of 9,026 patients were identified in this study with 4,513 patients presenting with sternal and thoracic spine fractures and 4,513 patients in the control group. Sternal and vertebral fracture coinjury was associated with higher rates of spinal cord injury (P < 0.0001), higher rates for spinal decompression/fusion (odds ratio = 4.38, P < 0.0001), and higher rates of thoracic surgery (odds ratio = 3.0, P < 0.0001). These patients were also statistically markedly more likely to develop hemodynamic, respiratory, cardiac, and renal complications (P < 0.001) at 90 days. DISCUSSION: Patients with thoracic spine fractures who sustain simultaneous sternal fractures are markedly more likely to have concomitant spinal cord injury, require spinal stabilization or decompression, and develop medical complications. Our findings point toward the role of the sternum as a fourth column of stability in cases of thoracic spinal fractures, which mitigate complications, surgery, and neurologic injury in cases of trauma.