The unstable thoracic cage injury: The concomitant sternal fracture indicates a severe thoracic spine fracture.

INTRODUCTION: The thoracic cage is an anatomical entity composed of the upper thoracic spine, the ribs and the sternum. The aims of this study were primarily to analyse the combined injury pattern of thoracic cage injuries and secondarily to evaluate associated injuries, trauma mechanism, and clinical outcome. We hypothesized that the sternal fracture is frequently associated with an unstable fracture of the thoracic spine and that it may be an indicator for unstable thoracic cage injuries.

PATIENTS AND METHODS: Inclusion criteria for the study were (a) sternal fracture and concomitant thoracic spine fracture, (b) ISS≥16, (c) age under 50 years, (d) presence of a whole body computed-tomography performed at admission of the patient to the hospital. Inclusion criteria for the control group were as follows: (a) thoracic spine fracture without concomitant sternal fracture, (b)-(d) same as study cohort.

RESULTS: In a 10-year-period, 64 patients treated with a thoracic cage injury met inclusion criteria. 122 patients were included into the control cohort. In patients with a concomitant sternal fracture, a highly unstable fracture (AO/OTA type B or C) of the thoracic spine was detected in 62.5% and therefore, it was significantly more frequent compared to the control group (36.1%). If in patients with a thoracic cage injury sternal fracture and T1-T12 fracture were located in the same segment, a rotationally unstable type C fracture was observed more frequently. The displacement of the sternal fracture did not influence the severity of the concomitant T1-T12 fracture.

CONCLUSIONS: The concomitant sternal fracture is an indicator for an unstable burst fracture, type B or C fracture of the thoracic spine, which requires surgical stabilization. If sternal and thoracic spine fractures are located in the same segment, a highly rotationally unstable type C fracture has to be expected.