Upper rib fractures and mediastinal widening: indications for aortography.

Survival of patients with posttraumatic thoracic aortic rupture depends on early diagnosis. It is frequently stated that fracture of the first or second ribs and mediastinal widening are findings suggestive of thoracic aortic rupture. We found that the probability of sustaining thoracic aortic rupture is the same for patients with upper rib fractures as for those with other rib fractures (1/64 versus 5/149; p = 0.85). Also, our data fail to show a statistical difference in the incidence of thoracic aortic rupture associated with upper (first and second) rib fractures compared with no rib fracture at all (1/64 versus 9/304; p = 0.85). Thus, patients with thoracic aortic rupture are not more likely to have rib fractures (7/21 versus 14/21; p = 0.15), and if a rib fracture is present, the probability of it being at the upper level is the same as that for a fracture at any other level (1/7 versus 6/7; p = 0.06). Ratios of mediastinal width to chest width were used as a measure of mediastinal widening, and were found to be an accurate predictor of thoracic aortic rupture. Ratios greater than 0.28 at the aortic knob were 100% specific and 85% sensitive for this condition.