Acute Blunt Temporal Bone Trauma: Maxillofacial vs Temporal Bone CT

Objective: To evaluate the radiographic workup of blunt temporal bone trauma and determine the utility of maxillofacial CT versus temporal bone CT in identifying carotid canal fractures. Study Design: Retrospective review. Methods: The charts of 227 patients evaluated at a level I trauma center receiving a temporal bone CT for blunt head trauma within 48 hours of admission were reviewed. Acute evaluation findings and complications were noted. Sensitivity, specificity, PPV and NPV were calculated for maxillofacial CT's ability to identify carotid canal fractures compared to temporal bone CT. Results: 140 fractures were found. Physical exam findings of blood in the EAC as the sole finding and blood in the EAC with associated hemotympanum were significantly associated with absence and presence of fracture respectively. The sensitivity and specificity of maxillofacial CT for identifying carotid canal fractures when compared to temporal bone CT were 90.3% and 94.4% respectively ( NPV > 95%). Only 6% of all patients either did have or should have had their management changed based on the temporal bone CT findings. All of these changes were regarding further work-up for blunt carotid artery injury. Conclusions: A combination of HCT and physical exam findings can allow for judicious use of temporal bone CT's when no maxillofacial CT is indicated. Temporal bone CT's rarely change acute management. But, when they do, it is in regard to the need for further work-up of possible vascular injury. Lastly, maxillofacial CT's are adequate for identifying carotid canal fractures.