Significance of post-traumatic maxillary sinus fluid, or lack of fluid, in a level II trauma population

Our goal was to test the predictive value of high-attenuation material within the maxillary sinus for adjacent facial bone fracture. After IRB approval, all blunt trauma facial CTs performed over a 5-month period at a level II trauma center were reviewed in consensus by three radiologists for the presence of facial fractures or high attenuation maxillary sinus opacity (≥30HU, ≥40HU, or ≥50HU). Three classes of fractures were analyzed: any fracture, any fracture contiguous with the maxillary sinus, and only fractures not contiguous with the maxillary sinus. Statistics were calculated using two-by-two tables. A total of 844 cases were reviewed with 273 patients having any fracture. There were 402 hemi-faces with any fracture and 62 hemi-faces with fracture contiguous with the maxillary sinus. Sensitivity, specificity, positive predictive value, and negative predictive value for any fracture (using the ≥40HU threshold) were 13, 99, 85, and 78 % respectively; for fracture contiguous with the sinus, these were 71, 99, 72, and 99 % respectively; and for only non-contiguous fractures, these were 2.3, 96, 13, and 80 %, respectively. We conclude that in this level II trauma population, lack of high attenuation maxillary sinus material nearly ruled out fractures in contiguity with the sinus. High-attenuation sinus material is only moderately predictive of a fracture contiguous with the maxillary sinus. Therefore, if after careful review a fracture is not identified, the radiologist should not be overly concerned that a fracture is being missed. High-attenuation sinus material is a poor marker for fractures not contiguous with the maxillary sinus.