Traumatic Impact Velocity or Frontal Sinus Morphology: What is the True Risk Factor for Anterior Table Fractures after Craniofacial Trauma?

Objectives: The most important part of frontal sinus injuries is whether they are displaced. Purpose of this study was to evaluate the risk factors for depressed anterior table fractures in patients with similar forehead trauma.

Methods: We conducted a case-control study with a case group of consecutive treated patients with displaced frontal sinus anterior table fractures. The control group was randomly sampled from patients who presented with a blunt forehead trauma in our institution’s emergency unit. In computed tomography data sets, all patients’ frontal sinus size was categorized by Guerram’s classification that is defined as aplasia, hypoplasia, medium-size and hyperplasia as well as metric sinus size was measured. Cause of fracture was assigned to a low and high velocity impact group based on knowledge about strength of traumatic forces from physical and forensic research. Secondary predictor was clinical sign of brain concussion. Bivariate analysis was used to compare the predictors between both groups.

Results: In total, 47 cases and 93 controls were included. Hyperplasia in the case group had an odds ratio of 46:1 (p<0.001) compared to the controls. Mean sinus width (73 mm vs. 46 mm; p<0.001) and sinus height (30 mm vs. 15 mm; p<0.001) were larger in the case group. Trauma cause showed no statistical difference between both study groups with low velocity impact as the major cause (cases 92% vs. controls 85%; p=0.275). Incidences of concussion did not differ between both study groups (p=0.45).

Conclusion: In depressed fractures of the frontal sinus anterior table, low velocity impact prevails as trauma cause. A large frontal sinus size is the physiologic risk factor for these fractures.