Isolated Bilateral Zygomatic Arch Fractures of the Facial Skeleton Are Associated with Skull Base Fractures

BACKGROUND: To date, only limited case reports involving isolated bilateral zygomatic arch fractures exist. This fracture pattern is defined by the presence of bilateral zygomatic arch fractures and the absence of any other facial fractures. The purpose of this study was to systematically review a large trauma database to determine whether this fracture pattern exists and, if so, to elucidate the mechanism of injury and associated concomitant injuries. METHODS: A retrospective review of all patients admitted to the R Adams Cowley Shock Trauma center from February of 1998 to December of 2009 was conducted. International Classification of Diseases, Ninth Revision coding of computed tomographic scans was used to identify patients with zygoma fractures. The facial computed tomographic scans of all patients coded with bilateral zygoma fractures were reviewed to determine whether any had isolated bilateral zygomatic arch fractures. Medical charts were reviewed extensively. RESULTS: Five patients (0.24 percent of all zygoma fractures, 3.18 percent of bilateral zygoma fractures) were found to have isolated bilateral zygomatic arch fractures. All five patients had evidence of skull impact with at least one skull fracture and one skull base fracture. Glasgow Coma Scale scores (range, 6 to 14; average, 8.2) were significantly lower (t test, two-sided, p=0.01) compared with all patients (average, 12.2) with facial trauma during the study period. CONCLUSIONS: Isolated bilateral zygomatic arch fractures do exist. The authors' findings suggest skull impacts as the inciting mechanism of injury and an intimate link with skull base force transmission. The severe nature of this injury warrants a search for concomitant injuries to the head, brain, and spinal cord.