Abstract: The Impact of Age, Injury Severity, and Mechanism on Orbital Blow-out Fracture Patterns after Blunt Trauma: An 11-Year Review

Abstract

BACKGROUND: Craniofacial injuries contribute substantially to morbidity after blunt trauma, with orbital fractures seen in approximately 10–25% of all traumatic facial fractures. Orbital blow-out fractures occur when an orbital wall is fractured with an intact orbital rim, and usually occurs after significant blunt trauma from an object larger than the orbital aperture. The aim of this study is to determine the impact of age, injury severity, and mechanism of injury on orbital blow-out fracture patterns. METHODS: We retrospectively reviewed all patients admitted to a regional Level 2 Trauma Center, who sustained blunt orbital fractures, over an 11-year period, from January 2006 to December 2016. We excluded all patients who had orbital rim fractures and all penetrating trauma. Only patients who had a computed tomography scan of their face on presentation were included. There were 825 patients who met inclusion criteria. Individual charts were reviewed for demographics, length-of-stay(LOS), mechanism of injury(MOI), injury severity score(ISS), and mortality. Individual facial CT scans were reviewed along with the formal radiologist report to determine fracture locations. Statistical significance was set at a p value ≤0.05. This study was approved by our Institutional Review Board. RESULTS: Our cohort consisted of 825 patients, with 42 mortalities (5.1%). The mean age was 40.4 years old (range 1–97) and there was an approximate 4:1 male:female ratio. The mean LOS was 5.4 days (range 0–78) and the mean ISS was 14.7(range 1–50). The most common MOI was motor vehicle collisions(MVC) in 211 patients, followed by assault, ground-level mechanical falls, All-Terrain Vehicle(ATV) accidents, motorcycle collisions(MCC), and other mechanisms in 171, 151, 112, 53, and 127 patients, respectively. Overall, the most common orbital blow-out fracture involved the orbital floor in 567 patients (68.7%), followed by the lateral, medial, superior(roof), and posterior walls in 310(37.6%), 183(22.2%), 160(19.3%), and 16(1.8%) patients, respectively. The most common fracture pattern combination was orbital floor and lateral wall fractures in 202 patients (24.5%). The mean number of orbital blow-out fractures per patient in the entire cohort was 1.50. Orbital floor fractures remained the most common blow-out fracture in all age groups, accounting for 72.4% in pediatrics (1–17 years old), 66.4% in adults (18–64 years), and 77.7% in the elderly (age ≥65 years). Patients with ISS <15 were significantly more likely to have an orbital floor fracture when compared to patients with ISS ≥15, with fractures present in 81.1% and 56.9% of patients, respectively(p<0.05). MCC resulted in the highest mean number of orbital blow-out fractures per patient (1.83), which was significantly higher than other mechanisms(p<0.05). Patients who had ground-level mechanical falls were most likely to have orbital floor blow-out fractures (90.0%) compared with other mechanisms(p<0.05). CONCLUSION: Orbital blow-out fractures are a common injury after significant blunt craniofacial trauma. The orbital floor is most frequently involved, and patients who have mechanical falls seem particularly prone to this injury. Patients with lower ISS in our cohort likely had more concentrated craniofacial injuries, explaining their worse fracture patterns. MCC appears to confer the greatest craniofacial trauma with the most severe orbital blow-out fracture patterns. Age did not independently predict fracture patterns.