Incidence of Pure Orbital Fractures with Concomitant Lacrimal Drainage System Injury in the Japanese Population: A Retrospective Study.

PURPOSE This study aims to determine the incidence of pure orbital fractures with concomitant lacrimal drainage system injuries. METHODS A retrospective observational study involving 956 sides from 940 pure orbital blowout fracture patients was conducted in our institution. Patients with concomitant orbital rim fracture and those with old orbital fractures were excluded. RESULTS A total of 13 sides (1.4%) from 13 patients were included in the study. Canalicular laceration, bony nasolacrimal canal fracture, and lacrimal sac wall laceration were found in 9, 4, and 1 patients, respectively (one overlapping). Majority of the injuries resulted from either sports or falls. Inferomedial orbital strut fracture (23.1% vs. 7.6%; p = .075) and orbital floor fracture occurring lateral to the infraorbital groove (30.8% vs. 9.9%; p = .035) tended to be higher in patients with lacrimal drainage system injuries. CONCLUSION There is a 1.4% incidence rate of pure orbital fractures with concomitant lacrimal drainage system injuries among the Japanese population included in this study. Inferomedial orbital strut fractures and orbital floor fracture lateral to the infraorbital groove were found to have higher association with lacrimal drainage system injuries.