Analysis of Orbital Blowout Fracture Location and Hess Area Ratio

This study aimed to analyze the Hess area ratio (HAR%) in cases of blowout fracture treated in our department and clarify the outline of eye movement disorders in blowout fractures. Patients who underwent surgery for orbital blowout fractures in our department were included. Fracture locations were classified into 5 types (A, outside floor; B, C, anterior and posterior floor; and D, E, anterior and posterior medial wall). The HAR% was compared before and after surgery in eligible cases. The relationship between the fracture location and preoperative HAR% was investigated using multiple regression analysis. The study involved 85 patients. Hess area ratio was higher postoperatively than preoperatively (70.75 ± 18.26 versus 90.06 ± 13.99, P  < 0.01). The postoperative HAR% tended to be higher when the iliac bones were compared to other materials; however, this difference was not significant (90.73 ± 12.91 versus 80.30 ± 17.81, P = 0.178). Fracture locations C and E significantly contributed to the prediction of HAR% as negative regression coefficients (P = 0.024 and 0.013, respectively). The posterior fracture area on both the orbital floor and medial wall contributed to the decrease in preoperative HAR%. This observation indicates that the reconstruction of the posterior region is extremely crucial.