Correlation between volume of herniated orbital contents and the amount of enophthalmos in orbital floor and wall fractures.

PURPOSE To analyze the correlation between the volume of herniated orbital contents and the amount of enophthalmos in orbital floor and wall fractures. MATERIALS AND METHODS Patients with secondary enophthalmos due to unilateral orbital floor and wall fractures were recruited. Computed tomography-assisted measurements of both orbits as well as of the amount of enophthalmos were performed. The following volumes were calculated: 1) the overall volume of both the healthy and fractured orbit, 2) the volume of herniated orbital contents at the orbital walls, 3) the volume of herniated orbital contents anterior and posterior to the vertical eyeball equator. The amount of enophthalmos was also measured by computed tomography. Multifactor linear regression analysis was performed to obtain correlations between the amount of enophthalmos and the measured volumes. RESULTS Twenty-three patients were included. The average enophthalmos was 4.0 mm (SD = 1.49). Although correlation between volume differences of healthy and fractured sides was not statistically significant, the overall volume of the herniated orbital contents was significantly correlated (P < .05) with the amount of enophthalmos. Regarding the specific orbital sites of herniation, the orbital floor was detected to be most significantly correlated to the amount of enophthalmos (P < .05), although only the herniation posterior to the vertical eyeball equator. CONCLUSION The overall volume of herniated orbital contents correlated significantly with the amount of enophthalmos. The orbital floor was detected to be the site most significantly correlated with the amount of enophthalmos (although only if herniation occurred posterior to the vertical eyeball equator). Only the volume of herniated soft tissues posterior to the eyeball equator showed correlation with the amount of enophthalmos.