ABSTRACT
BACKGROUND AND OBJECTIVES: We investigated the relationship between the degree of enophthalmos and the volume of herniated orbital tissue measured from computed tomography scan in the isolated blowout fractures of orbital wall. SUBJECTS AND METHOD: In this retrospective study, 100 patients with isolated blowout fractures were evaluated. We classified them into 4 groups according to the site of fracture (medial and inferior) and the presence of symptoms like diplopia and limitation of ocular motility, which needs an operation. The volume of orbit and herniated orbital tissue has been measured by computed tomography scans using three-dimensional reconstruction technique, and the degree of enophthalmos was evaluated with Hertel's ophthalmometer. We compared the volume from which we got from the computed tomography scan, the degree of enophthalmos and the presence of symptoms to figure out the mutual relation between the groups. RESULTS: In the case of medial blowout fracture group, the volume of herniated orbital tissues increased significantly with the presence of symptoms and was in proportion to the extent of enophthalmos (p<0.05). The volume expansion of orbit associated with 2 mm of enophthalmos as calculated by the regression curve was 3.1 ml or 12.8 % in the no-symptoms groups. Finally, in the case of inferior blowout fracture group, there was no evidence of mutual relation. CONCLUSION: These results suggest that surgical intervention is required even though there isn't any symptom for medial blowout fractures, especially when the orbit volume is more than 12.8%. In cases of inferior blowout fractures, a close follow-up is needed even though the extent of fracture is small.