[Posttraumatic enophthalmos correction by bone graft: Why the unpredictable results?]

Prediction of Post-Traumatic Enophthalmos Based on Orbital Volume Measurements: A Systematic Review

PURPOSE

Enophthalmos greater than 2 mm should be considered clinically relevant and can be responsible for esthetic and functional morbidity. The difficulty has always been the best method to use to accurately determine when the orbital wall displacement will lead to clinically relevant enophthalmos. None of the currently used techniques is able to accurately predict for post-traumatic enophthalmos (PE). The aim of the present study was to systematically review the use of orbital volumetric tools in the prediction of PE after orbital fracture.

MATERIALS AND METHODS

The terms searched in each database were "(orbital volumetry) and enophthalmos," "volumetry and enophthalmos," "volume and enophthalmos," and "volumetric and enophthalmos." The relationship between PE and the orbital volume (OV) was assessed.

RESULTS

The initial search yielded 346 results. Of the 346 studies, 14 were included and analyzed. Every study reported a different numerical relationship between the OV and PE, with a mean enophthalmos of 0.80 mm after a 1-cm³ increase in the OV.

CONCLUSIONS

The present review found that most studies concluded that a direct relationship exists between the OV and PE and defined the degree of PE in relation to the OV expansion. Enophthalmos assessment using radiologic evaluation provides increased accuracy and reproducibility compared with clinical measurement using an exophthalmometer. It has been notoriously difficult to determine when orbital wall displacement will lead to clinically relevant enophthalmos. Measurement of the OV could have a role in the decision for surgical or conservative treatment.

Correction of Delayed Traumatic Enophthalmos Using Customized Orbital Implants

PURPOSE

To determine the relation between overcorrection of orbital volume and ocular projection in patients with orbital trauma.

MATERIALS AND METHODS

A prospective cohort study was performed of patients with enophthalmos as a side effect of orbital trauma. The sample included patients older than 18 years who required reconstruction using customized implants to treat enophthalmos with or without diplopia. The exclusion criteria were patients who had multiple or extended fractures and patients with amaurosis or a prosthetic eye. Orbital volumes were calculated and the position of the eyeball in the healthy and traumatized sockets was determined before and after installing the implant and the ratio between these variables was calculated. Two variables were identified: 1) orbital volume and 2) enophthalmos. Analysis of the estimator variables was performed, defining 3 groups: 1) healthy eye socket, 2) traumatized eye socket without implant, and 3) traumatized eye socket with implant. The Shapiro-Wilk test, paired t test, and linear regression analysis were performed. A P value less than .05 (95% confidence interval) indicated significant differences.

RESULTS

Of 294 patients who underwent orbital zygomatic complex reconstruction surgery, 13 required customized implants and only 5 met the inclusion criteria. The average volumetric variation in the groups of traumatized eye sockets with and without implants was statistically significant (P < .05), overcorrecting by an average of 4.2 cm³. The average enophthalmos variation in the groups of traumatized eye sockets with and without implants was statistically significant (P < .05), projecting the eyeball by an average 1.80 mm. The ratio between the average orbital volume and projection of the eyeball was determined to be 1:0.721 (correlation, 45.6%).

CONCLUSION

This study concluded that the eyeball is projected 0.7 mm for every 1 cm³ of volume added in customized orbital implants. However, additional clinical studies with larger samples should be conducted.