Current Management of Late Posttraumatic Enophthalmos

The impact of orbital floor defect ratio on changes in the inferior rectus muscle and prediction of posttraumatic enophthalmos - A cadaver study

BACKGROUND

Orbital floor fractures result in critical changes in the shape and inferior rectus muscle (IRM) position. Radiological imaging of IRM changes can be used for surgical decision making or prediction of ocular symptoms. Studies with a systematic consideration of the orbital floor defect ratio in this context are missing in the literature. Accordingly, this study on human cadavers aimed to systematically investigate the impact of the orbital floor defect ratio on changes in the IRM and the prediction of posttraumatic enophthalmos.

METHODS

Seventy-two orbital floor defects were placed in cadaver specimens using piezosurgical removal. The orbital defect area (ODA), orbital floor area (OFA), position and IRM shape, and enophthalmos were measured using computed tomography (CT) scans.

RESULTS

The ODA/OFA ratio correlated significantly (p < 0.001) with the shape (Spearman's rho: 0.558) and position (Spearman's rho: 0.511) of the IRM, and with enophthalmos (Spearman's rho: 0.673). Increases in the ODA/OFA ratio significantly rounded the shape of the IRM (ß: 0.667; p < 0.001) and made a lower position of the IRM more likely (OR: 1.093; p = 0.003). In addition, increases in the ODA/OFA ratio were significantly associated with the development of relevant enophthalmos (OR: 1.159; p = 0.008), adjusted for the defect localization and shape of the IRM. According to receiver operating characteristics analysis (AUC: 0.876; p < 0.001), a threshold of ODA/OFA ratio ≥ 32.691 for prediction of the risk of development of enophthalmos yielded a sensitivity of 0.809 and a specificity of 0.842.

CONCLUSION

The ODA/OFA ratio is a relevant parameter in the radiological evaluation of orbital floor fractures, as it increases the risk of relevant enophthalmos, regardless of fracture localization and shape of the IRM. Therefore, changes in the shape and position of the IRM should be considered in surgical treatment planning. A better understanding of the correlates of isolated orbital floor fractures may help to develop diagnostic scores and standardize therapeutic algorithms in the future.

Revisiting bilateral bony orbital volumes comparison using 3D reconstruction in Korean adults: a reference study for orbital wall reconstruction, 3D printing, and navigation by mirroring

BACKGROUND

Orbital wall fractures can result in changes to the bony orbital volume and soft tissue. Restoring the bony orbital and intraconal fat volumes is crucial to prevent posttraumatic enophthalmos and hypoglobus. We aimed to establish an evidence-based medical reference point for "mirroring" in orbital wall reconstruction, which incorporates three-dimensional (3D)-printing and navigation-assisted surgery, by comparing bilateral bony orbital volumes.

METHODS

We retrospectively analyzed the data obtained from 100 Korean adults who did not have orbital wall fractures, categorized by age groups. The AVIEW Research software (Coreline Soft Inc., Seoul, South Korea) was used to generate 3D reformations of the bony orbital cavity, and bony orbital volumes were automatically calculated after selecting the region of interest on consecutive computed tomography slices.

RESULTS

The mean left and right orbital volume of males in their 20 s was 24.67 ± 2.58 mL and 24.70 ± 2.59 mL, respectively, with no significant difference in size (p = 0.98) and Pearson's correlation coefficient of 0.977 (p < 0.001). No significant differences were found in orbital volumes in other age groups without fractures or in patients with nasal bone fractures (p = 0.84, Pearson's correlation coefficient 0.970, p < 0.001). The interclass correlation coefficients (2,1) for inter- and intrarater reliability were 0.97 (p < 0.001) and 0.99 (p < 0.001), respectively.

CONCLUSIONS

No significant differences were found in the bilateral bony orbital volumes among males of any age. Thus, the uninjured orbit can be used as a volumetric reference point for the contralateral injured orbit during orbital wall reconstruction.