The Impact of Orbital Volume on Post-traumatic Enophthalmos: A Systematic Review and Meta-analysis

Purpose: Orbital volume increase has been previously linked with post-traumatic enophthalmos. However, this varies and some studies show no correlation. This systematic review and meta-analysis aimed to synthesize the correlation between orbital volume and enophthalmos and to determine if surgical intervention, enophthalmos measurement method, fracture location, or timing affect this correlation. Methods: Automation tools were used to assist in this review of 6 databases. Searches were performed across all dates. Included studies quantitatively reported orbital volume and enophthalmos following traumatic orbital wall fractures in at least 5 adult subjects. Correlational data were extracted or calculated. Random-effects meta-analysis was used with subgroup analyses for each of the secondary aims. Results: Twenty-five articles describing 648 patients were included. The pooled correlation between orbital volume and enophthalmos was r =0.71 ( R 2 =0.50, P <0.001). Operative status, enophthalmos measurement method, and fracture location did not affect pooled correlation. The delay between trauma or surgery and enophthalmos measurement was not shown to modulate correlation for unoperated patients ( R 2 =0.05, P =0.22) but showed a negative relationship for postoperative patients ( z =−0.0281, SE=0.0128, R 2 =0.63, P =0.03), but this was heavily influenced by a single article. All results had high residual heterogeneity. Studies were rated as moderate, low, or very low quality with few stating explicit hypotheses or limitations. Conclusions: Bony orbital volume expansion accounts for around 50% of post-traumatic enophthalmos. The other half is probably explained by soft tissue or geometric bony, rather than volumetric, changes.