How Accurate Are Surgeons at Calculating Orbital Volumes?

Bilateral orbital volume (OV) symmetry is imperative for successful orbital reconstruction to prevent complications such as enophthalmos, diplopia, and orbital dystopia. The purpose of this study was to determine the accuracy of surgeon-led in-house OV calculation for reconstructed orbits after orbital floor fracture.

This is a retrospective cross-sectional observational study of maxillofacial computed tomography scans for patients undergone orbital fracture repair by Emory Oral and Maxillofacial service at Grady Memorial Hospital (Atlanta, Georgia) from 2018 to 2020.The primary predictor variable was OV calculation approach (outsourced vs surgeon-led in-house approach). The primary outcome variable was OV. Secondary variables were age, gender, and race. Interobserver reliability was calculated with a 2-way mixed-effects model, intraclass correlation coefficients, 95% confidence intervals, and P values. Differences between OV (in-house and outsourced) were calculated using student t-test. Statistical significance was determined at P < .05.

During the study period, 172 patients sustained orbital floor fracture. Of them, 49 patients (31 male, 18 females; 98 orbits) with the mean age of 41.3 years (range, 19 to 89 years) met inclusion criteria. Subjects with incomplete medical records and inadequate computed tomography scans were excluded from the study. The racial distribution in descending order was 87.8% African American, 8.2% Caucasian, 2% Hispanic, and 2% Asian. There was excellent inter-rater reliability for calculating uninjured OV (OV-U, P < .0001) and reconstructed OV (OV-R, P < .0001). The mean OV difference of outsourced approach was 0.8 cm³and for surgeon-led in-house approach was 0.07 cm³. There was no significant difference in OV difference between outsourced and in-house approach (P = .16).

In conclusion, using open-source 3-dimensional imaging software is a reliable and a predictable method at calculating reconstructed OV in patients who underwent open reduction and internal fixation of orbital fractures. By having this software in our personal computers and laptops, one can easily calculate OVs in an efficient manner.