'Orbital volume restoration rate after orbital fracture'; a CT-based orbital volume measurement for evaluation of orbital wall reconstructive effect

Abstract

Purpose To evaluate the effect of orbital reconstruction and factors related to the effect of orbital reconstruction by assessing of orbital volume using orbital computed tomography (CT) in cases of orbital wall fracture. Methods In this retrospective study, 68 patients with isolated blowout fractures were evaluated. The volumes of orbits and herniated orbital tissues were determined by CT scans using a three-dimensional reconstruction technique (the Eclipse Treatment Planning System). Orbital CT was performed preoperatively, immediately after surgery, and at final follow ups (minimum of 6 months). We evaluated the reconstructive effect of surgery making a new formula, 'orbital volume reconstruction rate' from orbital volume differences between fractured and contralateral orbits before surgery, immediately after surgery, and at final follow up. Results Mean volume of fractured orbits before surgery was 23.01 +/- 2.60 cm(3) and that of contralateral orbits was 21.31 +/- 2.50 cm(3) (P = 0.005). Mean volume of the fractured orbits immediately after surgery was 21.29 +/- 2.42 cm(3), and that of the contralateral orbits was 21.33 +/- 2.52 cm(3) (P = 0.921). Mean volume of fractured orbits at final follow up was 21.50 +/- 2.44 cm(3), and that of contralateral orbits was 21.3 +/- 22.50 cm(3) (P = 0.668). The mean orbital volume reconstruction rate was 100.47% immediately after surgery and 99.17% at final follow up. No significant difference in orbital volume reconstruction rate was observed with respect to fracture site or orbital implant type. Patients that underwent operation within 14 days of trauma had a better reconstruction rate at final follow up than patients who underwent operation over 14 days after trauma (P = 0.039). Conclusion Computer-based measurements of orbital fracture volume can be used to evaluate the reconstructive effect of orbital implants and provide useful quantitative information. Significant reduction of orbital volume is observed immediately after orbital wall reconstruction surgery and the reconstruction effect is maintained for more than minimum 6 months. Patients that undergo surgery within 14 days of trauma has better reconstruction rates at final follow up, which supports the need for early surgery.