Three-Dimensional Cephalometric Analysis of Orbital Morphology Modification for Midface Correction Surgery.

OBJECTIVES: The aim of this study was to create an evidence-based three-dimensional cephalometric analysis of orbits in order to perform time-efficient measurements of postoperative orbital morphology changes.

MATERIALS AND METHODS: The authors used 23 (11 bilateral and 1 unilateral) anatomical landmarks. Based on these, 6 planes, 12 angular and 16 linear measurements were determined. A three dimensional analysis was performed twice by two observers on pre and post-operative computed tomography scans of six patients who had undergone midface advancement. The mean, minimal and maximal difference, as well as standard deviation (SD) and intraclass correlation coefficient (ICC) for the inter- and intra-observer landmark selection reliability were calculated. Additionally, the mean, minimal, maximal difference and standard deviation between pre- and post-operative angular and linear measurements were calculated to examine a connection between the established measurements and any morphological change.

RESULTS: The inter and intra-examiner accuracy of all landmarks for three axes was >0.9 ICC. Despite excellent inter and intra-examiner agreement (<2.49 mm ± 2.05 mm SD) for the landmark selection, linear and angular measurements showed a mismatch, the mean SD for angular measurements was found to be 8.2° and the linear 3.04 mm.

DISCUSSION: The possible causes of linear and angular measurement discrepancies are discussed and the future direction for the development of three-dimensional cephalometric analysis of orbits proposed.