What Do We Know Beyond Reliability in Voxel-Based Registration? Validation of the Accuracy of Regional Voxel-Based Registration (R-VBR) Techniques for Orthognathic Surgery Analysis

Purpose: Despite having excellent reproducibility, the accuracy of regional voxel-based registration (RVBR) techniques used for postoperative orthognathic surgical analysis has not been validated. The purpose of this study was to validate the accuracy of R-VBR. Methods: Preoperative (T0) and postoperative (T1) cone beam computed tomography (CBCT) of consecutive patients treated at a single center with nonsegmental LeFort I and bilateral sagittal split osteotomy were included. T1 CBCTs were oriented to match that of the standardized TO, and thus were assigned a known rotational transformation matrix in pitch/roll/yaw (P/R/Y), to create T1-prime (T1'). A copy of T1 (cT1) was made and was superimposed to T1' using R-VBR for 4 regions of interest (ROI): maxilla, distal mandible, right proximal mandible, and left proximal mandible, to create cT1'. The transformation matrix for each of the ROI was compared to those of T1' using paired t test and Bland-Altman analysis. Results: Twenty-eight eligible subjects' CBCTs were analyzed. Mean difference between T1' and cT1' ranged from -0.08 to 0.14 degrees (maximum 0.73 degrees), with no statistically significant differences (P = 0.216 to 1). Mean absolute difference ranged from 0.13 to 0.31 degrees (maximum 0.73 degrees). Bland-Altman analysis showed good agreement between T1' and cT1', indicating excellent accuracy. Conclusions: R-VBR using the maxilla, distal mandible, and the bilateral proximal mandibular segments as ROI has excellent accuracy in terms of rotational measurements. (C) 2021 The American Association of Oral and Maxillofacial Surgeons.

Automated summary

This study validates the accuracy of regional voxel-based registration (RVBR) techniques used for postoperative orthognathic surgical analysis. The results show that RVBR has excellent accuracy in rotational measurements.