Avaliação da acurácia entre o planejamento assistido por computador e resultados obtidos em cirurgia ortognática: estudo retrospectivo

Abstract

Purpose: The aim of this retrospective study was to evaluate the accuracy between actual outcomes and virtual surgical planning (VSP) in orthognathic surgery regarding the use of three-dimensional (3D) surface models for registration using ICP algorithm and color maps by reverse engineering software. Materials and Methods: Construction of planning and postoperative 3D models in STL files format (M0 and M1, respectively) from CBCTs of 25 subjects who had been submitted to bimaxillary orthognathic surgery was performed. The M0 and M1 were sent to Geomagic Wrap Software in automatic alignment surface meshes order of M0 and M1 for registration using the ICP algorithm to calculate mean deviation (MD, MD+, MD-, SD) and root mean square (RMS). Color maps were generated to assess qualitative congruence between M0 and M1. From deviation analysis, the RMS(s) were defined as 3D Error which behaved as a measurement indicator of accuracy. The sample characteristics were shown by descriptive statistics. To evaluate the reproducibility of this method, the workflow was performed by two independent evaluators multiple times. t tests were used to assess whether all means of MD, MD+, MD-, SD and 3D Error values would be lower than - 2 mm and greater than 2 mm. Results: high intra and inter evaluators correlation were found, supporting the reproducibility of the workflow in Geomagic Wrap software. t tests proved that all MD(s) and 3D Error values were greater than - 2 mm and lower than 2 mm. Conclusion: This study showed 3D error mean (1,27 mm) within the standards of clinical success lower than 2 mm. ICP algorithm in Geomagic Wrap software provided a reproducible method of alignment between 3D models (surface meshes) and generated color maps to evaluate 3D congruence, but did not answer all methodological parameters regarding the assessment of accuracy in orthognathic surgery.