Soft Tissue Changes Measured With Three-Dimensional Software Provides New Insights for Surgical Predictions

Abstract

Purpose Although computer-aided craniofacial reconstructions allow for simulation of hard tissue changes, the prediction of the final soft tissue facial changes remains a challenge. The purpose of the present study was to evaluate the 3-dimensional (3D) soft tissue changes in patients undergoing 2-jaw orthognathic surgery. Patients and Methods For the present retrospective cohort study, 40 consecutive patients (11 men and 29 women; mean age 23.5 ± 4.9 years) who had undergone 2-jaw orthognathic surgery were selected. We obtained the medical and dental records from 3 weeks before surgery and 6 months after surgery. We used image processing software to segment, superimpose, and quantify the hard and soft tissue displacements in 3 dimensions before and after surgery at 15 paired locations. The soft tissue and hard tissue changes were determined through quantification of homologous landmark displacements between the preoperative and postoperative computed tomography data. We measured the 3D soft and hard tissue changes and the anteroposterior, inferosuperior, and transverse components of the changes. We quantified the ratios between the soft and hard tissue changes, tested Pearson’s correlation between these changes, and developed a predictive regression equation for the observations at each location. Results We found that soft tissue movement followed the hard tissue movement, with a correlation nearly equal to 0.9 (range 0.85 to 0.98), suggesting that in general the soft tissues of the maxillary and mandibular landmarks are affected similarly by the skeletal movements. The anteroposterior component of the soft tissue 3D displacements followed the hard tissue movement with a ratio greater than 0.9 and with high correlation (r > 0.9) in the mandible. Conclusion The results of the present study provide surgeons with a ratio of hard to soft tissue change and the strength of the correlations, which will allow for more accurate 3D predictions for both midline and lateral structures in bimaxillary orthognathic surgical cases. In addition, predictive equations for various landmarks were developed and can be used in computer-based prediction programs to aid in treatment planning of soft tissue changes.

Effect of Le Fort I Maxillary Advancement and Clockwise Rotation on the Anteromedial Cheek Soft Tissue Change in Patients with Skeletal Class III Pattern and Midface Deficiency: A 3D Imaging-Based Prediction Study

“…A growing body of literature has appraised the relationship between facial bone and soft tissue changes after orthognathic surgery treatment, with most methodological designs being based on 3D landmark-based measurements [20][21][22][23][24][25]. To overcome the drawbacks of landmark-based techniques, a 3D facial region-based volumetric subtraction method was recently developed for the measurement of facial bone and soft tissue changes after orthognathic surgery [26].…”

Novel application and validation of in vivo micro‐CT to study bone modelling in 3D

“…In the clinical arena, superimposition of 3D data sets is becoming more common . However, in patient images, the resolution of the images is ~5‐10‐fold less than micro‐CT.…”

“…In the clinical arena, superimposition of 3D data sets is becoming more common. 20 However, in patient images, the resolution of the images is ~5-10-fold less than micro-CT. With animal studies and the use of micro-CT, finer resolution can be obtained to make measurements. Another unique aspect of the current technique is to the ability to observe overlaying of 3D models at two time points.…”

3D superimposition of craniofacial imaging—The utility of multicentre collaborations

“…The Dental and Craniofacial Bionetwork for Image Analysis (DCBIA‐https://sites.google.com/a/umich.edu/dentistry-image-computing/) group is composed by researchers, clinicians, computer scientists and engineers with the aims to (a) develop image analysis tools specifically to answer dentistry‐related clinical questions; (b) train researchers interested in those tools. These efforts resulted in international collaborations with South America, Europe, Asia and Oceania, not to mention other centres within the United States, with a large variety of application of the tools as follows: craniofacial anomalies, asymmetry, surgical outcomes and growth changes . Strengthening the relationship with other centres may eventually facilitate the development of big data that require secure but easily accessible de‐identified databases, with storage, mining and analytics capabilities.…”