Three-dimensional virtual simulation of alar width changes following bimaxillary osteotomies

Area of Science:

• Craniofacial surgery
• Orthognathic surgery
• 3D imaging and simulation

Background:

• Bimaxillary osteotomies significantly alter facial structures, including nasal width.
• Accurate prediction of soft tissue changes is crucial for surgical planning and patient satisfaction.
• Three-dimensional (3D) simulation offers a promising tool for predicting these outcomes.

Purpose of the Study:

• To assess the accuracy of a 3D soft tissue simulation for predicting nose width changes after bimaxillary osteotomies.
• To identify patient- and surgery-related factors influencing simulation accuracy.

Main Methods:

• Sixty patients undergoing bimaxillary osteotomies were included.
• Cone beam computed tomography (CBCT) scans were used for pre- and postoperative 3D virtual head models.
• A mass tensor model (MTM)-based algorithm simulated alar width changes, compared against actual outcomes using 3D cephalometric analysis.

Main Results:

• Postoperative alar width increased by an average of 1.6±1.1mm.
• The mean simulation error for alar width change was 1.0±0.9mm.
• Simulation predictability was not significantly correlated with age, sex, surgical techniques (alar cinch suture, VY closure), or prior interventions (surgically assisted rapid maxillary expansion).

Conclusions:

• The MTM-based 3D soft tissue simulation provides reasonably accurate predictions of postoperative alar width changes following bimaxillary osteotomies.
• While accurate, further refinement of the simulation model is warranted to improve predictability.