3-dimensional facial simulation in orthognathic surgery: is it accurate?

PURPOSE: The purpose of this study was to measure the accuracy of 3D computer simulation of soft tissue changes after orthognathic surgery. MATERIALS AND METHODS: Consecutive patients who underwent orthognathic surgery were studied by photogrammetric facial scanning and cone-beam computed tomography before and after surgery. The photogrammetric scan was then fused to the cone-beam computed tomogram, creating a patient-specific image. The surgery was simulated in 3D form and the simulated soft tissue face was compared with the actual facial scan obtained 6 months postoperatively. Absolute millimeter differences between the simulated and actual postoperative changes in selected cephalometric skin markings were computed. RESULTS: The study was composed of 23 subjects (mean age, 31 yr; 13 women and 10 men). Eighteen different cephalometric landmarks were measured (total, 28). For 15 landmarks, the difference between actual and simulated measurements was smaller than 0.5 mm. Only 3 landmarks had a difference of 0.5 mm, and these were in the region of the labial landmarks. CONCLUSION: Based on the present study, 3-dimensional computer surgical simulation of the soft tissue of the face for routine orthognathic surgery is accurate enough for routine clinical use.