New Technical Developments and Application of 3D Computer-Aided Surgical Planning, Surgical Simulation and Surgical Navigation in Orthognathic Surgery

Orthognathic surgery (OGS) aims to correct maxillomandibular deformity associated with dental malocclusion. Osteotomy was performed, and the bony segments were moved to achieve ideal dental occlusal relationship and facial appearance. Traditional approach is to apply normative data from lateral cephalometric analysis of different races. Recent development of 3-dimensional image technology and cone-beam computed tomography have rendered three-dimensional (3D) craniofacial image display convenient. The OGS surgical plan can be “performed” using computer-assisted 3D method, transferring the surgical plan to 3D image simulation. However, this surgical plan remains in 2-dimentional method using conventional cephalometric data. The process is lengthy, and the outcome may not be ideal as inherited disadvantage associated with the 2-dimensional method, such as overlapping landmarks, registration errors, etc. For these reasons, it is mandatory to establish normative 3D maxillofacial data and replace the 2-dimensional ones. Averageness has been recognized as a key element in facial attractiveness, and proved by a number of computerized studies. This concept will be applied in establishing 3D normative craniofacial data, a reference craniofacial osseous model. This model can be transformed for OGS simulation. To our knowledge, this has not been reported. This average model will be used to create a mesh model in order to provide relative information for preoperative evaluation, surgical planning, and simulation. This process should simplify the preoperative works, and avoid possible problems during the real surgery. After ideal planning and accurate simulation, the results are translated to the operating room. Our previous experience showed that even we already had 3D images and measurement there were still chances of discrepancy between virtual simulation and actual surgical result. As surgical guiding and navigation system have been applied in other surgical specialties, little has been used on OGS. We plan to add surgical positioning guide for LeFort I osteotomy and positioning, and use intraoperative navigation system to validate the final osseous position. By doing these, we hope to achieve surgical accuracy, decrease possible human errors, and shorten operation time. Foundations for 3D image methods and facility have been established in our laboratory. We aim to develop a novel 3D computer-assisted orthognathic surgery by 3D surgical planning, surgical simulation, intraoperative guiding and navigation, and postsurgical validation and analysis. Anticipated results include the following. 1. To generate general mesh model for both normal male and female craniofacial skeletons using geometric mesh transformation technology. 2. To establish 3D normative Taiwanese facial skeletal data. 3. To perform surgical simulation by mesh model superimposition using the 3D normative data. 4. To performed computer aided design and manufacture of surgical positioning guide. 5. To establish surgical navigation plan. 6. To translate virtual surgery to actual surgery using positioning guide and intraoperative navigation. 7. To validate surgical accuracy by comparing with the simulation images. 8. Final assessment of facial appearance.

Project ID:PC10401-1136
External Project ID:MOST103-2314-B182-028-MY3