The Three-dimensional Digital Study Of Unilateral Mandibular Distraction

Purpose1.Complete 5 unilateral mandibular distraction osteogenesis (DO) animal experiments, analyse the movement and resistance source of mandible of each goat according to the 3D (three-dimensional) data, to build a goat computer simulation model for mandibular DO design.2.Set up the 3D finite element model of one patient diagnosed HFM (hemifacial microsomia), simulate and analyse the biomechanical behaviour and movement of mandible in the process of mandibular DO.3.Collect the 3D skull data of HFM patients in clinic, according to the deformities of patients to choose a suitable operation method. Design the distractor placement, simulate the distraction and evaluate the outcome.Methods1.3D skull CT data at particular time point (pre-, post-operation and post-distraction) of 5 goats were collected. The images of bone tissue were reconstructed, using the Mimics software. The 3 reconstructed data of different time point were unified in the same frame of axes then, for better evaluating morphological and function pathological changes. The vector relationship between the distraction and the formation as well as the final position of mandible. Establish a scientific and effective simulation model.2. The 3D CT data of one HFM patient who would be experienced mandibular DO treatment in our department. The mandible, temporomandibular joint and masticatory muscles were reconstructed by Mimics software, after related modulus were set,the data were input the ANSIS software and the 3D finite element model was built.In this model, the distraction of the mandibular osteotomy were calculated, the movement and biomechanical behaviour were evaluated.3. The 3D CT data of 7 HMF patients in our department were collected. After the bone tissue was reconstructed, the mandibular data of each patient were measured and analyzed. According to the deformities and the key point can solved by mandibuluar DO treatment we concluded in part 1,5 appropriate patients were selected. When the suitable osteotomic line and distrator direction were designed, the operation and the distraction procedure were simulated in the computer design and simulate system. The simulated treatments on the 3D skull model were confirmed. At last, the operation was performed on the 5 selected patients and the outcomes were completely evaluated.Results1. Through the measured data of the mandibular distraction from the animal experiments, a computer simulation model of unilateral mandibular DO was constructed.2. The finite element model of the HFM patients were set up, the mandibular distraction procedure was calculated, the path of distraction and stress distribution was simulated.3. By using a computer simulation model and 3D resin skull model. The operation method and mandibular DO treatment of 5 patients were directly guided, and the results post-distration were satisfying.Conclusion3D reconstruction, rapid prototyping technology and 3D finite element techniques are useful in accurate pre-operative design and treatment result prediction. With it, the surgical time was saved, and the efficacy of operation outcome can be improved. through these new technologies, the potential of the previous treatment we can improve based on our clinical experience.