Facial esthetics engineering: a concept for integration of precision and beauty in computer

Towards the last years we can observe a strong trend towards preoperative planning and integration of rapid prototyp-ing methods into computer assisted surgery workflows. In this lecture we summarize the current state of development in the field of interactive teleplanning and present recent clinical results of navigation guided insertion of individualized 3D facial implants, manufactured according to soft tissue simulations. Furthermore, we recommend to include the pa-tient's hairline respectively the biomechanics of the haired skull in planning algorithms in order to consider the impact of hairline design for the patient's facial esthetics. 1 Problem Rapid protoyping has been gaining in significance within the frame of computer assisted (tele-)planning and image guided surgery workflows. Currently, the most prominent challenges address the fusion of soft-and hardtissue properties with abstract esthetical criteria, also comprising the patients' hairline. 2 Material and Methods Established augmented reality and image guided surgery methods for preoperative planning as well as for intraoperative navigation are merged with rapid prototyping procedures. 3D photogrammetry adds a quantitative measure in postoper-ative evaluations when merged with the corresponding preoperative soft tissue prediction. For this purpose the postop-erative patient's face is scanned using a 3D photogrammetry system (Dimensional Imaging Inc., Glasgow, Scotland, UK) two month after surgery. Simulation error is quantified by calculation of the Hausdorff distance using MESH 1.13 3 Results The navigated insertion of customized facial implants could already be successfully established in clinical routine, providing highly satisfying esthetical and functional outcome. A preoperative plan can be exactly transferred to the patients and – due to preoperative soft tissue simulations – enables a completely natural look. In our first clinical application the quantitative evaluation of correspondence between preoperative simulation (i.e. soft-tissue prediction) and postoperative photogrammetric imaging revealed high correspondence at facial regions covering the implants. 4 Discussion A major challenge for the near future will be the full integration of all functional and esthetic factors in cranio-maxillo-facial surgery in one comprehensive computer based plan, even if the surgical interventions are scheduled at different times and hospitals. This approach requires a sophisticated interactive platform, enabling the fusion of the precision from engineering with the abstract term " esthetics ". Therefore we call this concept " facial esthetics engineering ". It comprises also the future optimization of hair transplant surgery, which is – in fact – a " missing brick " in currently