Advances in interactive craniofacial surgery planning by 3D simulation and visualization.

In craniofacial surgery careful preoperative planning is essential. Traditional preoperative work-up consists of cast model surgery, cephalometric prediction tracing and analysis of photographs. Recently, we introduced 3-dimensional (3D) computed tomography (CT) model surgery in our preoperative work-up and presurgical prediction of the postoperative result. However, only limited information can be extracted concerning soft tissue changes which are most important for the patients' postoperative appearance. We propose a new system which will allow a precise preoperative visualization of not only bony structures but also the soft tissue surfaces. 3D CT data of the skull are integrated with 3D surface data acquired by laser scanning. Based on the 3D CT data the bony structures are segmented automatically and processed interactively to simulate the planned surgical procedure. Afterwards, the 3D soft tissue changes resulting from the shifting of bony segments are computed. The postoperative appearance of the patient is visualized using computer animation techniques.