Planning of orthognathic surgery with the hexapod system

Treatment of maxillofacial dysgnathia using a combined surgical/orthodontic approach requires careful orthodontic and orthognathic diagnosis and treat ment planning. In the present study, a system enabling on-line presentation of the necessary displacements of the jaw during surgery, while improving the accuracy of the planning, is described. Using the hexapod principle, it is possible to plan operations with six degrees of freedom and to measure the three-dimensional movements of jaws and jaw segments within the plannin g stage. Routinely prepared casts are employed for simulation of the operat ion. The displacements of the jaw are presented in a manner familiar to the orthodontic surgeon, namely in a surgical record. The accuracy achieved wi th the hexapod is superior to that achievable intra-operatively.