Immediate postoperative outcome of orthognathic surgical planning, and prediction of positional changes in hard and soft tissue, independently of the extent and direction of the surgical corrections required.

Our purpose was to evaluate the immediate postoperative outcome of preoperatively planned and predicted positional changes in hard and soft tissue in 100 prospectively and consecutively planned and treated patients; all had various dentofacial deformities that required single or double jaw orthognathic correction using the computerised, cephalometric, orthognathic, surgical planning system (TIOPS). Preoperative cephalograms were analysed and treatment plans and prediction tracings produced by computerised interactive simulation. The planned changes were transferred to models and finally to operation. Five to 6 weeks postoperatively, the changes in profile actually obtained in the hard and soft tissue were cephalometrically assessed. The mean accuracy was relatively high. At the cephalometric reference points where significant differences between planned or predicted, and actually obtained, positional changes in hard and soft tissue were apparent and the inaccuracies were, except for the predicted horizontal position of the lower lip, relatively small. However, the variability of the predicted outcome in individual hard and soft tissues was relatively high. Using the TIOPS planning system with the presently included soft tissue algorithms, the current study shows relatively high mean predictability of the immediately postoperative hard and soft tissue outcome, independent of the extent and direction of required orthognathic correction. Because of the relatively high individual variability, caution is required when presenting the planned and predicted positional changes in the hard and soft tissue preoperatively in individual patients.