SIMULATION-GUIDED NAVIGATION: PRELIMINARY STUDY OF VIRTUAL MODELS AS INTRAOPERATIVE TEMPLATES IN ORTHOGNATHIC SURGERY

Aim. Today, several computer systems are available to perform surgical planning and elaborate virtual simulations of patient’s skeletal changes and new soft tissue profiles, in order to predict the outcome of a craniofacial intervention before the actual surgery. However an accurate reproduction of the simulated project in the operating theatre remains challenging for the surgeon. Navigation is currently practiced in maxillofacial surgery with this aim for post-traumatic reconstruction as well as for ablative tumor surgery. This preliminary study intends to deal with the problem of reproducibility of the planned bone movements during orthognathic surgery, in particular the control of the maxillary repositioning. Indeed, despite good results in sagittal and transversal movements accuracy, there is still a lack of precision in controlling the vertical location of the maxilla. The purpose of this pilot study is to explore the possibility of a future validation of the use of Simulation-Guided Navigation (SGN) - surgery guided by the simulated planning - to increase the reproducibility of the results of the preoperative simulation on virtual models. Methods. This trial started in November 2008 untill December 2008 and recruited 5 patients affected by dento-facial deformities who underwent orthognathic surgery. The treatment was performed using virtual simulations as virtual templates in the operating theatre with the Stryker® eNlite Navigation System. Results. The average reproducibility - capacity of the procedure to reach the virtually planned bone segment positions during the operation - obtained by the first surgical navigation-assisted test group was 88.8%, with an 8.8% increase if compared to our control group without the use of surgical navigation (80.0%). Conclusion. This preliminary study suggest that Simulation-Guided Navigation would be a helpful procedure during orthognathic surgery, to improve reproducibility of the preoperative virtual surgical planning.