INTRAOPERATIVE NAVIGATION IN ORAL AND MAXILLOFACIAL SURGERY

Surgical procedures in the oral and maxillofacial region may be diffic ult in areas of complex anatomy. Up to now surgical planning has been based almost exclusively on the surgeon's experience and on the interp retation of 2-dimensional (2D) radiologic information. Our experiences with a commercially available 3D navigation system (Viewing Wand, ISG , Mississauga, Ontario, Canada) is reported upon. The system consists of a mechanical operating arm with 6 joints and 6 degrees of freedom w orking as a 3D digitizer and is interfaced to a computer graphics work station. After registration of the position of the patient's head in r elation to the tip of the instrument on the navigation arm, the surgeo n can observe the 3D position and direction of the instrument in use o n the monitor, i.e. on the computed tomography and/or magnetic resonan ce tomography images of the patient taken before. In 40 interventions performed so far, the accuracy was 2 mm and better. 3 cases are presen ted in this paper. The system facilitates surgery especially in anatom ically complicated situations without the risk of damaging neighbourin g structures. Planning of surgical interventions is much easier. By us ing computer assisted simulation and navigation systems, we expect an improvement in quality and a reduction in surgical risks. Thus, ''look ing ahead'' surgery has become possible. More extensive and more radic al interventions are likely to be performed in the near future. Respon sibility for the surgical intervention, however, remains exclusively w ith the surgeon.