A new concept for navigated laser surgery.

In this article, a new concept for navigated laser surgery is presented. Mechanically rotating instruments such as drills or mills for bone treatment have the disadvantage of damaging the surrounding bone by the generated frictional heat. Cooling of the instrument cannot avoid this damage completely. Laser systems are an alternative solution for bone removal. Areas of application for bone treatment laser systems are the dental implantology and the osteotomy. The goal of the approach presented here was to combine the advantages of laser treatment with the precision and safety of navigated control. During the use of medical laser systems, the tissue is not only removed exactly in the focus of the laser. It is removed inside of a remove range around the focus. The amount of removed bone cannot be determined only by performance adjustment and the position of the laser because the size of the remove range is unknown. The new approach is to use a position- and orientation-dependent power-controlled laser. Therefore, a calibration of the laser parameters has to be accomplished. The position and orientation of the laser handpiece is measured by an optical measurement system. The laser parameters and the tissue properties are determined by a calibration procedure. On the basis of a preoperative planning, the laser remove range is adjusted by modulation of the laser power. Near to border areas or sensitive structure, the laser power is decreased. Therewith, a precise and safe bone removal according to a preoperative planning without damaging the bone by frictional heat is possible. The inaccuracies as result of simplifications by the calibration procedure have to be verified.