[Optimization of the spiral drill for use in medicine].

Cutting tools are used in medicine a long time ago. Varying mechanical and thermal damage to bone tissue results from using cutting tools. These are often commented in the literature, but there is hardly any systematic studies of optimization of cutting tools. This present study was initiated in an attempt to improve the drill bit geometry and machining conditions. The study includes the thermal damage of bone and the soft-tissue injury, especially beyond the bone, by drilling of bone. The result of this study is a new drill bit geometry, which reduces the time of drilling. Thus lower temperature rises and less danger of thermal damage are achieved. It is easy to center and to start the cut with this new drill. The physical effort of the surgeon is substantially lessened. The danger of the soft-tissue injury can be disregarded. Optimized practice in medicine is gained by avoiding thermal and mechanical damage.