Optical sensors for a synergistically controlled osteotomy system

Cutting bone is an important task in many surgical interventions (e.g. orthopedic surgery, neurosurgery). However it is often performed close to critical structures such as vessels or central nervous structures with an inherent high risk of serious damage. In this paper a concept for improving the safety of these surgical procedures is presented, by combining a soft tissue preserving saw with optical sensors in a semiautomatic controlled instrument. A real-time system acquires and analyses the data from an optical sensor and allows a indirect detection of the actual local bone thickness and the automatic adjustment of the sawing depth. To determine material characteristics (e.g. soft tissue, bone) a color sensor has been used in combination with a hysteresis controller. To show the feasibility of this concept a simple prototype has been built and evaluated with bone samples and parts of an artificial Sawbones skullcap. The system performed well with different materials and geometries, but further research has to be directed towards sensor integration and dynamic performance.