Hand-held bone cutting tool with autonomous penetration detection for spinal surgery

In spinal surgery, a surgeon often needs to remove some parts of the spine to relieve the pressure on the spinal cord or other nerves. In this procedure, the surgeon needs to cut and drill some holes in the spine. This operation is very risky because there are some nerves beneath the target bones, and this procedure therefore requires a skilled and experienced surgeon. However, if the cutting tool could detect penetration of the bone autonomously, the safety of the procedure would be improved drastically. This study presents a hand-held bone cutting tool system that detects the penetration of the workpiece. The system learns the cutting states and motion states from demonstrations by a surgeon, and it autonomously detects the penetration of the workpiece and stops the actuation of the cutting tool immediately before total penetration. The proposed scheme for penetration detection does not require knowledge of the shape and the position of the workpiece and, therefore, it does not require any costly systems, such as robotic arms and position sensor systems. In addition, the proposed scheme can be easily applied to various shapes of the cutting tool, such as drills and saws. The developed system was evaluated through experiments. The results showed that the performance of the developed system was satisfactory in both a motorized and a hand-held setup.