Miniaturised cutting tool with triaxial force sensing capabilities for minimally invasive surgery

This paper reports a miniaturised triaxial force sensorized cutting tool for minimally invasive robotic surgery. This device exploits a silicon based MEMS triaxial force sensor that acts as the core component of the system. The outer diameter of the proposed device is less than 3 mm, thus enabling the insertion through a 9 French catheter guide. Characterization tests are performed for both normal and tangential loadings. A linear transformation relating the sensor output to the external applied force is introduced in order to have a triaxial force output in real time. Normal force resolution is 8.2 bits over a force range between 0 N and 30 N, while tangential resolution is 8.1 over a range of 6 N. Force signals with frequencies up to 250 Hz can successfully be detected, enabling haptic feedback and tissue mechanical properties investigation. Preliminary ex vivo muscular tissue cutting experiments are introduced and discussed in order to evaluate the device overall performances.