Miniature temperature insensitive fiber optic sensors for minimally invasive surgical devices

This paper presents the concept of implementing miniature temperature insensitive optical fiber sensors into minimally invasive surgical devices such as graspers, staplers and scissors. The lack of temperature insensitive and accurate force feedback end effectors make the current minimally invasive surgeries (MIS) less effective especially in the area of electrosurgery. The failure to provide accurate force feedback information reduces the user's sense of immersion in the operating procedure. In this paper we present fiber sensors based on photonic crystal fibers (PCF) for force feedback from the end effectors. Two types of miniature temperature insensitive PCF sensors can be implemented for MIS applications; a Fabry-Perot interferometric sensor based on hollow core PCF and a tapered modal interferometric sensor based on a solid core PCF. A concept for interrogating these sensors effectively at minimal cost is also presented. The integration of sensors onto the end effectors is also important as one has to find an optimum position for maximum strain/force transfer to the fiber sensor without interfering with the operation of the surgical tool. We have also presented the methodology for incorporating the sensors into surgical end-effectors in this paper.