Design, fabrication, and testing of a piezoresistive hardness sensor in Minimally Invasive Surgery

In the present paper, a novel and reliable tactile sensor is proposed to provide the required tactile feedback to the surgeon allowing the annuloplasty surgery to be performed by Minimally Invasive Surgery (MIS) techniques. The proposed sensor can differentiate between the hardness of different kind of elastomers. The structure of the sensor is very simple and it can easily be microfabricated, and integrated to various surgery devices such as catheters. The paper discusses the design, modeling, and fabrication of the sensor. Several hardness measuring tests are carried out on the sensor and the output is compared to a standard method of hardness measurement by a durometer. Two elastomers with hyperelastic behaviour, representing two different heart tissues were modelled mathematically to verify the sensor´s output. It is shown that the output of the sensor is reliable.