Needle Insertion Forces Studies for Optimal Surgical Modeling

Needle insertion for minimally invasive surgery is a technique explored and studied in order to adhere to the strict regulatory requirement for medical device development. While the instruments and techniques determine the success of every surgical procedure, minimal attention was given to the medium, the interaction force for testing, the development tools and surgical techniques. In this paper, we present the interaction forces involve during the needle insertion into porcine back tissue and simulated flesh-like tissue, independently measured by a testing setup developed for this purpose. The experimental setup and test procedure provides an understanding on the mechanics of needle insertion, potentially aid the design improvement on surgical instrument. Investigation on the composition of the force components helps to define the bio-mechanical properties of back abdomen tissue upon insertion. These forces comprises of stiffness, friction and cutting force. These results estimate the true insertion depth of the needle in the tissue. Needle insertion forces were measured for gelatine analogues developed to model the consistency of the tissues in the lumbar region of the back. This study was the first step in developing a force feedback controlled surgical instrument for needle insertion which will be used in kidney surgical operation.