Project summary : Many so-called mini-invasive surgical procedures rely on the use of medical needles for the localized treatment of tumors or biopsies (branchy therapy, neurosurgery …). The use of medical needles allows deep access into the volume of organs and access to internal structures without damaging the surrounding tissues. For example, a biopsy involves inserting a needle into an organ to take a sample of tissue for examination. In this procedure, the effectiveness of the treatment or the accuracy of the diagnosis is directly related to the accuracy of insertion. The desired accuracy is often less than a millimeter, while the surgeon is limited by the constraints of medical imaging, tissue deformation and deformation or bending of the needle. To assist the surgeon in this task, several robotic systems have been proposed, but taking into account the deformation of tissues remains a major obstacle to the development of these new techniques. The goal of this work is to use finite element simulations to drive the robot during needle insertion into a deformable gel. The robot, needle and gel assembly can then be considered as a deformable robot with an infinite number of degrees of freedom (see FIG. 3). In this project we seek to use finite element simulations to anticipate deformations and propose new control laws for robotic systems.

Figure: Inserting the needle inside a deformable silicone gel. A curved path is defined (dashed black) to avoid an obstacle (gray circle). To perform the insertion, it is necessary to deform the silicone gel (with a tangential movement of the base of the needle) in order to modify the trajectory and to align it with the axis of the needle (more rigid than the gel). The goal of our project is to automatically calculate the displacement of a robot (on which is fixed the needle), allowing the generation of this deformation, to carry out the insertion.

Participants in the project: This project is an IDEX “attractite”. It also includes a doctoral fellowship that funded the thesis of Yinoussa Adagolodjo which is directed by Michel de Mathelin and Hadrien Courtecuisse. Laurent Goffin, research engineer in the AVR / ICube team provides technical and support for robotics integration and control.

Publications: This project resulted in 2 publications [AGMC16, ACTG15].