Section: New Results

Suturing simulation based on complementarity constraints

Participants : Christophe Guebert, Christian Duriez, Jérémie Allard, Stéphane Cotin, Laurent Grisoni.

This work introduces a new method, based on complementarity constraints, for simulating virtual sutures in soft tissues. Complementarity constraints are known for the modeling of contacts with friction between solid objects, however they can be used for other types of interactions. In this paper, we focus on modeling the physical nature of the interactions with the needle and surgical thread during the suture of soft anatomical structure. In particular we model needle puncture through soft tissues, followed by the friction that occurs when sliding through the tissue, the punture and cutting forces associated to different tissue layers, and the collision with boundary membranes or stiffer structures. Although the proposed constraint formulation is independent of the physical models used for the needle, thread or soft tissue, the choice of these models is key to obtain real-time performance. Therefore we also propose to combine two models that can handle geometrically non-linear deformations: the thread model is based on beam theory and the soft tissue model relies on a volumetric Þnite element method. A common iterative solver is used for all constraints, in combination with an implicit integration scheme, providing fast and stable simulations even for complex scenarios.

One part of this work was published at SCA conference this year [19]