Modeling skin wrinkling for reconstructive surgery: the effects of natural tension

A model is presented for the simulation of procedures of reconstructive surgery characterized by the excision of a cutaneous defect and the closure and suture of the wound edges. The skin is modeled as a plane membrane undergoing large deformations having a Fung type constitutive response. Skin wrinkling, which is a typical outcome of the surgery in the form of extrusion of the wound edges and dog-ears, is accounted for through a modification of the elastic potential as proposed by Pipkin’s Relaxed Energy Density theory. The post buckling analysis of a stretched annular membrane performed by Geminard et. al (2004) is used to validate the model under conditions similar to those of the surgery and to highlight the influence of a pre-existing tension in the membrane on the extension of the wrinkled regions. The model is applied to simulate different surgical procedures and investigate the effects of the natural tension in the skin and the shape and size of the excisions.