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Pectus excavatum is the most common congenital deformity of the anterior chest wall, in which an abnormal
formation of the rib cage gives the chest a caved-in or sunken appearance. Today, the surgical correction of this
deformity is carried out in children and adults through Nuss technic, which consists in the placement of a prosthetic bar
under the sternum and over the ribs. Although this technique has been shown to be safe and reliable, not all patients have
achieved adequate cosmetic outcome. This often leads to psychological problems and social stress, before and after the
surgical correction. This paper targets this particular problem by presenting a method to predict the patient surgical
outcome based on pre-surgical imagiologic information and chest skin dynamic modulation. The proposed approach uses
the patient pre-surgical thoracic CT scan and anatomical-surgical references to perform a 3D segmentation of the left
ribs, right ribs, sternum and skin. The technique encompasses three steps: a) approximation of the cartilages, between the
ribs and the sternum, trough b-spline interpolation; b) a volumetric mass spring model that connects two layers - inner
skin layer based on the outer pleura contour and the outer surface skin; and c) displacement of the sternum according to
the prosthetic bar position.
A dynamic model of the skin around the chest wall region was generated, capable of simulating the effect of the
movement of the prosthetic bar along the sternum. The results were compared and validated with patient postsurgical
skin surface acquired with Polhemus FastSCAN system.
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