Protrusion deformities of the anterior chest wall are 10 times less frequent than depression deformities. Associated disorders, including congenital heart disease, Marfan’s syndrome, spine abnormalities, and musculoskeletal defects are as frequent as in patients with pectus excavatum. The deformity typically is mild or absent in early childhood and becomes increasingly prominent during the rapid growth in early adolescence.
Pectus carinatum is believed to stem from an overgrowth of rib cartilages, with forward buckling and deforming pressure on the body of the sternum. Carinatum deformities are more variable than excavatum defects, with two principle forms. In one form the protuberance is maximal in the upper portion of the sternum and the middle of the sternum is directed posteriorly. The second and more common form shows the greatest prominence in the lower portion or body of the sternum. Minor forms may exist in which rib cartilages may buckle outward without sternal deformity. Persistent discomfort may warrant removal of the protruding cartilages.
In most cases, pectus carinatum produces no symptoms beyond local tenderness or pain in the protruding portion of the chest. No heart or lung abnormalities result from this deformity, in contrast to pectus excavatum. In some cases, its association with spine abnormalities results in altered lung function. A quarter of patients will have other family members with chest deformities and musculoskeletal defects are seen in 20%.
Variation in surgical treatment is a result of the diversity of pectus carinatum deformities. The same exposure is used as for the excavatum defects, with removal of the affected rib cartilages. The sternum is also cut to make a hinge that will allow it to be secured in a more downward position. Modifications are used for more asymmetrical abnormalities. Complications are similar to those for excavatum surgery.
Article and graphics adapted from O'Neill: Principles of Pediatric Surgery. © 2003, Elsevier.