Overgrowth of costal cartilage is not the etiology of pectus excavatum

PurposeThe etiology of pectus excavatum (PE) has not been clarified. In 1944, Sweet (Sweet RH. Pectus excavatum. Ann Surg 1944;119:922-934) mentioned about the possibility of the overgrowth of costal cartilage being involved. However, no additional report that supports his hypothesis is available. In this study, we investigated whether the overgrowth of costal cartilage was an actual cause of PE through measurement of the costal cartilage length in PE patients and healthy controls.Materials and MethodsWe investigated the length of the fifth and sixth costal cartilages and ribs in PE patients from reconstructed images of 3-dimensional computed tomography. To examine the relative costal cartilage length, we calculated the C/R ratio, defined as the quotient of the costal cartilage length divided by the adjacent rib length, and compared it between PE patients and healthy controls.ResultsIn PE patients, the C/R ratios were not larger than in healthy controls at any level. At the left sixth, the C/R ratio was significantly smaller in patients than in the healthy control group.DiscussionThe results revealed that, in PE patients, relative costal cartilage lengths were not longer than in healthy controls. We conclude that the overgrowth of costal cartilage is not the etiology of PE.