Correlation of asymmetric chest wall deformity and growth in patients with pectus excavatum

Pectus excavatum involves wide range of chest wall depression. The degree of depression or asymmetry varies between young and adolescent patients. It has not been clear how the deformity progresses as patients grow. To elucidate the change of asymmetric deformity, preoperative computed tomography (CT) scan was evaluated according to different age groups.

Preoperative CT scans of 154 patients with pectus excavatum were collected and analyzed using Haller's CT index, asymmetric index and sternal rotation angle. Patients were divided into 5 age groups as follows; group 1: 4-6 y (n=53), group 2: 7-9 y (n=25), group 3: 10-12 y (n=25), group 4: 13-15 y (n=23), group 5: 16-23 y (n=28). The degree of asymmetric chest wall deformity was expressed using sternal rotation angle as follows; symmetrical (-5º to +5º), left-mild (-5º to -15º), right-mild (+5º to +15º), right-moderate (+15º to +25º) and right-severe (over +25º).

As the age of patients increased, asymmetric index increased from 1.025±0.065 in group 1 to 1.124±0.111 in group 5 and sternal rotation angle also increased from 6.11±8.61 in group 1 to 15.41±11.98 in group 5. In these two parameters, significant difference was seen between group 1 and 4, group 2 and 4, group 1 and 5 and group 2 and 5. However, average CT index revealed no significant difference in any age groups. In group 1, 83% of patients were classified in symmetrical or left- and right-mild. The incidence of right-moderate plus right-severe was 17% in group 1, 20% in group 2, 40% in group 3, 52.1% in group 4 and 50% in group 5.

The degree of chest depression did not show any change in all age groups. Asymmetric deformity on the right side progressed around the age of 10 to 12. Half of patients over the age of 13 showed moderate or severe asymmetry. These results were suggestive to consider the optimum age for the correction of pectus excavatum.