The morphological changes of thorax in pediatric microtia patients after costal cartilage harvesting

The surgical treatment of microtia generally starts in childhood, and costal cartilage is the most widely used material for auricular reconstruction. However, multiple costal cartilage harvests lead to local cartilage defects, which may influence the growth of the hemithorax, that need close attention by doctors. In this study, morphological changes of the thorax were measured and analyzed in different follow-up groups.

Twenty-eight adolescent microtia patients underwent auricular reconstruction using 6th-8th costal cartilage. Thoracic computed tomography (CT) with three-dimensional reconstruction was performed preoperatively and during follow-up. Comparison of the hemithorax on the operated and unoperated sides was performed by measuring several thoracic parameters using Mimics software (Materialise, Belgium). The data were further analyzed by a paired-samples t-test.

In the operated hemithorax, the costochondral junction midpoints moved medially (6th-8th), posteriorly (6th-7th) and descended less (6th-9th) with significant differences as P < 0.05 compared to the unoperated hemithorax. In addition, height differences indicated local depressions in the chest wall in the areas of cartilage defects (6th-9th, P < 0.05). Following local depression of the chest wall and migration of the ribs, the operated hemithorax also had a smaller area than the unoperated hemithorax (6th-9th, P < 0.05). The differences in the hemithorax were more significant in the midterm group (5-10 y) than in the other follow-up groups, while most parameters showed no significant differences in the long-term group (10-15 y). No significant differences were found in the modified Haller index.

Multiple costal cartilage harvests caused morphological changes and asymmetry of the thorax in adolescent patients. As indicated by thoracic CT, significant changes occurred in the local area of cartilage defects, which did not affect the overall thorax. In the long term, more than 10 years after harvesting, the differences in the hemithorax between the operated and unoperated sides decreased significantly. This study provides an important reference for thoracic changes when applying auricular reconstruction in the pediatric microtia patients.