The Regenerated Tissue at the Donor Site After Costal Cartilage Harvest for Auricular Reconstruction.

To observe and summarize the nature of the regenerative tissue at the donor site after harvesting costal cartilage for auricular reconstruction and to explore the contribution of the perichondrium to the regeneration of costal cartilage in the clinic. From January 2016 to June 2017, 23 patients with microtia who were performed chest computed tomography (CT) after costal cartilage harvest for ear reconstruction were reviewed. And they had the surgery for at least 6 months. Of 23 patients, 17 patients were males and 6 were females; these patients were aged 7 to 43 years (mean age, 15.2 years). The authors divided the patients into 2 groups according to whether the perichondrium was retained or not. Group 1 was patients with intact perichondrium, total 20. Group 2 was patients with damaged perichondrium, total 3. Every patients' regenerative tissue CT value at the donor-site region of costal cartilage was measured and recorded. In addition, 2 regenerated tissue samples for examined histologic evaluation by hematoxylin and eosin stain were collected. Of 23 patients, regenerated tissue with high CT value (above 100 Hounsfield unit [Hu]) was observed in 19 (82.61%) patients from group 1. And the direction of the regenerated tissue is roughly similar to that of the resected cartilage in the early surgery. Of 4 patients (1 from group and 3 from group 2), nothing on the donor site was found. From histologic evaluation, fibrocalcific tissue was seen, and cartilage cells were not seen in 2 patients with high CT value. Clinical observation presented that regenerative tissue at the donor site after harvesting costal cartilage, leaving the subjacent perichondrium completely intact, was mostly fibrocalcific tissue rather than cartilage tissue. The authors suspect that the perichondrium itself may not have regenerative power, but as an envelope for regeneration, perichondrium has a role.