Generating ears from cultured autologous auricular chondrocytes by using two-stage implantation in treatment of microtia.

BACKGROUND: Microtia is a congenital ear hypoplasia associated with auricular defects. Conventional treatment involves implanted costal cartilage. The impact of surgical invasion and donor-site morbidity can be particularly severe in pediatric patients, and the collectable volume of autologous cartilage is limited. The authors therefore developed a new technique for microtia and applied it to treat four patients.
METHODS: Through the development of a multilayer chondrocyte culture system and two-stage implantation technique, the authors successfully generated human ears. In culture, the chondrocytes are expanded to a sufficiently large volume, produce rich chondroid matrix, and form immature cartilaginous tissues. In the authors' two-stage implantation, the cultured chondrocytes are injection-implanted into the lower abdomen of the patient, where the cells grow into a large, newly generated cartilage with neoperichondrium in 6 months. This cartilage is harvested surgically, sculptured into an ear framework, and implanted subcutaneously into the position of the new ear.
RESULTS: The cultured chondrocytes formed a mature cartilage block with sufficient elasticity for use as an auricular cartilage. The formed block had the same histologic origin as elastic cartilage. The ear framework produced from this block was implanted into the auricular defect area, and an auricle with a smooth curvature and shape was subsequently configured. In the 2 to 5 years of postoperative monitoring, the neocartilage maintained good shape, without absorption.
CONCLUSIONS: The authors' four patients are the first successful cases of regenerative surgery for microtia using cultured ear chondrocytes. The benefits of the technique include minimal surgical invasion, lower donor-site morbidity, lessened chance of immunologic rejection, and implantation stability.