Surgical simulation of otoplasty by silicon costal cartilage model based upon ultrasonography data

Auricular reconstruction for microtia has been and is still one of the most challenging surgeries in the field of plastic surgery. After establishing a system for producing noninvasively life-size laser lithography models from ultrasonography costal cartilage data in 1995, we started to produce a silicone model of the costal cartilage because its flexibility made realistic surgical simulation possible from 1998. First we made a hollow female mold of the costal cartilage from a pair of separable laser lithography models, clamped the two halves of the mold together and then injected the silicone material into the mold. After the silicone had cured, the mold was separated and the silicone costal cartilage model was removed. From this costal cartilage model we could then decide upon the optimal sites for actual cartilage harvesting. The selected pieces of simulated cartilage were then cut, carved and assembled to form the template for the auricle framework. Following the simulation, the silicone framework was disassembled to make individual pieces which could be used as templates in actual harvesting. We minimized both the time of the operation and the amount of harvested cartilage required. We think that the rehearsal surgery with the silicone cartilage model enables the surgeons to perform this delicate surgery with more confidence than ever and also provides tools for use in the education of residents, patients and family. However this system consists of time and cost-consuming procedures and it cannot be applied to all patients at this moment. Therefore, further effort to design and produce an automatic and less-expensive system is needed.