Background: Mustardé sutures and conchal setback are widely used for surgical correction of prominent ear, and numerous cartilage-manipulation techniques accompanying these two methods are also available. However, it is unknown how each technique works biomechanically. The effects of otoplasty were evaluated by finite element analysis.
Methods: Data of eight prominent ears were obtained with a noncontact three-dimensional digitizer, and three-dimensional auricular cartilage models were produced. These models were modified to cartilage-manipulation models: scaphal-incision, abrasion, conchal-incision, and conchal-excision models. The loads corresponding to Mustardé sutures were then applied to the no-manipulation, scaphal-incision, and abrasion models. Loads corresponding to conchal setback were applied to the no-manipulation, conchal-incision, and conchal-excision models. Stresses and deformed shapes were evaluated using finite element method.
Results: When Mustardé sutures and conchal setback were compared in the no-manipulation models, maximal stresses occurred around loads in Mustardé sutures and at the root of the helix in conchal setback. The entire ear laid down in conchal setback, whereas in Mustardé sutures, strong bending occurred at the upper third. In Mustardé sutures, maximal stresses decreased to 82 percent with scaphal incision and 95 percent with abrasion. However, the setback effect was also reduced in these two models. In conchal setback, high stresses were markedly decreased with conchal incision or excision. There was no significant difference between incision and excision.
Conclusions: For successful otoplasty, precise understanding of biomechanical reactions is essential. This study provides improved insight into otoplasty for many surgeons.