Application of digital technology aided in auricle location and personalized framework design in ear reconstruction for microtia patients with craniomaxillofacial asymmetry

Objective To seek an accurate and objective method to locate reconstructed auricles and design frameworks with digital technology for microtia patients with craniomaxillofacial asymmetry, improving the symmetry of the postoperative ears. Methods From September 2014 to February 2016, 50 unilateral microtia patients with craniomaxillofacial asymmetry who were scheduled for auricular reconstruction were included in the study. The digital models of the patients′ ears and heads were based on the scan data preoperatively, which were collected by the three dimensional(3D) photogrammetric scanning technique. The reconstructed auricle was positioned by the mirror image of the contralateral side on the digital models. Based on the location, the morphological parameters and the corrective parameters of the autogenous cartilage frameworks could be obtained. With the guidance of the above information, ear reconstruction with tissue expander could be carried out. Results Auricular and craniofacial morphology could be reflected vividly by the digital models. Meanwhile, the location and parameters of the reconstructed ear could be acquired. And the outcomes of the 50 reconstructed ears were satisfactory with symmetrical appearance. With 1 to 8 months (average 6.8 months) of follow-up, both the doctors and the patients were satisfied with the postoperative result. Conclusions Utilizing the location and parameters which were obtained from the digital models based on 3D photogrammetric scanning is an accurate and objective way to gain more symmetrical result in clinical ear reconstruction for microtia patients with craniomaxillofacial asymmetry. Key words: Digitization technology; Reconstruction of auricle; Microtia; Craniomaxillofacial asymmetry