数字化辅助定位及支架设计在颅面不对称患者耳廓再造中的应用

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

目的结合数字化技术，针对颅面不对称小耳畸形患者，探寻一种较为客观、精确的再造耳定位方法及特型支架设计方法，提升耳廓再造术后双侧对称效果。方法2014年9月至2016年2月收治合并颅面畸形的50例单侧小耳畸形患者，术前进行三维摄影扫描并生成数字化模型，在数字化模型上根据健侧耳廓位置行再造耳镜影定位，并根据定位获取自体肋软骨支架的形态参数及矫正参数。以上述定位信息及参数为指导行皮肤软组织扩张法耳廓再造术。结果数字模型可反映耳廓及颅面的形态学特点，并获得再造耳定位及参数信息；50例合并颅面不对称小耳畸形患者三期术后再造耳形态满意，再造耳与健侧耳廓对称度良好。三期术后随访1～12个月，平均6．8个月，术者及患方术后评价满意，对称度良好。结论以三维摄影扫描建立数字化模型，并获取再造耳定位信息及形态学和矫正参数，指导合并颅面不对称患者的耳廓再造，可以提高术后耳廓的对称度。

ObjectiveTo 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. MethodsFrom 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. ResultsAuricular 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. ConclusionsUtilizing 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.