Abstract:

Objectives To discuss the application of 3D printing auricular model in auricle reconstruction surgery and its effect on the symmetry and accuracy of the reconstructed auricles，and to provide the basis for evaluation on the clinical application of 3D auricular model. Methods A retrospective analysis was conducted on the clinical data of 76 patients with unilateral microtia treated with auricular reconstruction surgery.The normal auricle was scanned by the pre-operative CT to obtain the DICOM files， which were transformed into the light cured stereolithography （STL） files after mirroring and smoothing treatment. After being input into the 3D printer， the 3D auricular model which was consistent with the shape of normal auricle was printed. All the patients underwent the auricle reconstruction surgery by Nagata method. The first phase of the surgery was performed by using the costal cartilage as the material， the auricle scaffold was reconstructed and fine carved according to the 3D printing auricular model； the second phase of the surgery was enhancing the reconstructed auricle and forming the otocranial sulcus according to the 3D printing auricular model. The postoperative follow-up time was 6－12 months， and the length and width of the reconstructed and normal auricles，the length， width and depth of the conchal cavity， depth of the triangular fossa， and the cranioauricular angle were measured and compared. The satisfaction degrees of the patients with the position， size， cranioauricular angle， symmetry， and stability of the reconstructed auricles were investigated， and the satisfaction rates of the patient were calculated. Results A total of 76 patients received postoperative follow-up and all the reconstructed auricles were survived. The satisfaction rates of the patients and their families for the symmetry of the reconstructed auricle reached 85.5%， and the satisfaction rates for the size， position， and stability were all > 90%， the satisfaction rate for the otocranial angle was 68.4%， and the average satisfaction rate was 87.4%. Compared with healthy side auricle， there were no statistically significant differences in the length and width of the reconstructed auricle， the length and depth of the conchal cavity， and the depth of the triangular fossa （P>0.05）. Compared with healthy side auricle，the otocranial angle of the reconstructed auricle was significantly decreased（P=0.014 1）. The similarity of shape between the reconstructed auricle and the healthy side auricle was high， and the similarity of fine structure of the auricle was also high. Conclusion The 3D printing auricular models based on the 3D printing technology can make the reconstructed auricle to be similar highly with the healthy side auricle， and it is worth to apply in the clinical treatment.

Key words: Three-dimensional printing technology, Auricle reconstruction, Microtia, Auricular scaffold, Auricle reconstruction