The Application Of Three-dimensional Earmould In Individual Microtia Reconstruction

BackgroundAuricle is three-dimensional anatomic structure,which is covered by skin on the elastic cartilage and its appendages,auricle reconstruction are considered very difficult.Microtia yield a rate of 3.06 per 10,000 births during 1996-2007,Isolated microtia had a prevalence of 2.25 per 10,000 births,whereas among nonisolated cases,the prevalence was 0.81 per 10,000 births.Auricle reconstruction in microtia patient,including precise positioning and detailed carvings,such as the maintenance of cranioauricular angle,has always been the difficulty in plastic surgery.The visual inspection method,su shi positioning method or manufacturing template is currently main positioning method to accurate locate and curve anatomical structure of auricle scaffold,3-d printing technology and taking the impression with silicone has been applied in the external auditory canal plasty in recent years to fill the auditory canal,few application in auricle reconstruction for microtia patient.This study aims to according to the appearance of the healthy auricle to individual reconstruction for microtia patient,3-d image processing technology,the technology of fused deposition technology and taking the impression with silicone is used to manufacture the auricle to precise positioning and detailed carvings for macrotia patients to meet the requirement of individual auricle reconstruction.ObjectiveTo assist individualized auricle reconstruction in unilateral microtia patient,three-dimensional(3-D)image processing software and the technology of fused deposition molding(FDM)and taking the impression with silicone was used for casting 3-D silicone earmould.MethodsHigh resolution computed tomography(HRCT)images of the temporal bone in unilateral microtia patient were scanned.Auricle and its surrounding structure of auricle on the healthy side was mirrored and reconstructed by using mimics software,3-D earmould was designed by using 3-matic software and then silicone mirrored ear auricle model and 3-D silicone earmould was manufactured by FDM technology and silicone impression,the former is used as reconstructed auricular templates,the latter is used as guide plate respectively on the affected side to increase the precision in fabrication of cymba conchae,the cavum conchae,triangular fossa,the helix,antihelix and other anatomical substructure of auricle and maintainanceof cranioauricular angle.We made a comparison about the appearance between reconstructed ear and normal ear in size and shape and substructure of auricle.ResultsThe appearance of reconstructed auricle with the application of 3-D earmould has no difference with the normal auricle.Cranioauricular angle is symmetrical,and anatomical substructure of auricle is clear.ConclusionIndividual design of 3-D silicone earmould can microtia reconstruction,and it makes the anatomical structure of the sculpture more realistic in microtia reconstruction.InnovationFirstly,matching and 3-D silicone earmould and anatomical structure of the mirrored ear with silicone material repeatedly improve to have an intuitive feelings of anatomical structure of the auricular surface in preoperative analysis,which plays a direct role in guiding the surgical process.Then,silicone mirrored ear auricle model and 3-D silicone earmould was manufactured,the former was used as reconstructed auricular templates,the latter was used as guide plate respectively.We matched and marked and the surface of carved rib cartilage scaffold intraoperative by 3-D silicone earmould,as guide plate or template to assist to carve the rib cartilage scaffold.We adjusted cranioauricular angle with the 3D earmould,which can improve the accuracy of positioning rib cartilage scaffold and avoid secondary surgerye in traditional surgery because of asymmetry of cranioauricular angle.Lastly,3-d silicone earmould are soft in texture,which can fix and oppress auricle and make rib cartilage in accordance with structure stress status.3-d silicone earmould make the rib cartilage keep the recovery of high precision,Cranioauricular angle is symmetrical and accurate.Anatomical substructures of auricle is clear,lifelike and high aesthetic feeling.