Clinical Study And Biomechanical Evaluation Of Reduction Malarplasty With The Bracing Structure

Aims:The concept of reduction malarplasty with the bracing structure is first introduced in the study.The study aims to provide the basis of this method in clinical application by the following aspects:1.To introduce the surgery concept of reduction malarplasty with the bracing structure in detail based on computer aided design.2.To compare the morphology changes of the bony structure and soft tissue before and after the reduction malarplasty with the bracing structure,based on the measurements and analysis of the 3D CT images.3.To compare the morphology changes of the bony structure between the reduction malarplasty with the bracing structure and the reduction malarplasty with I-shaped osteotomy preoperatively and postoperatively,based on the measurements and analysis of the 3D CT images.4.To establish the 3D finite element model of the reduction malarplasty with the bracing structure and the reduction malarplasty with I-shaped osteotomy,and to compare and explore the biomechanical characteristics of the surgeries.Methods:1.Selected one CT data of the patient with prominent zygoma,using Proplan CMF 2.0 software to design and introduce the reduction malarplasty with the bracing structure.2.33 patients who underwent the reduction malarplasty with the bracing structure in Cranio-maxillo-facial Surgery Department 2,Plastic Surgery Hospital were involved in this study,their preoperative and postoperative CT data were measured and analyzed to study the change of the bony and soft tissue structure.3.33 patients who underwent the reduction malarplasty with the bracing structure and 26 patients who underwent the reduction malarplasty with I-shaped osteotomy in Cranio-maxillo-facial Surgery Department 2,Plastic Surgery Hospital were involved in this study,their preoperative and postoperative CT data were measured and compared to study the change of the bony structure.4.Based on one CT data of patient with prominent zygoma,established the 3D finite element models of the bracing structure and 26 patients who underwent the reduction malarplasty with I-shaped osteotomy,and compared the biomechanical characteristics of the surgeries.Results:1.Based on the computer-aided design,the surgical method was vividly described.2.Compared with the measurements of preoperative of the reduction malarplasty with the bracing structure,the width of bilateral bony zygomatic body and zygomatic arch were decreased postoperatively.3.Compared with the measurements of preoperative of the reduction malarplasty with the bracing structure,the width of bilateral soft tissue zygomatic body and zygomatic arch were decreased postoperatively.4.When considering the incidence rate of postoperative complication,the reduction malarplasty with the bracing structure was lower than the I-shaped osteotomy.5.The width of the bilateral bony zygomatic arch deceased more in the reduction malarplasty with the bracing structure than the I-shaped osteotomy.6.The 3D finite element models of the reduction malarplasty with the bracing structure and the reduction malarplasty with I-shaped osteotomy were established.7.When applying the same load(5.81N,75.25N and 295.63N)to the models,the maximum displacements in the reduction malarplasty with the bracing structure model were smaller than those in the reduction malarplasty with I-shaped osteotomy.At the same time,the displacements decreased rapidly in the platform area in the reduction malarplasty with the bracing structure model.8.When applying the same load(5.81N,75.25N and 295.63N)to the models,the maximum von Mises stress in the reduction malarplasty with the bracing structure model were smaller than those in the reduction malarplasty with I-shaped osteotomy.Conclusion:1.The surgical method could be vividly described using on the computer aided design.The reduction malarplasty with the bracing structure aimed to correct the prominent zygoma,at the same time reduce the postoperative complications.2.The method of reduction malarplasty with the bracing structure could reduce the zygomatic body and the zygomatic arch effectively.3.Compared with the reduction malarplasty with I-shaped osteotomy,the method of reduction malarplasty with the bracing structure could reduce the zygomatic arch more effectively and had less postoperative complications.4.The FEM of reduction malarplasty with the bracing structure displayed less displacement and smaller stress than the I-shaped reduction malarplasty.The stress concentration was located on the zygomatic arch,the bone callous in the front of zygomatic body and the superior margin of zygomatic body cross the osteotomy line.The concept of the reduction malarplasty with the bracing structure could be more reasonable.