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Med Eng Phys ; 69: 8-16, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31229384


In this study, a multi-objective topology optimization method has been formulated and carried out for various resection types, with minimization of a weighted sum of the compliance (maximized stiffness) under six routine activities of daily life as the objective function and volume reduction as a constraint. Unique prosthetic geometries with low weight and remarkable strength closely matching the pelvic bone shape were obtained. The strength of the optimized implants was investigated through finite element analysis and it has been found that the initial geometries of the optimized implants could withstand the static loading conditions of various routine activities having less stress concentration areas. A 3D printed patient-specific topology optimized hemi-pelvic prosthesis has been designed based on the proposed method and implanted successfully in a patient with pelvic sarcoma. Therefore, pelvic prostheses can be designed and then manufactured via additive manufacturing technologies with the minimum material in less time and having robust mechanical fixation responses. Conclusively, the topology optimization method used for the design of pelvic prostheses improves the biomechanical performance of the implants with reduced weight and higher stiffness than the traditional implants. Including the topology optimization procedure in the phase of designing patient-specific pelvic implants is therefore, highly recommended.

Análise de Elementos Finitos , Ossos Pélvicos , Desenho de Prótese/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Ossos Pélvicos/cirurgia , Resistência ao Cisalhamento , Estresse Mecânico
Proc Inst Mech Eng H ; 231(6): 525-533, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28639517


The aim of this study was to design a hemi-pelvic prosthesis for a patient affected by pelvic sarcoma. To investigate the biomechanical functionality of the pelvis reconstructed with designed custom-made prosthesis, a patient-specific finite element model of whole pelvis with primary ligaments inclusive was constructed based on the computed tomography images of the patient. Then, a finite element analysis was performed to calculate and compare the stress distribution between the normal and implanted pelvis models when undergoing three different static conditions-both-leg standing, single-leg standing for the healthy and the affected one. No significant differences were observed in the stresses between the normal and reconstructed pelvis for both-leg standing, but 20%-40% larger stresses were predicted for the peak stress of the single-leg standing (affected side). Moreover, two- to threefold of peak stresses were predicted within the prostheses compared to that of the normal pelvis especially for single-leg standing case, however, still below the allowable fatigue limitation. The study on the load transmission functionality of prosthesis indicated that it is crucial to carry out finite element analysis for functional evaluation of the designed customized prostheses before three-dimensional printing manufacturing, allowing better understanding of the possible peak stresses within the bone as well as the implants for safety precaution. The finite element model can be equally applicable to other bone tumor model for biomechanical studying.

Neoplasias Ósseas/terapia , Análise de Elementos Finitos , Ossos Pélvicos , Desenho de Prótese/métodos , Fenômenos Biomecânicos , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/fisiopatologia , Humanos , Ossos Pélvicos/diagnóstico por imagem , Ossos Pélvicos/fisiopatologia , Impressão Tridimensional , Tomografia Computadorizada por Raios X