A finite element analysis of the pelvic reconstruction using fibular transplantation fixed with four different rod-screw systems after type I resection  

作　　者：Jim Yong-wei CHENG Li-ming YU Guang-rong DU Cheng-fei YANG Zhi-yong YU Yan DING Zu-quan 

机构地区：[1]Orthopedic Department, Tongji Hospital, Tongji University, Shanghai 200065, China [2]School of Life Science and Technology, Tongji University, Shanghai 200092, China

出　　处：《Chinese Medical Journal》2008年第4期321-326,共6页中华医学杂志（英文版）

基　　金：This study was supported by grants from National Natural Science Foundation of China （No. 30571895）, Program for New Century Excellent Talents in University （No. NCET-06-0375）, and Shanghai Foundation for the Development of Science and Technology （No. 044119739）.

摘　　要：Background The pelvis often needs to be reconstructed after bone tumor resection. A major challenge here for the orthopedic surgeons is to choose a method that gives the best performance which depends upon its biomechanical properties. In this study, a 3-dimensional finite element analysis （FEA） was used to analyze the biomechanical properties of reconstructed pelvis using fibula transplant fixed by four commonly used rod-screw systems. Methods A total pelvic finite-element model including the lumbar-sacral spine and proximal femur was constructed based on the geometry of CT image from a healthy volunteer. Three-dimensional finite element models of different implants including fibula, rod and screw were simulated using ways of solid modeling. Then various reconstructed finite element models were assembled with different finite element implant model and type Ⅰ resected pelvic finite element model. The load of 500 N was imposed vertically onto the superior surface of L3 vertebral body, and the pelvis was fixed in bilateral leg standing positions. FEA was performed to account for the stress distribution on the bones and implants. The pelvis displacement of the different rod-screw fixation methods and the maximum equivalent stress （max EQV） on all nodes and element were figured out to evaluate the advantages and disadvantages of different reconstructive methods.Results Stress concentration in the fibula transplant was extremely high in the reconstructed pelvis, but could be substantially decreased by internal fixation, which partially transferred the stress from the fibula to the rod-screw systems. High stress concentration was also found in the implants, especially in the connection sites between screw arid rod. Among the four methods of fixation, a double rod system with L5-S1 pedicle and ilium screws （L5-S1 HR） produced the best performance： least stress concentrations and least total displacement.Conclusion According to the stability and stress concentration, the method of L5-S1 HR fixation combinBackground The pelvis often needs to be reconstructed after bone tumor resection. A major challenge here for the orthopedic surgeons is to choose a method that gives the best performance which depends upon its biomechanical properties. In this study, a 3-dimensional finite element analysis （FEA） was used to analyze the biomechanical properties of reconstructed pelvis using fibula transplant fixed by four commonly used rod-screw systems. Methods A total pelvic finite-element model including the lumbar-sacral spine and proximal femur was constructed based on the geometry of CT image from a healthy volunteer. Three-dimensional finite element models of different implants including fibula, rod and screw were simulated using ways of solid modeling. Then various reconstructed finite element models were assembled with different finite element implant model and type Ⅰ resected pelvic finite element model. The load of 500 N was imposed vertically onto the superior surface of L3 vertebral body, and the pelvis was fixed in bilateral leg standing positions. FEA was performed to account for the stress distribution on the bones and implants. The pelvis displacement of the different rod-screw fixation methods and the maximum equivalent stress （max EQV） on all nodes and element were figured out to evaluate the advantages and disadvantages of different reconstructive methods.Results Stress concentration in the fibula transplant was extremely high in the reconstructed pelvis, but could be substantially decreased by internal fixation, which partially transferred the stress from the fibula to the rod-screw systems. High stress concentration was also found in the implants, especially in the connection sites between screw arid rod. Among the four methods of fixation, a double rod system with L5-S1 pedicle and ilium screws （L5-S1 HR） produced the best performance： least stress concentrations and least total displacement.Conclusion According to the stability and stress concentration, the method of L5-S1 HR fixation combin

关 键 词：PELVIS bone tumor RECONSTRUCTION fibular transplantation finite element analysis 

分 类 号：R658[医药卫生—外科学]