title: Relationship between sample volumes and modulus of human vertebral trabecular bone in micro-finite element analysis.
abstract: Micro-finite element (μFE) models have been widely used to assess the biomechanical properties of trabecular bone. How to choose a proper sample volume of trabecular bone, which could predict the real bone biomechanical properties and reduce the calculation time, was an interesting problem. Therefore, the purpose of this study was to investigate the relationship between different sample volumes and apparent elastic modulus (E) calculated from μFE model. 5 Human lumbar vertebral bodies (L1-L5) were scanned by micro-CT. Cubic concentric samples of different lengths were constructed as the experimental groups and the largest possible volumes of interest (VOI) were constructed as the control group. A direct voxel-to-element approach was used to generate μFE models and steel layers were added to the superior and inferior surface to mimic axial compression tests. A 1% axial strain was prescribed to the top surface of the model to obtain the E values. ANOVA tests were performed to compare the E values from the different VOIs against that of the control group. Nonlinear function curve fitting was performed to study the relationship between volumes and E values. The larger cubic VOI included more nodes and elements, and more CPU times were needed for calculations. E values showed a descending tendency as the length of cubic VOI decreased. When the volume of VOI was smaller than (7.34mm(3)), E values were significantly different from the control group. The fit function showed that E values approached an asymptotic values with increasing length of VOI. Our study demonstrated that apparent elastic modulus calculated from μFE models were affected by the sample volumes. There was a descending tendency of E values as the length of cubic VOI decreased. Sample volume which was not smaller than (7.34mm(3)) was efficient enough and timesaving for the calculation of E.
authors.affiliation: Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China.
authors.forename: Xin-Xin
authors.initials: XX
authors.lastname: Wen
authors.affiliation: Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors.forename: Chun-Lin
authors.initials: CL
authors.lastname: Zong
authors.affiliation: Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China.
authors.forename: Ya-Fei
authors.initials: YF
authors.lastname: Feng
authors.affiliation: Department of Orthopedics, 463 Hospital of PLA, Shenyang, China.
authors.forename: Xiang-Yu
authors.initials: XY
authors.lastname: Ma
authors.affiliation: Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China.
authors.forename: Fa-Qi
authors.initials: FQ
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China. Electronic address: giamyimpoh@hotmail.com.
authors.forename: Ya-Bo
authors.initials: YB
authors.lastname: Yan
authors.affiliation: Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China. Electronic address: leiwei@fmmu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Lei
mesh_terms: D000071556:Cancellous Bone / Q000502:physiology*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology*; D055114:X-Ray Microtomography
keywords: Apparent elastic modulus; Human; Micro-finite element analysis; Trabecular bone; Volumes of interest