title: Clinical versus pre-clinical FE models for vertebral body strength predictions.
abstract: The finite element analysis is an accepted method to predict vertebral body compressive strength. This study compares measurements obtained from in vitro tests with the ones from two different simulation models: clinical quantitative computer tomography (QCT) based homogenized finite element (hFE) models and pre-clinical high-resolution peripheral QCT-based (HR-pQCT) hFE models. About 37 vertebral body sections were prepared by removing end-plates and posterior elements, scanned with QCT (390/450μm voxel size) as well as HR-pQCT (82μm voxel size), and tested in compression up to failure. Non-linear viscous damage hFE models were created from QCT/HT-pQCT images and compared to experimental results based on stiffness and ultimate load. As expected, the predictability of QCT/HR-pQCT-based hFE models for both apparent stiffness (r(2)=0.685/0.801) and strength (r(2)=0.774/0.924) increased if a better image resolution was used. An analysis of the damage distribution showed similar damage locations for all cases. In conclusion, HR-pQCT-based hFE models increased the predictability considerably and do not need any tuning of input parameters. In contrast, QCT-based hFE models usually need some tuning but are clinically the only possible choice at the moment.
authors: Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Austria. Electronic address: pahr@ilsb.tuwien.ac.at.
authors: Dieter H
authors: DH
authors: Pahr
authors: Institute for Surgical Technology and Biomechanics, University of Bern, Switzerland.
authors: Jakob
authors: J
authors: Schwiedrzik
authors: Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Austria.
authors: Enrico
authors: E
authors: Dall'Ara
authors: Institute for Surgical Technology and Biomechanics, University of Bern, Switzerland.
authors: Philippe K
authors: PK
authors: Zysset
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D019245:Compressive Strength; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D013131:Spine / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
keywords: Finite element modeling; Non-linear analysis; Vertebral body