###### Abstract  
Finite element (FE) analyses contribute to a better understanding of the human lumbar spine's biomechanics and serve as an effective predictive tool. This study aims to present the development of two L1-L5 FE models using literature-based (LBM) and patient-specific (PSM) bone material assignment approaches. The geometry of the lumbar spine was developed based on quantitative computed tomography scans. The LBM and the PSM were compared under pure and combined loads. Various biomechanical parameters were investigated to validate the models. The total range of motion of the LBM in pure flexion-extension, lateral bending, and axial rotation were 30.5\({}^{\circ}\), 29\({}^{\circ}\), and 13.7\({}^{\circ}\), respectively, while for the PSM, it was 31.6\({}^{\circ}\), 28.6\({}^{\circ}\), and 14.1\({}^{\circ}\). The required computational time of the PSM to complete against pure and combined loads were 12.1 and 16.6 times higher on average compared to the LBM. This study demonstrated that both models agree with experimental and in silico results, although the cumulative distribution of the stress and characterization of strain values showed a noteworthy difference between the two models. Based on these findings, the clinically-focused biomechanical FE studies must perceive the differences in internal mechanical parameters and computational demand between the different bone modelling approaches. validation; finite element model; lumbar spine; material assignment technique; patient-specific; medical imaging; 3D modelling +
Footnote †: journal: Applied Sciences  
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Footnote †: journal: Applied Sciences  
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Footnote 1: _Applied Sciences_  
while the material properties are literature-based [13; 14; 15]. This approach is frequently employed in various in silico studies, for instance, to determine stress and strain patterns in anatomical components [13], to investigate degenerative lesions [14], to evaluate the effect of surgical procedures [15], or to analyse spinal implants [16]. [PERSON] created an L1-L5 lumbar spine FE model using a 65-year-old male cadaver's computed tomography (CT) images with material properties taken from the literature to investigate the stress response in soft tissues under various load cases [13]. [PERSON] et al. developed an L1-S1 lumbosacral spine FE model utilising the CT scans of a 26-year-old male with literature-based material properties to investigate the biomechanics of disc degeneration [14]. [PERSON] et al. created an L1-L5 lumbar spine FE model using the CT scans of a 46-year-old male cadaver, adapting the material properties from the literature to investigate the biomechanical consequences of total disc arthroplasty [15]. Another possible modelling technique is the \"fully patient-specific\" approach. In this case, both the geometry and bone material properties are defined based on the medical images. Such models can be used to investigate the load-fracture mechanism of bony structures, either with single vertebra models [11; 17; 18] or motion segments [19; 12]. [PERSON] et al. created a voxel-based vertebral body FE model to investigate vertebral compressive strength with CT-derived bone material properties and geometry [18]. [PERSON] et al. assessed the biomechanical characteristic of vertebrae with lytic lesions using a subject-specific FE model [11]. [PERSON] et al. developed an FE model of the L4-L5 lumbar motion segment using patient-specific bone material properties to analyse its kinematics by measuring the range of motion (ROM) and comparing it with experimental results [12]. The effects of medical imaging-based bone material properties were evaluated in the literature by comparing their results with simulations employing literature-based material properties. [PERSON] and [PERSON] compared geometrically parametric models with \"fully patient-specific\" models to analyse the strain and displacement patterns in healthy and metastatically involved vertebrae in a T6-T8 spinal motion segment.