Disc measurement, nucleus calibration increase accuracy in lumbar model: Study

Definitions of the relative nucleus position and its cross-sectional area ratio do not conform to a uniform standard in Finite element analysis.

The computational accuracy and efficiency of in-silico study can be improved in the lumbar Finite element analysis model constructed using smoothened surfaces with measured and calibrated relative nucleus position and its cross-sectional area ratio, reports a recent research conducted at the Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital/West China School of Medicine for Sichuan University, China.

The study is published in the Journal of Orthopaedic Surgery and Research.

Jingchi Li and colleagues carried out the study. To increase the accuracy and efficiency of Finite element analysis, nucleus position and cross-sectional area ratio were measured from imaging data.

A Finite element analysis model with smoothened surfaces was constructed using measured values. Nucleus position was calibrated by estimating the differences in the range of motion (RoM) between the Finite element analysis model and that of an in-vitro study.

Then, the differences were re-estimated by comparing the range of motion, the intradiscal pressure, the facet contact force, and the disc compression to validate the measured and calibrated indicators. The computational time in different models was also recorded to evaluate the efficiency.

Computational results indicated that 99% of accuracy was attained when measured and calibrated indicators were set in the Finite element analysis model, with a model validation of greater than 90% attained under almost all of the loading conditions.

Computational time decreased by around 70% in the fitted model with smoothened surfaces compared with that of the reconstructed model.

As a result, it was concluded that the computational accuracy and efficiency of in-silico study can be improved in the lumbar Finite element analysis model constructed using smoothened surfaces with measured and calibrated relative nucleus position and its cross-sectional area ratio.

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Li, J., Xu, C., Zhang, X. et al. Disc measurement and nucleus calibration in a smoothened lumbar model increases the accuracy and efficiency of in-silico study. J Orthop Surg Res 16, 498 (2021). https://doi.org/10.1186/s13018-021-02655-4