Automated finite element meshing of the lumbar spine: Verification and validation with 18 specimen-specific models

Abstract

The purpose of this study was to seek broad verification and validation of human lumbar spine finite element models created using a previously published automated algorithm. The automated algorithm takes segmented CT scans of lumbar vertebrae, automatically identifies important landmarks and contact surfaces, and creates a finite element model. Mesh convergence was evaluated by examining changes in key output variables in response to mesh density. Semi-direct validation was performed by comparing experimental results for a single specimen to the automated finite element model results for that specimen with calibrated material properties from a prior study. Indirect validation was based on a comparison of results from automated finite element models of 18 individual specimens, all using one set of generalized material properties, to a range of data from the literature. A total of 216 simulations were run and compared to 186 experimental data ranges in all six primary bending modes up to 7.8Nm with follower loads up to 1000N. Mesh convergence results showed less than a 5% difference in key variables when the original mesh density was doubled. The semi-direct validation results showed that the automated method produced results comparable to manual finite element modeling methods. The indirect validation results showed a wide range of outcomes due to variations in the geometry alone. The studies showed that the automated models can be used to reliably evaluate lumbar spine biomechanics, specifically within our intended context of use: in pure bending modes, under relatively low non-injurious simulated in vivo loads, to predict torque rotation response, disc pressures, and facet forces.

The Finite Element Model of Seated Whole Human Body for Vibration Investigations of Lumbar Spine in Complex System

“…With the development of computer technology and finite element (FE) technology, more and more researches on the human spine biomechanics using FE method are now available. FE study of human spine biomechanics is developing towards the automation of the modeling process [8,9], the optimization of simulation methods [10], the diversification of clinical evaluation [11,12], and the clinicalization of artificial lumbar discs [13]. The application of FE method to study human biomechanics has great advantages.…”

Is there any advantage of using stand-alone cages? A numerical approach

“…The intact model was validated comparing the ROM of each segment with experimental and computational results from the literature [37, 56–58] as shown in Additional file 1. Two different validations were made.…”

“…Furthermore, an additional validation with different moment value was also performed. The more recent study of Campbell et al [58] was used, and here the total rotation of the lumbar spine (L1–L5 rotation) was evaluated. In this case, the results for extension, lateral bending and axial rotation perfectly fitted within Campbell et al results.…”

Vibration Response Analysis of the Lumbar Spine based on High-speed Train Crew

“…Just like the method Chenggang Shen [9] used in, combing with modern CT and reverse engineering, to build and analyze the finite element model of lumbar segments. The main special points of the lumbar spine are extracted and a three-dimensional finite element model of human lumbar vertebral L1~L5 is established [10]. The finite element model of the whole lumbar spine mainly includes vertebral cortical bone, cancellous bone, posterior structure, end plate cartilage, articular cartilage, fibrous ring matrix, ring fiber, intervertebral disc nucleus pulposus and various kinds of ligaments, as shown in Fig.1.…”