FEM-Based Compression Fracture Risk Assessment in Osteoporotic Lumbar Vertebra L1

Algirdas Maknickas,Marija Tamulaitienė,Rimantas Kačianauskas,Oleg Ardatov,Vidmantas Alekna,Olga Chabarova,Darius Zabulionis

doi:10.3390/app9153013

Algirdas Maknickas, Marija Tamulaitienė + Show 5 more

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https://doi.org/10.3390/app9153013

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Abstract

This paper presents a finite element method (FEM)-based fracture risk assessment in patient-specific osteoporotic lumbar vertebra L1. The influence of osteoporosis is defined by variation of parameters such as thickness of the cortical shell, the bone volume–total volume ratio (BV/TV), and the trabecular bone score (TBS). The mechanical behaviour of bone is defined using the Ramberg–Osgood material model. This study involves the static and nonlinear dynamic calculations of von Mises stresses and follows statistical processing of the obtained results in order to develop the patient-specific vertebra reliability. In addition, different scenarios of parameters show that the reliability of the proposed model of human vertebra highly decreases with low levels of BV/TV and is critical due to the thinner cortical bone, suggesting high trauma risk by reason of osteoporosis.

Highlights

Spinal bones can be affected by several diseases, but spinal brittleness is mainly caused by osteoporosis
Important parameters that impact the state of lumbar body, such as the thickness of the cortical shell and the bone volume–total volume ratio (BV/TV) relation, were combined between themselves and investigated due to various values of external load
The results show that maximal calculated stress reaches 38% of yield stress due to a 0.75 MPa load on the model with the lowest BV/TV ratio (0.1)

Summary

Introduction

Spinal bones can be affected by several diseases, but spinal brittleness is mainly caused by osteoporosis. Due to the importance of studying this disease and its consequences, various social and medical aspects of osteoporosis have been investigated all over the world [1,2,3,4]. The paper emphasized numerical modeling as the main directions for future research. The adequacy of the modeling of finite elements strongly depends on the selection of the mechanical properties, the geometrical form of the numerical model, and mesh making possibilities. Some developments are restrained to small fragments of the vertebra [6,7], but most studies concerning the vertebral body in isolation [8,9,10,11] use a simplified form, excluding the posterior elements [12,13]

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