Toward Patient Specific Models of Pediatric IVDs: A Parametric Study of IVD Mechanical Properties.

Peter Pivonka,Edmund Pickering,J. Paige Little

doi:10.3389/fbioe.2021.632408

Peter Pivonka, Edmund Pickering + Show 1 more

Open Access

https://doi.org/10.3389/fbioe.2021.632408

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Abstract

Patient specific finite element (FE) modeling of the pediatric spine is an important challenge which offers to revolutionize the treatment of pediatric spinal pathologies, for example adolescent idiopathic scoliosis (AIS). In particular, modeling of the intervertebral disc (IVD) is a unique challenge due to its structural and mechanical complexity. This is compounded by limited ability to non-invasively interrogate key mechanical parameters of a patient's IVD. In this work, we seek to better understand the link between mechanical properties and mechanical behavior of patient specific FE models of the pediatric lumbar spine. A parametric study of IVD parameter was conducted, coupled with insights from current knowledge of the pediatric IVD. In particular, the combined effects of parameters was investigated. Recommendations are made toward areas of importance in patient specific FE modeling of the pediatric IVD. In particular, collagen fiber bundles of the IVD are found to dominate IVD mechanical behavior and are thus recommended as an area of primary focus for patient specific FE models. In addition, areas requiring further experimental research are identified. This work provides a valuable building block toward the development of patient specific models of the pediatric spine.

Highlights

Development of patient specific spine models is of increased interest in the treatment of pediatric spinal pathologies
It becomes important to understand how the material parameters and related mechanics of the pediatric intervertebral disc (IVD) differs from those of adults. We address this challenge by first understanding how pediatric IVD material parameters differ from adults, followed by exploring how this affects the overall IVD mechanics
To determine those parameters which have a significant effect on IVD stiffness, a threshold of ±10% was set

Summary

Introduction

Development of patient specific spine models is of increased interest in the treatment of pediatric spinal pathologies. Such models aim to revolutionize clinical practice by providing practitioners with detailed predictions of a patient’s spinal biomechanics. Such models are already showing promise in predicting outcomes of corrective interventions for AIS (Little and Adam, 2011; Vergari et al, 2015; Aubin et al, 2018). Patient specific material parameters cannot be directly interrogated and are a greater challenge As a substitute, these are commonly extracted from experimental biomechanics studies. Most FE models of the pediatric IVD use material parameters extracted from studies on adult IVDs (for example Sairyo et al, 2006; Little et al, 2008; Cahill et al, 2012; Dong et al, 2013)

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