Finite element models of the thigh-buttock complex for assessing static sitting discomfort and pressure sore risk: a literature review

Abstract

Being seated for long periods, while part of many leisure or occupational activities, can lead to discomfort, pain and sometimes health issues. The impact of prolonged sitting on the body has been widely studied in the literature, with a large number of human-body finite element models developed to simulate sitting and assess seat-induced discomfort or to investigate the biomechanical factors involved. Here, we review the finite element models developed to investigate sitting discomfort or risk of pressure sores. Our study examines finite element models from twenty-seven papers, seventeen dedicated to assessing seating discomfort and ten dedicated to investigating pressure ulcers caused by prolonged sitting. The models' mesh composition and material properties are found to differ widely. These models share a lack of validation and generally make little allowance for anthropometric diversity.

Our contemporary understanding of the aetiology of pressure ulcers/pressure injuries

“…These imaging modalities can be used in combination with subject‐specific theoretical computational models such as finite element (FE) models; FE modelling is a method of solving (bio)mechanical problems by means of a capable computer workstation and dedicated software, to estimate deformations, strains, and stresses throughout cell and tissue structures, and thereby predict the risk of cell and tissue damage. However, even the best and most accurate FE models are theoretical assumptions 25 and clinical reality is infinitely complex, PUs/PIs develop as a result of the internal tissue response to the mechanical loading state in the individual. Understanding the aetiology of PUs/PIs therefore relies on knowledge concerning the internal cell and tissue responses to mechanical loads (including the responses of vascular and lymphatic structures) and not on just what is apparent on the outside of the body or at the skin surface 26‐28 …”

Effects of seat parameters and sitters’ anthropometric dimensions on seat profile and optimal compressed seat pan surface

“…The data of external contact forces could be useful when computational human models are used to estimate the difficult-to-measure internal loads, such as inter-disc pressure, muscle forces, or soft tissue deformation. From a recent review of finite element (FE) models for assessing sitting discomfort, Savonnet et al (2018) concluded that existing models suffer from lack of validation and inability to define appropriate boundary conditions. Partial models only covering the buttocks and thighs require boundary conditions that cannot be adequately defined without knowing the full range of contact forces.…”

Novel hyperelastic models for large volumetric deformations

“…Accurate modelling of the volumetric behaviour of materials like soft foams and lattices is of interest since it is relevant to the design of support structures (see review [11]), such as foam cushions and seats [12,13,14,15], helmets [16], and shoes and insoles ( [17,18,19]). Furthermore compliant lattices and foams are also employed in the design of soft robotics [20,21,22,23].…”