Sensitivity of muscle and intervertebral disc force computations to variations in muscle attachment sites

Abstract

The current paper aims at assessing the sensitivity of muscle and intervertebral disc force computations against potential errors in modeling muscle attachment sites. We perturbed each attachment location in a complete and coherent musculoskeletal model of the human spine and quantified the changes in muscle and disc forces during standing upright, flexion, lateral bending, and axial rotation of the trunk. Although the majority of the muscles caused minor changes (less than 5%) in the disc forces, certain muscle groups, for example, quadratus lumborum, altered the shear and compressive forces as high as 353% and 17%, respectively. Furthermore, percent changes were higher in the shear forces than in the compressive forces. Our analyses identified certain muscles in the rib cage (intercostales interni and intercostales externi) and lumbar spine (quadratus lumborum and longissimus thoracis) as being more influential for computing muscle and disc forces. Furthermore, the disc forces at the L4/L5 joint were the most sensitive against muscle attachment sites, followed by T6/T7 and T12/L1 joints. Presented findings suggest that modeling muscle attachment sites based on solely anatomical illustrations might lead to erroneous evaluation of internal forces and promote using anatomical datasets where these locations were accurately measured. When developing a personalized model of the spine, certain care should also be paid especially for the muscles indicated in this work.

Biomechanics of the tether breakage: tensile behaviour of a single-unit vertebral body tethering construct

“…The slippage force values reported in our work were significantly close to the reported physiological loads in the literature, which could explain the tether breakage in vivo. In a recent study, intervertebral disc reaction forces during a 30-degree lateral bending were reported as 453 N, 460 N, and 652 N on the T6/T7, T12/L1, and L4/L5, respectively [ 19 ]. In another study, disc compressive forces during a 30-degree lateral bending on T11/T12 and L4/L5 were reported as 100% and 130% of the body weight, respectively, which corresponds to approximately 320–750 N for a 10–20-year-old adolescent (average 32–58 kg weight) [ 33 ].…”

“…[ 15 , 17 , 18 ]. However, recent biomechanical studies investigating the loads on the spine show that the highest physiological loads reach only up to approximately 650 N on the L4/L5 level, which corresponds to only 52 MPa (assuming the loads are coinciding with the tether’s axis) [ 19 ]. Furthermore, recent studies have shown that a correction force of 150–200 N is sufficient to modify the asymmetrical compression in AIS patients [ 20 ].…”

Muscle-driven forward dynamic active hybrid model of the lumbosacral spine: combined FEM and multibody simulation

“…Reported values for K vary between 10 and 100 N/cm 2 ( Daggfeldt and Thorstensson, 2003 ; Hansen et al, 2006 ). In models of the lower back, most commonly values of 46 ( Bogduk et al, 1992 ; Stokes and Gardner-Morse, 1995 ; Christophy et al, 2012 ), 60 ( Arjmand and Shirazi-Adl, 2006a ), 90 ( Arshad et al, 2016 ), or 100 N/cm 2 ( Bruno et al, 2015 ; Bayoglu et al, 2019 ; Favier et al, 2021a ; Lerchl et al, 2022 ; Malakoutian et al, 2022 ) were assumed. Thus, we tested values of 46, 73, and 100 N/cm 2 for K , expected ≤ 1.0°, and that no muscle was fully activated by the TC.…”

“…Most validated and extensively used biomechanical spine models belong to either the musculoskeletal multibody (MB) ( de Zee et al, 2007 ; Christophy et al, 2012 ; Bruno et al, 2015 ; Senteler et al, 2016 ; Malakoutian et al, 2018 ; Bayoglu et al, 2019 ; Lerchl et al, 2022 ; Meszaros-Beller et al, 2023 ) or implicit finite element (FE) method ( Schmidt et al, 2006 ; Ayturk and Puttlitz, 2011 ; Dreischarf et al, 2014 ; Naserkhaki et al, 2018 ; Turbucz et al, 2022 ). Musculoskeletal MB models are used to analyze mechanisms consisting of rigid bodies subject to mechanically simplifying joints and constraints.…”

“…Studies thus examined interindividual muscle activation patterns, joint reaction forces, or vertebral movements in varying postures during different activities. Resulting muscle redundancy problems are commonly solved inverse dynamically ( de Zee et al, 2007 ; Erdemir et al, 2007 ; Bayoglu et al, 2019 ). New approaches omit the specification of accurate kinematic data for the spine by forward dynamics simulation of a fully articulated spine ( Rupp et al, 2015 ; Malakoutian et al, 2018 ; Meszaros-Beller et al, 2023 ) and including stiffening effects caused by compressive loads ( Wang et al, 2020 ).…”