A forward dynamics simulation of human lumbar spine flexion predicting the load sharing of intervertebral discs, ligaments, and muscles

Abstract

Determining the internal dynamics of the human spine's biological structure is one essential step that allows enhanced understanding of spinal degeneration processes. The unavailability of internal load figures in other methods highlights the importance of the forward dynamics approach as the most powerful approach to examine the internal degeneration of spinal structures. Consequently, a forward dynamics full-body model of the human body with a detailed lumbar spine is introduced. The aim was to determine the internal dynamics and the contribution of different spinal structures to loading. The multi-body model consists of the lower extremities, two feet, shanks and thighs, the pelvis, five lumbar vertebrae, and a lumped upper body including the head and both arms. All segments are modelled as rigid bodies. 202 muscles (legs, back, abdomen) are included as Hill-type elements. 58 nonlinear force elements are included to represent all spinal ligaments. The lumbar intervertebral discs were modelled nonlinearly. As results, internal kinematics, muscle forces, and internal loads for each biological structure are presented. A comparison between the nonlinear (new, enhanced modelling approach) and linear (standard modelling approach, bushing) modelling approaches of the intervertebral disc is presented. The model is available to all researchers as ready-to-use C/C++ code within our in-house multi-body simulation code demoa with all relevant binaries included.

Force reduction induced by unidirectional transversal muscle loading is independent of local pressure

“…Considering that most muscles are packed within other muscles, one can speculate that muscle architecture minimizes mutual transversal loading within muscle groups or leads to homogenous transversal pressure in all directions for inner muscles. Therefore, it seems important to examine the intermuscular pressure in muscle groups and threedimensional muscle deformations during contraction (Böl et al, 2015Röhrle et al, 2012;Rupp et al, 2015) in more detail. With such studies, questions related to evolution of sometimescomplex muscle architecture (e.g., distributions of varying fiber lengths and pennation angles or inner tendon sheets (Gorb and Fischer, 2000;Hiepe et al, 2014;Schenk et al, 2013;Siebert et al, 2015;Stark and Schilling, 2010)) could be addressed.…”

Simulation of lumbar and neck angle flexion while ingress of paratransit (angkot) in Indonesia as a preliminary design study

“…The spinal condition has been reported to interact with both upper and lower limb muscle with regard to fatigue [40]. Gait characteristics also affect lumbar muscular load [41], [42].…”

Human body modeling method to simulate the biodynamic characteristics of spine in vivo with different sitting postures

“…This indicated that the muscle was an important factor for the frequency characteristics of the human spine in vivo. In fact, in addition to lumbar vertebrae, LID, and ligament, the muscle between the vertebrae also bears the load acted on the upper body . Especially, in the case of high vibration amplitude, the muscle counter reaction activity is very important .…”

“…Many investigations used FE models, lumped parameters or multibody models, and artificial neural network models to study biodynamic characteristics of the human spine. Kitazaki and Griffin proposed a FE model of the entire human spine to perform a modal analysis.…”