Comparative characteristics of the efficiency of using various accesses to the lumbar spinal segment LV-SI in a recurrent degenerative process

Object The center (axis) of rotation (COR) in the lumbar spine has been studied well. However, there is limited information on the kinetic and kinematic consequences of imposed shift in the location of the COR, although this type of shift can be seen after surgeries using motion preservation or dynamic stabilization devices. The objective of this study was to assess the kinetic and kinematic changes in the lumbar spinal segment due to various imposed CORs. Methods A 3D finite element model of the L4–5 segment was constructed and validated. The segment was loaded under a 7.5-Nm bending moment while constrained to rotate about various imposed CORs in the sagittal and axial motion planes. Range of motion, ligament forces, facet loads, and disc stresses were measured. Results The present model showed an agreement with previous in vitro and finite element studies under the same load and boundary conditions. Range of motion, facet forces, disc stresses, and ligament loads showed a strong association with the location of the COR. Conclusions Acute alterations in the location of the COR can significantly change the load sharing characteristics within the spine segment. The normal location of the COR is a result of the tendency of the vertebra to move in the path of least cumulative resistance.

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A non-linear finite element model of human L4-L5 lumbar spinal segment with three-dimensional solid element ligaments

Theoretical and Applied Mechanics Letters ◽

10.1063/2.1106401 ◽

2011 ◽

Vol 1 (6) ◽

pp. 064001 ◽

Cited By ~ 3

Author(s):

Zhitao Xiao ◽

Liya Wang ◽

He Gong ◽

Dong Zhu ◽

Xizheng Zhang

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Three Dimensional ◽

Element Model ◽

Spinal Segment ◽

Linear Finite Element ◽

Solid Element ◽

Non Linear ◽

Lumbar Spinal

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Functional involvement of the lumbar spinal cord after contusion to T8 spinal segment of the rat

Restorative Neurology and Neuroscience ◽

10.3233/rnn-2010-0549 ◽

2010 ◽

Vol 28 (6) ◽

pp. 781-792

Author(s):

Guillermo García-Alías ◽

Abel Torres-Espín ◽

Carolina Vallejo ◽

Xavier Navarro

Keyword(s):

Spinal Cord ◽

Lumbar Spinal Cord ◽

Spinal Segment ◽

Functional Involvement ◽

Lumbar Spinal

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Coding of Locomotor Phase in Populations of Neurons in Rostral and Caudal Segments of the Neonatal Rat Lumbar Spinal Cord

Journal of Neurophysiology ◽

10.1152/jn.1999.82.6.3563 ◽

1999 ◽

Vol 82 (6) ◽

pp. 3563-3574 ◽

Cited By ~ 51

Author(s):

Matthew C. Tresch ◽

Ole Kiehn

Keyword(s):

Spinal Cord ◽

Spike Activity ◽

Neuronal Population ◽

Ventral Root ◽

Neonatal Rat ◽

Lumbar Spinal Cord ◽

Spinal Segment ◽

Rhythmic Motor ◽

Lumbar Spinal ◽

Rostrocaudal Gradient

Several experiments have demonstrated that rostral segments of the vertebrate lumbar spinal cord produce a rhythmic motor output more readily and of better quality than caudal segments. Here we examine how this rostrocaudal gradient of rhythmogenic capability is reflected in the spike activity of neurons in the rostral (L2) and caudal (L5) lumbar spinal cord of the neonatal rat. The spike activity of interneurons in the ventromedial cord, a region necessary for the production of locomotion, was recorded intracellularly with patch electrodes and extracellularly with tetrodes during pharmacologically induced locomotion. Both L2 and L5 neurons tended to be active in phase with their homologous ventral root. L5 neurons, however, had a wider distribution of their preferred phases of activity throughout the locomotor cycle than L2 neurons. The strength of modulation of the activity of individual L2 neurons was also larger than that of L5 neurons. These differences resulted in a stronger rhythmic signal from the L2 neuronal population than from the L5 population. These results demonstrate that the rhythmogenic capability of each spinal segment was reflected in the activity of interneurons located in the same segment. In addition to paralleling the rostrocaudal gradient of rhythmogenic capability, these results further suggest a colocalization of motoneurons and their associated interneurons involved in the production of locomotion.

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Bone Remodelling Model Incorporating Both Shape and Internal Structure Changes by Three Different Reconstruction Mechanisms. A Lumbar Spine Case

Archive of Mechanical Engineering ◽

10.1515/meceng-2016-0031 ◽

2016 ◽

Vol 63 (4) ◽

pp. 549-563

Author(s):

Paweł Wymysłowski ◽

Tomasz Zagrajek

Keyword(s):

Internal Structure ◽

Bone Remodelling ◽

Spinal Segment ◽

Element Analysis ◽

Site Specific ◽

Structure Changes ◽

Ansys System ◽

Artificial Intervertebral Disc ◽

Lumbar Spinal ◽

Adaptive Elasticity

AbstractThe paper presents a method of analysis of bone remodelling in the vicinity of implants. The authors aimed at building a model and numerical procedures which may be used as a tool in the prosthesis design process. The model proposed by the authors is based on the theory of adaptive elasticity and the lazy zone concept. It takes into consideration not only changes of the internal structure of the tissue (described by apparent density) but also surface remodelling and changes caused by the effects revealing some features of “creep”. Finite element analysis of a lumbar spinal segment with an artificial intervertebral disc was performed by means of the Ansys system with custom APDL code. The algorithms were in two variants: the so-called siteindependent and site-specific. Resultant density distribution and modified shape of the vertebra are compared for both of them. It is shown that this two approaches predict the bone remodelling in different ways. A comparison with available clinical outcomes is also presented and similarities to the numerical results are pointed out.

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Biomechanical Study of Lumbar Spinal Fixation Device

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.232.142 ◽

2012 ◽

Vol 232 ◽

pp. 142-146 ◽

Cited By ~ 1

Author(s):

Filip Manek ◽

Petr Marcián ◽

Zdeněk Florian ◽

Jiří Valášek ◽

Veronika Ebringerová

Keyword(s):

Physiological State ◽

Strain Analysis ◽

Biomechanical Study ◽

Spinal Fixation ◽

Fixation Device ◽

Spinal Segment ◽

Fem Method ◽

The Difference ◽

Lumbar Spinal ◽

Spine Fixation

This article is focused on computational modeling of an interaction of malleable lumbar spine fixation device with ambient bone tissue focusing on solving problems of clinical practise. It describes creation of computational model including model of geometry, materials, loads and constraints. There is a comparative stress strain analysis of spinal segment after fixation device application with its physiological state. Computations are performed with use of FEM method. To simulate natural way of loading we used the compression of motional spinal segment. Results show the difference between the system including intervertebral disc in between vertebras and the system with applied lumbar spinal fixation device.

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