Biomechanical comparison between lumbar disc arthroplasty and fusion

Chen, Shih Hao; Zhong, Zheng Cheng; Chen, Chen Sheng; Chen, Wen Jer; Hung, Ching-Hua

doi:10.1016/j.medengphy.2008.07.007

Cited by 93 publications

(65 citation statements)

References 44 publications

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“…Such result supports previous interpretations reported about semi-constrained BoS implants [37]. Nonetheless, FJ contact forces computed with the updated devices were within the range of in vitro measured values and did not show relative alterations of up to 150-660% as predicted with BoS implant models [1,2,37].…”

Section: Facet Joint Biomechanicssupporting

confidence: 90%

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In silico evaluation of a new composite disc substitute with a L3–L5 lumbar spine finite element model

et al. 2011

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When the intervertebral disc is removed to relieve chronic pain, subsequent segment stabilization should restore the functional mechanics of the native disc. Because of partially constrained motions and the lack of intrinsic rotational stiffness ball-on-socket implants present many disadvantages. Composite disc substitutes mimicking healthy disc structures should be able to assume the role expected for a disc substitute with fewer restrictions than ball-on-socket implants. A biomimetic composite disc prototype including artificial nucleus fibre-reinforced annulus and endplates was modelled as an L4-L5 disc substitute within a L3-L5 lumbar spine finite element model. Different device updates, i.e. changes of material properties fibre distributions and volume fractions and nucleus placements were proposed. Load-and displacement-controlled rotations were simulated with and without body weight applied. The original prototype reduced greatly the flexibility of the treated segment with significant adjacent level effects under displacement-controlled or hybrid rotations. Device updates allowed restoring large part of the global axial and sagittal rotational flexibility predicted with the intact model. Material properties played a major role, but some other updates were identified to potentially tune the device behaviour against specific motions. All device versions altered the coupled intersegmental shear deformations affecting facet joint contact through contact area displacements. Loads in the bony endplates adjacent to the implants increased as the implant stiffness decreased but did not appear to be a strong limitation for the implant biomechanical and mechanobiological functionality. In conclusion, numerical results given by biomimetic composite disc substitutes were encouraging with greater potential than that offered by ball-on-socket implants.

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Section: Facet Joint Biomechanicssupporting

confidence: 90%

“…Under extension, earlier FE predictions showed that BoS implants could affect surgical level ROM by 50% [37] to 120-140% [47] at 7.5 Nm and by 80-90% under 10 Nm [1,2]. In the present study the best device version led to a maximum ROM relative change of about 50%.…”

Section: Segment Kinematicssupporting

confidence: 61%

In silico evaluation of a new composite disc substitute with a L3–L5 lumbar spine finite element model

et al. 2011

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“…The stiffness of the spinal structure changes depending on the contact status, so the standard contact option in ANSYS was adopted to account for the changing-state nonlinear problem in this study. A more detailed description of this intact lumbar spine FE model has been presented in our earlier studies [18,19]. The FE model of the intact lumbar spine consisted of 112,174 elements and 94,162 nodes.…”

Section: Fe Model Of the Intact Lumbar Spine (Int Model)mentioning

confidence: 99%

“…Under a 10-Nm moment with a 150-N preload, the current INT model showed some stiffer behaviour in flexion when compared with mean value of in vitro tests. Second, FCF in torsion of each level was compared with Chen's [19] and ShiraziAdl's [16] FE studies. A similar trend was achieved and demonstrated in our previous study.…”

Section: Convergence Test and Model Validationmentioning

confidence: 99%

Effect of the cord pretension of the Dynesys dynamic stabilisation system on the biomechanics of the lumbar spine: a finite element analysis

Liu

Zhong²,

Hsu³

et al. 2011

Eur Spine J

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The Dynesys dynamics stabilisation system was developed to maintain the mobility of motion segment of the lumbar spine in order to reduce the incidence of negative effects at the adjacent segments. However, the magnitude of cord pretension may change the stiffness of the Dynesys system and result in a diverse clinical outcome, and the effects of Dynesys cord pretension remain unclear. Displacement-controlled finite element analysis was used to evaluate the biomechanical behaviour of the lumbar spine after insertion of Dynesys with three different cord pretensions. For the implanted level, increasing the cord pretension from 100 to 300 N resulted in an increase in flexion stiffness from 19.0 to 64.5 Nm/deg, a marked increase in facet contact force (FCF) of 35% in extension and 32% in torsion, a 40% increase of the annulus stress in torsion, and an increase in the high-stress region of the pedicle screw in flexion and lateral bending. For the adjacent levels, varying the cord pretension from 100 to 300 N only had a minor influence on range of motion (ROM), FCF, and annulus stress, with changes of 6, 12, and 9%, respectively. This study found that alteration of cord pretension affects the ROM and FCF, and annulus stress within the construct but not the adjacent segment. In addition, use of a 300 N cord pretension causes a much higher stiffness at the implanted level when compared with the intact lumbar spine.

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“…The FE model of the osseoligamentous lumbar segment included the vertebrae, one intervertebral disc, endplates, posterior elements and the following ligaments: supraspinous, interspinous, ligamentum flavum, transverse, posterior longitudinal, anterior longitudinal and capsular. The material properties of the intact L4-L5 segment were assumed to be homogeneous, and a detailed description has been presented in our previous studies [57][58]. The ligaments were simulated using ten-node link elements with tension resistance only, and the elements were arranged in the anatomic orientation.…”

Section: Experimental Fe Model Of Intact L4-l5 Segment Lumbar Spine (mentioning

confidence: 99%

Biomechanical Study between the Rigid and Dynamic Fixation Systems of the Spinal Column Analyzed by the Finite Element Method

Zahaf¹,

Kebdani²

2017

Nano BioMed ENG

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Orthopedic fixation devices are widely used in treatment of spinal diseases. It is expected that application of dynamic stabilization confers valuable movement possibility besides its main role of load bearing. Comparative investigation between pedicle screw model rigid fixation and (B Dyne, Elaspine, Bioflex, Coflex rivet) models dynamic fixation systems may elucidate the efficacy of each design. The goal of the present study is to evaluate the efficacy of five fixation systems mounted on L4-L5 motion segment. In this numerical study, a 3D precious model of L4, L5 and their intervertebral disc has been employed based on CT images. Five fixation devices have been also implanted internally to the motion segment. Finite element method was used to evaluate stress distribution in the disc and determine the overall displacement of the segment as a measure of movement possibility. The results show that the Coflex rivet implantation can provide stability in all motions and reduce disc annulus stress at the surgical segment L4-L5. On the other hand, maximum stress in the disc has been observed in dynamic systems but within the safe range. The greater movement of the motion segment has also appeared in dynamic fixations. Existence of the fixation systems reduced the stress on the intervertebral disc which might be exerted in intact cases. Use of the fixation devices can considerably reduce the load on the discs and prepare conditions for healing of the injured ones. Furthermore, dynamic modes of fixation confer possibility of movement to the motion segments in order to facilitate the spinal activities.

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Biomechanical comparison between lumbar disc arthroplasty and fusion

Cited by 93 publications

References 44 publications

In silico evaluation of a new composite disc substitute with a L3–L5 lumbar spine finite element model

In silico evaluation of a new composite disc substitute with a L3–L5 lumbar spine finite element model

Effect of the cord pretension of the Dynesys dynamic stabilisation system on the biomechanics of the lumbar spine: a finite element analysis

Biomechanical Study between the Rigid and Dynamic Fixation Systems of the Spinal Column Analyzed by the Finite Element Method

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