Effects of Charité Artificial Disc on the Implanted and Adjacent Spinal Segments Mechanics Using a Hybrid Testing Protocol

Goel, Vijay K.; Grauer, Jonathan N.; Patel, Tushar; Biyani, Ashok; Sairyo, Koichi; Vishnubhotla, Srilakshmi; Matyas, Aaron; Cowgill, Ian; Shaw, Miranda N.; Long, Rebecca A.; Dick, David; Panjabi, Manohar M.; Serhan, Hassan

doi:10.1097/01.brs.0000195897.17277.67

Cited by 206 publications

(137 citation statements)

References 34 publications

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“…These results indicate that Dynesys can alleviate facet loading on the implanted level under extension, and they follow a similar trend to the results presented by Rohlmann [11]. Although FCF was noticeably increased at the adjacent levels, it remains much lower than the values of the fusion model (?169% under extension; ?28.9% under torsion) [20]. At present, several clinical reports have demonstrated that Dynesys implantation does not induce a problem in the adjacent facet joint [2][3][4][5][6][7].…”

Section: Discussionmentioning

confidence: 90%

“…For the convergence test, three mesh densities (coarse model: 4,750 elements/4,960 nodes; normal model: 27,244 elements/30,630 nodes; finest model: 112,174 elements/ 94,162 nodes) were selected to test the ROM changes in the INT model, and the finest mesh density was selected because the changes between the normal model and finest model were within 1.03% in flexion (\0.2°), 4.39% in extension (\0.5°), 0.01% in torsion (\0.2°), and 0.001% in lateral bending (\0.1°), respectively [20].…”

Section: Convergence Test and Model Validationmentioning

confidence: 99%

“…The loading condition of a constant ROM has been shown to be more clinically relevant in predicting the adjacent level effects following the insertion of a spinal implant [18,20]; for this reason, this study used the displacement control method. For all Dynesys cases, three load steps were included in the whole simulation process.…”

Section: Loading and Boundary Conditionsmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 90%

Section: Convergence Test and Model Validationmentioning

confidence: 99%

Section: Loading and Boundary Conditionsmentioning

confidence: 99%

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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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“…Adjacent level effects were analyzed using a modified hybrid flexibility-stiffness protocol [40] which is a modified form of the hybrid protocol promoted by Panjabi and colleagues [12,[26][27][28][29]. This analysis technique is graphically illustrated for the flexion-extension response of a typical specimen in Fig.…”

Section: Modified Hybrid Protocolmentioning

confidence: 99%

“…However, some of the studies that have been performed to study TDR's adjacent to fusions [10,25,34] did not apply hybrid testing methods [10,34], or applied bending using an offset shear force that resulted in combined bending and shear loading [25]. The kinematics of isolated or multiple total disc replacements and isolated fusions have also been studied in the past [5,12,26,27,40]. However, to the authors' knowledge, there are no biomechanical studies documenting the range of motion and quality of kinematics (i.e.…”

Section: Introductionmentioning

confidence: 99%

Kinematic evaluation of one- and two-level Maverick lumbar total disc replacement caudal to a long thoracolumbar spinal fusion

et al. 2012

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Purpose Adjacent level degeneration that occurs above and/or below long fusion constructs is a documented clinical problem that is widely believed to be associated with the considerable change in stiffness caused by the fusion. Some researchers have suggested that early degeneration at spinal joints adjacent to a fusion could be treated by implanting total disc replacements at these levels. It is thought that further degeneration could be prevented through the disc replacement's design aims to reproduce normal disc heights, kinematics and tissue loading. For this reason, there is a clinical need to evaluate if a total disc replacement can maintain both the quantity of motion (i.e. range) and the quality of motion (i.e. center of rotation and coupling) at segments adjacent to a long spinal fusion. The purpose of this study was to experimentally evaluate range of motion (ROM-the intervertebral motion measured) and helical axis of motion (HAM) changes due to one-and two-level Maverick total disc replacement (TDR) adjacent to a long spinal fusion. Methods Seven spine specimens (T8-S1) were used in this study (66 ± 19 years old, 3F/4 M). A continuous pure moment of ±5.0 Nm was applied to the specimen in flexion-extension (FE), lateral bending (LB) and axial rotation (AR), with a compressive follower preload of 400 N. The 5.0 Nm data were analyzed to evaluate the operated segment biomechanics at the level of the disc replacements. The data were also analyzed at lower moments using a modified version of Panjabi's proposed ''hybrid'' method to evaluate adjacent segment kinematics (intervertebral motion at the segments adjacent to the fusion) under identical overall (T8-S1) specimen rotations. The motion of each vertebra was monitored with an optoelectronic camera system. The biomechanical test was completed for (1) the intact condition and repeated after each surgical technique was applied to the specimen, (2) capsulotomy at L4-L5 and L5-S1, (3) T8-L4 fusion and capsulotomy at L4-L5 and L5-S1, (4) Maverick at L4-L5, and (5) Maverick at L5-S1. The capsulotomy was performed to allow measurement of facet joint loads in a companion study. Paired t tests were used to determine if differences in the kinematic parameters measured were significant. Holm-Sidak corrections for multiple comparisons were applied where appropriate. replacement (mean = 22 %, compared to the fused condition). Two-level Maverick implantation also tended to reduce L4-S1 ROM (mean 18, 7 and 31 % in FE, LB and AR, respectively, compared to the fused condition without TDR). Following TDR replacement, the HAM location tended to shift posteriorly in FE (at L5-S1), anteriorly in AR, and inferiorly in LB. However, although the abovementioned trends were observed, neither one-nor two-level TDR replacement showed statistically significant ROM or HAM change in any of the three directions. At the identical T8-S1 posture identified by the modified hybrid analysis, the L4-L5 and L5-S1 levels underwent significant larger motions, relative to the overall speci...

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Total disc replacement for chronic low-back pain

Jacobs

Tuschel

Kleuver³

et al. 2010

The Cochrane Database of Systematic Reviews

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Effects of Charité Artificial Disc on the Implanted and Adjacent Spinal Segments Mechanics Using a Hybrid Testing Protocol

Cited by 206 publications

References 34 publications

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

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

Kinematic evaluation of one- and two-level Maverick lumbar total disc replacement caudal to a long thoracolumbar spinal fusion

Total disc replacement for chronic low-back pain

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