Neutral zone and range of motion in the spine are greater with stepwise loading than with a continuous loading protocol. An in vitro porcine investigation

Goertzen, Darrell; Lane, Chris; Oxland, Thomas R.

doi:10.1016/s0021-9290(03)00307-5

Cited by 82 publications

(67 citation statements)

References 12 publications

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“…Dynamic surrogates of the quasistatic NZ have been previously suggested. The width of the hysteresis loop as proposed by Wilke et al (Wilke et al, 1998b) has been reported to be smaller than the quasistatic NZ despite the terminal load being the same (Goertzen et al, 2004). This is likely due to the creep associated with quasistatic loading.…”

Section: Discussionmentioning

confidence: 83%

“…Goertzen et al compared the ROM and the width of the hysteresis loop between quasistatic and continuous loading methods. They found both ROM and hysteresis loop width to be less in the continuous motion protocol (Goertzen et al, 2004). Thompson et al proposed the amount of movement occurring while the slope of the moment-displacement curve is near 0 as a dynamic NZ.…”

Section: Introductionmentioning

confidence: 99%

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The effect of loading rate and degeneration on neutral region motion in human cadaveric lumbar motion segments

Ilharreborde

Zhao

Boumediene

et al. 2008

Clinical Biomechanics

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Background-The quasistatic neutral zone is a surrogate for neutral region stiffness of spinal motion segments. No similar measure of dynamic stiffness has been validated. Because parameters related to stiffness are likely to be affected by loading rate and disc degeneration, we examined the effect of those factors on motion parameters derived from continuous motion data. Methods-Fifteenhuman lumbar motion segments were tested with continuous flexion-extension pure moments at 0.5, 3.0 and 6.0 degrees/second. Range of motion, width of the hysteresis loop, transitional zone width, and slopes of the upper and lower arms of the hysteresis loop within the transitional zone were measured. Discs were then graded for degeneration.Findings-As the loading rate increased from 0.5 to 6.0 degree/second there were significant increases in ROM, hysteresis area, hysteresis loop width, and the upper and lower transitional zone slopes. At the same time transitional zone width decreased significantly. Degeneration had a significant effect on all parameters except hysteresis loop width. The transition zone slopes appeared to best discriminate between normal and degenerative discs.Interpretation-Loading rate had a significant effect on all parameters. As degeneration increased consistent effects were observed indicating decreasing stiffness from grade 1 to grade 3 then slightly increased stiffness in grade 4 specimens. The slopes of the transitional zone have potential to be a useful measure of neutral region stiffness during dynamic motion testing.

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Section: Discussionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

The effect of loading rate and degeneration on neutral region motion in human cadaveric lumbar motion segments

Ilharreborde

Zhao

Boumediene

et al. 2008

Clinical Biomechanics

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“…Using the University of British Columbia (UBC) Spine Motion Simulator [13] (Fig. 1), a pure moment of ±5 Nm was applied to the superior-most free vertebra (T8) in flexion/extension (FE), lateral bending (LB), and axial rotation (AR), for each surgical condition.…”

Section: Flexibility Test Protocolmentioning

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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“…Six human cadaveric lumbosacral spine specimens, L3-S1, were subjected to three-dimensional flexibility testing in axial rotation, lateral bending and flexion-extension, using an unconstrained testing machine [24]. The data from an additional seven specimens were used in conjunction for the validation of the FE model.…”

Section: Specimen Preparation and Biomechanical Loadingmentioning

confidence: 99%

“…The spine motion simulator applied pure non-constraining ± 10 Nm moments to the top vertebra at approximately 2°/s in flexion-extension, lateral bending, and axial rotation for three cycles [24]. A 600 N compressive preload followed the contour of the spine ensuring compression perpendicular to the endplates between each segment [25,26].…”

Section: Specimen Preparation and Biomechanical Loadingmentioning

confidence: 99%

Biomechanical evaluation of the Total Facet Arthroplasty System® (TFAS®): loading as compared to a rigid posterior instrumentation system

et al. 2012

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Neutral zone and range of motion in the spine are greater with stepwise loading than with a continuous loading protocol. An in vitro porcine investigation

Cited by 82 publications

References 12 publications

The effect of loading rate and degeneration on neutral region motion in human cadaveric lumbar motion segments

The effect of loading rate and degeneration on neutral region motion in human cadaveric lumbar motion segments

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

Biomechanical evaluation of the Total Facet Arthroplasty System® (TFAS®): loading as compared to a rigid posterior instrumentation system

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