Validity and interobserver agreement of a new radiographic grading system for intervertebral disc degeneration: Part I. Lumbar spine

Wilke, Hans‐Joachim; Rohlmann, Friederike; Neidlinger‐Wilke, Cornelia; Werner, Karin; Kettler, Annette

doi:10.1007/s00586-006-1078-8

Cited by 28 publications

(53 citation statements)

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“…For the flexibility tests pure bending moments of ±7.5 Nm without preload were applied as recommended for lumbar spine in vitro testing [16]. Furthermore, it could be shown that this load is almost physiological if the anterior column of the spine is intact [7].…”

Section: Discussionmentioning

confidence: 99%

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Biomechanical effect of different lumbar interspinous implants on flexibility and intradiscal pressure

et al. 2008

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Interspinous implants are used to treat lumbar spinal stenosis or facet joint arthritis. The aims of implanting interspinous devices are to unload the facet joints, restore foraminal height and provide stability especially in extension but still allow motion. The aim of this in vitro study was to compare four different interspinous implants--Colfex, Wallis, Diam and X-Stop--in terms of their three-dimensional flexibility and the intradiscal pressure. Twenty-four human lumbar spine specimens were divided into four equal groups and tested with pure moments in flexion/extension, lateral bending and axial rotation: (1) intact, (2) defect, (3) after implantation. Range of motion and the intradiscal pressure were determined.In each implant-group the defect caused an increase in range of motion by about 8% in lateral bending to 18% in axial rotation. Implantation had similar effects with all four implants. In extension, Coflex, Wallis, Diam, and X-Stop all overcompensated the instability caused by the defect and allowed about 50% of the range of motion of the intact state. In contrast, in flexion, lateral bending and axial rotation the values of the range of motion stayed about the values of the defect state. Similarly the intradiscal pressure after implantation was similar to that of the intact specimens in flexion, lateral bending and axial rotation but much smaller during extension. All tested interspinous implants had a similar effect on the flexibility: they strongly stabilized and reduced the intradiscal pressure in extension, but had almost no effect in flexion, lateral bending and axial rotation.

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Section: Discussionmentioning

confidence: 99%

“…As recommended for spinal implant testing, pure moments of ±7.5 Nm were applied without preload in lateral bending right/left, flexion/extension and axial rotation left/ right [16]. The motor speed was 0.5°/s in every loading direction.…”

Section: Test Proceduresmentioning

confidence: 99%

Biomechanical effect of different lumbar interspinous implants on flexibility and intradiscal pressure

et al. 2008

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“…where K is a normally distributed random variable having mean value 0.42 and standard deviation 0.05 ( [48], in turn derived from [12]). …”

Section: Models Of the Non-degenerated Spine Segmentsmentioning

confidence: 99%

“…The objective macroscopic grading system for intervertebral disc degeneration introduced by Wilke et al [48] was used as the basis to build the models of the degenerated spine segments. This system estimates the overall degree of disc degeneration as the sum of six scores of different degenerative characteristics (appearance of nucleus pulposus, annulus fibrosus and endplate cartilage; height loss; osteophyte formation; diffuse sclerosis), which can be evaluated on mid-sagittal sections of lumbar specimens.…”

Section: Models Of the Degenerated Spine Segmentsmentioning

confidence: 99%

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The mechanical response of the lumbar spine to different combinations of disc degenerative changes investigated using randomized poroelastic finite element models

et al. 2010

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Degeneration of the intervertebral disc is related to progressive changes in the disc tissue composition and morphology, such as water loss, disc height loss, endplate calcification, osteophytosis. These changes may be present separately or, more frequently, in various combinations. This work is aimed to the biomechanical investigation of a wide range of clinical scenarios of disc degeneration, in which the most common degenerative changes are present in various combinations. A poroelastic non-linear finite element model of the healthy L4-L5 human spine segment was employed and randomly scaled to represent ten spine segments from different individuals. Six different degenerative characteristics (water loss in the nucleus pulposus and annulus fibrosus; calcification and thickness reduction of endplate cartilage; disc height loss; osteophyte formation; diffuse sclerosis) were modeled in 30 randomly generated models, 10 for each overall degree of degeneration (mild, moderate, severe). For each model, a daily loading cycle including 8 h of rest, 16 h in the standing position with superimposed two flexion-extension motion cycles was simulated. A tendency to an increase of stiffness with progressing overall degeneration was observed, in compression, flexion and extension. Hence, instability for mild degeneration was not predicted. Facet forces and fluid loss decreased with disc degeneration. Nucleus, annulus and endplate degeneration, disc height loss, osteophytosis and diffuse sclerosis all induced a statistically significant decrease in the total daily disc height variation, facet force and flexibility in flexion-extension. Therefore, grading systems for disc degeneration should include all the degenerative changes considered in this work, since all of them had a significant influence on the spinal biomechanics.

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The effect of disc degeneration on anterior shear translation in the lumbar spine

Melnyk

Kelly

Chak

et al. 2015

Journal Orthopaedic Research

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Many pathologies involving disc degeneration are treated with surgery and spinal implants. It is important to understand how the spine behaves mechanically as a function of disc degeneration. Shear loading is especially relevant in the natural and surgically stabilized lumbar spine. The objective of our study was to determine the effect of disc degeneration on anterior translation of the lumbar spine under shear loading. We tested 30 human cadaveric functional spinal units (L3-4 and L4-5) in anterior shear loading. First, the specimens were imaged in a 1.5 T magnetic resonance scanner. The discs were graded according to the Pfirrmann classification. The specimens were then loaded up to 250 N in anterior shear with an axial compression force of 300 N. Motion of the vertebrae was captured with an optoelectronic camera system. Inter-and intra-observer reliability for disc grading was determined (Cohen's and Fleiss' Kappa), and a non-parametric test was performed on the translation data to characterize the effect of disc degeneration on this parameter. We found fair to moderate agreement between and within observers for the disc grading. We found no significant effect of disc degeneration on anterior shear translation (Kruskal-Wallis ANOVA). Our results indicate that disc degeneration, as classified with the Pfirrmann scale, does not predict lumbar spinal motion in shear. ß

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Validity and interobserver agreement of a new radiographic grading system for intervertebral disc degeneration: Part I. Lumbar spine

Abstract: ERRATUMThe online version of the original can be found at http://dx.

Cited by 28 publications

References 0 publications

Biomechanical effect of different lumbar interspinous implants on flexibility and intradiscal pressure

Biomechanical effect of different lumbar interspinous implants on flexibility and intradiscal pressure

The mechanical response of the lumbar spine to different combinations of disc degenerative changes investigated using randomized poroelastic finite element models

The effect of disc degeneration on anterior shear translation in the lumbar spine

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