Change of Disc Height, Radial Disc Bulge, and Intradiscal Pressure From Discectomy An in Vitro Investigation on Human Lumbar Discs

Brinckmann, Paul; Grootenboer, H.J.

doi:10.1097/00007632-199106000-00008

Cited by 345 publications

(235 citation statements)

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“…Anatomic measurements found the anterior disc height of intact human lumbar discs of the present study to be similar to those previously reported [32][33][34][35][36]. Many anatomical human measurements of the present study of males, Table 1, found a mean size slightly greater than prior reports, which typically reported measurements from combined male and female spines [33;37;38].…”

Section: Discussionsupporting

confidence: 88%

Mature runt cow lumbar intradiscal pressures and motion segment biomechanics

2009

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Background Context-The optimal animal model for in vivo testing of spinal implants, particularly total or partial disc replacement devices, has not yet been determined. Mechanical and morphological similarities of calf and human spines have been reported; however, limitations of the calf model include open growth plates and oversized vertebrae with growth. Mature runt cows (Corrientes breed) may avoid these limitations.

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Section: Discussionsupporting

confidence: 88%

Mature runt cow lumbar intradiscal pressures and motion segment biomechanics

2009

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“…As glycosaminoglycan content of the nucleus is reduced, a decreased swelling pressure and increased aggregate modulus 16 lead to an altered load sharing between the nucleus and annulus, and larger deformations may occur prior to annulus fibers being engaged and loaded. 6,43,44 On the other hand, the nucleus plays less of a role at high compressive and tensile loads: the annulus fibrosus resists the applied loads and is dominant in determining deformation behavior via both the developed circumferential hoop tension and also direct axial support by the annulus glycosaminoglycan and water network. 35 Viscoelastic creep behavior is dependent on nucleus glycosaminoglycan content, especially at early times.…”

Section: Discussionmentioning

confidence: 99%

Nucleus pulposus glycosaminoglycan content is correlated with axial mechanics in rat lumbar motion segments

et al. 2006

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The unique biochemical composition and structure of the intervertebral disc allow it to support load, permit motion, and dissipate energy. With degeneration, both the biochemical composition and mechanical behavior of the disc are drastically altered, yet quantitative relationships between the biochemical changes and overall motion segment mechanics are lacking. The objective of this study was to determine the contribution of nucleus pulposus glycosaminoglycan content, which decreases with degeneration, to mechanical function of a rat lumbar spine motion segment in axial loading. Motion segments were treated with varying doses of Chondroitinase-ABC (to degrade glycosaminoglycans) and loaded in axial cyclic compression-tension, followed by compressive creep. Nucleus glycosaminoglycan content was significantly correlated ( p < 0.05) with neutral zone mechanical behavior, which occurs in low load transition between tension and compression (stiffness: r ¼ 0.59; displacement: r ¼ À0.59), and with creep behavior (viscous parameter h 1 : r ¼ 0.34; short time constant t 1 : r ¼ 0.46). These results indicate that moderate decreases in nucleus glycosaminoglycan content consistent with early human degeneration affect overall mechanical function of the disc. These decreases may expose the disc to altered internal stress and strain patterns, thus contributing through mechanical or biological mechanisms to the degenerative cascade. ß

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“…In contrast, discectomy benefits good shortterm effects of pain relieve, but it reduces disc height and increases segmental instability. This can lead to more stress in the remaining annulus but also in the facet joints [3,4,14,15], which may lead to an accelerated further degeneration.…”

Section: Introductionmentioning

confidence: 99%

Is a collagen scaffold for a tissue engineered nucleus replacement capable of restoring disc height and stability in an animal model?

et al. 2006

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The idea of a tissue engineered nucleus implant is to seed cells in a three-dimensional collagen matrix. This matrix may serve as a scaffold for a tissue engineered nucleus implant. The aim of this study was to investigate whether implantation of the collagen matrix into a spinal segment after nucleotomy is able to restore disc height and flexibility. The implant basically consists of condensed collagen type-I matrix. For clinical use, this matrix will be used for reinforcing and supporting the culturing of nucleus cells. In experiments, matrixes were concentrated with barium sulfate for X-ray purposes and cell seeding was disclaimed in order to evaluate the biomechanical performance of the collagen material. Six bovine lumbar functional spinal units, aging between 5 and 6 months, were used for the biomechanical in-vitro test. In each specimen, an oblique incision was performed, the nucleus was removed and replaced by a collagen-type-I matrix. Specimens were mounted in a custom-built spine tester, and subsequently exposed to pure moments of 7.5 Nm to move within the three anatomical planes. Each tested stage (intact, nucleotomy and implanted) was evaluated for range of motion, neutral zone and change in disc height. Removal of the nucleus significantly reduced disc height by 0.84 mm in respect to the intact stage and caused an instability in the segment. Through the implantation of the tissue engineered nucleus it was possible to restore this height and stability loss, and even to increase slightly the disc height of 0.07 mm compared with the intact stage. There was no statistical difference between the stability provided by the implant and intact stage. Results of movements in lateral bending and axial rotation showed the same trend compared to flexion/extension. However, implant extrusions have been observed in three of six cases during the flexibility assessment. The results of this study directly reflect the efficacy of vital nucleus replacement to restore disc height and to provide stability to intervertebral discs. However, from a biomechanical point of view, the challenge is to employ an appropriate annulus fibrosus sealing method, which is capable to keep the nucleus implant in place over a long-time period. Securing the nucleus implant inside the disc is one of the most important biomechanical prerequisites if such a tissue engineered implant shall have a chance for clinical application.

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Change of Disc Height, Radial Disc Bulge, and Intradiscal Pressure From Discectomy An in Vitro Investigation on Human Lumbar Discs

Cited by 345 publications

References 0 publications

Mature runt cow lumbar intradiscal pressures and motion segment biomechanics

Mature runt cow lumbar intradiscal pressures and motion segment biomechanics

Nucleus pulposus glycosaminoglycan content is correlated with axial mechanics in rat lumbar motion segments

Is a collagen scaffold for a tissue engineered nucleus replacement capable of restoring disc height and stability in an animal model?

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