Osmo-inelastic response of the intervertebral disc

Derrouiche, Amil; Zaouali, A.; Zaïri, Fahmi; Ismail, Jewan; Chaabane, Mohamed; Qu, Zhengwei; Zaïri, Fahed

doi:10.1177/0954411919827983

Cited by 25 publications

(16 citation statements)

References 48 publications

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“…The biomechanics of the disc soft tissues should be considered in furthermore accurate models 30,31 along with deeper understanding of the disc functionality. 32–34 In the current study, it was therefore necessary to carry out direct measurements “in vivo” in order to limit these biases.…”

Section: Discussionmentioning

confidence: 99%

Relevance of a novel external dynamic distraction device for treating back pain

Zaïri

Moulart²,

Fontaine³

et al. 2020

Proc Inst Mech Eng H

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Low back pain is a common, expensive, and disabling condition in industrialized countries. There is still no consensus for its ideal management. Believing in the beneficial effect of traction, we developed a novel external dynamic distraction device. The purpose of this work was to demonstrate that external distraction allows limiting the pressure exerted in standing-up position on the lower intervertebral discs. Numerical and cadaveric studies were used as complementary approaches. Firstly, we implemented the device into a numerical model of a validated musculoskeletal software (Anybody Modeling System) and we calculated the lower disc pressure while traction forces were applied. Secondly, we performed an anatomical study using a non-formalin preserved cadaver placed in a sitting position. A pressure sensor was placed in the lower discs under fluoroscopic control through a Jamshidi needle. The intradiscal pressure was then measured continuously at rest while applying a traction force of 200 N. Both numerical and cadaveric studies demonstrated a decrease in intradiscal pressures after applying a traction force with the external device. Using the numerical model, we showed that tensile forces below 500 N in total were sufficient. The application of higher forces seems useless and potentially deleterious. External dynamic distraction device is able to significantly decrease the intradiscal pressure in a sitting or standing position. However, the therapeutic effects need to be proven using clinical studies.

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Section: Discussionmentioning

confidence: 99%

Relevance of a novel external dynamic distraction device for treating back pain

Zaïri

Moulart²,

Fontaine³

et al. 2020

Proc Inst Mech Eng H

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“…The compression of the whole disc (due in-vivo to muscular tension and body weight) provokes the uniaxial circumferential stretching of the annulus due to swelling of the nucleus (inner gel-like disc portion), combined to multiaxial mechanical paths during body movements. Although in-vitro experiments allowed to bring insights on the mechanics of the whole disc 46 – 48 , the annulus/nucleus interaction under complex external mechanical loadings is still an open issue. The construction of a whole disc model including our annulus model (with the regional effects) and the explicit presence of the nucleus would be useful for a thorough understanding of the functionality of the disc and its local behavior.…”

Section: Discussionmentioning

confidence: 99%

Interlamellar matrix governs human annulus fibrosus multiaxial behavior

Kandil

Zaïri

Messager

et al. 2020

Sci Rep

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Establishing accurate structure–property relationships for intervertebral disc annulus fibrosus tissue is a fundamental task for a reliable computer simulation of the human spine but needs excessive theoretical-numerical-experimental works. The difficulty emanates from multiaxiality and anisotropy of the tissue response along with regional dependency of a complex hierarchic structure interacting with the surrounding environment. We present a new and simple hybrid microstructure-based experimental/modeling strategy allowing adaptation of animal disc model to human one. The trans-species strategy requires solely the basic knowledge of the uniaxial circumferential response of two different animal disc regions to predict the multiaxial response of any human disc region. This work demonstrates for the first time the determining role of the interlamellar matrix connecting the fibers-reinforced lamellae in the disc multiaxial response. Our approach shows encouraging multiaxial predictive capabilities making it a promising tool for human spine long-term prediction.

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“…Indeed, under mechanical loading, the fluid, flowed out, leads to chemical imbalances that generate fluid inflow [1,2]. The time-dependent response of the disc tissues is largely governed by the interactions between the inelastic features of the tangled ECM (representing all non-fibrillar "solid" components) and the surrounding physiological fluid by osmotic effect [3][4][5][6][7][8][9][10][11]. The resulting chemo-mechanical couplings in the disc tissues are now well accepted but not fully understood [12,13] and corresponding data are rare in the literature.…”

Section: Introductionmentioning

confidence: 99%

The two Poisson’s ratios in annulus fibrosus: relation with the osmo-inelastic features

et al. 2020

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The annulus fibrosus of the intervertebral disc is a highly complex layered structure in which the inelastic features of the tangled extracellular matrix interact with the surrounding physiological fluid by osmotic effect. In this in vitro study, the time-dependent transversal behavior in the two planes (fibers and lamellae planes) of multi-lamellae annulus tissues is reported by means of an accurate optical strain measuring technique based upon digital image correlation. Fresh annulus specimens of square cross section, extracted from bovine cervical discs, are tested under quasi-static (cyclic uniaxial stretching) and relaxation (interrupted stretching) loading with variation in osmolarity and strain rate conditions. Significant osmotic and strain rate effects are found on the elastic stiffness and the apparent Poisson's ratios (p < 0.05, ANOVA). Under quasi-static loading, the apparent Poisson's ratio is found higher than 0.5 in fibers plane and negative (i.e., auxetic) in lamellae plane. This material property evolves progressively towards classical bounds with relaxation time, i.e., between 0 and 0.5. The strong dependence of the auxetic behavior on time and chemical environment provides valuable insights about internal fluid exchanges. An interpretation of the osmo-inelastic mechanisms is proposed in which mechanical-based and chemical-based fluid flow interact until chemo-mechanical equilibrium. The new information allows a better understanding of the disc functionality and must be considered in accurate modeling of the disc annulus.

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Osmo-inelastic response of the intervertebral disc

Cited by 25 publications

References 48 publications

Relevance of a novel external dynamic distraction device for treating back pain

Relevance of a novel external dynamic distraction device for treating back pain

Interlamellar matrix governs human annulus fibrosus multiaxial behavior

The two Poisson’s ratios in annulus fibrosus: relation with the osmo-inelastic features

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