Laboratory Conditions for Tensile Tests in Annulus Fibrosus from Human Intervertebral Discs

Objectives Intervertebral disc (IVD) is key to spine biomechanics, and it is often involved in the cascade leading to spinal deformities such as idiopathic scoliosis, especially during the growth spurt. Recent progress in elastographic techniques allowed access to noninvasively measure cervical IVD in adults; the aim of this study was to determine the feasibility and reliability of shear wave elastography in healthy children lumbar IVD.Methods Elastographic measurements were performed in thirty-one healthy children (6 to 17 years old), in the annulus fibrosus and in the transverse plane of L5-S1 or L4-L5 IVD. Reliability was determined by 3 experienced operators repeating measurements.Results Average shear wave speed in IVD was 2.9 ± 0.5 m/s; no significant correlations were observed with sex, age or body morphology. Intra-operator repeatability was 5.0 % while inter-operator reproducibility was 6.2 %. Intraclass correlation coefficient was higher than 0.9 for each operator.Conclusions Feasibility and reliability of IVD shear wave elastography was demonstrated. The measurement protocol is compatible with the clinical routine, and the results show the potential to give an insight into spine deformity progression and early detection.Keywords: Spine; Spinal diseases; Fibrocartilage; Tissue elasticity imaging; Pediatrics Key points: Intervertebral disc mechanical properties are key to spine biomechanics. Feasibility of shear wave elastography in children lumbar disc was assessed. Measurement was fast and reliable. Elastography could represent a novel biomarker for spine pathologies.

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“…Moreover, in vitro testing presents limitations such as specimen preparation, hydration, conditioning and preload, etc. [21][22][23].…”

Section: Discussionmentioning

confidence: 99%

Lumbar annulus fibrosus biomechanical characterization in healthy children by ultrasound shear wave elastography

et al. 2015

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“…These include the tensile properties of annulus fibrosus (Hirsch and Galante, 1967), hydrostatic pressure of the nucleus (Nachemson, 1960), ROM (Panjabi et al, 1985), and compressive stiffness and hysteresis (Smeathers and Joanes, 1988). In contrast, freezing does appear to affect porcine spines.…”

Section: Discussionmentioning

confidence: 99%

Effect of multiple freeze–thaw cycles on intervertebral dynamic motion characteristics in the porcine lumbar spine

Hongo

Gay

Hsu

et al. 2008

Journal of Biomechanics

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Fresh frozen spine specimens are commonly used in biomechanical investigations of the spine. Since many study designs require staged preparation and testing, the effect of multiple freeze-thaw cycles on motion behavior should be understood. The objective of this study was to investigate the effect of multiple freeze-thaw cycles on the biomechanical parameters measured during dynamic pure moment loading. Ten porcine lumbar motion segments were harvested immediately after death and potted in acrylic fixtures. Specimens were tested in continuous pure moment flexion-extension, lateral flexion, and rotation cycles up to a limit of +/-5Nm. Moment-angular displacement data were analyzed and parameters quantified including range of motion, elastic zone, transitional zone (neutral region) size and slope, and width of the hysteresis loop. All specimens were tested at baseline and after each of three subsequent cycles of freezing and thawing. The transitional zone size decreased and the transitional zone slope increased during flexion-extension and lateral bending after the initial freeze-thaw cycle. These parameters were not altered after subsequent cycles. No significant change was observed in the elastic zone or width of hysteresis loop. Although freezing porcine spine specimens increased the stiffness in the neutral region of motion, up to three subsequent cycles of freezing and thawing did not further affect these motion characteristics. This suggests that data obtained from porcine spines which have been frozen and thawed multiple times are stable after initial freezing.

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“…In the present study, the apparent lamellar thickness in the excised AF samples, ranging from 200 to 600m by visual inspection, is probably an overestimate from its in situ value because of the equilibration and swelling procedure allowed during sample preparation. The AF exhibits a large propensity to imbibe fluid, or swell, when excised from the disc due to a large osmotic pressure generated by negatively charged proteoglycans within the tissue (29,30).…”

Section: Discussionmentioning

confidence: 99%

Diffusion tensor microscopy of the intervertebral disc anulus fibrosus

Hsu¹,

Setton²

1999

Magn. Reson. Med.

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Morphologically accurate biomechanical models of the intervertebral disc anulus fibrosus (AF) require precise knowledge of its lamellar architecture; however, available methods of assessment are limited by poor spatial resolution or the destructive nature of the technique. In a novel approach, diffusion tensor microscopy was used in this study to characterize the microstructure of excised porcine AF samples. Results show diffusion in the AF to be anisotropic. The orientations of anisotropy exhibit a layered morphology that agrees with light micrographs of the corresponding samples, and the behavior of the orientation angles is consistent with the known AF collagen fiber architecture. A static magnetic field-dependent relaxation anisotropy was observed in the AF, which has methodological implications for magnetic resonance (MR) imaging of ordered collageneous tissues. These findings present MR diffusion tensor microscopy as a potentially valuable tool to assess quantitatively and nondestructively water diffusion anisotropy and lamellar structure of the intervertebral disc AF. Magn Reson Med 41:992-999, 1999. 1999 Wiley-Liss, Inc.

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Laboratory Conditions for Tensile Tests in Annulus Fibrosus from Human Intervertebral Discs

Cited by 66 publications

References 8 publications

Lumbar annulus fibrosus biomechanical characterization in healthy children by ultrasound shear wave elastography

Lumbar annulus fibrosus biomechanical characterization in healthy children by ultrasound shear wave elastography

Effect of multiple freeze–thaw cycles on intervertebral dynamic motion characteristics in the porcine lumbar spine

Diffusion tensor microscopy of the intervertebral disc anulus fibrosus

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