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Raphaël Vialle - One of the best experts on this subject based on the ideXlab platform.
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Microstructural characterization of Annulus Fibrosus by ultrasonography: a feasibility study with an in vivo and in vitro approach.
Biomechanics and modeling in mechanobiology, 2019Co-Authors: Tristan Langlais, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël Vialle, Judith R. Meakin, Peter Winlove, Pierre Desprairies, Pierre-yves Rohan, Claudio VergariAbstract:The main function of the intervertebral disc is biomechanical function, since it must resist repetitive high loadings, while giving the spine its flexibility and protecting the spinal cord from over-straining. It partially owes its mechanical characteristics to the lamellar architecture of its outer layer, the Annulus Fibrosus. Today, no non-invasive means exist to characterize Annulus lamellar structure in vivo. The aim of this work was to test the feasibility of imaging Annulus Fibrosus microstructure in vivo with ultrasonography. Twenty-nine healthy adolescents were included. Ultrasonographies of L3–L4 disc were acquired with a frontal approach. Annulus Fibrosus was segmented in the images to measure the thickness of the lamellae. To validate lamellar appearance in ultrasonographies, multimodality images of two cow tail discs were compared: ultrasonography, magnetic resonance and optical microscopy. In vivo average lamellar thickness was 229.7 ± 91.5 μm, and it correlated with patient body mass index and age. Lamellar appearance in the three imaging modalities in vitro was consistent. Lamellar measurement uncertainty was 7%, with good agreement between two operators. Feasibility of ultrasonography for the analysis of lumbar Annulus Fibrosus structure was confirmed. Further work should aim at validating measurement reliability, and to assess the relevance of the method to characterize Annulus alterations, for instance in disc degeneration or scoliosis.
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Shear Wave Elastography can evaluate Annulus Fibrosus Alteration in Adolescent Scoliosis
European radiology, 2018Co-Authors: Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël VialleAbstract:In vitro studies showed that Annulus Fibrosus lose its integrity in idiopathic scoliosis. Shear-wave ultrasound elastography can be used for non-invasive measurement of shear-wave speed (SWS) in vivo in the Annulus Fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar Annulus Fibrosus of scoliotic adolescents and compare it to healthy subjects. SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of 30 healthy adolescents (13 ± 1.9 years old) and 30 adolescent idiopathic scoliosis patients (13 ± 2 years old, Cobb angle: 28.8° ± 10.4°). SWS was compared between the scoliosis and healthy control groups. In healthy subjects, average SWS (all disc levels pooled) was 3.0 ± 0.3 m/s, whereas in scoliotic patients it was significantly higher at 3.5 ± 0.3 m/s (p = 0.0004; Mann-Whitney test). Differences were also significant at all disc levels. No difference was observed between males and females. No correlation was found with age, weight and height. Non-invasive shear-wave ultrasound is a novel method of assessment to quantitative alteration of Annulus Fibrosus. These preliminary results are promising for considering shear-wave elastography as a biomechanical marker for assessment of idiopathic scoliosis. • Adolescent idiopathic scoliosis may have an altered lumbar Annulus Fibrosus. • Shear-wave elastography can quantify lumbar Annulus Fibrosus mechanical properties. • Shear-wave speed was higher in scoliotic Annulus than in healthy subjects. • Elastography showed potential as a biomechanical marker for characterizing disc alteration.
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Shear Wave Elastography can evaluate Annulus Fibrosus Alteration in Adolescent Scoliosis
European Radiology, 2018Co-Authors: Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël VialleAbstract:Objectives In vitro studies showed that Annulus Fibrosus lose its integrity in idiopathic scoliosis. Shear wave ultrasound elastography can be used for noninvasive measurement of shear wave speed (SWS) in vivo in the Annulus Fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar Annulus Fibrosus of scoliotic adolescents and compare it to healthy subjects. Methods SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of thirty healthy adolescents (13 yo ± 1.9) and thirty adolescent idiopathic scoliosis patients (13 yo ± 2, Cobb angle: 28.8° ± 10.4°). SWS was compared between scoliosis and healthy control group. Results In healthy subjects, average SWS (all disc levels pooled) was 3.0 ± 0.3 m/s whereas, in scoliotic patients it was significantly higher at 3.5 ± 0.3 m/s (p = 0.0004; Mann-Whitney test). Differences were also significant at all disc levels. No difference was observed between males and females. No correlation was found with age, weight and height. Conclusion Non-invasive shear wave ultrasound is a novel method of assessment to quantitative alteration of Annulus Fibrosus. These preliminary results are promising to consider shear wave elastography as a biomechanical marker for assessment of idiopathic scoliotic.
Claudio Vergari - One of the best experts on this subject based on the ideXlab platform.
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Microstructural characterization of Annulus Fibrosus by ultrasonography: a feasibility study with an in vivo and in vitro approach.
Biomechanics and modeling in mechanobiology, 2019Co-Authors: Tristan Langlais, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël Vialle, Judith R. Meakin, Peter Winlove, Pierre Desprairies, Pierre-yves Rohan, Claudio VergariAbstract:The main function of the intervertebral disc is biomechanical function, since it must resist repetitive high loadings, while giving the spine its flexibility and protecting the spinal cord from over-straining. It partially owes its mechanical characteristics to the lamellar architecture of its outer layer, the Annulus Fibrosus. Today, no non-invasive means exist to characterize Annulus lamellar structure in vivo. The aim of this work was to test the feasibility of imaging Annulus Fibrosus microstructure in vivo with ultrasonography. Twenty-nine healthy adolescents were included. Ultrasonographies of L3–L4 disc were acquired with a frontal approach. Annulus Fibrosus was segmented in the images to measure the thickness of the lamellae. To validate lamellar appearance in ultrasonographies, multimodality images of two cow tail discs were compared: ultrasonography, magnetic resonance and optical microscopy. In vivo average lamellar thickness was 229.7 ± 91.5 μm, and it correlated with patient body mass index and age. Lamellar appearance in the three imaging modalities in vitro was consistent. Lamellar measurement uncertainty was 7%, with good agreement between two operators. Feasibility of ultrasonography for the analysis of lumbar Annulus Fibrosus structure was confirmed. Further work should aim at validating measurement reliability, and to assess the relevance of the method to characterize Annulus alterations, for instance in disc degeneration or scoliosis.
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Shear Wave Elastography can evaluate Annulus Fibrosus Alteration in Adolescent Scoliosis
European radiology, 2018Co-Authors: Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël VialleAbstract:In vitro studies showed that Annulus Fibrosus lose its integrity in idiopathic scoliosis. Shear-wave ultrasound elastography can be used for non-invasive measurement of shear-wave speed (SWS) in vivo in the Annulus Fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar Annulus Fibrosus of scoliotic adolescents and compare it to healthy subjects. SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of 30 healthy adolescents (13 ± 1.9 years old) and 30 adolescent idiopathic scoliosis patients (13 ± 2 years old, Cobb angle: 28.8° ± 10.4°). SWS was compared between the scoliosis and healthy control groups. In healthy subjects, average SWS (all disc levels pooled) was 3.0 ± 0.3 m/s, whereas in scoliotic patients it was significantly higher at 3.5 ± 0.3 m/s (p = 0.0004; Mann-Whitney test). Differences were also significant at all disc levels. No difference was observed between males and females. No correlation was found with age, weight and height. Non-invasive shear-wave ultrasound is a novel method of assessment to quantitative alteration of Annulus Fibrosus. These preliminary results are promising for considering shear-wave elastography as a biomechanical marker for assessment of idiopathic scoliosis. • Adolescent idiopathic scoliosis may have an altered lumbar Annulus Fibrosus. • Shear-wave elastography can quantify lumbar Annulus Fibrosus mechanical properties. • Shear-wave speed was higher in scoliotic Annulus than in healthy subjects. • Elastography showed potential as a biomechanical marker for characterizing disc alteration.
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Shear Wave Elastography can evaluate Annulus Fibrosus Alteration in Adolescent Scoliosis
European Radiology, 2018Co-Authors: Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël VialleAbstract:Objectives In vitro studies showed that Annulus Fibrosus lose its integrity in idiopathic scoliosis. Shear wave ultrasound elastography can be used for noninvasive measurement of shear wave speed (SWS) in vivo in the Annulus Fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar Annulus Fibrosus of scoliotic adolescents and compare it to healthy subjects. Methods SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of thirty healthy adolescents (13 yo ± 1.9) and thirty adolescent idiopathic scoliosis patients (13 yo ± 2, Cobb angle: 28.8° ± 10.4°). SWS was compared between scoliosis and healthy control group. Results In healthy subjects, average SWS (all disc levels pooled) was 3.0 ± 0.3 m/s whereas, in scoliotic patients it was significantly higher at 3.5 ± 0.3 m/s (p = 0.0004; Mann-Whitney test). Differences were also significant at all disc levels. No difference was observed between males and females. No correlation was found with age, weight and height. Conclusion Non-invasive shear wave ultrasound is a novel method of assessment to quantitative alteration of Annulus Fibrosus. These preliminary results are promising to consider shear wave elastography as a biomechanical marker for assessment of idiopathic scoliotic.
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Bovine and degenerated human Annulus Fibrosus: a microstructural and micromechanical comparison.
Biomechanics and modeling in mechanobiology, 2017Co-Authors: Claudio Vergari, Daniel Chan, Andrew Clarke, Jessica C. Mansfield, Judith R. Meakin, Peter WinloveAbstract:The complex structure of the Annulus Fibrosus is strongly related to its mechanical properties. Recent work showed that it is possible to observe the relative movement of fibre bundles in loaded cow tail Annulus; the aim of this work was to describe and quantify Annulus Fibrosus micromechanics in degenerated human disc, and compare it with cow tail Annulus, an animal model often used in the literature. Second harmonic generation was used to image the collagen matrix in twenty strips of Annulus Fibrosus harvested from intervertebral disc of seven patients undergoing surgery. Samples were loaded to 6% tensile strain in 1% steps. Elastic modulus was calculated from loading curves, and micromechanical strains were calculated from the images using custom software. The same protocol was applied to twenty strips of Annulus harvested from cow tail discs. Significant morphological differences were found between human and cow tail samples, the most striking being the lack of collagen fibre crimp in the former. Fibres were also observed bending and running from one lamella to the other, forming a strong flexible interface. Interdigitation of fibre bundles was also present at this interface. Quantitative results show complex patterns of inter-bundle and inter-lamellar behaviour, with inter-bundle sliding being the main strain mechanism. Elastic modulus was similar between species, and it was not affected by the degree of degeneration. This work gives an insight into the complex structure and mechanical function of the Annulus Fibrosus, which should be accounted for in disc numerical modelling.
Tristan Langlais - One of the best experts on this subject based on the ideXlab platform.
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Microstructural characterization of Annulus Fibrosus by ultrasonography: a feasibility study with an in vivo and in vitro approach.
Biomechanics and modeling in mechanobiology, 2019Co-Authors: Tristan Langlais, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël Vialle, Judith R. Meakin, Peter Winlove, Pierre Desprairies, Pierre-yves Rohan, Claudio VergariAbstract:The main function of the intervertebral disc is biomechanical function, since it must resist repetitive high loadings, while giving the spine its flexibility and protecting the spinal cord from over-straining. It partially owes its mechanical characteristics to the lamellar architecture of its outer layer, the Annulus Fibrosus. Today, no non-invasive means exist to characterize Annulus lamellar structure in vivo. The aim of this work was to test the feasibility of imaging Annulus Fibrosus microstructure in vivo with ultrasonography. Twenty-nine healthy adolescents were included. Ultrasonographies of L3–L4 disc were acquired with a frontal approach. Annulus Fibrosus was segmented in the images to measure the thickness of the lamellae. To validate lamellar appearance in ultrasonographies, multimodality images of two cow tail discs were compared: ultrasonography, magnetic resonance and optical microscopy. In vivo average lamellar thickness was 229.7 ± 91.5 μm, and it correlated with patient body mass index and age. Lamellar appearance in the three imaging modalities in vitro was consistent. Lamellar measurement uncertainty was 7%, with good agreement between two operators. Feasibility of ultrasonography for the analysis of lumbar Annulus Fibrosus structure was confirmed. Further work should aim at validating measurement reliability, and to assess the relevance of the method to characterize Annulus alterations, for instance in disc degeneration or scoliosis.
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Shear Wave Elastography can evaluate Annulus Fibrosus Alteration in Adolescent Scoliosis
European radiology, 2018Co-Authors: Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël VialleAbstract:In vitro studies showed that Annulus Fibrosus lose its integrity in idiopathic scoliosis. Shear-wave ultrasound elastography can be used for non-invasive measurement of shear-wave speed (SWS) in vivo in the Annulus Fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar Annulus Fibrosus of scoliotic adolescents and compare it to healthy subjects. SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of 30 healthy adolescents (13 ± 1.9 years old) and 30 adolescent idiopathic scoliosis patients (13 ± 2 years old, Cobb angle: 28.8° ± 10.4°). SWS was compared between the scoliosis and healthy control groups. In healthy subjects, average SWS (all disc levels pooled) was 3.0 ± 0.3 m/s, whereas in scoliotic patients it was significantly higher at 3.5 ± 0.3 m/s (p = 0.0004; Mann-Whitney test). Differences were also significant at all disc levels. No difference was observed between males and females. No correlation was found with age, weight and height. Non-invasive shear-wave ultrasound is a novel method of assessment to quantitative alteration of Annulus Fibrosus. These preliminary results are promising for considering shear-wave elastography as a biomechanical marker for assessment of idiopathic scoliosis. • Adolescent idiopathic scoliosis may have an altered lumbar Annulus Fibrosus. • Shear-wave elastography can quantify lumbar Annulus Fibrosus mechanical properties. • Shear-wave speed was higher in scoliotic Annulus than in healthy subjects. • Elastography showed potential as a biomechanical marker for characterizing disc alteration.
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Shear Wave Elastography can evaluate Annulus Fibrosus Alteration in Adolescent Scoliosis
European Radiology, 2018Co-Authors: Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël VialleAbstract:Objectives In vitro studies showed that Annulus Fibrosus lose its integrity in idiopathic scoliosis. Shear wave ultrasound elastography can be used for noninvasive measurement of shear wave speed (SWS) in vivo in the Annulus Fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar Annulus Fibrosus of scoliotic adolescents and compare it to healthy subjects. Methods SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of thirty healthy adolescents (13 yo ± 1.9) and thirty adolescent idiopathic scoliosis patients (13 yo ± 2, Cobb angle: 28.8° ± 10.4°). SWS was compared between scoliosis and healthy control group. Results In healthy subjects, average SWS (all disc levels pooled) was 3.0 ± 0.3 m/s whereas, in scoliotic patients it was significantly higher at 3.5 ± 0.3 m/s (p = 0.0004; Mann-Whitney test). Differences were also significant at all disc levels. No difference was observed between males and females. No correlation was found with age, weight and height. Conclusion Non-invasive shear wave ultrasound is a novel method of assessment to quantitative alteration of Annulus Fibrosus. These preliminary results are promising to consider shear wave elastography as a biomechanical marker for assessment of idiopathic scoliotic.
Tae-hong Lim - One of the best experts on this subject based on the ideXlab platform.
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Flexibility of lumbar spinal motion segments correlated to type of tears in the Annulus Fibrosus
Journal of Neurosurgery: Spine, 2000Co-Authors: Victor M. Haughton, Timothy A. Schmidt, Kevin Keele, Tae-hong LimAbstract:Object. The authors conducted a study in which their objective was to measure the effect of tears in the Annulus Fibrosus on the motions of lumbar spinal motion segments. Methods. Lumbar spinal motion segments were harvested from human cadavers and studied using a 1.5-tesla magnetic resonance imager. The motion segments were subjected to incremental flexion, extension, rotation, and lateral bending torques. Displacements and rotations were measured using a kinematic system. The segments were sectioned on a cryomicrotome to verify the presence of tears in the Annulus Fibrosus. Conclusions. Tears in the Annulus Fibrosus increase the amount of motion that results from a torque applied to the motion segment. Radial and transverse tears of the Annulus Fibrosus have a greater effect on motions produced by an axial rotatory torque than on those produced by flexion, extension, or lateral bending torques. The difference between normal discs and discs with annular tears is more marked during moments of axial rotational than during those of flexion, extension, or lateral bending.
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Flexibility of lumbar spinal motion segments correlated to type of tears in the Annulus Fibrosus.
Journal of neurosurgery, 2000Co-Authors: Victor M. Haughton, Timothy A. Schmidt, Kevin Keele, Tae-hong LimAbstract:The authors conducted a study in which their objective was to measure the effect of tears in the Annulus Fibrosus on the motions of lumbar spinal motion segments. Lumbar spinal motion segments were harvested from human cadavers and studied using a 1.5-tesla magnetic resonance imager. The motion segments were subjected to incremental flexion, extension, rotation, and lateral bending torques. Displacements and rotations were measured using a kinematic system. The segments were sectioned on a cryomicrotome to verify the presence of tears in the Annulus Fibrosus. Tears in the Annulus Fibrosus increase the amount of motion that results from a torque applied to the motion segment. Radial and transverse tears of the Annulus Fibrosus have a greater effect on motions produced by an axial rotatory torque than on those produced by flexion, extension, or lateral bending torques. The difference between normal discs and discs with annular tears is more marked during moments of axial rotational than during those of flexion, extension, or lateral bending.
Raphael Pietton - One of the best experts on this subject based on the ideXlab platform.
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Microstructural characterization of Annulus Fibrosus by ultrasonography: a feasibility study with an in vivo and in vitro approach.
Biomechanics and modeling in mechanobiology, 2019Co-Authors: Tristan Langlais, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël Vialle, Judith R. Meakin, Peter Winlove, Pierre Desprairies, Pierre-yves Rohan, Claudio VergariAbstract:The main function of the intervertebral disc is biomechanical function, since it must resist repetitive high loadings, while giving the spine its flexibility and protecting the spinal cord from over-straining. It partially owes its mechanical characteristics to the lamellar architecture of its outer layer, the Annulus Fibrosus. Today, no non-invasive means exist to characterize Annulus lamellar structure in vivo. The aim of this work was to test the feasibility of imaging Annulus Fibrosus microstructure in vivo with ultrasonography. Twenty-nine healthy adolescents were included. Ultrasonographies of L3–L4 disc were acquired with a frontal approach. Annulus Fibrosus was segmented in the images to measure the thickness of the lamellae. To validate lamellar appearance in ultrasonographies, multimodality images of two cow tail discs were compared: ultrasonography, magnetic resonance and optical microscopy. In vivo average lamellar thickness was 229.7 ± 91.5 μm, and it correlated with patient body mass index and age. Lamellar appearance in the three imaging modalities in vitro was consistent. Lamellar measurement uncertainty was 7%, with good agreement between two operators. Feasibility of ultrasonography for the analysis of lumbar Annulus Fibrosus structure was confirmed. Further work should aim at validating measurement reliability, and to assess the relevance of the method to characterize Annulus alterations, for instance in disc degeneration or scoliosis.
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Shear Wave Elastography can evaluate Annulus Fibrosus Alteration in Adolescent Scoliosis
European radiology, 2018Co-Authors: Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël VialleAbstract:In vitro studies showed that Annulus Fibrosus lose its integrity in idiopathic scoliosis. Shear-wave ultrasound elastography can be used for non-invasive measurement of shear-wave speed (SWS) in vivo in the Annulus Fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar Annulus Fibrosus of scoliotic adolescents and compare it to healthy subjects. SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of 30 healthy adolescents (13 ± 1.9 years old) and 30 adolescent idiopathic scoliosis patients (13 ± 2 years old, Cobb angle: 28.8° ± 10.4°). SWS was compared between the scoliosis and healthy control groups. In healthy subjects, average SWS (all disc levels pooled) was 3.0 ± 0.3 m/s, whereas in scoliotic patients it was significantly higher at 3.5 ± 0.3 m/s (p = 0.0004; Mann-Whitney test). Differences were also significant at all disc levels. No difference was observed between males and females. No correlation was found with age, weight and height. Non-invasive shear-wave ultrasound is a novel method of assessment to quantitative alteration of Annulus Fibrosus. These preliminary results are promising for considering shear-wave elastography as a biomechanical marker for assessment of idiopathic scoliosis. • Adolescent idiopathic scoliosis may have an altered lumbar Annulus Fibrosus. • Shear-wave elastography can quantify lumbar Annulus Fibrosus mechanical properties. • Shear-wave speed was higher in scoliotic Annulus than in healthy subjects. • Elastography showed potential as a biomechanical marker for characterizing disc alteration.
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Shear Wave Elastography can evaluate Annulus Fibrosus Alteration in Adolescent Scoliosis
European Radiology, 2018Co-Authors: Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphaël VialleAbstract:Objectives In vitro studies showed that Annulus Fibrosus lose its integrity in idiopathic scoliosis. Shear wave ultrasound elastography can be used for noninvasive measurement of shear wave speed (SWS) in vivo in the Annulus Fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar Annulus Fibrosus of scoliotic adolescents and compare it to healthy subjects. Methods SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of thirty healthy adolescents (13 yo ± 1.9) and thirty adolescent idiopathic scoliosis patients (13 yo ± 2, Cobb angle: 28.8° ± 10.4°). SWS was compared between scoliosis and healthy control group. Results In healthy subjects, average SWS (all disc levels pooled) was 3.0 ± 0.3 m/s whereas, in scoliotic patients it was significantly higher at 3.5 ± 0.3 m/s (p = 0.0004; Mann-Whitney test). Differences were also significant at all disc levels. No difference was observed between males and females. No correlation was found with age, weight and height. Conclusion Non-invasive shear wave ultrasound is a novel method of assessment to quantitative alteration of Annulus Fibrosus. These preliminary results are promising to consider shear wave elastography as a biomechanical marker for assessment of idiopathic scoliotic.