Disc volume properties from MRI in adolescent idiopathic scoliosis: correlation to surgical outcome

In young scoliotic patients, the post-operative consequence of spine fusion upon the free lower lumbar spine is one of the major concerns of the surgical treatment. The remodeling of free-motion segment and the role of discs below thoraco-lumbar fusions remains unknown. However, disc hydration and mass exchange flow between disc and vertebral body should play a significant role in the mechano-biology of the vertebral segment. Magnetic resonance imaging is relevant to study intervertebral discs in young scoliotic patients since related to hydration and non-radiant

A solution of torsional problem by energy method in case of anisotropic cross-section

We proposed an original method to investigate the problem of torsion of anisotropic cross-section. We implemented an energy method to calculate the stress function represented by infinite series of trigonometric functions adapted to rectangular cross-section. After validation, we implemented a parametric sensitivity study to investigate the influence of the cross-section aspect ratio and the anisotropy level on the stress function, the strain energy density and the torsion stiffness. The process showed a fast convergence with a very good accuracy. The model showed a potential interest for the experimental identification of anisotropic material properties

Optimum Static Balancing of a Parallel Robot for Medical 3D-Ultrasound Imaging

International audienceStatic balancing of mechanical systems is useful and required in many situations. The objective of such balancing is the compensation of gravitational forces in order to achieve a static equilibrium. A balanced system becomes safer and actuators are reduced in size. However, balancing a system requires numerous complex mechanical add-ons or unavoidable addition of mass. This is the reason why methods of partial static balancing have been developed and applied in practice. In this paper, a newly designed parallel robot for medical 3D-ultrasound imaging is required to be statically balanced without complicated design modifications. Simple mechanical add-on that is optimally designed can reduce substantially the effect of gravity. The efficiency of these suggested solutions is illustrated by numerical simulation of the robot

Dispositif et procédé de la mesure de rigidité des tissus orbitaires

Dispositif de mesure de la rigidité des tissus orbitaires, caractérisé en ce qu'il comprend : - une poutre élastique (PE) ayant une extrémité libre (B), dite distale, et une extrémité opposée (A), dite proximale, encastrée dans une base (BP); - un système de fixation crânienne (BF), pour maintenir ladite base en contact avec le front (FP) d'un patient; - une interface mécanique d'appui (CO) s'étendant à partir de ladite poutre pour venir en contact avec un œil (OP) dudit patient; - au moins quatre jauges d'extensométrie (XI - X4) fixées sur au moins une face de la poutre; et - un module de traitement des signaux (MTS) configuré pour fournir une valeur de rigidité des tissus orbitaires (K) à partir des signaux générés par lesdites jauges d'extensométrie lorsqu'une force (Fl) est appliquée à ladite poutre provoquant sa flexion, de telle sorte que ladite interface mécanique d'appui exerce une pression sur ledit œil du patient. Utilisation d'un tel dispositif pour mesurer la rigidité des tissus orbitaires d'un patient

Spino-pelvic alignment influences disc hydration properties after AIS surgery: a prospective MRI-based study

To analyze the disc hydration and volumetric changes of the intervertebral disc after scoliosis surgery depending on the sagittal spino-pelvic organization

Hydration properties of the lumbar intervertebral discs in AIS after surgical correction:five years follow-up and comparison with an age-matched control group

We compared disc hydration properties of adolescent idiopathic scoliosis before and 5 years after spinal fusion with an age-matched control group. We conducted a prospective MRI follow-up of 23 patients. Disc and nucleus volumes were reconstructed on T2 weighted sequence. In the scoliotic group, vd and vn were lower than control group, hydration ratio (Vn/Vd) was lower. After surgery, subjacent discs rehydrated. AIS induces a loss of IVD hydration. Surgical correction can reverse homeostasis disturbances related to spinal deformity

Risk factors for adjacent segment degeneration after adolescent idiopathic scoliosis surgery: the intervertebral disc stability concept

Ideal surgical management of adolescent idiopathic scoliosis (AIS) aims for an optimal correction of the deformity while preserving mobility. An unbalanced rigid spine puts the mobile segment at higher risk of disk degeneration. The goal of our study is to clarify the long term outcome of AIS after spinal fusion

Increase in Il-31 Serum Levels Is Associated with Reduced Structural Damage in Early Axial Spondyloarthritis

In spondyloarthritis, little is known about the relation between circulating cytokines and patient phenotype. We have quantified serum levels of T helper type 1 cell (Th1), Th2 and Th17 cytokines in patients with recent-onset axial spondyloarthritis (AxSpA) from the DESIR cohort, a prospective, multicenter French cohort consisting of 708 patients with recent-onset inflammatory back pain (duration >3 months but <3 years) suggestive of AxSpA. Serum levels of Th1, Th2, and Th17 cytokines were assessed at baseline in patients from the DESIR cohort fulfilling the ASAS criteria (ASAS+) and were compared with age- and sex-matched healthy controls. At baseline, ASAS+ patients (n = 443) and healthy controls (n = 79) did not differ in levels of most of the Th1, Th2 and Th17 cytokines except for IL-31, and sCD40L, which were significantly higher for ASAS+ patients than controls (p < 0.001 and p = 0.012, respectively). On multivariable analysis of ASAS+ patients, IL-31 level was associated with sCD40L level (p < 0.0001), modified Stoke AS Spine Score (mSASSS) < 1 (p = 0.035). The multivariable analyses showed that IL-31 was an independent factor associated with mSASSS < 1 (p = 0.001) and low bone mineral density (p = 0.01). Increased level of IL-31 might protect against structural damage but is also related to low BMD

Contribution à la quantification objective des pathologies ostéo-articulaires par une approche interdisciplinaire en imagerie et biomécanique

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF