Shear-wave elastography can evaluate annulus fibrosus alteration in adolescent scoliosis

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.