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

Abstract

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.