Muscle elasticity in patients with neonatal brachial plexus palsy using shear-wave ultrasound elastography. Preliminary results.

Abstract

Ultrasound shear wave elastography (SWE) is a noninvasive, reliable and reproducible method, used for the qualitative and quantitative evaluation of tissues. The aim of this study was to compare muscle elasticity between the healthy and the involved sides in children with neonatal brachial plexus palsy (NBPP) using the elastography tool and to assess whether the difference was correlated with the Mallet grading system. We repeatedly measured the shear modulus coefficient of several muscles around the shoulder in stretched or passively relaxed positions on 14 patients. We evaluated the abductor muscles (supraspinatus and deltoid), the infraspinatus, the pectoralis major and the latissimus dorsi. We found a mean shear modulus significantly higher in most studied muscles in the pathologic side (P < 0.001), especially in the stretched position (P < 0.001). Moreover, the shear modulus increases with the degradation of the Mallet score for the abduction and external rotation tasks. SWE seems to be a reliable and reproducible tool to assess muscle elasticity in NBPP.