Shear wave elastography of the brachial plexus roots at the interscalene groove

Sonoelastography is an emerging technology that has been used to evaluate the musculoskeletal system including the brachial plexus of peripheral nerves, which has been only recently considered for study by shear wave elastography. The purpose of this study is to establish the normal sonoelastographic features of the C5-C7 nerve roots of the brachial plexus.

Forty healthy individuals (21 males and 19 females) were enrolled in the study. Shear wave elastography was used to evaluate the C5-C7 nerve roots of the brachial plexus at the interscalene interval. Normal sonoelastographic values were obtained.

The mean shear elastic modulus of the C5 nerve root was 16.9 kPa (range 5.9-28.8 ± 4.9 standard deviation, SD), 15.7 kPa (range 5.4-26.3 ± 4.3 SD) for the C6 nerve root, and 16 kPa (range 8-29 ± 4.6 SD) for the C7 nerve root. There was a significant statistical difference between both sexes in the elastic modulus at the C6 and C7, but not at the C5 nerve roots. Significant inverse correlation with height was noted at the C6 nerve root. There was no statistical significant difference in tissue stiffness between right- and left-handed subjects, age, and body mass index.

The elastic modulus of the C5-C7 nerve roots has been determined in asymptomatic individuals and can serve as a reference when studying pathological conditions of these structures.

BMI: body mass index; SWE: shear wave elastography.