Median nerve stiffness with three movement sequences of the upper limb neurodynamic test 1: An ultrasound shear-wave elastography study

Abstract

Background

During the Upper Limb Neurodynamic Test 1 (ULNT1) joint movement order can be varied to improve its diagnostic accuracy. However, nerve behavior with neurodynamic sequences still requires in vivo research.

Objective

To quantify differences in median nerve (MN) stiffness measuring shear-wave velocity (SWV) with ultrasound elastography during three sequences of the ULNT1.

Design

Cross-sectional study.

Methods

MN SWV was measured in 35 asymptomatic subjects at the wrist and elbow at the initial and final position (P1) of the standard (ULNT1-STD), proximal-to-distal (ULNT1-PROX) and distal-to-proximal (ULNT1-DIST) sequences of the ULNT1.

Results

Significantly different increases at P1 in nerve stiffness occurred between sequences and locations (p < 0.001). At the wrist, the ULNT1-PROX produced the smallest increase (44.32% ± 44.06, SWV: 4.49 ± 0.95 m/s), the ULNT1-STD produced a larger increase (82.13% ± 45.36, SWV: 5.67 ± 0.79 m/s, p < 0.001) and the ULNT1-DIST produced the largest (92.90% ± 55.37, SWV: 5.97 ± 0.79 m/s, p < 0.001). Differences between the ULNT1-DIST and ULNT1-STD did not reach significance.

At the elbow, the ULNT1-PROX showed a 119.92% ± 53.51 increase (SWV: 4.08 ± 0.84 m/s), the ULNT1-DIST a 134.84% ± 53.83 (SWV: 4.34 ± 0.77 m/s), and the ULNT1-STD a 113.30% ± 59.28 (SWV: 3.98 ± 1.04 m/s). No significant differences were found among the sequences.

Conclusion

The ULNT1-STD and ULNT1-DIST showed greater increases at MN stiffness at the wrist compared to the ULNT1-PROX. This supports a basis for future investigation of the mechanisms of neurodynamic testing in which emphasizing anatomical locations for improving diagnostic efficacy might be applied.