Reliability of Ultrasound and Shear Wave Elastography in Assessing Lower Extremity Nerve Stiffness and Excursion: A Systematic Review and Meta-Analysis

This study aimed to evaluate the reliability and methodological quality of ultrasonography and ultrasound elastography in assessing neural excursion and stiffness through shear wave elastography (SWE) of lower extremity nerves. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted across MEDLINE, Scopus, Web of Science, CINAHL, and SPORTDiscus databases, covering publications from 2014 to 2024. Out of 270 studies initially identified, 26 met the eligibility criteria, involving a total of 778 participants and 1,448 nerves. Reliability metrics included intraclass correlation coefficients (ICC), standard error of measurement (SEM), and minimal detectable change (MDC). Meta-analyses were performed for the sciatic and tibial nerves, incorporating data from studies employing SWE and B-mode ultrasonography. The pooled ICC for SWE in the sciatic nerve was 0.96 (95% CI: 0.93–0.98, I² = 25.6%), indicating excellent reliability. For the tibial nerve, ICCs varied by position, with an overall ICC of 0.87 (95% CI: 0.75–0.99, I² = 84.2%) for supine and prone positions and 0.96 (95% CI: 0.94–0.98, I² = 1.5%) for longitudinal excursion in weight-bearing and side-lying positions. Subgroup analyses revealed no significant differences between the two groups. This systematic review and meta-analysis support the reliability of SWE in assessing sciatic and tibial nerve stiffness, along with tibial nerve excursion in specific positions. However, these findings should be interpreted with caution, as evidence for the saphenous and femoral nerves remains limited.