Dynamic ultrasound assessment of sciatic nerve excursion during neurodynamic mobilizations: a prospective observational study

This study evaluates sciatic nerve excursion at the hamstring level during active and passive neurodynamic mobilization (NDM) of the tibial, superficial peroneal, deep peroneal, and sural nerves. The aim is to determine which NDM (active or passive) generates higher excursion.

This analytical observational study was carried out at the University Clinic of the University of Manresa over a period of 17 weeks. Participants were placed in a side-lying SLUMP position with 60° of hip flexion and full knee extension. Neurodynamic mobilizations were performed randomly either actively or passively. Simultaneously, sciatic nerve excursion was recorded using high-frequency ultrasound and subsequently quantified using MATLAB software (version 2019b) through a frame-by-frame cross-correlation analysis.

Twenty-two participants voluntarily took part in the study (17 women and 5 men), with a mean age of 26.36 ± 6.04 years and a body mass index (BMI) of 22.15 ± 2.78 kg/m². Mean sciatic nerve excursion during active mobilization was 1.45 ± 0.76 mm, whereas passive mobilization produced an excursion of 1.07 ± 0.74 mm. A statistically significant difference was observed between the two conditions (p < 0.001).

The sciatic nerve can be mobilized through its four terminal branches using both active and passive neurodynamic techniques, all of which generate a proximal mechanical effect. Active self-mobilization, particularly through the tibial nerve, may represent an effective therapeutic intervention for patients with proximal sciatic nerve involvement, as it produces greater sciatic nerve excursion at the hamstring level.