Association Between Lower Limb Neural Mechanosensitivity and Functional Disability in Patients with Lumbosacral Radiculopathy: An Observational Study

Abstract

Background: Lumbosacral radiculopathy (sciatica) commonly arises from lumbar disc herniation and presents with radiating leg pain, paresthesia, and functional disability. Neurodynamic tests such as the Straight Leg Raise (SLR) and Slump tests are routinely used to evaluate neural mechanosensitivity; however, quantitative comparisons between symptomatic and asymptomatic individuals remain limited.

Objective: To quantify and compare lower limb neurodynamic responses between individuals with lumbosacral radiculopathy and healthy controls, and to determine the association between neural mechanosensitivity and functional disability.

Design: Cross-sectional observational case–control study.

Methods: Thirty patients with unilateral lumbosacral radiculopathy and thirty age- and sex-matched asymptomatic controls underwent neurodynamic testing. Primary outcomes included the angle of symptom onset during SLR and the knee extension angle at symptom onset during the Slump test. Secondary outcomes were pain intensity (Numeric Pain Rating Scale, NPRS) and functional disability (Oswestry Disability Index, ODI). Independent t-tests and Pearson’s correlations were used for analysis.

Results: The radiculopathy group showed significantly earlier symptom onset during SLR (38.7 ± 8.9°) compared with controls (78.3 ± 7.4°; p < 0.001). Similarly, Slump test knee extension angle was reduced (41.5 ± 10.2° vs. 78.9 ± 8.1°; p < 0.001). Pain intensity was higher in the radiculopathy group (SLR: 6.2 ± 1.4; Slump: 6.8 ± 1.2). ODI averaged 46.8 ± 8.7%, indicating moderate-to-severe disability. Lower SLR and Slump angles correlated with higher ODI scores (r = –0.57, p = 0.001; r = –0.62, p < 0.001).

Conclusion: Patients with lumbosacral radiculopathy exhibit heightened neural mechanosensitivity correlating with functional disability. Quantifying symptom onset angles in neurodynamic tests offers a practical measure of functional severity for physiotherapists.