Effect of dry needling on lumbar muscle stiffness in patients with low back pain: A double blind, randomized controlled trial using shear wave elastography

Background: Dry needling treatment focuses on restoring normal muscle function in patients with musculoskeletal pain; however, little research has investigated this assertion. Shear wave elastography (SWE) allows quantification of individual muscle function by estimating both resting and contracted muscle stiffness. Objective: To compare the effects of dry needling to sham dry needling on lumbar muscle stiffness in individuals with low back pain (LBP) using SWE. Methods: Sixty participants with LBP were randomly allocated to receive one session of dry needling or sham dry needling treatment to the lumbar multifidus and erector spinae muscles on the most painful side and spinal level. Stiffness (shear modulus) of the lumbar multifidus and erector spinae muscles was assessed using SWE at rest and during submaximal contraction before treatment, immediately after treatment, and 1 week later. Treatment effects were estimated using linear mixed models. Results: After 1 week, resting erector spinae muscle stiffness was lower in individuals who received dry needling than those that received sham dry needling. All other between-groups differences in muscle stiffness were similar, but non-significant. Conclusion: Dry needling appears to reduce resting erector spinae muscle following treatment of patients with LBP. Therefore, providers should consider the use of dry needling when patients exhibit aberrant stiffness of the lumbar muscles.