A randomized clinical trial on the changing of median nerve cross-sectional area and pain after extracorporeal shock wave and low-level laser therapy added to conventional physical therapy in patients with mild-to-moderate carpal tunnel syndrome

Background: Carpal tunnel syndrome (CTS) is the most common mononeuropathy in the upper limb. It remains uncertain whether adding extracorporeal shockwave therapy (ESWT) or low-level laser therapy (LLLT) to conventional treatment benefits CTS patients.

Purpose: This study aimed to compare the effectiveness of ESWT and LLLT in conjunction with conventional treatments (including carpal mobilization, transcutaneous electrical nerve stimulation, and ultrasound) on the cross-sectional area (CSA) of the median nerve and pain in mild-to-moderate CTS patients.

Study design: This was a single-blinded randomized clinical trial with registration number IRCT20220504054734N1.

Methods: Thirty-six patients were randomly assigned using block balanced randomization to receive either four sessions of ESWT or 10 sessions of LLLT in addition to 10 sessions of conventional treatments over 2 weeks. Patients received numbered closed envelopes indicating their treatment group. CSA (primary) and pain (secondary) in 18 patients who completed the treatment were assessed at baseline and after 2 weeks by a blinded assessor. Paired and independent sample t-tests were used for analyses due to the normal distribution of data was checked by Kolmogorov-Smirnoff. Cohen's d effect size was used to assess the intervention's magnitude.

Results: Both ESWT and LLLT groups showed significant improvements in CSA (p = 0.002) and pain (p < 0.001) from baseline to posttreatment. CSA improvement was moderate for ESWT (mean difference: 1.2, 95% CI 0.51-1.9) and mild for LLLT (mean difference: 0.76, 95% CI 0.4-1.14). Conversely, pain improvement was substantial in both groups (ESWT: mean difference 4.4, 95% CI 3.6-5.3; LLLT: mean difference 4.4, 95% CI 3.7-5.2). No substantial differences between ESWT and LLLT were observed, highlighting their comparable efficacy.

Conclusion: The addition of either LLLT or ESWT to conventional treatment effectively reduced pain and median nerve CSA in mild-to-moderate CTS. The absence of significant differences between ESWT and LLLT indicates their comparable efficacy in pain relief and CSA reduction.