The effect of manual lymphatic drainage on intraneural edema of the median nerve in patients with carpal tunnel syndrome: A randomized controlled trial.

Background: Intraneural edema is an important factor in the pathophysiology of carpal tunnel syndrome (CTS). Manual Lymphatic Drainage (MLD) is a manual treatment widely used to treat edema in a variety of conditions.

Purpose: This study aimed to evaluate the effect of MLD on intraneural edema of the median nerve in CTS patients, as well as its impact on symptom severity and hand function.

Study Design: Randomized controlled study.

Methods: Twenty-seven patients (aged 48.9 ± 9.9) with mild-to-moderate bilateral CTS were recruited for the study. One hand of each subject was allocated to the experimental group and the other hand in the control group randomly. The experimental group underwent MLD, myofascial release (MFR) therapy and conventional physiotherapy (CP). The control group received sham MLD, MFR and CP. Interventions were performed 2 days a week for 6 weeks. The distal motor latency (DML), motor nerve (MNCV), and sensory nerve (SNCV) conduction velocity of the median nerve were evaluated using electrodiagnostic techniques. As secondary evaluations, grip strength, pressure pain threshold, pain intensity, symptom severity, and hand functions were assessed. The cross-sectional area (CSA) of the median nerve was measured by ultrasound. All assessments were performed at baseline and 6 weeks after intervention.

Results: According to the analysis of a two-way repeated measures of ANOVA, the experimental group showed greater improvement in CSA (p < 0.001; η2 = 0.510), DML (p < 0.001; η2 = 0.549), sensory (p < 0.001; η2 = 0.408), and motor conduction velocity (p < 0.001; η2 = 0.419) of the median nerve than the control group. There was no significant difference between the groups in the secondary evaluation results (p > 0.05).

Conclusion: MLD may contribute to symptom relief in CTS by reducing intraneural edema in the median nerve.