Comparing the direct effect of lymphatic dynamic transport after lower-level laser therapy in healthy volunteers: a...

This study is aimed to explore the direct effects of low-level laser therapy (LLLT) at different wavelengths on lymphatic motility int healthy individuals. The goal was to identify the most effective protocol and assess the potential application of LLLT in managing lymphedema. The study included 32 healthy participants (12 males, and 20 females), divided into two groups. Each participant underwent a single session of unilateral upper extremity manual lymphatic drainage (UE MLD), followed by two types of LLLT applied to the ipsilateral axilla region to promote lymphatic drainage. Indocyanine green (ICG) lymphography was used during each treatment session to evaluate the immediate effect of LLLT on lymphatic motility. Additionally, extracellular fluid (ECF) and local tissue water level were assessed before and after the intervention using multiple frequency bioelectrical impedance analysis (MFBIA) and tissue dielectric constant (TDC). The overall reduction in body water content post-intervention was observed across multiple areas in both groups but without consistent statistical significance between groups. After UE MLD, the number of lymph packets significantly increased in both groups (Group A: from 3.20 ± 0.76 to 6.00 ± 1.38; Group B: from 2.80 ± 0.95 to 5.38 ± 1.44). However, during LLLT, the lymph packet count decreased significantly (Group A: to 1.73 ± 0.51; Group B: to 1.96 ± 0.67). Linear mixed model analysis showed that LLLT was associated with a reduction in lymph packet velocity (Estimate = - 1.22, 95% CI: - 2.08 to - 0.36, p = 0.006) and count (Estimate = - 1.11, 95% CI: - 1.57 to - 0.66, p < 0.001), while UE MLD significantly increased packet count (Estimate = 2.73, 95% CI: 2.28 to 3.19, p < 0.001). No significant intergroup differences were observed in lymphatic motility. This study quantitatively assessed lymphatic motility and tissue water content following different types of LLLT in healthy individuals. The findings suggest the need for further clinical studies to evaluate the effect of various LLLT parameters in lymphedema patients.Clinical trial number Not applicable.