Dose and time-response of photobiomodulation by LEDs (Light - Emitting Diodes) on chronic low back pain

Abstract

Introduction: Chronic low back pain can be defined as a continuous pain, with same intensity and persisting for over 3 months. There are several treatment modalities to treat low back pain, as drugs for muscle relaxation, anti-inflammatory and analgesic effects. However, the prolonged use of these drugs can promote adverse effects. The photobiomodulation (FBM) has gained prominence in this context due to its effectiveness in pain modulation. However, no studies have investigated the dose and time-response of the FBM for pain relief, functional ability and flexibility of the spine of patients with chronic low back pain. Objective: To evaluate the effect of three doses of FBM on pain, functional ability and flexibility in patients with chronic low back pain over 24 hours. Methodology: This is a randomized, double-blind, crossover and placebo-controlled trial. Thirty-six volunteers diagnosed with chronic low back pain will be enrolled in this study. Volunteers will be assessed for pain intensity, pain relief, functional incapacity and flexibility. There will be 3 FBM sessions (dose-response): 1) Effective FBM with low light dose (J 50); 2) Effective with high light dose (500 J) and 3) placebo FBM (J 0). The FBM will be applied on the dorsal root ganglion region at lumbar 2 (L2) region by a cluster of 69 LEDs (light-emitting diodes) with 35 LEDs in the red range (630 ± 10nm) and 34 LEDs in the infrared range (830 ± 20nm). All volunteers will be evaluated in 5 moments (time-response): 1) pre intervention; 2) 1 hour after FBM; 3) 3 hours after FBM; 4) 6 hours after FBM and 5) 24 hours after FBM. Between each session of FBM, will be applied an washout of 45 days. For the data analysis, a significance level of 5% will be adopted. (AU)