Neglect of relevant treatment recommendations in the conduct and reporting of a laser therapy knee osteoarthritis trial: letter to the editor.

We read with interest the article by Gomes et al. entitled: "Exercise program combined with electrophysical modalities in subjects with knee osteoarthritis: A randomised, placebo-controlled clinical trial". Gomes et al. concluded that the low-level laser therapy (LLLT) did not reduce knee osteoarthritis pain when applied as an adjunct to exercise therapy. We argue that Gomes et al. neglected relevant laser treatment recommendations in the conduct and reporting of the trial.Gomes et al. did not state the Joules per treatment spot applied. We calculated the Joules applied from other laser information in the report and found that it is too low of a dose according to the World Association for Laser Therapy (WALT) guidelines. Furthermore, we have published a meta-analysis of 22 placebo-controlled trials demonstrating a significant difference in pain-relieving effect between doses in adherence and non-adherence to the WALT guidelines. However, neither the WALT guidelines, nor our meta-analysis was mentioned by Gomes et al.Moreover, Gomes et al. did not state whether the output power of the laser device was measured, and this is concerning because in the city of São Paulo, where the trial was conducted, most laser devices have been found to deliver less of a dose than specified by the manufacturers.In summary, we found that the best available evidence regarding effective and ineffective LLLT dosing from systematic reviews was neglected in the conduct and reporting of the trial, and that the laser device may not have been calibrated.

Electrical Stimulation in Lower Limb During Exercise to Improve Gait Speed and Functional Motor Ability 6 Months Poststroke. A Review with Meta-Analysis.

INTRODUCTION: Stroke is the third most common cause of disability in adults over 65 years of age and there are 30.7 million survivors after stroke worldwide. Stroke survivors have the highest odds of reporting severe disability and the greatest variety of individual domains of disability compared to a range of other conditions. Electrical stimulation of peripheral sensory-motor systems increases voluntary movement and muscle strength and thereby raises the activities of daily living (ADL). Little is known about electrical stimulation during physical activity in rehabilitation; the objective of this review is therefore to investigate whether external electrical stimulation combined with activity improves functional motor ability and gait speed in patients who have experienced a stroke within the last 6 months. METHODS: A review and random effects meta-analysis of randomized controlled clinical trials on gait speed and functional motor ability measured with Barthel Index (BI) and Bergs Balance Scale (BBS). RESULTS: Eight trials were included (n = 191). Explorative meta-analysis was performed on gait speed (5 trials, n = 120), BI (3 trials, n = 74), and BBS (3 trial n = 79). A small, significant difference on gait speed 0.15 (95% confidence interval [CI]: 0.08-0.21) m/s, but no difference in BI 2.88 (95 % CI: -3.3 to 9.07) and BBS 1.73 (95% CI: -2.8 to 6.27). CONCLUSIONS: Sparse, low-quality evidence indicates that electrical stimulation combined with activity is a relevant intervention to improve ADL within 6 months poststroke.

Should open excisions and sutured incisions be treated differently? A review and meta-analysis of animal wound models following low-level laser therapy.

Although low-level laser therapy (LLLT) was discovered already in the 1960s of the twentieth century, it took almost 40 years to be widely used in clinical dermatology/surgery. It has been demonstrated that LLLT is able to increase collagen production/wound stiffness and/or improve wound contraction. In this review, we investigated whether open and sutured wounds should be treated with different LLLT parameters. A PubMed search was performed to identify controlled studies with LLLT applied to wounded animals (sutured incisions-tensile strength measurement and open excisions-area measurement). Final score random effects meta-analyses were conducted. Nineteen studies were included. The overall result of the tensile strength analysis (eight studies) was significantly in favor of LLLT (SMD = 1.06, 95% CI 0.66-1.46), and better results were seen with 30-79 mW/cm2 infrared laser (SMD = 1.44, 95% CI 0.67-2.21) and 139-281 mW/cm2 red laser (SMD = 1.52, 95% CI 0.54-2.49). The overall result of the wound contraction analysis (11 studies) was significantly in favor of LLLT (SMD = 0.99, 95% CI 0.38-1.59), and the best results were seen with 53-300 mW/cm2 infrared laser (SMD = 1.18, 95% CI 0.41-1.94) and 25-90 mW/cm2 red laser (SMD = 1.6, 95% CI 0.27-2.93). Whereas 1-15 mW/cm2 red laser had a moderately positive effect on sutured wounds, 2-4 mW/cm2 red laser did not accelerate healing of open wounds. LLLT appears effective in the treatment of sutured and open wounds. Statistical heterogeneity indicates that the tensile strength development of sutured wounds is more dependent on laser power density compared to the contraction rate of open wounds.

Pain pressure threshold algometry in knee osteoarthritis: intra- and inter-rater reliability.

INTRODUCTION: Synovitis and effusion can cause pain sensitization in persons with knee osteoarthritis (KOA). Pain Pressure Threshold (PPT) algometry is a means to quantify somatosensory abnormalities, including inflammatory-mediated pressure hyperalgesia. We investigated the reliability of PPT algometry with three raters. METHODS: Twenty-seven persons (50 knees) with KOA, according to the American College of Rheumatology criteria, were included. The PPT of the most tender spot in the joint line of each knee, identified by palpation, was assessed using a digital pressure algometer with a round 1 cm2 rubber tip. The algometer was applied three times with at least twenty-second intervals by three physiotherapists each in a single session. Two of the physiotherapists had no experience with the procedure prior to the study. We estimated the Intraclass Correlation Coefficient (ICC) model 2.1, 95% within-subject standard deviation (sw), and Minimal Detectable Difference (MDD). RESULTS: The mean PPTs ranged from 39.94 to 41.81 Newton (N), the intra-rater ICC ranged from 0.909 to 0.956, the sw ranged from 6.44 to 10.77 N, and the related MDD ranged from 9.11 to 15.23 N. The three raters achieved an inter-rater ICC of 0.707, an sw of 17.68 N, and an MDD of 25.01 N. The results were homoscedastic. CONCLUSIONS: Our results indicate that PPT algometry is a suitable method for assessment of pain in osteoarthritic knees. After a short session of PPT procedure training, good intra-rater and acceptable inter-rater ICCs were achieved.

Pain and Disability of Conservatively Treated Distal Radius Fracture: A Triple-Blinded Randomized Placebo-Controlled Trial of Photobiomodulation Therapy.

Objective: Many patients with distal radius fracture (DRF) experience pain and disability after removal of the cast. The aim of this study was to investigate if photobiomodulation therapy (PBMT) applied after cast removal provides an add-on effect to a home-based exercise program in rehabilitation after DRF. Methods: In this triple-blinded placebo-controlled trial, 50 patients with conservatively treated DRF were randomized to receive either active PBMT or placebo PBMT after cast removal in addition to a home-based exercise therapy program. The outcome measures were the Patient-Rated Wrist and Hand Evaluation (PRWHE) questionnaire, night pain (NP), and consumption of analgesic medication (AM) and were evaluated after cast removal at 4 (baseline), 8, 12, and 26 weeks after injury. NP and AM were also evaluated 7 weeks after injury (end of active/placebo PBMT). Results: There was a significant between-group difference in PRWHE scores in favor of active PBMT 8, 12, and 26 weeks after DRF. NP and consumption of AM were significantly lower in the active PBMT group from 7 to 26 weeks. There was a minimum clinically important improvement between the groups in favor of active PBMT in total score at 12 weeks, in pain subscore at 8, 12, and 26 weeks, and in disability subscore at 8 and 12 weeks. Conclusions: PBMT is safe and has long-term positive effect on pain and disability in DRF patients, when applied in combination with a home-based rehabilitation exercise program. Clinical Trial registration number: NCT03014024.

Efficacy of low-level laser therapy in patients with lower extremity tendinopathy or plantar fasciitis: systematic review and meta-analysis of randomised controlled trials.

OBJECTIVES: We investigated the effectiveness of low-level laser therapy (LLLT) in lower extremity tendinopathy and plantar fasciitis on patient-reported pain and disability. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Eligible articles in any language were identified through PubMed, Embase and Physiotherapy Evidence Database (PEDro) on the 20 August 2020, references, citations and experts. ELIGIBILITY CRITERIA FOR SELECTION OF STUDIES: Only randomised controlled trials involving participants with lower extremity tendinopathy or plantar fasciitis treated with LLLT were included. DATA EXTRACTION AND SYNTHESIS: Random effects meta-analyses with dose subgroups based on the World Association for Laser Therapy treatment recommendations were conducted. Risk of bias was assessed with the PEDro scale. RESULTS: LLLT was compared with placebo (10 trials), other interventions (5 trials) and as an add-on intervention (3 trials). The study quality was moderate to high.Overall, pain was significantly reduced by LLLT at completed therapy (13.15 mm Visual Analogue Scale (VAS; 95% CI 7.82 to 18.48)) and 4-12 weeks later (12.56 mm VAS (95% CI 5.69 to 19.42)). Overall, disability was significantly reduced by LLLT at completed therapy (Standardised Mean Difference (SMD)=0.39 (95% CI 0.09 to 0.7) and 4-9 weeks later (SMD=0.32 (95% CI 0.05 to 0.59)). Compared with placebo control, the recommended doses significantly reduced pain at completed therapy (14.98 mm VAS (95% CI 3.74 to 26.22)) and 4-8 weeks later (14.00 mm VAS (95% CI 2.81 to 25.19)). The recommended doses significantly reduced pain as an add-on to exercise therapy versus exercise therapy alone at completed therapy (18.15 mm VAS (95% CI 10.55 to 25.76)) and 4-9 weeks later (15.90 mm VAS (95% CI 2.3 to 29.51)). No adverse events were reported. CONCLUSION: LLLT significantly reduces pain and disability in lower extremity tendinopathy and plantar fasciitis in the short and medium term. Long-term data were not available. Some uncertainty about the effect size remains due to wide CIs and lack of large trials. PROSPERO REGISTRATION NUMBER: CRD42017077511.

Short- and Long-Term Effectiveness of Low-Level Laser Therapy Combined with Strength Training in Knee Osteoarthritis: A Randomized Placebo-Controlled Trial.

BACKGROUND: Both physical activity and low-level laser therapy (LLLT) can reduce knee osteoarthritis (KOA) inflammation. We conducted a randomized clinical trial to investigate the short- and long-term effectiveness of LLLT combined with strength training in persons with KOA. METHODS: Fifty participants were randomly divided in two groups, one with LLLT plus strength training (n = 26) and one with placebo LLLT plus strength training (n = 24). LLLT and strength training were performed triweekly for 3 and 8 weeks, respectively. In the laser group, 3 joules 904 nm wavelength laser was applied to fifteen points (45 joules) per knee per session. Patient-reported outcomes, physical tests, and ultrasonography assessments were performed at baseline and 3, 8, 26, and 52 weeks after initial LLLT or placebo therapy. The primary outcomes were pain on movement, at rest, at night (Visual Analogue Scale), and globally (Knee injury and Osteoarthritis Outcome Score (KOOS) subscale). Parametric data were assessed with analysis of variance using Sidák's correction. RESULTS: There were no significant between-group differences in the primary outcomes. However, in the laser group there was a significantly reduced number of participants using analgesic and non-steroidal anti-inflammatory drugs and increased performance in the sit-to-stand test versus placebo-control at week 52. The joint line pain pressure threshold (PPT) improved more in the placebo group than in the laser group, but only significantly at week 8. No other significant treatment effects were present. However, pain on movement and joint line PPT were worse in the placebo group at baseline, and therefore, it had more room for improvement. The short-term percentage of improvement in the placebo group was much higher than in similar trials. CONCLUSIONS: Pain was reduced substantially in both groups. LLLT seemed to provide a positive add-on effect in the follow-up period in terms of reduced pain medication usage and increased performance in the sit-to-stand test.

Efficacy of mobilisation with movement in chronic shoulder pain: protocol for a systematic review and meta-analysis of controlled trials.

INTRODUCTION: Shoulder pain affects approximately one in four adults and is thus one of the most common musculoskeletal problems. Only 50% of patients who begin treatment for shoulder pain are cured within 6 months. There is a need for systematic reviews to estimate the effectiveness of shoulder treatments. We decided to evaluate the effect of mobilisation with movement (MWM) on chronic shoulder pain in a systematic review. METHODS AND ANALYSIS: The review will include controlled trial articles identified via five electronic databases (PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, Physiotherapy Evidence Database and Cochrane Central Register of Controlled Trials), reference lists, citations searches and experts in the field. Only controlled trials involving participants with a mean duration of pain of ≥3 months, in which the effectiveness of MWM has been compared with non-invasive treatments, sham mobilisation or wait-and-see will be included. The included trials will be synthesised with random effects meta-analyses. Risk-of-bias will be assessed with the Physiotherapy Evidence Database 0-10 point scale. ETHICS AND DISSEMINATION: The review does not require ethics approval as it is based on anonymised data from trial reports. The results of the review will be disseminated through a peer-reviewed publication. PROSPERO REGISTRATION NUMBER: CRD42018109380.

Treatment of Distal Radius Fracture During Immobilization with an Orthopedic Cast: A Double-Blinded Randomized Controlled Trial of Photobiomodulation Therapy.

Objective: With distal radius fracture (DRF) many patients experience stiffness and pain after removal of the cast. The aim of this study was to investigate possible effects of photobiomodulation therapy (PBMT) in DRF during immobilization with semicircular orthopedic cast. Methods: In this double-blinded, placebo-controlled trial, 53 patients with DRF were randomized to receive nine treatments of either PBMT or placebo-PBMT. The fractures were irradiated through openings in the cast. Patient-Rated Wrist and Hand Evaluation (PRWHE) questionnaire and clinical outcomes were measured at baseline, 4, 8, 12, and 26 weeks after the trauma. Results: No significant differences were found for PRWHE scores, although PBMT was significantly superior to placebo regarding active range of motion [AROM; 95% (confidence interval) CI: -65.25° to -20.42° and -25.57° to -0.73°, respectively] and grip strength at week 4 (95% CI: -12.10 to -1.67 kg). Side-to-side differences between injured and noninjured wrists were significantly smaller in the PBMT group regarding grip and pinch strength at week 4 (95% CI: 0.89 to 8.87 kg and 0.55 to 3.79 kg, respectively). Significantly less patients in the PBMT group reported night pain at week 3. Conclusions: PBMT administered during the immobilization period of DRF had no effect on perceived pain and function measured through PRWHE. Night pain was significantly reduced after 3 weeks by PBMT. PBMT significantly improved pinch and grip strength and AROM, but these findings did not translate to the subjective experience of pain and function. Trial registration number: Clinical.trials.gov number NCT02749929. The study was approved by the Regional ethics committee (REK-Vest) in Norway (App. No: 2015/330). Informed consent was obtained from all patients.

Effectiveness of Low-Level Laser Therapy Associated with Strength Training in Knee Osteoarthritis: Protocol for a Randomized Placebo-Controlled Trial.

Physical activity and low-level laser therapy (LLLT) can reduce knee osteoarthritis (KOA) inflammation. We are conducting a randomized placebo-controlled trial to investigate the long-term effectiveness of LLLT combined with strength training (ST) in persons with KOA, since it, to our knowledge, has not been investigated before. Fifty participants were enrolled. LLLT and ST was performed 3 times per week over 3 and 8 weeks, respectively. In the LLLT group, 3 Joules of 904 nm wavelength laser was applied to 15 spots per knee (45 Joules/knee/session). The primary outcomes are pain during movement, at night and at rest (Visual Analogue Scale) and global pain (Knee injury and Osteoarthritis Outcome Score, KOOS) pain subscale. The secondary outcomes are KOOS disability and quality-of-life, analgesic usage, global health change, knee active range of motion, 30 s chair stand, maximum painless isometric knee extension strength, knee pain pressure threshold and real-time ultrasonography-assessed suprapatellar effusion, meniscal neovascularization and femur cartilage thickness. All the outcomes are assessed 0, 3, 8, 26 and 52 weeks post-randomization, except for global health change, which is only evaluated at completed ST. This study features the blinding of participants, assessors and therapists, and will improve our understanding of what occurs with the local pathophysiology, tissue morphology and clinical status of persons with KOA up to a year after the initiation of ST and a higher 904 nm LLLT dose than in any published trial on this topic.

Reliability of pain pressure threshold algometry in persons with conservatively managed wrist fractures.

OBJECTIVE: Wrist fracture is a common injury in Norway. Pressure algometry is widely used to quantify patients' pain threshold in various anatomical locations. The aim of this study was to explore the reliability of pain pressure threshold (PPT) algometry in persons with conservatively managed distal radius fractures. METHODS: In this cross-sectional study, three raters (A, B, and C) tested the PPT of participants (18-97 years of age) with a unilateral distal radius fracture after removal of the cast. The raters conducted two measurements of both wrists. Intrarater reliability was examined in 75, 50, and 25 participants by Raters A, B, and C, respectively. Interrater reliability was tested in 50 and 25 participants by Rater Pairs A-B and A-C, respectively. Relative reliability was calculated with intraclass correlation coefficient (ICC1.1 ) and absolute reliability using within-subject standard deviation (Sw ). RESULTS: There was a significant difference in the PPT between the participants' injured and noninjured wrists (p < .0001). The mean PPT was 29% lower in the injured than in the noninjured wrists, 175 kPa (SD ± 62) versus 248 kPa (SD ± 83). Intrarater reliability (A) of PPT algometry was better in injured wrists than in noninjured wrists (ICC1.1  = 0.825 vs. 0.765 and Sw  = 27 vs. 43 kPa). Similarly, interrater reliability of PPT algometry was better in injured wrists than in noninjured wrists. In injured wrists, the interrater reliability of PPT algometry between Raters A and B was 0.617 (ICC1.1 ) and Sw was 51 kPa, and between Raters A and C, the interrater reliability was 0.706 (ICC1.1 ) and Sw was 48 kPa. CONCLUSION: PPT algometry is a useful measurement tool with acceptable reliability and thus suitable for monitoring and quantifying pain in persons with conservatively managed wrist fractures. To be more certain that a change has occurred, the same rater should perform the measurements.

What is the optimal time-response window for the use of photobiomodulation therapy combined with static magnetic field (PBMT-sMF) for the improvement of exercise performance and recovery, and for how long the effects last? A randomized, triple-blinded, placebo-controlled trial.

BACKGROUND: The optimal time-response window for photobiomodulation therapy (PBMT) using low-level laser therapy (LLLT) and/or light emitting diodes therapy (LEDT) combined with static magnetic fields (sMF) before physical activity still was not fully investigated. The aim of the present study was to investigate the better of four time-response windows for PBMT combined with sMF (PBMT-sMF) use before exercise in humans. METHODS: A prospectively registered, randomized, triple-blinded (volunteers, therapists and assessors) placebo-controlled trial was carried out. Sixty healthy untrained male subjects were randomly allocated to six experimental groups (n = 10 per group): PBMT-sMF 5 mins, PBMT-sMF 3 h, PBMT-sMF 6 h, PBMT-sMF 1-day, placebo, and control. The control group performed all procedures, however did not receive any kind of intervention. PBMT-sMF active or PBMT-sMF placebo was applied precisely in different time points after baseline MVC test to ensure that both MVC tests and eccentric exercise protocol would occur at the same hour of the day in all groups. Then, after five minutes, 3 h, 6 h or 1-day (24 h) of PBMT-sMF treatment (active or placebo) the eccentric exercise protocol was performed. The primary outcome was peak torque obtained from maximum voluntary contraction (MVC). The secondary outcomes were creatine kinase (CK), and delayed onset muscle soreness (DOMS). The primary and secondary outcomes were measured at baseline, immediately after, 1 h, 24 h and 48 h after the eccentric exercise protocol. RESULTS: Sixty patients were randomized and analyzed to each sequence. The outcomes in absolute values show that all active PBMT-sMF groups increased (p < 0.05) MVC from immediately after to 1 h after eccentric exercise, and decreased (p < 0.05) CK activity at all time points. However, PBMT-sMF 5 mins, 3 h and 6 h groups showed better results in MVC and CK analysis from 24 h to 48 h, and also to DOMS (p < 0.05) at all time points. Participants did not report any adverse events. CONCLUSIONS: PBMT-sMF can be used from 5 min to 6 h before exercise, and the effects can last up to 54 h after treatment. However, the effects start to decrease when a 1-day (24 h) time-response window is used. TRIAL REGISTRATION: NCT03420391. Registered 05 February 2018.

Photobiomodulation therapy does not decrease pain and disability in people with non-specific low back pain: a systematic review.

QUESTION: In people with non-specific low back pain (LBP), what are the effects of photobiomodulation therapy (PBMT) on pain, disability and other outcomes when compared with no intervention, sham PBMT and other treatments, and when used as an adjunct to other treatments? DESIGN: Systematic review of randomised trials with meta-analysis. PARTICIPANTS: People with acute/subacute or chronic non-specific LBP. INTERVENTIONS: Any type of PBMT (laser class I, II and III and light-emitting diodes) compared with no treatment, sham PBMT and other types of treatment, or used as an adjunct to another treatment. OUTCOME MEASURES: Pain intensity, disability, overall improvement, quality of life, work absence and adverse effects. RESULTS: Twelve randomised controlled trials were included (pooled n = 1,046). Most trials had low risk of bias. Compared with sham PBMT, the effect of PBMT on pain and disability was clinically unimportant in people with acute/subacute or chronic LBP. In people with chronic LBP, there was no clinically important difference between the effect of PBMT and the effect of exercise on pain or disability. Although benefits were observed on some other outcomes, these estimates were imprecise and/or based on low-quality evidence. PBMT was estimated to reduce pain (MD -11.20, 95% CI -20.92 to -1.48) and disability (MD -11.90, 95% CI -17.37 to -6.43) more than ultrasound, but these confidence intervals showed important uncertainty about whether the differences in effect were worthwhile or trivial. Conversely, PBMT was estimated to reduce pain (MD 19.00, 95% CI 9.49 to 28.51) and disability (MD 17.40, 95% CI 8.60 to 26.20) less than Tecar (Energy Transfer Capacitive and Resistive) therapy, with marginal uncertainty that these differences in effect were worthwhile. CONCLUSION: Current evidence does not support the use of PBMT to decrease pain and disability in people with non-specific LBP. REGISTRATION: CRD42018088242.

Efficacy of low-level laser therapy on pain and disability in knee osteoarthritis: systematic review and meta-analysis of randomised placebo-controlled trials.

OBJECTIVES: Low-level laser therapy (LLLT) is not recommended in major knee osteoarthritis (KOA) treatment guidelines. We investigated whether a LLLT dose-response relationship exists in KOA. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Eligible articles were identified through PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, Physiotherapy Evidence Database and Cochrane Central Register of Controlled Trials on 18 February 2019, reference lists, a book, citations and experts in the field. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: We solely included randomised placebo-controlled trials involving participants with KOA according to the American College of Rheumatology and/or Kellgren/Lawrence criteria, in which LLLT was applied to participants' knee(s). There were no language restrictions. DATA EXTRACTION AND SYNTHESIS: The included trials were synthesised with random effects meta-analyses and subgrouped by dose using the World Association for Laser Therapy treatment recommendations. Cochrane's risk-of-bias tool was used. RESULTS: 22 trials (n=1063) were meta-analysed. Risk of bias was insignificant. Overall, pain was significantly reduced by LLLT compared with placebo at the end of therapy (14.23 mm Visual Analogue Scale (VAS; 95% CI 7.31 to 21.14)) and during follow-ups 1-12 weeks later (15.92 mm VAS (95% CI 6.47 to 25.37)). The subgroup analysis revealed that pain was significantly reduced by the recommended LLLT doses compared with placebo at the end of therapy (18.71 mm (95% CI 9.42 to 27.99)) and during follow-ups 2-12 weeks after the end of therapy (23.23 mm VAS (95% CI 10.60 to 35.86)). The pain reduction from the recommended LLLT doses peaked during follow-ups 2-4 weeks after the end of therapy (31.87 mm VAS significantly beyond placebo (95% CI 18.18 to 45.56)). Disability was also statistically significantly reduced by LLLT. No adverse events were reported. CONCLUSION: LLLT reduces pain and disability in KOA at 4-8 J with 785-860 nm wavelength and at 1-3 J with 904 nm wavelength per treatment spot. PROSPERO REGISTRATION NUMBER: CRD42016035587.

Effects of photobiomodulation therapy on inflammatory mediators in patients with chronic non-specific low back pain: Protocol for a randomized placebo-controlled trial.

INTRODUCTION: Low back pain (LBP) is ranked as one of the most prevalent health conditions. It is likely that some inflammatory mediators could be associated with pain and disability in these patients. Photobiomodulation therapy (PBMT) is a non-pharmacological therapy often used in patients with LBP and one of the possible mechanisms of action of therapy is modulate inflammatory mediators. However, to date there are no studies that evaluated the effects of PBMT on the levels of inflammatory mediators in patients with LBP. The aim of this study is to evaluate the acute effects of PBMT on systemic levels of inflammatory mediators and pain intensity in patients with chronic non-specific low back pain. METHODS AND ANALYSIS: This is a prospectively registered, two-arm randomized placebo-controlled trial with blinded patients, assessors and therapists. Eighteen patients with chronic non-specific LBP will be randomized into 2 groups: placebo or active PBMT. The treatment will be provided in a single session. The primary outcome will be levels of prostaglandin E2 (PGE2). The secondary outcomes will be levels of necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and pain intensity. Biochemical and clinical outcomes will be measured at baseline and 15 minutes after the single treatment session. DISCUSSION: Despite PBMT be used in musculoskeletal disorders such as LBP, to the best of our knowledge this is the first study that will investigate a possible biological mechanism behind the positive clinical effects of PBMT on non-specific chronic low back pain. ETHICS AND DISSEMINATION: The study was approved by the Regional Research Ethics Committee. The results will be disseminated through publication in peer-reviewed international journal and conferences. TRIAL REGISTRATION NUMBER: NCT03859505.