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.

Efficacy of prolonged application of low-level laser therapy combined with exercise in knee osteoarthritis: A randomized controlled double-blind study.

OBJECTIVES: To investigate the effect of prolonged low-level laser therapy application combined with exercise on pain and disability in patients with osteoarthritis of the knee. DESIGN: A randomized controlled trial. SETTING: Special rehabilitation services. SUBJECTS: Forty-three participants with knee osteoarthritis. INTERVENTION: Following initial assessment, participants were randomly allocated to the Laser group (n = 22, 44 knees) and received low-level laser therapy while the Placebo group (n = 21, 42 knees) received placebo therapy three times a week for 3 weeks. Both groups then received low-level laser therapy combined with exercise three times a week for the following 8 weeks. MAIN OUTCOME MEASURES: The primary outcome was change in knee pain and disability (Lequesne). Secondary outcomes included change in mobility (Timed Up and Go test), range of motion (goniometer), muscular strength (dynamometer), activity (Western Ontario and McMaster Universities Osteoarthritis questionnaire), and medication intake and relief. RESULTS: Mean (SD) age of participants was 63.02 (9.9) years. Pain scores at baseline, 3 weeks, 11 weeks, and 6 months follow-up were 9.1 (1.3), 2.6 (2.3), 0.2 (0.9), and 0.2 (0.8) for the Laser group and 9.5 (8.0), 7.7 (5.3), 5.6 (2.4), and 7.4 (5.0) for the Placebo group, respectively. Disability scores at baseline, 3 weeks, 11 weeks, and 6 months follow-up were 14.9 (4.7), 7.6 (4.8), 3.9 (4.2), and 3.5 (4.1) for the Laser group and 17.8 (14.7), 15.2 (11.5), 11.6 (6.4), and 15.8 (11.9) for the Placebo Group, respectively. CONCLUSION: In participants with osteoarthritis of the knee, the isolated application of low-level laser therapy in the initial 3 weeks and combined with exercises in the final 8 weeks reduced pain, disability, and intake of medication over a 6-month period.

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.

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.

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.

Efficacy of low-level laser therapy combined with exercise for subacromial impingement syndrome: A randomised controlled trial.

OBJECTIVE: To investigate the effect of low-level laser therapy (LLLT) combined with exercise on shoulder pain and disability in patients with subacromial impingement syndrome (SIS). DESIGN: Randomised controlled trial. SETTING: Pontifical Catholic University. SUBJECTS: We enrolled 120 subacromial impingement syndrome patients. INTERVENTION: Groups I (n = 42), II (n = 42) and III (n = 36) were treated with Low-level laser therapy and exercise, exercise only and Low-level laser therapy only, respectively. Interventions were conducted three times a week for 8 weeks. MAIN OUTCOME MEASURES: The primary outcome was the change in shoulder pain and disability index (SPADI). Secondary outcomes included changes in the numeric pain rating scale and medication intake. RESULTS: Average ages of patients in groups I, II and III were 51.9 ± 8.7 years, 56.0 ± 10.4 years and 54.2 ± 7.1 years, respectively. Pain scores at baseline (P = 0.829), 2 months (P = 0.057) and 3 months follow-ups (p = 0.004) were 6.8 (4.7-7.7), 0.2 (0.0-0.5) and 0.3 (0.0-1.0) for group I; 6.6 (5.7-8.0), 0.5 (0.2-2.0) and 0.2 (0.0-3.3) for group II; and 6.5 (5.1-7.4), 2.4 (0.1-6.7) and 4.0 (2.0-5.0) for group III, respectively. SPADI scores at baseline (P = 0.029), 2 months (P < 0.001) and 3 months follow-ups (P = 0.001) were 60.8 (37.7-70.8), 3.8 (0.0-10.8) and 2.3 (0.8-10.8) for group I; 61.5 (41.5-71.5), 9.2 (3.8-29.2) and 14.2 (1.5-38.0) for the group II; and 73.3 (59.2-80.8), 34.2 (16.9-54.6) and 33.1 (22.3-49.2) for the group III, respectively. CONCLUSION: Low-level laser therapy combined with exercises reduce pain intensity, improve shoulder function and reduces pain intensity and medication intake over 3 months. CLINICAL TRIAL REGISTRATION NUMBER: NCT02725749.

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 Modulates Muscle Gene Expression and Improves Performance of Rats Subjected to a Chronic Resistance Exercise Protocol.

Objective: In professional sports activities, the search for increased performance is constant. Electrophysical agents, including photobiomodulation (PBM), have been used in the sports context to accelerate postworkout recovery, prevent injuries, and even to improve performance. This study aims to investigate the effects of infrared laser (904 nm) on skeletal muscle gene expression of performance-related proteins of rats submitted to a chronic resistance training protocol. Materials and methods: Male Wistar rats (n = 40), weighing ±300 g were divided into four groups: sedentary control (CT, n = 10); irradiated control (CTL, n = 10); exercised not irradiated (EX, n = 10); exercised irradiated (EXL, n = 10). To assess the performance, the maximum carrying test was adapted and applied 72 h prior the training and 72 h after the last exercise session. The vertical weight climbing protocol was adapted for resistance training 3 × per week with 48 h interval between each session: first week adaptation, second week 25% of body weight (BW), third week 50% BW, fourth week 75% BW, and fifth week 100% BW. Animals were irradiated before exercise on hind paws 50 sec each, with infrared laser 904 nm 5 days per week, during 4 weeks, 9 J per leg in a total of 18 J energy per day. Results: The EXL performed more climbing (7.1 ± 0.91) compared to EX (4.4 ± 0.63). PBM promoted increased expression of lactate dehydrogenase enzyme, mammalian target of rapamycin protein, and androgen receptor (p < 0.05) but not the myosin heavy chain (p = 0.43). Conclusions: PBM therapy increases the expression of performance-related muscle mass gain genes besides improving the resistance training performance.

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.

Effect of 12 Weeks of Endurance Training Combined with Creatine Supplement, Photobiomodulation Therapy, or Both on Performance and Muscle Damage in Rats.

Background: Photobiomodulation therapy (PBMT) and creatine (Cr) intake have been used in conjunction with heavy training, but little is known about their possible effects during a long-term training program. Objective: We assessed long-term use of PBMT and Cr in an exercise training program. Methods: Twenty-five male Wistar rats weighing ∼300 g were randomly allocated to one of five groups: a nontraining control group, a training group, a training group receiving Cr, a training group receiving PBMT, and a training group receiving both PBMT and Cr. The training program consisted of 12 weeks of daily swimming training. PBMT was delivered in six points with a laser device (808 nm, 100 mW, 30 sec per point of irradiation, 3 J, 75 J/cm2). Results: All training groups showed significantly higher peak force and longer time to 50% decay of force, and lower creatine kinase (CK) levels than the nontraining control group, thus confirming the benefit of the training program. In all outcomes related to muscle performance, the groups receiving PBMT with or without Cr supplement performed significantly better (p < 0.05) peak force and time of force decay during an electrical stimulation protocol than all the other groups. In addition, CK levels were also significantly lower for the PBMT groups than for the other groups. Conclusions: We conclude that PBMT alone or in conjunction with Cr supplement during a 12-week training program resulted in significantly better muscle performance and lower levels of CK, a biochemical marker of muscle damage.

904 nm Low-Level Laser Irradiation Decreases Expression of Catabolism-Related Genes in White Adipose Tissue of Wistar Rats: Possible Roles of Laser on Metabolism.

Background: Adipose tissue is the main energy storage tissue in the body. Its catabolic and anabolic responses depend on several factors, such as nutritional status, metabolic profile, and hormonal signaling. There are few studies addressing the effects of laser photobiomodulation (PBM) on adipose tissue and results are controversial. Objective: Our purpose was to investigate the metabolic effects of PBM on adipose tissue from Wistar rats supplemented or not with caffeine. Materials and methods: Wistar rats were divided into four groups: control (CTL), laser-treated [CTL (L)], caffeine (CAF), and caffeine+PBM [CAF (L)]. Blood was extracted for quantification of triglyceride and cholesterol levels and white adipose tissues were collected for analysis. We evaluated gene expression in the adipose tissue for the leptin receptor, lipase-sensitive hormone, tumor necrosis factor alpha, and beta adrenergic receptor. Results: We demonstrated that the low-level laser irradiation was able to increase the feed intake of the animals and the relative mass of the adipose tissue in the CTL (L) group compared with CTL. Laser treatment also increases serum triglycerides [CTL = 46.99 ± 5.87; CTL (L) = 57.46 ± 14.38; CAF = 43.98 ± 5.17; and CAF (L) = 56.9 ± 6.12; p = 0.007] and total cholesterol (CTL = 70.62 ± 6.80; CTL (L) = 79.41 ± 13.07; CAF = 71.01 ± 5.52; and CAF (L) = 79.23 ± 6.881; p = 0.003). Conclusions: Laser PBM decreased gene expression of the studied genes in the adipose tissue, indicating that PBM is able to block the catabolic responses of this tissue. Interestingly, the CAF (L) and CAF animals presented the same CLT (L) phenotype, however, without increasing the feed intake and the relative weight of the adipose tissue. The description of these phenomena opens a new perspective for the study of the action of low-level laser in adipose tissue.

Infrared Low-Level Laser Therapy (Photobiomodulation Therapy) before Intense Progressive Running Test of High-Level Soccer Players: Effects on Functional, Muscle Damage, Inflammatory, and Oxidative Stress Markers-A Randomized Controlled Trial.

The effects of preexercise photobiomodulation therapy (PBMT) to enhance performance, accelerate recovery, and attenuate exercise-induced oxidative stress were still not fully investigated, especially in high-level athletes. The aim of this study was to evaluate the effects of PBMT (using infrared low-level laser therapy) applied before a progressive running test on functional aspects, muscle damage, and inflammatory and oxidative stress markers in high-level soccer players. A randomized, triple-blind, placebo-controlled crossover trial was performed. Twenty-two high-level male soccer players from the same team were recruited and treated with active PBMT and placebo. The order of interventions was randomized. Immediately after the application of active PBMT or placebo, the volunteers performed a standardized high-intensity progressive running test (ergospirometry test) until exhaustion. We analyzed rates of oxygen uptake (VO2 max), time until exhaustion, and aerobic and anaerobic threshold during the intense progressive running test. Creatine kinase (CK) and lactate dehydrogenase (LDH) activities, levels of interleukin-1ß (IL-1-ß), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), levels of thiobarbituric acid (TBARS) and carbonylated proteins, and catalase (CAT) and superoxide dismutase (SOD) activities were measured before and five minutes after the end of the test. PBMT increased the VO2 max (both relative and absolute values-p < 0.0467 and p < 0.0013, respectively), time until exhaustion (p < 0.0043), time (p < 0.0007) and volume (p < 0.0355) in which anaerobic threshold happened, and volume in which aerobic threshold happened (p < 0.0068). Moreover, PBMT decreased CK (p < 0.0001) and LDH (p < 0.0001) activities. Regarding the cytokines, PBMT decreased only IL-6 (p < 0.0001). Finally, PBMT decreased TBARS (p < 0.0001) and carbonylated protein levels (p < 0.01) and increased SOD (p < 0.0001)and CAT (p < 0.0001) activities. The findings of this study demonstrate that preexercise PBMT acts on different functional aspects and biochemical markers. Moreover, preexercise PBMT seems to play an important antioxidant effect, decreasing exercise-induced oxidative stress and consequently enhancing athletic performance and improving postexercise recovery. This trial is registered with Clinicaltrials.gov NCT03803956.

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.

Clinical and scientific recommendations for the use of photobiomodulation therapy in exercise performance enhancement and post-exercise recovery: current evidence and future directions.

BACKGROUND: There is about ten years since the first randomized controlled trial looking for the effects of photobiomodulation therapy using low-level laser therapy and/or light emitting diodes therapy in athletic performance enhancement was published. Since then, the knowledge in this field has increasing exponentially. OBJECTIVE: Given the fast advance in clinical interest, research and development in the use of photobiomodulation therapy for athletic performance enhancement and also to accelerate post-exercise recovery, as pioneers in this research field we felt the need to establish recommendations to ensure the correct use of the therapy, and also to guide the further studies in this area looking for the achievement of highest scientific evidence. It is important to highlight that the establishment of both clinical and scientific recommendations in this masterclass article were based on the most recent systematic reviews with meta-analysis and randomized controlled trials published in this field. It is important to stress that the recommendations of this masterclass article are based on most recent systematic reviews with meta-analysis and RCTs published in this research field. Future guidelines must follow the same direction and must be based only at the highest scientific evidence, avoiding overstatements and extrapolations based on animal experiments and case-studies.

Characterization of Skeletal Muscle Strain Lesion Induced by Stretching in Rats: Effects of Laser Photobiomodulation.

BACKGROUND: Unusual and exhaustive physical exercise can lead to muscle lesions depending on the type of contraction, intensity, duration, age, and level of conditioning. Different therapies have been proposed to prevent or reduce exercise-induced muscle damage. OBJECTIVE: In this study, we investigate the effects of low-level laser therapy on skeletal muscle strain in an experimental model in rats. MATERIALS AND METHODS: Male Wistar rats (200 g) were used. The animals were randomized into groups of six animals. We performed tibialis muscle elongation using a previously described protocol. The animals were anesthetized and submitted to passive stretching of the anterior tibial muscle attached to a weight corresponding to 150% of the body mass of the animal for 20 min, rested for 3 min, and received a second traction for 20 min. The cytokines, tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), IL-6, and IL-10, edema, and C-reactive protein (CRP) levels were determined in the tibialis anterior muscle. RESULTS: Plasma extravasation of groups treated with different doses of laser energy, lesion +1 J (2.61 ± 0.46), lesion +3 J (2.33 ± 0.13), lesion +6 J (2.92 ± 0.91), and lesion +9 J (2.80 ± 0.55), shows a significant reduction of extravasation when compared with the injury group (5.46 ± 1.09). Laser therapy was able to significantly reduce CRP and cytokine levels (TNF-α, IL-1ß, IL-6, and IL-10). CONCLUSIONS: Laser photobiomodulation reduced skeletal muscle edema as well as cytokines and CRP, leading to a significant reduction in inflammatory markers.

High doses of laser phototherapy can increase proliferation in melanoma stromal connective tissue.

It is well established that laser phototherapy (LP) is contraindicated directly over cancer cells, due to its bio modulatory effects in cell and blood vessel proliferation. The aim of the present study was to analyze the influence of typical low-level laser therapy (LLLT) and high intensity laser therapy (HILT) and an in-between dose of 9 J on collagen fibers and blood vessels content in melanoma tumors (B16F10) implanted in mice. Melanoma tumor cells were injected in male Balb C mice which were distributed in four groups: control (no irradiated) or irradiated by 3, 9, or 21 J (150; 450, or 1050 J/cm2). LP was performed in daily sessions for 3 days with a InGaAlP-660 nm (mean output: 50 mW, spot size: 2 mm2). Tumor volume was analyzed using (1) picrosirius staining to quantify collagen fibers content and (2) Verhoeff's method to quantify blood vessels content. Tumor growth outcome measured in the 3-J group was not significantly different from controls. Nine and 21-J groups, presented significant and dose-dependent increases in tumor volume. Quantitative analysis of the intensity of collagen fibers and their organization in stroma and peri-tumoral microenvironment showed significant differences between irradiated and control group. Blood vessels count of 21-J group outnumbered the other groups. High doses (≥ 9 J) of LP showed a dose-dependent tumor growth, different collagen fibers characteristics, and eventually blood vessel growth, while a typical LLLT dose (3 J) appeared harmless on melanoma cell activity.

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.