Blinding techniques in randomized controlled trials of laser therapy: an overview and possible solution

The Effects of Photobiomodulation on Knee Function, Pain, and Exercise Tolerance in Older Adults: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To assess whether photobiomodulation therapy (PBMT) enhances the benefits of exercise in older adults.

DATA SOURCES

PubMed, Scopus, Medline, and Web of Science, dated to February 2023.

STUDY SELECTION

All included studies were randomized controlled trials of PBMT combined with exercise co-intervention in persons 60 years and older.

OUTCOME MEASURES

Western Ontario and McMaster University Osteoarthritis Index (WOMAC-total, pain, stiffness and function), perceived pain intensity, timed Up and Go (TUG) Test, 6-min walk test (6MWT), muscle strength, and knee range of motion were included.

DATA EXTRACTION

Two researchers independently performed data extraction. Article data were extracted in Excel and summarized by a third researcher.

DATA SYNTHESIS

The meta-analysis included 14 of the 1864 studies searched in the database. No statistical differences were found between the treatment and control groups in terms of WOMAC-stiffness (mean difference [MD]=-0.31, 95% confidence interval [CI] -0.64 to 0.03), TUG (MD=-0.17, 95% CI -0.71 to 0.38), 6MWT (MD=32.2, 95% CI -44.62 to 109.01), or muscle strength (standardized mean difference=0.24, 95% CI -0.02 to 0.50). However, statistically significant differences were found for WOMAC-total (MD=-6.83, 95% CI -12.3 to -1.37), WOMAC-pain (MD=-2.03, 95% CI -4.06 to -0.01), WOMAC-function (MD=-5.03, 95% CI -9.11 to -0.96), visual analog scale/numeric pain rating scale (MD=-1.24, 95% CI -2.43 to -0.06), and knee range of motion (MD=1.47, 95% CI 0.07 to 2.88).

CONCLUSIONS

In older adults who exercise regularly, PBMT can potentially provide additional pain relief, improve knee joint function, and increase knee joint range of motion.

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 Šidák’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.

Correlation Analysis Between Pain Intensity, Functional Disability and Range of Motion Using Low-Level Laser Therapy in Patients With Discogenic Lumbar Radiculopathy: A Cross-sectional Study

Introduction: Low-level laser is a pain-free and non-invasive treatment modality. It is used in many acute and chronic painful conditions. This study aimed to determine the correlation between pain intensity, functional disability, and range of motion using low-level laser therapy (LLLT) in patients with discogenic lumbar radiculopathy. Methods: This cross-sectional study was conducted as a part of a randomized controlled trial of LLLT to treat patients with discogenic lumbar radiculopathy in physical therapy departments of three different hospitals in Islamabad, Pakistan, from August 2021 to September 2021. The study was conducted according to STROBE guidelines. Fifty-Five patients from the experimental group of the trial were invited to participate in this study. The outcomes of the treatment were recorded on a semi-structured questionnaire on the first day and last day of their treatment from each patient's pain intensity, functional disability, and Lumbar range of motion (L-ROM) (flexion and extension) by using the visual analogue scale (VAS) for pain intensity, Oswestry Disability Index (ODI) for functional disability, and dual inclinometer for L-ROM. The data were analyzed through SPSS version 26.0. Results: The results of the correlation coefficient/Pearson's correlation of VAS, ODI, and dual inclinometer were varied. The strength of correlation between variables was weak to moderate (r=0.033 to 0.425) with statistically insignificant correlation coefficient (P > 0.05, 95% CI) except for lumbar flexion (P<0.05, 95% CI). Conclusion: For acute low back pain (LBP) with discogenic lumbar radiculopathy, LLLT at a wavelength of 830-nm and a dose of 3J/point in conjunction with conventional physical therapy had no significant correlation, but rather weak to moderate values with pain intensity, functional disability, and L-ROM.

Effectiveness of Low-Level Laser Therapy in Patients with Discogenic Lumbar Radiculopathy: A Double-Blind Randomized Controlled Trial

Purpose

To determine the effectiveness of low-level laser therapy (LLLT) in patients with discogenic lumbar radiculopathy and correlation among pain intensity, functional disability, and lumbar range of motion (LROM). Study Design/Setting. A double-blind RCT was conducted at physical therapy departments of different hospitals of Islamabad, Pakistan. The study period was March 2020 to August 2021. Patient Sample. The study comprised 110 patients with acute LBP and unilateral discogenic lumbar radiculopathy. Outcome Measures. The outcomes of the treatment were measured on the first day and then after 18 sessions from each patient's pain intensity, functional disability, L-ROM, and straight leg raise by using visual analogue scale, Oswestry disability index, dual inclinometer, and straight leg raise test.

Methods

A total of 110 participants with a mean age of 38 ± 7.4 years were randomly assigned into two groups of 55 each. The experimental group of 55 patients was treated with LLLT and conventional physical therapy. The control group of 55 patients was treated with conventional physical therapy alone. Both groups had received 18 treatment sessions. The data were analyzed through SPSS-21.0.

Results

The results of the Wilcoxon signed-rank test score as well as Mann–Whitney U test indicated a statistically significant difference in values (p < 0.05 in all instances) within the groups and between the groups, respectively.

Conclusions

The LLLT is proved as an efficient adjunct therapy to conventional physical therapy for discogenic lumbar radiculopathy.

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.

Laser Acupuncture for Carpal Tunnel Syndrome: A Single-Blinded Controlled Study

Objectives: This study aimed to compare the efficacy of laser acupuncture (LA) treatment with that of placebo LA treatment in patients with idiopathic, mild-to-moderate carpal tunnel syndrome (CTS), as measured by subjective symptom assessments and objective changes in nerve conduction studies (NCSs). Design: A randomized, single-blinded, controlled study. Settings: A Teaching Hospital in the Taichung, Taiwan between March 2013 and November 2013. Subjects: 84 consecutive treatment-naive patients with CTS. Interventions: Participants were randomly divided into two treatment arms: (1) LA, administered at traditional Chinese acu-points on the affected side, once a day, 5 times a week, for 4 weeks (N = 43); and (2) placebo LA, administered using the same device and protocol, with the LA device switched off (N = 41). Outcome measures: Patients completed the Global symptom score (GSS) at baseline and two and four weeks later. The primary outcome was changes in GSS. NCSs were performed at baseline and repeated at the end of the study as a secondary outcome. Results: There was a significantly greater reduction in GSS in the LA group than in the placebo group at week 2 (-9.30 ± 4.94 vs. -2.29 ± 4.27, respectively, P < 0.01) and at week 4 (-10.67 ± 5.98 vs. -2.90 ± 5.61, respectively, P < 0.01). However, NCSs did not show significant difference between the two groups. Conclusions: LA may be more effective than placebo LA in the treatment of mild-to-moderate idiopathic CTS in terms of subjective measurement. For patients who fear needle-based treatment, such as acupuncture or local injections, or those who do not opt for early surgical decompression, LA treatment can be considered as an effective and alternative form of acu-points stimulation therapy.

Low-level laser therapy for chronic non-specific low back pain: a meta-analysis of randomised controlled trials

OBJECTIVE

The efficacy of low-level laser treatment (LLLT) for chronic back pain remains controversial due to insufficient trial data. We aimed to conduct an updated review to determine if LLLT (including laser acupuncture) has specific benefits in chronic non-specific low back pain (CNLBP).

METHODS

Electronic databases were searched for randomised trials using sham controls and blinded assessment examining the intervention of LLLT in adults with CNLBP. Primary outcomes were pain and global assessment of improvement with up to short-term follow-up. Secondary outcomes were disability, range of back movement, and adverse effects. A random effects meta-analysis was conducted. Subgroup analyses were based on laser dose, duration of baseline pain, and whether or not laser therapy used an acupuncture approach.

RESULTS

15 studies were selected involving 1039 participants. At immediate and short-term follow-up there was significant pain reduction of up to WMD (weighted mean difference) -1.40 cm (95% CI -1.91 to -0.88 cm) in favour of laser treatment, occurring in trials using at least 3 Joules (J) per point, with baseline pain <30 months and in non-acupuncture LLLT trials. Global assessment showed a risk ratio of 2.16 (95% CI 1.61 to 2.90) in favour of laser treatment in the same groups only at immediate follow-up.

CONCLUSIONS

We demonstrated moderate quality of evidence (GRADE) to support a clinically important benefit in LLLT for CNLBP in the short term, which was only seen following higher laser dose interventions and in participants with a shorter duration of back pain. Rigorously blinded trials using appropriate laser dosage would provide greater certainty around this conclusion.

Low-dose laser acupuncture for non-specific chronic low back pain: a double-blind randomised controlled trial

Objective

To determine if infrared laser acupuncture (LA) may have a specific effect in reducing pain and disability in treatment of chronic low back pain (LBP).

Methods

This was a double-blind sham laser controlled trial performed in general practices in Perth, Western Australia. The participants were 144 adults with chronic non-specific LBP. They were randomised to receive eight once-weekly treatments. Laser machines (20 mW, 840 nm diode, power density 0.1 W/cm²) stimulated points in three treatment groups: sham (0 joules/point), low dose (0.2 J/point) and high dose (0.8 joules/point). Participants were followed-up at 1 and 6 weeks, and 6 and 12 months post treatment. Primary outcomes were pain (Numerical Pain Rating Scale (NPRS)) and disability (Oswestry Disability Inventory (ODI)) at 6 weeks post treatment. Secondary outcomes included numerical rating scale for limitation of activity, global assessment of improvement, analgesic usage and adverse effects after treatment.

Results

The analysis showed no difference between sham and the laser groups at 6 weeks for pain or disability. There was a significant reduction in mean pain and disability in all groups at 6 weeks (p<0.005); NPRS: sham (−1.5 (95% CI −2.1 to −0.8)), low dose (−1.3 (−2.0 to −0.8)), high dose (−1.1 (−1.7 to −0.5)). ODI: sham (−4.0 (−7.1 to −1.0)), low dose (−4.1, (−6.7 to −1.5)), high dose (−2.6 (−5.7 to 0.5)). All secondary outcomes also showed clinical improvement over time but with no differences between groups.

Conclusions

LA using energy density range (0–4 J/cm²) for the treatment of chronic non-specific LBP resulted in clinical improvement unrelated to laser stimulation.

Trial registration

http://www.anzctr.org.au ACTRN12610000043033.

ST36 laser acupuncture reduces pain-related behavior in rats: involvement of the opioidergic and serotonergic systems

Laser acupuncture is a modality of low-level light therapy used as an alternative to needling for the past three decades. Although it has proved effective for the treatment of various conditions, the mechanisms underlying its effects are not fully understood. To contribute to this understanding, this study was designed to (1) evaluate the antinociceptive effect of ST36 laser acupuncture (830 nm, 3 J/cm(2)) in rat models of acute nociception and (2) to investigate the opioidergic and serotonergic systems involvement in this effect. Our results demonstrate that ST36 laser acupuncture inhibited (36 ± 2 %) acetic acid-induced abdominal constrictions and both neurogenic (48 ± 7 %) and inflammatory (phase IIA 42 ± 8 % and phase IIB 83 ± 6 %) phases of formalin-induced nociceptive behavior. Moreover, the antinociceptive activity of laser irradiation in the acetic acid test was significantly reversed by preadministration of naloxone (1 mg/kg, nonselective opioid receptor antagonist), pindolol (1 mg/kg, subcutaneous; nonselective 5-HT 1A/B receptor antagonist), and ketanserin (1 mg/kg; selective 5-HT2A receptor antagonist) but not by ondansetron (1 mg/kg, selective 5-HT3 receptor antagonist). Taken together, our data demonstrate, for the first time, that (1) ST36 laser acupuncture elicited significant antinociceptive effect against acetic acid- and formalin-induced behavior in rats and that (2) this effect is mediated by activation of the opioidergic and serotonergic (5-HT1 and 5-HT2A receptors) systems.

Efficacy of acupuncture for chronic knee pain: protocol for a randomised controlled trial using a Zelen design

Background

Chronic knee pain is a common and disabling condition in people over 50 years of age, with knee joint osteoarthritis being a major cause. Acupuncture is a popular form of complementary and alternative medicine for treating pain and dysfunction associated with musculoskeletal conditions. This pragmatic Zelen-design randomised controlled trial is investigating the efficacy and cost-effectiveness of needle and laser acupuncture, administered by medical practitioners, in people with chronic knee pain.

Methods/Design

Two hundred and eighty two people aged over 50 years with chronic knee pain have been recruited from metropolitan Melbourne and regional Victoria, Australia. Participants originally consented to participate in a longitudinal natural history study but were then covertly randomised into one of four treatment groups. One group continued as originally consented (ie natural history group) and received no acupuncture treatment. The other three were treatment groups: i) laser acupuncture, ii) sham laser or, iii) needle acupuncture. Acupuncture treatments used a combined Western and Traditional Chinese Medicine style, were delivered by general practitioners and comprised 8–12 visits over 12 weeks. Follow-up is currently ongoing. The primary outcomes are pain measured by an 11-point numeric rating scale (NRS) and self-reported physical function measured by the Western Ontario and McMaster (WOMAC) Universities Osteoarthritis Index subscale at the completion of treatment at 12 weeks. Secondary outcomes include quality of life, global rating of change scores and additional measures of pain (other NRS and WOMAC subscale) and physical function (NRS). Additional parameters include a range of psychosocial measures in order to evaluate potential relationships with acupuncture treatment outcomes. Relative cost-effectiveness will be determined from health service usage and outcome data. Follow-up assessments will also occur at 12 months.

Discussion

The findings from this study will help determine whether laser and/or needle acupuncture is efficacious, and cost-effective, in the management of chronic knee pain in older people.

Trial registration

Australian New Zealand Clinical Trials Registry reference: ACTRN12609001001280

Laser acupuncture for the treatment of asthma in children: a systematic review of randomized controlled trials

BACKGROUND AND OBJECTIVES

Laser acupuncture has often been recommended as a treatment of asthma. The technique is noninvasive, and seems particularly suitable for children. However, the results from several clinical trials are contradictory. The objective of this review was to assess the effectiveness of laser acupuncture in the treatment of childhood asthma.

METHODS

Literature searches of electronic database were conducted in The Cochrane Library, Medline, EMBASE, AMED, CINAHL, and two Chinese literature databases (CNKI and VIP) up to February 2012. Randomized controlled trials (RCTs) testing laser acupuncture for asthma in children were included. No language restrictions were applied. Three authors independently selected articles, extracted data, and assessed trial quality.

RESULTS

Our searches identified 13 potential eligible studies, of which three with a total number of 176 patients met our inclusion criteria. The quality of included RCTs were low. One RCT with a parallel group design showed positive results, while two crossover RCTs generated negative results. There was variation in the type of patients, the interventions, and outcome measures. Because of the significant clinical and methodological heterogeneity, no meta-analysis was performed.

CONCLUSIONS

The number of RCTs and their total sample sizes are small; and their methodological quality is low. Therefore, no compelling evidence exists to suggest that laser acupuncture is not an effective treatment for childhood asthma. Further rigorous studies are warranted.

Laser acupuncture for chronic non-specific low back pain: a controlled clinical trial

OBJECTIVE

the primary aim was to determine if laser acupuncture (LA) is more effective than sham laser in reducing pain and disability in adults with chronic non-specific low back pain.

METHODS

the design was a double blind, two-group parallel randomised controlled trial. The active intervention was an 830 nm (infrared), 10 mW, Ga-Al-As laser diode laser for acupuncture and a sham control. The primary outcome measures were changes in pain (visual analogue scale) and disability (Oswestry Disability Index) at the end of 5-10 treatment sessions. Secondary outcomes were patient global assessment, psychological distress (Depression Anxiety Stress Scale) and subjective wellbeing (Personal Wellbeing Index). Follow up was performed at 6 weeks and 6 months after completion of treatment.

RESULTS

100 participants were enrolled and treated in a general practice setting. Per protocol analysis of the primary outcome measures using ANOVA suggested that although there was a significant overall improvement in pain and disability after the course of treatments (p<0.01), there was no significant difference between the intervention and control group in both the primary and most secondary outcome measures.

CONCLUSION

this study did not show a specific effect for LA using infrared laser at 0.2 Joules per point for chronic low back pain. The overall intervention appeared effective because of placebo and other factors. As there was some concern about baseline inequality between the groups further research using tighter inclusion criteria should attempt to replicate the result and examine if a dose response may exist.

[Low power laser in the treatment of the acute low back pain]

BACKGROUND/AIM

Acute low back pain (ALBP) is one of the most frequent painful conditions in the human population. The objective of the paper was to compare the efficacy of the low power laser (LPL) in the pain and the muscular spasm reduction with conservative methods of physical medicine.

METHOD

The prospective cohort study was done. The study involved 70 patients, both men and women, from 25 to 64 years of age with the diagnosis of ALBP. Two groups were formed. There were 40 patients in the first group and they were treated with the LPL with frequency of 73 Hz. The second group was the control one and it consisted of 30 patients who were treated with conservative methods of physical medicine (electrotherapy: diadynamic currents CP +/- 3 and CP +/- 3, interferent currents--90 Hz for 15 min; electrophoresis with novocaine). The ALBP were diagnosed by clinical examination and by the nuclear magnetic resonance imaging (NMRI). The low power laser--Gallium Arsenide (GaAs) was used. The laser sonde consisted of 4 laser diodes, each powered of 15 mW, wavelength 904 nm and with frequency 73 Hz. The total period of time for each treatment was 10 minutes and the total dose per treatment was 15 J. The intensity of acute low back pain was assessed by Roland's scale. The degree of the spasm was assessed in the relaxed position and during movements. Results. The average score in the first group before the onset of rehabilitation was 3.3 +/- 1.1 (Me = 3.0), and in the control group was 3.43 +/- 0.89 (Me = 3.0). After five treatments in patients who were treated with LPL the average score in Roland's scale was decreased (1.12 +/- 1.3, Me = 2.0) and in the control group there were no changes. After 10 treatments with the LPL the analgesic effect was obtained in 82.5% of patients from the first group and in 20% of patients in the control group. The analgesic effect in patients of the first group was obtained after 7.5 +/- 2.1 treatments and in the second group after 17.9 +/- 3.2 treatments. The difference was statistically significant (t = 15.652173, p < 0.001). The spasm disappeared in 92.5% of patients in the first group and in 20% of patients in the control group after 7.02 +/- 2.2 and 17.9 +/- 3.2 treatments respectively. The difference was statistically significant (t = 15.652173, p < 0.001).

CONCLUSION

The pain and spasm reduction were obtained in the greater number of patients by usage of the LPL than by usage of conservative methods of physical medicine.

Is sham laser a valid control for acupuncture trials?

Methodological problems of acupuncture trials focus on adequate placebo controls. In this trial we evaluated the use of sham laser acupuncture as a control procedure. Thirty-four healthy volunteers received verum laser (invisible infrared laser emission and red light, 45 s and 1 J per point) and sham laser (red light) treatment at three acupuncture points (LI4, LU7 and LR3) in a randomized, double-blinded, cross-over design. The main outcome measure was the ratio of correct to incorrect ratings of treatment immediately after each session. The secondary outcome measure was the occurrence of deqi-like sensations at the acupuncture points and their intensity on a 10-fold visual analog scale (VAS; 10 being the strongest sensible sensation). We pooled the results of three former trials to evaluate the credibility of sham laser acupuncture when compared to needle acupuncture. Fifteen out of 34 (44%) healthy volunteers (age: 28 ± 10.7 years) identified the used laser device after the first session and 14 (41%) after the second session. Hence, both treatments were undistinguishable (P = .26). Deqi-like sensations occurred in 46% of active laser (2.34 VAS) and in 49.0% of sham laser beams (2.49 VAS). The credibility of sham laser was not different from needle acupuncture. Sham laser acupuncture can serve as a valid placebo control in laser acupuncture studies. Due to similar credibility and the lack of sensory input on the peripheral nervous system, sham laser acupuncture can also serve as a sham control for acupuncture trials, in order to evaluate needling effects per se.