Photomedicine and Laser Surgery, Volume 30, N2012
Meta-analysis of pain relief effects of laser irradiation on joint surfaces
Ho Jang, M.S., and Hyunju Lee, Ph.D
Department of Information and Communication, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
Executive Summary
Background: Laser therapy has been proposed as a physical therapy for musculoskeletal disorders and has gained popularity because no side effects have been reported after treatment. However, its true effectiveness is still controversial, as several clinical trials have reported the ineffectiveness of lasers in treating pain.
The methods: In this systematic review, we examine the clinical effectiveness of low-level laser therapy (LLLT) for joint pain. Included are clinical studies on joint pain that fulfil the following conditions: The laser is irradiated on the joint area, the score on the PEDro scale is at least 5, and the effectiveness of the study is measured using a visual analogue scale (VAS) To estimate the overall effectiveness of all the clinical trials included, a mean weighted difference in pain change on the VAS was used.
Results: MEDLINE is the main source for the literature search. After the literature search, 22 studies on joint pain were selected. The average methodological quality score of the 22 trials involving 1014 patients was 7.96 on the PEDro scale; 11 trials reported positive effects and 11 trials reported negative effects. The mean weighted difference in the change in pain on the VAS was 13.96�mm (95% CI, 7.24�20.69) in favour of the active LLLT groups. Looking only at the clinical trials where the absorbed dose was within the dose range proposed in the 2003 review by Bjordal et al. and the World Association for Laser Therapy (WALT) dose recommendation, the mean effect sizes were 19.88 and 21.05�mm in favour of the true LLLT groups.
Conclusion: The review shows that laser therapy on the joint relieves patients� pain. In addition, if we limit the energy doses of laser therapy to the dose window recommended in the previous study, we can expect more reliable pain treatments.
Ef�ciency of low-level laser therapy to reduce pain induced by orthodontic forces
Ali Altug Bicakci, D.D.S., M.S., 1Burcu Kocoglu-Altan, D.D.S., M.S., Ph.D
2 Hulya Toker, D.D.S., M.D.S., Ilhan Mutaf, M.D.S., 1 and Zeynep Sumer, M.D., M.D., Dr. 4
Summary
Objective: The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on the reduction of orthodontic pain after fitting by evaluating changes in the composition of the gingival crevicular �uid (GCF) at the level of prostaglandin E2 (PGE2) and visual analogue scale (VAS). Background data: LLLT has been shown to be effective in relieving pain. PGE2 has the greatest influence on the process of pain signals and can be detected in GCF to study the response of dental and periodontal tissue in a biochemical way.
The methods: Nineteen patients (11 women and 8 men; mean age 13.9 years) were included in this study. Maxillary molars �rst were bandaged and then a randomly selected �rst molar was irradiated on one side (820 nm; continuous wave; output power: 50 mW; focal spot: 0.0314 cm2; exposure duration: 5 s; power flux density: 1.59 W/cm2; absorbed dose: 0.25 J; energy flux density: 7.96 J/cm2 f? for each exposure), while the molar on the other side served as a placebo control. GCF was taken from the gingival gap of each molar to assess PGE2 concentrations before band placement and 1 and 24 h after laser irradiation. Pain intensity was analysed by VAS 5 min, 1 h and 24 h after band placement.
Results: Although no difference in pain perception was found after 5 minutes and 1 hour, a significant reduction in pain intensity was observed 24 hours after application by laser treatment ( p < 0.05). Mean PGE2 values were elevated in the control group signi�cantly, while a gradual decrease was observed in the laser group. The difference in PGE2 concentrations both 1 and 24 hours after treatment was statistically signi�cant between two groups ( p < 0.05).
Conclusion: The signi�cant reductions in both pain intensity and PGE2 concentrations showed that LLLT ef�cient reduced orthodontic pain after fitting.
Published in "The Lancet".
Effectiveness of low-level laser therapy in the treatment of neck pain: a systematic review and meta-analysis of randomised, placebo- or active-treatment-controlled trials
Dr Roberta T. Chow MBBS, Prof Mark I. Johnson PhD, Prof. Rodrigo AB. Lopes-Martins PhD, Prof. Jan M. Bjordal PT
Executive summary
Background: Neck pain is a common and costly condition for which pharmacological treatment has limited evidence of efficacy and side effects. Low Level Laser Therapy (LLLT) is a relatively rare, non-invasive treatment for neck pain that uses non-thermal laser irradiation at the painful sites. We have conducted a systematic review and meta-analysis of randomised controlled trials to assess the effectiveness of LLLT in neck pain.
The methods: We searched computerised databases and compared the effectiveness of LLLT using any wavelength with placebo or with active control in acute or chronic neck pain. The effect size for the primary outcome, pain intensity, was defined as a pooled estimate of the mean difference in mm of the change on a visual analogue scale of 100 mm.
Findings: We identified 16 randomised controlled trials involving a total of 820 patients. In acute neck pain, the results of two studies showed a relative risk (RR) of 1Â-69 (95% CI 1Â-22â€�2Â-33) of pain improvement with LLLT compared to placebo. Five studies on chronic neck pain with categorical data showed an RR for pain improvement with LLLT of 4Â-05 (2Â-74â€�5Â-98). Patients in 11 trials who reported changes in the visual analogue scale had a 19Â-86 mm reduction in pain intensity (10Â-04â€�29Â-68). Seven studies provided follow-up data for 1â€�22 weeks after completion of treatment, with short-term pain relief continuing over the medium term with a reduction of 22Â-07 mm (17Â-42â€�26Â-72). The side effects of LLLT were mild and did not differ from those of placebo.
Interpretation: We show that LLLT reduces pain immediately after treatment for acute neck pain and up to 22 weeks after completion of treatment in patients with chronic neck pain.
The effect of a 300 mW, 830 nm laser in chronic neck pain: a double-blind, randomised, placebo-controlled study.
Chow RT, Heller GZ, Barnsley L.
Castle Hill Medical Centre, 269-271 Old Northern Road, Castle Hill, NSW 2154, Australia.
A randomised, double-blind, placebo-controlled, low-level laser therapy (LLLT) study of 90 volunteers with chronic neck pain was conducted to determine the efficacy of a 300 mW, 830 nm laser in the treatment of chronic neck pain. The subjects were randomised to receive a course of 14 treatments over 7 weeks with either active or sham laser on sensitive areas of the neck. The primary outcome measure was the change in a 10 cm Visual Analogue Scale (VAS) for pain. Secondary outcome measures included the Short-Form 36 Quality-of-Life Questionnaire (SF-36), Northwick Park Neck Pain Questionnaire (NPNQ), Neck Pain and Disability Scale (NPAD), McGill Pain Questionnaire (MPQ) and Pain Improvement Self-Assessment (SAI) using VAS. The measurements were taken at the start of the study, at the end of a seven-week treatment period and 12 weeks after the start of the study. The mean VAS pain values improved by 2.7 in the treated group and worsened by 0.3 in the control group (difference 3.0, 95% CI 3.8-2.1). Significant improvements were found in the active group compared to placebo for SF-36-Physical Score (SF36 PCS), NPNQ, NPAD, MPQVAS and SAI. The results of the SF-36 Mental Score (SF36 MCS) and other MPQ component scores (afferent and sensory) did not differ significantly between the two groups. Low level laser therapy (LLLT) was effective in relieving pain in patients with chronic neck pain over a period of 3 months for the parameters used in this study.
PMID: 16806710 [PubMed - under development
Photoradiation in acute pain: a systematic review of possible mechanisms of action and clinical effects in randomised, placebo-controlled studies
Apr 2006, Vol. 24, No. 2: 158-168 Photomedicine and Laser Surgery
Dr Jan Magnus Bjordal, P.T., Ph.D.
Section of Physiotherapy Science, University of Bergen, and Institute of Physiotherapy, Bergen University College, Bergen, Norway.
Dr. Mark I. Johnson, Ph.D.
Faculty of Health, Metropolitan University of Leeds, Leeds, United Kingdom.
Vegard Iversen, Ph.D.
Institute of Biomedical Sciences, Department of Physiology, University of Bergen, Bergen, Norway.
Flavio Aimbire, M.Sc.
Laboratory for Animal Testing, IP&D Universidade Vale do Paraiba (UNIVAP), São José dos Campos, SP, Brazil.
Rodrigo Alvaro Brandao Lopes-Martins, M.Pharmacol., Ph.D
Institute of Biomedical Sciences, Pharmacology Department, Universidade Sao Paulo, São Paulo, SP, Brazil.
Executive Summary
Objective: The aim of this study was to evaluate the biological and clinical short-term effects of photoradiation in acute pain due to soft tissue injury.
Background data: It is unclear whether and how photoradiation can reduce acute pain.
Methods: Literature review of (i) controlled laboratory studies investigating potential biological mechanisms for pain relief and (ii) randomised placebo-controlled clinical trials measuring results within the first 7 days after acute soft tissue injury.
Results: From 19 out of 22 controlled laboratory studies, there is strong evidence that photoradiation can modulate inflammatory pain by reducing levels of biochemical markers (PGE2, mRNA Cox 2, IL-1β, TNFα), neutrophil cell influx, oxidative stress and the formation of edema and bleeding in a dose-dependent manner (mean dose 7.5 J/cm2, range 0.3�19 J/cm2). Four comparisons with non-steroidal anti-inflammatory drugs (NSAIDs) in animal studies showed that optimal doses of photoradiation and NSAIDs are equally effective. Seven randomised placebo-controlled trials found no significant results after only a single point on the skin above the injury site was irradiated or after using a total absorbed dose of less than 5 joules. Nine randomised placebo-controlled trials (n = 609) were of acceptable methodological quality and irradiated three or more points and/or more than 2.5 cm2 at the site of the injury or surgical incision with a total absorbed dose of 5.0�19.5 joules.
The results in these nine trials were significantly in favour of the photoradiation groups over the placebo groups in 15 of 18 outcome comparisons. Poor and heterogeneous data presentation made it difficult to statistically compile continuous data. The categorical data on subjective improvement were homogeneous (Q-value = 7.1) and could be calculated from four studies (n = 379), which showed a significant relative risk of improvement of 2.7 (95% confidence interval [CI], 1.8�3.9) in a fixed effects model.
Conclusion: Photoradiation can modulate inflammatory processes in a dose-dependent manner and can be titrated to significantly reduce acute inflammatory pain in the clinical setting. Further clinical studies with adequate photoradiation doses are needed to accurately estimate the effect size of photoradiation in acute pain.
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Braz Dent J. 2001;12(3):187-90.
Evaluation of the anti-inflammatory effect of 830 nm laser light using C-reactive protein levels.
Freitas AC, Pinheiro AL, Miranda P, Thiers FA, Vieira AL.
Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, PUC-RS, Porto
Alegre, RS, Brazil.
The anti-inflammatory effect of non-surgical lasers has been suggested earlier, but has not been scientifically proven. One method of assessing the degree of inflammation is to measure C-reactive protein (CRP), which increases as the inflammation progresses. The aim of this study was to assess the effect of 830 nm laser irradiation after the removal of impacted third molars using CRP as a marker of inflammation.
Twelve patients were irradiated with 4.8 J laser light per session 24 and 48 h after surgery. A control group (N = 12) was treated with a sham laser. Blood samples were taken before and 48 and 72 hours after the operation. The CRP values were more symmetrical and better distributed for the irradiated group (0.320 mg/dl) than for the control group (0.862.mg/dl) 48 h after surgery, but there was no statistically significant difference. After 72 h, both groups showed statistically similar CRP values (0.272 and 0.608 mg/dl), which is due to the normal tendency of decreasing CRP values.
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