Inflammation

The effect of 300 mW, 830 nm laser on chronic neck pain: a double-blind, randomized, placebo-controlled study.

Chow RT, Heller GZ, Barnsley L.

Castle Hill Medical Centre, 269-271 Old Northern Road, Castle Hill, NSW 2154, Australia. rtchow@bigpond.net.au

A randomized, double-blind, placebo-controlled study of low-level laser therapy (LLLT) in 90 subjects with chronic neck pain was conducted with the aim of determining the efficacy of 300 mW, 830 nm laser in the management of chronic neck pain. Subjects were randomized to receive a course of 14 treatments over 7 weeks with either active or sham laser to tender areas in the neck. The primary outcome measure was change in a 10 cm Visual Analogue Scale (VAS) for pain. Secondary outcome measures included Short-Form 36 Quality-of-Life questionnaire (SF-36), Northwick Park Neck Pain Questionnaire (NPNQ), Neck Pain and Disability Scale (NPAD), the McGill Pain Questionnaire (MPQ) and Self-Assessed Improvement (SAI) in pain measured by VAS. Measurements were taken at baseline, at the end of 7 weeks' treatment and 12 weeks from baseline. The mean VAS pain scores 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 seen 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), at the parameters used in this study, was efficacious in providing pain relief for patients with chronic neck pain over a period of 3 months.

PMID: 16806710 [PubMed - in process]

Photoradiation in Acute Pain: A Systematic Review of Possible Mechanisms of Action and Clinical Effects in Randomized Placebo-Controlled Trials

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.

Mark I. Johnson, Ph.D.

Faculty of Health, Leeds Metropolitan University, Leeds, United Kingdom.

Vegard Iversen, Ph.D.

Institute of Biomedical Sciences, Department of Physiology, University of Bergen, Bergen, Norway.

Flavio Aimbire, M.Sc.

Laboratory of Animal Experiments, 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.

Objective: The aim of this study was to review the biological and clinical short-term effects of photoradiation in acute pain from soft-tissue injury. Background Data: It is unclear if and how photoradiation can reduce acute pain. Methods: Literature search of (i) controlled laboratory trials investigating potential biological mechanisms for pain relief and (ii) randomized placebo-controlled clinical trials which measure outcomes within the first 7 days after acute soft-tissue injury.

Results: There is strong evidence from 19 out of 22 controlled laboratory studies 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 formation of edema and hemorrhage in a dose-dependent manner (median dose 7.5 J/cm², range 0.3–19 J/cm²). Four comparisons with non-steroidal anti-inflammatory drugs (NSAIDs) in animal studies found optimal doses of photoradiation and NSAIDs to be equally effective. Seven randomized placebo-controlled trials found no significant results after irradiating only a single point on the skin overlying the site of injury, or after using a total energy dose below 5 Joules. Nine randomized placebo-controlled trials (n = 609) were of acceptable methodological quality, and irradiated three or more points and/or more than 2.5 cm² at site of injury or surgical incision, with a total energy of 5.0–19.5 Joules.

Results in these nine trials were significantly in favor of photoradiation groups over placebo groups in 15 out of 18 outcome comparisons. Poor and heterogeneous data presentation hampered statistical pooling of continuous data. Categorical data of subjective improvement were homogeneous (Q-value = 7.1) and could be calculated from four trials (n = 379) giving a significant relative risk for 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 clinical settings. Further clinical trials with adequate photoradiation doses are needed to precisely estimate the effect size for photoradiation in acute pain.

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Braz Dent J. 2001;12(3):187-90.
Assessment Of Anti-Inflammatory Effect Of 830nm 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 proposed previously,
however it was not scientifically proven. One method to assess levels of inflammation is the measurement of C-reactive protein (CRP), which is increased with the course of inflammation. The aim of this study was to assess the effect of 830 nm laser irradiation after the removal of impacted third molars using the CRP as the marker of inflammation.
Twelve patients were irradiated with 4.8 J of 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 prior to, and 48 and 72 h after surgery. CRP values were more symmetric and better distributed for the irradiated group (0.320 mg/dl) than for the control (0.862.mg/dl) 48 h after surgery, however there was no statistically significant difference. After 72 h, both groups had statistically similar CRP levels (0.272 and 0.608 mg/dl), because of the normal tendency of decreasing CRP levels.