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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

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Systematic review of the literature of low-level laser therapy (LLLT) in the management of neck pain

and .

Review published: .

CRD summary

This review examined the effectiveness of low-level laser therapy (LLLT) in the management of non-specific neck pain. The authors conclude that limited evidence suggests that LLLT with infrared wavelengths appears to be effective for the treatment of neck pain. In general, this was a well-conducted review and the authors' conclusions are likely to be reliable.

Authors' objectives

To determine the effectiveness of low-level laser therapy (LLLT) in the management of non-specific neck pain.

Searching

MEDLINE (1966 to 2004), PREMEDLINE (2004), EMBASE (1974 to 2004), CINAHL (1982 to 2004), Biological Abstracts (1984 to 2004), the Cochrane Database of Systematic Reviews (2004 update), the Cochrane CENTRAL Register (2004 update), ACP Journal Club (2004 update), DARE (2004 update), PEDro (earliest ref. 1929), the Science Citation Index (1980 to 2004), BIOSIS Previews (1980 to 2004) and AMED (1985 to 2004) were searched; the search terms were reported. In addition, the reference lists of retrieved articles and known articles of textbooks were handsearched, and experts in the field were consulted for additional references. The search was not restricted by language, although trials published in a language other than English were not included.

Study selection

Study designs of evaluations included in the review

Prospective randomised controlled trials (RCTs) were included in the review. Studies using a crossover design were excluded, as were those using the contralateral body side as the control.

Specific interventions included in the review

Trials of LLLT of any wavelength were eligible for inclusion. Studies of laser acupuncture in which acupuncture points were stimulated by laser were excluded. The lasers used in the included studies had wavelengths of 780, 820 to 830, or 904 nm; average output power varied from 5 to 60 mW, in pulsed and continuous modes; and the energy density ranged from 0.9 to 1,800 J/cm2. In the majority of trials, patients received between 5 and 10 sessions of treatment, given on a daily or every second day basis. However, in one study, patients received only one treatment session. The treatment sites varied from a single trigger point to 12 arbitrary points over the neck. The majority of studies compared LLLT with a sham control; one also compared it with visible laser, and another compared it with exercise plus LLLT, and exercise alone.

Participants included in the review

Trials of participants with acute or chronic mechanical (non-specific) neck pain, including conditions described as myofascial pain, trigger points, or localised fibromyalgia, and who were older than 16 years, were included in the review. Studies of participants with inflammatory conditions such as rheumatoid arthritis were excluded, as were trials treating widespread pain such as fibromyalgia.

Outcomes assessed in the review

Studies that reported some measure of neck pain as an outcome were eligible for inclusion. The primary outcome was an observed change in pain scores before and after treatment. Other outcomes included range of movement, function or disability measures, quality of life and adverse effects.

How were decisions on the relevance of primary studies made?

The authors did not state how studies were selected for the review, or how many reviewers performed the selection. However, they did state that any differences or difficulties in study selection were resolved by consensus.

Assessment of study quality

The methodological quality of the included studies was assessed using the Jadad criteria, which includes an assessment of randomisation, blinding and withdrawals. In addition, the authors scored the technical aspects of the laser application out of a maximum 18, which indicated all parameters were reported or could be calculated, permitting replication of the trial. Two reviewers carried out the quality assessment independently.

Data extraction

The authors did not state how many reviewers performed the data extraction. However, they did state that differences or difficulties in the data extraction were resolved by consensus. Details of laser parameters used, methods of application and treatment protocols were extracted into a predefined form. An effect size was calculated for all studies where possible.

Methods of synthesis

How were the studies combined?

The studies were combined in a narrative.

How were differences between studies investigated?

Differences between the studies were displayed in the table and discussed in the text.

Results of the review

Five RCTs, with a total of 273 participants, were included in the review.

Four of the 5 studies were of satisfactory quality (Jadad score at least 3 out of 5). One study was single-blind and of low methodological quality (Jadad score 2 out of 5). The technical quality scores ranged from 12 to 17 out of 18.

Four of the studies found a statistically significant improvement after receiving LLLT, compared with the control. One trial of acute pain found a significant improvement, both after receiving LLLT (P<0.0019) and at the 6-month follow-up (P<0.05). Effective treatment (defined as a self-reported improvement of 60%) was achieved in 94.95% of the participants in the treated group compared with 38.24% in the sham group. A second study found that individuals treated with LLLT showed a statistically significant improvement in pain relative to sham laser (P<0.01). Eighty-two per cent of participants receiving LLLT achieved effective pain relief versus 42% in the placebo group. One study found a significant improvement in neck pain, disability, and functional outcome measures (effect size 3.9, P<0.001). The fourth study found a significant benefit of exercise with LLLT compared with exercise alone (effect size 1.8, P<0.001). The results of one study were inconclusive.

Two studies reported no adverse effects of LLLT. One study reported adverse events in the LLLT group which did not occur in the sham control group. These included nausea, faintness, tiredness, shakiness, euphoria, weakness, stomach distension and increased pain. Two trials did not report the occurrence of adverse effects.

Authors' conclusions

Limited evidence suggests that LLLT with infrared wavelengths appears to be effective for the treatment of neck pain.

CRD commentary

The study question was defined clearly in terms of the participants, interventions, outcomes and study design. A thorough search of several databases was conducted, which reduces the likelihood of missing relevant studies. The included studies were limited to those published in English, which could increase the risk of language bias. However, the search was not limited by language and the authors stated that the only study that was excluded solely because of language had a positive result and, as such, was unlikely to have affected findings. The methods used to select studies and extract the data were not explicitly stated. However, it appears that more than one reviewer was involved in these processes, which helps to reduce the risk of bias. Quality was assessed on appropriate criteria and the assessment carried out in duplicate, thereby helping to reduce the risk of bias. Adequate study details were presented and, given the clinical heterogeneity between studies, it was appropriate that the studies were combined in a narrative. In general, this was a well-conducted review and the authors' conclusions are likely to be reliable.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that larger studies with long-term follow-up are required to confirm the review's findings and to determine the most effective laser parameters, sites and modes of application.

Bibliographic details

Chow R T, Barnsley L. Systematic review of the literature of low-level laser therapy (LLLT) in the management of neck pain Lasers in Surgery and Medicine 2005; 37(1): 46-52. [PubMed: 15954117]

Indexing Status

Subject indexing assigned by NLM

MeSH

Humans; Laser Therapy, Low-Level; Neck Pain /therapy; Treatment Outcome

AccessionNumber

12005001110

Database entry date

30/11/2006

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

Copyright © 2014 University of York.
Bookshelf ID: NBK72248

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