Authors' objectives

To assess the effectiveness of 904 nm low level laser therapy (LT) in musculoskeletal disorders.

Searching

MEDLINE and EMBASE (both up to 1996) and the Database of the Cochrane Field "Rehabilitation and Therapy" at Maastricht University, The Netherlands were searched. The keywords used regarding the intervention and the study design were given. Additionally, Current Contents and Physiotherapy Index, reviews, congress reports, and handbooks on LT were checked. Retrieved papers were followed up by citation tracking. Papers published in English, French, German, Dutch, Spanish, Italian, Norwegian, Swedish and Danish were eligible for inclusion. Abstracts and unpublished studies were not included.

Study selection

Assessment of study quality

The methodology of included studies was assessed using a modified version of a list originally designed by Ter Riet et al (see Other Publications of Related Interest). This criteria list was adapted for LT, with respect to intervention, laser parameters, and relevant outcome measures. Studies were scored for methodological quality according to five categories which dealt with study population, interventions, blinding, outcome, and data presentation and analysis. A maximum score of 100 points could be obtained. The authors do not state how the papers were assessed for quality, or how many of the authors performed the quality assessment.

Data extraction

The authors do not state how the data were extracted for the review, or how many of the authors performed the data extraction.

With respect to the evidence on effectiveness of LT, a study was considered "positive" if its author(s) concluded that laser treatment was more effective than the reference treatment. A study was labelled "negative" if no difference between the study treatments was reported, or if the reference treatment showed better results.

Methods of synthesis

Results of the review

Twenty-one randomised controlled trials comprising 811 participants were included in the review.

The methodological scores of the included studies ranged from 6 (very poor) to 65 (reasonable).

Three studies reported on the efficacy of LT in rheumatoid arthritis. Two studies reported no effect and one study found a positive effect using a pre-post comparison of the data; no between effect was present.

Two out of three studies reported positive effects regarding the efficacy of LT on myofascial pain; the other study reported negative effects. One of the positive studies was hampered by a drop-out rate of 15%.

Four studies reported the efficacy of LT in knee problems. Two of these found a positive although not significant trend towards effectiveness, and one study found no effect. The positive results from the other study were due to pre-post comparison of the data, and disappeared in a between-groups analysis.

Only one study reported on the efficacy of LT on trigger points and this showed favourable results.

Three studies reported on the efficacy of LT in the treatment of pressure ulcers. All three studies were positive, but no firm conclusions about efficacy could be drawn due to various methodological limitations of the studies.

All four studies investigating the efficacy of LT on tennis elbow found no effect. There was only one study on tendonitis and this reported positive results.

Two studies reported on the efficacy of LT in low back pain. One found an effect and one found no effect, but both had methodological limitations.

Studies reporting efficacy had used on average, a dose of 1.3 J per cm squared, whereas studies reporting no results had used an average dose of 2.1 J per cm squared.

Studies with a negative outcome had on average a significantly better methodological score (p=0.002). The average methodological score for positive studies was 24 and for negative studies was 47.

Authors' conclusions

The results clearly show that the efficacy of LT in musculoskeletal disorders is questionable. In none of the studied diseases in which LT is supposed to be effective could firm evidence be provided to demonstrate that LT was superior to placebo, sham or other treatment modalities. Also, outcome measures such as general improvement or change in range of movement failed to show any advantageous effects of LT. A study of the dosage in these trials did not reveal any firm relationships between the dosage and the outcome of the study.

There is little evidence that 904 nm LT is effective in musculoskeletal disorders. Larger trials with better methodological quality could provide more definite and convincing answers.

CRD commentary

The review focuses on a well defined question. Inclusion and exclusion criteria were appropriate. Sufficient details of the individual studies were presented and the studies were summarised appropriately.

A reasonable effort was made to identify relevant literature. However, unpublished studies were not included, leading to possible publication bias. The quality of the included studies was assessed, however, the number of authors who independently extracted this information was not stated.

This is a well conducted review, however, no firm conclusions could be drawn due to the low methodological quality and small size of included trials.

Implications of the review for practice and research

The authors state that larger trials with better methodological quality are required. They suggest that future research should pay more attention to larger sample sizes, improved prognostic comparability of the groups, and avoiding drop-outs and co-interventions. Side effects, and the use of between group comparisons should also be reported.

Bibliographic details

de Bie R A, Verhagen A P, Lenssen A F, de Vet H C, van den Wildenberg F A, Kootstra G, Knipschild P G. Efficacy of 904 nm laser therapy in the management of musculoskeletal disorders: a systematic review. Physical Therapy Reviews 1998; 3(2): 59-72.

Other publications of related interest

1. Ter Riet G, Kleijnen J, Knipschild P. Acupuncture and chronic pain: a criteria based meta-analysis. J Clin Epid 1990;43:1191-9.

This additional published commentary may also be of interest. Baxter GD. Low-intensity infrared laser therapy in musculoskeletal management: inconclusive evidence of efficacy. FACT 1999;42:142-3.

Indexing Status

Subject indexing assigned by CRD

MeSH

Lasers /therapeutic use; Musculoskeletal Diseases /radiotherapy; Netherlands

AccessionNumber

11998005562

Database entry date

31/03/2000

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.