To evaluate the efficacy of infrared low-level laser therapy (LT) on wound healing in humans.

MEDLINE, EMBASE and CINAHL were searched from 1975 to 1998; the keywords were listed in the article. The references of retrieved articles were checked for additional relevant studies. In addition, the databases of the Cochrane Rehabilitation and Related Therapies Field and the International Society for Optical Engineering (SPIE) were screened. Abstracts, congress reports, reviews, handbooks and unpublished studies were checked for relevant citations. The studies had to be published in English, German, French or Dutch to be included.

Study designs of evaluations included in the review

The studies had to be randomised controlled trials comparing the intervention with placebo or standard active treatment.

Specific interventions included in the review

Studies in which at least one of the interventions investigated included infrared LT were eligible. The interventions assessed in the review were laser treatment (1 to 7 times per week) compared with placebo or ultrasound/ultraviolet treatment.

Participants included in the review

Studies of patients with topical ulcerations or wounds were eligible for inclusion. The patients included in the studies had venous leg ulcers, pressure ulcers and various types of skin ulcers with delayed post-operative healing.

Outcomes assessed in the review

No inclusion criteria relating to the outcomes were specified. The outcomes assessed in the review related to wound size. The primary outcome was the number of patients having a poor outcome, i.e. not responding to treatment (wounds still open at the end of the trial period).

How were decisions on the relevance of primary studies made?

Two reviewers independently screened the studies for relevance. In cases of disagreement, consensus was sought with the other authors. All selected publications were masked for author(s), journal, results and conclusions in an effort to minimise reviewer bias.

The studies were assessed on the basis of four methodological categories: study population, description of the intervention, measurement of the outcomes, and analysis and data presentation. These four categories were divided into a set of 17 methodological criteria; these were presented in the article together with the scoring criteria. Each criteria was weighted according to its relative importance, and a quality score was calculated by summing the weights for all criteria satisfied. Two reviewers independently scored all retrieved studies for methodological quality. Any disagreements in the scoring were identified and resolved through consensus. If consensus could not be reached, a third reviewer made the final decision.

The authors of the studies were contacted for further information on wound size. Data were retrieved from all authors contacted. The relative risks (RRs) for the number of patients with open wounds at the end of the trial were calculated.

How were the studies combined?

The RRs for a poor outcome were pooled. Pooling was carried out using the Mantel-Haenzel fixed-effect method if the studies were homogeneous, and the DerSimonian and Laird random-effects model if the studies were heterogeneous.

How were differences between studies investigated?

Differences between the studies were investigated using the chi-squared test for heterogeneity.

Four studies (n=128) were included.

The studies were of a poor methodological quality, with the scores ranging from 29 to 47 out of a possible 100.

Three studies reported no effect of LT, while the other reported a favourable outcome. The latter study (with favourable outcome) used an almost identical dose to the studies with negative results. No major complications or side-effects were reported in any of the studies.

One of the studies that found no benefit of LT was not included in the meta-analysis as it did not report the primary outcome measure (the RR for the number of patients with open wounds at the end of the study). The pooled RR indicated that low-level LT had no significant beneficial effect on wound healing (pooled RR 0.76, 95% confidence interval: 0.41, 1.40).

The authors concluded that there were no scientific arguments for the routine application of infrared (904 nm) low-level LT on wound healing in patients with decubitus ulcers, venous leg ulcers, or other chronic wounds.

This was a well-conducted and clearly presented review. The review answered a focused question supported by clearly defined inclusion criteria. An extensive literature search, which included attempts to locate unpublished studies, was carried out. However, as some language restrictions were imposed, it is possible that studies may have been missed. A detailed quality assessment was carried out and the details of the review process were reported; these included appropriate steps to minimise bias. All important study details were presented in tabular format. The authors' conclusions are supported by the results presented, but the review was severely limited by the lack of primary studies and their poor quality.

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

Research: The authors stated that clinical treatment decisions for patients affected with chronic wounds can only be improved by additional evidence from further clinical research.

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.