To determine the efficacy of conservative treatments for relieving the symptoms of carpal tunnel syndrome (CTS).

MEDLINE (from 1966 to 2000), EMBASE (from 1988 to 2000) and the Cochrane Controlled Trials Register (Issue 1, 2000) were searched; the search terms were reported. In addition, the reference lists of retrieved articles were checked. Only studies where the results were published as a full report in English, German, French or Dutch were eligible for inclusion.

Study designs of evaluations included in the review

Randomised controlled trials (RCTs) were eligible for inclusion.

Specific interventions included in the review

Studies of one or more conservative treatments were eligible for inclusion. The interventions included steroid injection, ultrasound treatment, pyridoxine, diuretics, oral steroids, non-steroidal anti-inflammatory drugs (NSAIDs), chiropractic care, yoga, laser treatment and splints. The comparators were placebo, no treatment and standard care.

Participants included in the review

Patients with CTS were eligible for inclusion.

Outcomes assessed in the review

The primary outcomes assessed in the review were pain and the percentage of patients with improved symptoms. Relief from paraesthesias and side-effects of treatment were also reported.

How were decisions on the relevance of primary studies made?

Two reviewers independently selected the studies for inclusion and any disagreements were discussed until consensus was reached.

The methodological quality of the included studies was assessed using the following criteria: eligibility criteria specified; concealment and randomisation of allocation; comparability of the groups at baseline; description of the interventions; blinding of care provider, patient and outcome assessor; acceptable levels of compliance and drop-out or loss to follow-up, and were they accounted for; relevance of the outcome measures, description of side-effects given; duration of follow-up; sample size; and adequate data presentation. The criteria were scored as positive, negative or unclear, with the quality score being based on the number of positives for internal validity. An RCT was considered high quality if it scored positive on at least 6 of the 11 internal validity criteria. Two reviewers independently assessed the methodological quality of all selected studies. Any disagreements between the reviewers were discussed until consensus was achieved.

Two reviewers independently extracted the data using a standard form. The extracted data included the number of patients treated in both hands, the number of patients or hands randomised, treatment schedule, proportions, point estimates, confidence intervals (CIs), and timing of follow-up. Short-term outcomes were defined as 3 months or less, and long-term outcomes as more than 3 months.

How were the studies combined?

A narrative synthesis of the studies was undertaken, with the number of studies, their methodological quality and consistency of findings being used to rate the level of evidence.

How were differences between studies investigated?

Details of the studies were grouped according to the intervention. Sensitivity analyses were performed to assess the effect of redefining high quality as at least 5 or at least 7 positive responses for internal validity criteria, as opposed to 6 or more.

Fourteen RCTs (n=569) were included in the review.

Three RCTs evaluated steroid injections (n=129), 2 ultrasound (n=52), 2 pyridoxine (n=50), 3 oral medications (n=157) and 4 other interventions (n=181). Seven of these were deemed to be high-quality trials (n=396), of which 2 evaluated steroid injections (n=97), 1 ultrasound (n=34), 1 pyridoxine (n=35), 2 oral medications (n=139) and 1 chiropractic or medical care (n=91).

Steroids.

Symptoms were improved by 77% when steroids were injected proximal to the carpal tunnel, compared to a 20% improvement with placebo (difference 57%, 95% CI: 36, 77). Symptoms were also improved when steroids were injected into the carpal tunnel compared with injection into the deltoid muscle: 50 and 16% improvement, respectively (difference 34%, 95% CI: 6, 63). Oral steroids improved symptoms when compared with placebo. However, in one study this improvement was only short term.

Ultrasound.

In one RCT ultrasound improved symptoms in comparison with placebo. However, no short-term difference was seen in another RCT.

Other treatments.

The use of pyridoxine, diuretics or NSAIDs did not result in improved symptoms when compared with placebo. Some patients using diuretics, NSAIDs or oral prednisolone experienced some minor side-effects. The efficacy of other treatments was inconclusive.

More high-quality trials, focusing on both the short- and long-term effects of conservative treatment options for CTS, are needed.

The review was methodologically sound with clear inclusion criteria. The search for eligible studies was reasonable and two reviewers independently selected the studies, assessed quality and extracted the data. The authors made a comprehensive assessment of validity, covering criteria for internal, external and statistical validity. However, only those scored for internal validity were utilised in the review. Since the studies were heterogeneous the narrative synthesis was appropriate. The conservative conclusions drawn by the authors, and the recommendation for further research, were appropriate considering the evidence presented.

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

Research: The authors recommended further high-quality trials to provide data on the long- and short-term effects of conservative treatments for CTS.

Health Care Insurance Council.

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.