Which Nonsurgical Treatments for Carpal Tunnel Syndrome Are Beneficial?

JANET H. PIEHL, M.D., Monash Institute of Health Services Research, Melbourne, Australia

The Cochrane Abstract below is a summary of a review from the Cochrane Library. It is accompanied by an interpretation to help clinicians put evidence into practice. Janet H. Piehl, M.D., presents a clinical scenario and question based on the Cochrane Abstract, along with an evidence-based answer and a full critique of the abstract.

This clinical content conforms to AAFP criteria for evidence-based continuing medical education (EB CME). EB CME is clinical content presented with practice recommendations supported by evidence that has been systematically reviewed by an AAFP-approved source. The practice recommendations in this activity are available at www.update-software.com/abstracts/ab003219.htm.

Clinical Scenario

A 38-year-old female machinist complains of intermittent right wrist pain of several weeks' duration. Her job requires her to press a single button on a drill press once per second.

Clinical Question

Which nonsurgical treatments for carpal tunnel syndrome are beneficial?

Evidence-Based Answer

A 10- to 14-day course of oral corticosteroids, wrist splints, ultrasonography, yoga, and carpal bone mobilization provide short-term benefit. Ergonomic keyboards, nonsteroidal anti-inflammatory drugs, diuretics, pyridoxine (vitamin B₆), exercise, neurodynamic mobilization, magnet therapy, chiropractic treatment, and laser acupuncture provide no benefit. A related Cochrane review¹ found steroid injection to be superior to oral corticosteroids.

Cochrane Abstract Background. Nonsurgical treatment for carpal tunnel syndrome frequently is offered to patients with mild to moderate symptoms. The effectiveness and duration of benefit from nonsurgical treatment for carpal tunnel syndrome are unknown. Objectives. To evaluate the effectiveness of nonsurgical treatment (other than steroid injection) for carpal tunnel syndrome versus placebo or other nonsurgical, control interventions in improving clinical outcome. Search Strategy. The authors2 searched the Cochrane Neuromuscular Disease Group specialized register (searched March 2002), MEDLINE (searched January 1966 to February 7, 2001), EMBASE (searched January 1980 to March 2002), CINAHL (searched January 1983 to December 2001), AMED (searched 1984 to January 2002), Current Contents (January 1993 to March 2002), PEDro, and reference lists of articles. Selection Criteria. Randomized or quasi-randomized studies of participants with the diagnosis of carpal tunnel syndrome who had not previously undergone surgical release. The authors considered all nonsurgical treatments except local steroid injection. The primary outcome measure was improvement in clinical symptoms after at least three months following the end of treatment. Data Collection and Analysis. Three reviewers independently selected the trials to be included. Two reviewers independently extracted data. Studies were rated for their overall quality. Relative risks and weighted mean differences with 95 percent confidence intervals (CI) were calculated for the primary and secondary outcomes in each trial. Results of clinically and statistically homogeneous trials were pooled to provide estimates of the efficacy of nonsurgical treatments. Primary Results. Twenty-one trials involving 884 people were included. A hand brace significantly improved symptoms after four weeks (weighted mean difference [WMD], -1.07; 95 percent CI, -1.29 to -0.85) and function (WMD, -0.55; 95 percent CI, -0.82 to -0.28). In an analysis of pooled data from two trials that included 63 participants, ultrasonographic treatment for two weeks was not significantly beneficial. However, one trial showed significant symptom improvement after seven weeks of ultrasonography (WMD, -0.99; 95 percent CI, -1.77 to - 0.21) that was maintained at six months (WMD, -1.86; 95 percent CI, -2.67 to -1.05). Four trials involving 193 people examined various oral medications (e.g., corticosteroids, diuretics, nonsteroidal anti-inflammatory drugs) versus placebo. Compared with placebo, pooled data for two-week oral steroid treatment demonstrated a significant improvement in symptoms (WMD, -7.23; 95 percent CI, -10.31 to -4.14). One trial also showed improvement after four weeks (WMD, -10.8; 95 percent CI, -15.26 to -6.34). Compared with placebo, diuretics and nonsteroidal anti-inflammatory drugs did not demonstrate significant benefit. In two trials involving 50 people, vitamin B6 did not significantly improve overall symptoms. In one trial involving 51 people, yoga significantly reduced pain after eight weeks (WMD, -1.40; 95 percent CI, -2.73 to -0.07) compared with wrist splinting. In one trial involving 21 people, carpal bone mobilization significantly improved symptoms after three weeks (WMD, -1.43; 95 percent CI, -2.19 to -0.67) compared with no treatment. In one trial involving 50 people with diabetes, steroid and insulin injections significantly improved symptoms over eight weeks compared with steroid and placebo injections. Two trials involving 105 people compared ergonomic keyboards with control and demonstrated equivocal results for pain and function. Trials of magnet therapy, laser acupuncture, exercise, and chiropractic care did not demonstrate symptom benefit compared with placebo or control. Reviewers' Conclusions. Current evidence shows significant short-term benefit from oral corticosteroids, splinting, ultrasound therapy, yoga, and carpal bone mobilization. Other nonsurgical treatments do not produce significant benefit. More trials are needed to compare treatments and ascertain the duration of benefit. These summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in The Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (www.cochrane.org).

Cochrane Critique

Did the authors address a focused clinical question? Yes.

Were the criteria used to select articles for inclusion appropriate? Yes.

Is it likely that important relevant articles were missed? No.

Was the validity of the individual articles appraised? Yes.

Were the assessments of studies reproducible? Yes.

Were the results similar from study to study? Yes, when more than one study addressed the particular intervention.

How precise were the results? The precision of the included studies was quite variable; oral steroid treatment was the most precise.

Can the results be applied to patient care? Yes.

Do the conclusions make biologic and clinical sense? Yes.

Are the benefits worth the harms and costs? Yes.

Reading the Numbers Clinically and statistically similar trials (also called homogeneous trials) can be combined statistically to provide a summary estimate. A fixed effect model assumes that there is no variance between studies, while a random effect model accounts for variance within and between studies.

Practice Pointers

This Cochrane review addresses the most common nonsurgical treatments for carpal tunnel syndrome. Unfortunately, most studies provided limited follow-up after the intervention, with only three of 21 trials following patients for up to three months. Although nonsteroidal anti-inflammatory drugs are used commonly to treat carpal tunnel syndrome, this review identified only one randomized controlled trial comparing this treatment with placebo, and it found no significant benefit.

Three related Cochrane reviews provide additional insight into treatment of carpal tunnel syndrome, but poor data confuse the results. Compared with placebo, local corticosteroid injection for carpal tunnel syndrome provides symptomatic relief for up to one month and clinical improvement for up to three months.¹ A Cochrane review³ on biopsychosocial rehabilitation for upper limb repetitive strain injuries reveals a lack of reliable data and a need for high-quality trials in this area. An additional Cochrane review⁴ compares surgical versus nonsurgical treatment of carpal tunnel syndrome; unfortunately, it uncovered only one small, poor-quality study performed 40 years ago.

Based on this review, a 10- to 14-day course of oral corticosteroids, use of wrist splints at night, workplace modification, and enrollment in a yoga class could be first-line therapy for the patient described in the clinical scenario. Although this review does not address this combination of therapies, they are unlikely to cause additional harm. The dosage of prednisolone used in the studies ranged from 25 mg for 10 days to 20 mg for one to two weeks followed by 10 mg for one to two weeks.

If the patient had contraindications or objections to therapy with oral corticosteroids, physical therapy with ultrasonography, carpal bone mobilization, and wrist splints would be first-line therapy. If these treatments were unsuccessful, steroid injection could be considered because of its longer duration of effect, as long as the workplace environment also was being adapted.

Janet H. Piehl, M.D., is currently in clinical practice in Seattle, Wash. She formerly was a research fellow at the Australasian Cochrane Centre in Melbourne, Australia. Dr. Piehl received her medical degree from the University of Washington School of Medicine, Seattle, and completed a family practice residency at Valley Medical Center, Renton, Wash.

Address correspondence to Janet H. Piehl, M.D. (e-mail: Janet_ Piehl@alum.wellesley.edu). Reprints are not available from the author.

REFERENCES

1. Marshall S, Tardif G, Ashworth N. Local corticosteroid injection for carpal tunnel syndrome. Cochrane Database Syst Rev, 2003: CD001554.
2. O'Connor D, Marshall S, Massy-Westropp N. Non-surgical treatment (other than steroid injection) for carpal tunnel syndrome. Cochrane Database Syst Rev, 2003:CD003219.
3. Karjalainen K, Malmivaara A, van Tulder M, Roine R, Jauhiainen M, Hurri H, et al. Biopsychosocial rehabilitation for upper limb repetitive strain injuries in working age adults. Cochrane Database Syst Rev 2003:CD002269.
4. Verdugo RJ, Salinas RS, Castillo J, Cea JG. Surgical versus non-surgical treatment for carpal tunnel syndrome. Cochrane Database Syst Rev 2003:CD001552.