Low-Level Laser Therapy for Carpal Tunnel Syndrome and Chronic Neck Pain
Executive Summary
Background
Low-level laser, defined as red-beam or near-infrared lasers with a wavelength between 600 and 1,000 nm and power from 5-500 mW, has been proposed to have therapeutic effects, particularly for musculoskeletal conditions.
Objective
This Assessment will review evidence to determine if low-level laser therapy is effective treatment for carpal tunnel syndrome and chronic neck pain.
Search Strategy
A search of the MEDLINE® database (via PubMed) was completed for the period up through May 2010. The search strategy used the terms “laser” or “low-level laser” as textwords or subject terms. Articles were limited to those published in English language and enrolling human subjects. The MEDLINE® search was supplemented by an examination of article bibliographies and relevant review articles, which were searched for citations.
Selection Criteria
The Assessment was meant to review rigorous clinical trials of low-level laser therapy that had clinically relevant outcomes. Thus, sham-controlled clinical trials that assessed outcomes at least 2 weeks beyond the end of treatment were selected.
Main Results
For the indication of carpal tunnel syndrome, 4 studies enrolling a total of 151 patients met inclusion criteria. The 4 randomized sham-controlled clinical trials of low-level laser therapy have serious limitations. However, 2 of the 4 studies show statistically significant differences in pain assessed on a VAS scale showing benefit of low-level laser therapy. One of the studies showing benefit had a small sample size of 19 and enrolled patients with rheumatoid arthritis. The other study had limited follow-up of only 2 weeks beyond the period of treatment. One of the studies that did not show a significant difference between laser and sham treatment had a sample size of only 15.
For the indication of chronic neck pain, 6 clinical trials enrolling a total of 285 patients met inclusion criteria. The 6 selected studies showed variable results. Two of the 6 studies showed statistically significant findings for the principal outcome of change in VAS pain score. Two studies showed magnitudes of change in VAS pain score consistent with benefit, but were not statistically significant. One of these studies had a small sample size and the other may have had a flawed analysis. Two studies showed similar improvements in pain scores in both laser- and sham-treated control groups and thus resulted in no difference between the treatments.
Discussion
For carpal tunnel syndrome, none of the 4 studies of low-level laser therapy stands out as particularly methodologically strong so that definitive conclusions can be based on its results. For low-level laser therapy in chronic neck pain, there are numerous differences in patient selection, treatment regimen, and trial co-interventions so that it is not possible to coherently explain the differences in results. Again, no single study is so methodologically strong that it by itself makes a sufficient case for a definitive conclusion regarding the effect of laser therapy.
Based on the available evidence, the Blue Cross and Blue Shield Association Medical Advisory Panel made the following judgments about whether low-level laser therapy for the treatment of carpal tunnel syndrome or chronic neck pain meets the Blue Cross and Blue Shield Association Technology Evaluation Center (TEC) criteria.
1. The technology must have final approval from the appropriate governmental regulatory bodies.
Several low-level laser devices have received 510(k) marketing clearance from the U.S. Food and Drug Administration for the clinical indication of carpal tunnel syndrome.
2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes.
For the clinical indication of carpal tunnel syndrome, the existing randomized clinical trials are insufficient to make conclusions regarding the effect of low-level laser therapy. The findings of the 4 studies are inconsistent. No one study is so methodologically sound that its results would be definitive. In general, the studies were small and most studies did not follow patients for long periods of time beyond treatment.
For the clinical indication of chronic neck pain, the existing randomized clinical trials are insufficient to make conclusions regarding the effect of low-level laser therapy. The findings of the 6 studies are variable. Again, no one study is so methodologically sound that its results would be definitive. In general, the studies were small and most studies did not follow patients for long periods of time beyond treatment.
3. The technology must improve the net health outcome; and
4. The technology must be as beneficial as any established alternatives.
The evidence is insufficient to make conclusions regarding whether low-level laser therapy either improves the net health outcome or is as beneficial as any established alternatives for the indications of carpal tunnel syndrome or chronic neck pain.
5. The improvement must be attainable outside the investigational settings.
It has not yet been demonstrated whether low-level laser therapy improves health outcomes in the investigational setting. Therefore, it cannot be demonstrated whether improvement is attainable outside the investigational settings.
For the above reasons, low-level laser therapy for carpal tunnel syndrome or for chronic neck pain does not meet the TEC criteria.
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arthritis; cervical; chronic pain; compressive; diode; entrapment; functional status; infrared; low-power; meta-analysis; MIC; MID; musculoskeletal; myofascial; neuropathy; Northwick Park Neck Pain Questionnaire; tendinopathy; VAS; WALT; World Association of Laser Therapy;
