We would like to thank Dr. Dodes for his interest in our article and the opportunity to comment on some of the issues that he raised.
Dr. Dodes refers to a 1990 article by Dedo and colleagues1 that states that the effect of transcutaneous nerve stimulation, or TENS, for treatment of low-back pain is no greater than placebo. Since this article was written, a search of MEDLINE shows that an additional 700 articles have been published on the use of TENS, the large majority of which demonstrate efficacy.
While it is generally accepted that one can find articles in the literature to support almost any position that one wants, we would caution against placing too much importance on any single article and prefer to assess the aggregate body of literature.
We certainly support the concept of evidence-based practice and the need for placebo controls. This has proven difficult for TENS techniques, because it is very apparent to the patient when the device is active. However, to cite some of the literature, in a Cochrane-based literature review of the effectiveness of TENS on knee osteoarthritis, Osiri and colleagues2 concluded that TENS was effective in pain control over placebo.
Additionally, Ghoname and colleagues3 designed a sham-controlled study with a randomized crossover design to test the analgesic response of TENS therapy for the treatment of low-back pain. While the sham-TENS treatments failed to produce positive changes, all the test frequencies of TENS produced significant decreases in the severity of pain, increases in physical activity, improvements in the quality of sleep and decreases in oral analgesic requirements.
In a subsequent article to the one cited, Feine and Lund4 reviewed articles and controlled clinical trials for temporomandibular disorders and similar chronic musculoskeletal pain disorders. They concluded that "although little evidence was found that any specific therapy had long-term efficacy greater than placebo, we did find strong evidence that symptoms improve during treatment with most forms of physical therapy, including placebo." In effect, they indicated that no form of physical therapy was better than placebo, but patients did improve with treatment.
The comment about relying on anecdotal reports for pain reduction is problematic. Pain by its very nature is subjective, and reduction in pain effectively can only be ascertained by subjective inquiry. While visual analogue scales and other such devices attempt to objectify the patient information, in the final analysis, any report of reduction of pain is subjective input.
Finally, we would like to point out that our article was simply a description of a preventive technique to avoid muscular pain from lengthy dental procedures. We did not attempt to review the TENS literature in its entirety, nor did we advocate routine use of TENS for treatment of pain in the head and neck area. We do believe, though, that the literature clearly supports the use of TENS for relief of chronic pain and treatment of musculoskeletal disorders.
We hope that these comments adequately address the raised concerns.
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