OBJECTIVE
We evaluated the clinical efficacy and the unwanted side effects of transcutaneous electrical nerve stimulation (TENS) in a consecutive group of patients with intractable pain due to different pain syndromes.
METHODS
Two hundred eleven patients with different pain syndromes, coded according to the International Association for the Study of Pain (IASP), were treated with TENS, using a standardized protocol. After a 6-month treatment period, an independent investigator estimated the effect of TENS in retrospect through assessment of patient files, standardized questionnaires, and diaries. In addition, a physical examination to determine the IASP code was performed, and unwanted side effects were evaluated.
RESULTS
TENS showed a favorable response in the majority of patients with pain caused by peripheral nerve damage (53%), anginal pain resulting from ischemic heart disease (75%), and pain of the musculoskeletal system due to mechanical degenerative causes (69%). TENS employed in patients with prominent psychological and social distress, and for pain caused by central and autonomic dysfunction, alleviated pain in only 10-25% of the patients. Side effects occurred in 35% during the initial period of the treatment and were usually able to be resolved, especially with thorough supporting instructions during the initial treatment period.
CONCLUSIONS
In this study, the beneficial effect of TENS appeared to be related to the etiology of the underlying pain. The effect of TENS was maintained for > 6 months in the majority of patients with an immediate favorable response. Supporting instructions are crucial for long-term success.