Methodological Properties of Transcutaneous Electrical Nerve Stimulation (TENS) Equipment Used for Analgesia in Humans: a Systematic Review

Pain is considered a public health problem due to its high economic cost, high prevalence, and great impact on the quality of life of patients and their families. Transcutaneous electrical nerve stimulation (TENS) has been shown to be a safe, inexpensive option with satisfactory results in improving pain control. However, the success of this therapy presents as key factors the parameters used, among them the intensity and duration of treatment. However, little is known about the validation of such equipment. To perform a systematic review of the equipment available for the application of electrostimulation as a therapeutic resource for analgesia, which had their methodological properties tested. A systematic literature search was conducted for all relevant scientific articles in the SCIELO, Medline/PubMed, PEDRo, and EBSCO databases. A total of 318 articles were found. Sixty-six were duplicate studies, 252 were selected by title, 72 by abstract, 5 by text full reading, and finally only 2 were included, since the others did not meet the pre-established inclusion criteria. The evidence gathered in this study shows that the performance evaluation of commercially available electrostimulation equipment may be a responsibility of the national regulatory agency. Our findings reinforce the importance of greater availability of information about the regulatory processes of these devices and the verification of the parameters of the regulated devices, so that the achievement of therapeutic goals is not compromised.