Transcutaneous Electrical Nerve Stimulation

Transcutaneous electrical nerve stimulation, or TENS, is a therapeutic approach employing electric current to activate peripheral nerves for pain relief. The TENS unit, a compact, often battery-powered device, can easily fit into a pocket (see Transcutaneous Electrical Nerve Stimulator). Electrodes are applied to the skin around the targeted region and connected to the TENS unit via wires. Users can then adjust the pulse amplitude, frequency, duration, and pattern of the currents. Thus, high user tolerance is achieved with minimal side effects and no potential for overdose. Low frequencies (<10 Hz) and high intensity induce muscle contractions, while high frequencies (>50 Hz) with low intensity produce paresthesia without contractions.  The historical debate over TENS efficacy persists despite proven clinical benefits. Disagreements persist regarding the appropriateness of TENS for specific pain syndromes and conditions. TENS has a rich history dating back to around 60 A.D. when Roman physician Scribonius Largus proposed using an "electric fish" for relief. Electric eels were also historically utilized for pain management benefits. By the 18th century, various devices aimed to treat multiple conditions with electrostatic exposures. A device for clinical therapy using electricity called the "Electreat" was introduced in the 19th century, but its use was discontinued due to limitations. The modern concept of TENS is credited to American neurosurgeon Dr. C. Norman Shealy. His training at Duke University and additional experience at Barnes-Jewish Hospital and Massachusetts General Hospital led to the development of today's TENS units. Dr. Shealy aimed to create an impactful therapy for migraines, back pain, and gout. As the study of TENS advanced, new techniques emerged, including intense TENS, acupuncture TENS, and conventional TENS. While the medical community engages in an ongoing debate about the efficacy of TENS, a clearer picture is likely to form as more trials emerge with optimal dosing and specific outcome measures. Despite the controversy and confusion surrounding TENS, numerous studies point towards positive outcomes in pain management. Acknowledging contraindications is crucial, yet the risk of complications or side effects is minimal when TENS is operated within manufacturer parameters. For those willing to explore alternative avenues, the fusion of TENS with pharmacotherapy holds promise.