TENS (Transcutaneous Electrical Nerve Stimulation) is a non-invasive therapy that has been used to treat pain for many years. It works by sending electrical impulses through the skin to the nerves, which can help to reduce pain and promote nerve healing. TENS works in two different ways. Firstly, it uses electrical impulses to stop pain signals from reaching the brain.
As long as the brain doesn't receive pain signals, it won't cause pain. TENS also works by increasing the body's production of endorphins, which are natural painkillers. The combination of these two effects is what makes TENS so effective. Studies have shown that TENS can stimulate low-threshold skin afferents to inhibit the positive transmission of nociceptive information in the central nervous system and, therefore, alleviate pain.
In one study, TENS was able to improve 72 patients with pain not related to cancer, including peripheral nerve pain, which had severely affected life and lasted more than 3 months. In addition to relieving pain, TENS has also been found to be effective in promoting nerve regeneration. A study comparing the effects of direct stimulation (IES) and transcutaneous stimulation (TES) on rats with sciatic nerve injury found that the rats in the TENS group showed a better recovery than those in the injured group. The distribution of the vector field showed that the field was orthogonal to the spread of the sciatic nerve in the TEs group, while it was parallel in the IES group; this suggested that the TeS group was less effective in nerve stimulation.
NMES (Neuromuscular Electrical Stimulation) is another non-invasive therapy that has been used to restore skeletal muscle mass and function in patients with PNI (Peripheral Nerve Injury). A significantly higher concentration and intensity were observed around the sciatic nerve in the IES group than in the TE group. In some cases, it has also been found that repeated TENS treatments can increase the duration of pain relief. The latest research has shown that the use of pulsed ES to act on injured muscle and record changes in muscle fibers, called the muscle velocity recovery cycle (MVRC), can provide a detailed understanding of the in vivo evidence of the potential for depolarized rest after PNI.
In a randomized, controlled trial with 301 patients with fibromyalgia, 44% of those who used TENS unitary therapy experienced significant pain relief compared to patients who weren't using the therapy. Overall, TENS is an effective therapy for relieving pain and promoting nerve healing. It is non-invasive and safe for use in people with pain. However, it is important to note that it may not be as effective as direct stimulation for some people.