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The gate control theory has opened ways for new pain management strategies like pain relief by electrical nerve stimulation. These strategies are used for drug-refractory and intractable pain caused by various disease conditions. The electrical nerve stimulation techniques can be invasive or non-invasive. Some of the currently used approaches include Transcutaneous Electrical Nerve Stimulation, repetitive Transcranial Magnetic Stimulation (rTMS), transcranial Direct Current Stimulation (tDCS), Peripheral Nerve Stimulation (PNS), Nerve Root Stimulation (NRS), Spinal Cord Stimulation (SCS), Deep Brain Stimulation (DBS) and Motor Cortex Stimulation (MCS).

In this technique, external electrical impulses are produced by electrodes placed over various parts of the body. These stimuli interrupt the pain signals and prevent them from reaching the brain. Thus there is no pain perception.
Mechanisms behind pain relief
Various mechanisms have been proposed to explain the pain relief produced by these techniques. The gate-control theory and the release of endogenous opioids by the electrical stimulation are two of them. These techniques have been used as supplementary modalities of pain management in many disease conditions. However, various studies that analyzed this approach of pain management produced conflicting results with regard to the effectiveness and long term benefits. These techniques are also contraindicated in patients with pacemaker and in pregnant women. They should not be used over places where sensations are compromised as they have the risk of causing burns.
Effects of electrical nerve stimulation in various conditions causing pain
In spite of heterogeneous results regarding the effectiveness and benefits of electrical nerve stimulation as a pain management approach, these techniques have been found to be useful in many patients suffering from pain caused by various disease conditions. Of these techniques, TENS is widely used for pain relief.
- Studies show reliable and positive effects of TENS in pain due to diabetic neuropathy.
- TENS is found to be good in post-operative pain.
- It has also been found to be effective in fibromyalgia pain relief. Fibromyalgia is a syndrome that commonly affects women. It is characterized by chronic pain and tenderness over specific points of the body. It is also common for the people affected by this disorder to complain of sleep disturbances, memory problems and fatigue. Studies suggest that besides providing pain relief, TENS can also help reduce fatigue, anxiety and stiffness in these patients.
- Another condition causing chronic and excruciating pain that is also disabling is migraine. Percutaneous Electrical Nerve Stimulation has been proven to be an effective alternative to the pharmaceutical grade medications used for chronic headache and migraine. This is an invasive procedure which requires the intervention of a medical doctor. In this procedure, needles are placed around the nerves that serve the painful area and are then stimulated. TENS has also been evaluated in reducing the frequency of headache attacks and it has been found to have moderate positive results.
- Pain relief by TENS has been demonstrated in arthritic pain.
- TENS has also been found to be a good option for low back pain relief during pregnancy. It has also been proven to be an effective pain relieving strategy during labor and delivery with no adverse effects on the mother and the newborn.
- However, the technique has not been found to be effective in treating chronic low back pain. Cancer pain is another complex sensation that is very difficult to treat with medications alone. It also affects the quality of life of the patients. Unfortunately, there are not much satisfactory results with electrical nerve stimulation in case of cancer pain.
Of all the electrical nerve stimulation techniques, TENS has been used in pain management for decades. The effects are beneficial in some patients and nil in others.
See Also: Crossing Your Arms Relieves Pain
The decision of using this modality for pain relief needs individualization and the decision depends on the type of pain, its response to other treatment modalities and the general conditions of the patient.
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- Photo courtesy of Roger Mommaerts by Flickr : www.flickr.com/photos/rmommaerts/5622825392
- Photo courtesy of Yeza by Wikimedia Commons : en.wikipedia.org/wiki/Transcutaneous_electrical_nerve_stimulation#mediaviewer/File:Tens.jpg