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PDF format, more detail... Introduction:
T.E.N.S. is mostly used in the treatment of electrodes with electric stimulation. The lead wire from the stimulator is attached to electrodes, the selection of Wave form, Wave Mode, Pulse Rate, Pulse Width and Intensity are carefully performed to suit different kinds of syndromes in order to achieve the best effect and benefit to the patient.
T.E.N.S. is used to treat different kinds of pain, including acute,chronic and post operative pain. Here are some guidelines for reference. What is pain?
Pain is a sensory signal indicating something is wrong in a person's body. There are enormous variations in our sensitivity to pain and our perception of pain, and to ignore such useful warnings could be very harmful. Evidence shows that in many cases when chronic pain persists changes of a permanent nature may occur in the nervous system. It has been found that even if the original cause of pain is removed the sensation of pain remains.
Chronic pain ( the cause of which is not known or which cannot be relieved or removed ), and pains which limit the function and movement of the body, serve very little purpose. The blockage of such destructive pain is essential and necessary. The four stages of pain:
Drugs ease the pain, but with side effects such as drowsiness and nausea. TENS principle and theory
Transctaneous Electrical Nerve Stimulation (TENS) is a non-invasive, non-narcotic method of managing pain. By transmitting tiny electrical impulses across the skin’s surface to underlying nerves that carry pain messages to the brain, TENS provides a safe yet dramatic reduction of chronic, acute, and postoperative pain. And, unlike most prescribed analgesics, it does not interact with drugs, is non-addictive, and is not subject to abuse. The Gate Theory of Pain Control - Electrical impulses of a certain intensity (amplitude) and duration (pulse width) can electrically stimulate the primary sensory nerve receptors (A-alpha-beta). This interrupts the neural impulse that transmit pain information (signals) to the brain and alters pain perception. Pain impulses are transmitted via small nerve fibers. Electric stimulation had been found to stimulate the large (Beta) fibers in the area which transmits the sense of touch. Electric stimulation signals sent via the large nerve fibers travel to the spinal cord at a much faster rate than the pain signals sent via the smaller nerve fibers, over-riding the pain signals and closing the hypothetical “pain gate”. The Endorphin Theory of Pain Control - The human body naturally produces endorphins and enkephalins that block pain signals in a manner similar to conventional drug therapy. Some of these substances, isolated, have been found to be 200 times stronger than morphine. Electrical stimulation with a low rate and pulse width can trigger the release of these natural opiates and there by reduce the perception of pain. Using high frequency 15-150 Hz, stimulation of the large diameter nerve fibers acts as a “gate control” to block pain transmission. Alternative, by using low frequency BURST stimulation 2 Hz increase in the body’s own pain relieving endorphins / enkephalins provides analgesia. Pain control over time sensory adaptation over a period of time, continuous, unvarying stimulation may become physically and psychologically uncomfortable, nerve fatigue may occur, and the effectiveness decreases. These phenomena indicate that the body has accommodated itself to a particular stimulation, and the regimen has lost its analgesic effect. Selection of Waveforms
The most common used wave form is symmetric biphasic rectangular (a positive square wave with a negative spike), or Asymmetric rectangular / square. The spike waveform is the most energy efficient while being very comfortable for the patient with its typically narrow pulse width. The square waveform provides deeper stimulation, particularly with wider pulse widths. This setting is indicated in areas with adipose or scar tissue. Square wave, used with discontinue wave mode, has a greater ability to induce a viable muscle twitch. Biphasic waves are much smoother to the skin than monophasic. Monophasic waves are known to cause skin burns in long treatments. -Provides variation for acute and chronic pain syndromes which may have become accommodated to the conventional (normal) waveform. -Prevent sensory adaptation, thus increasing duration of effective pain relief . -Chronic pain (also reduce long term tolerance) sustained analgesia. Burst waveform, a narrow spiky waveform which consists of approximately seven bursts which are interrupted every 1-3 seconds for a period of 1-3 seconds. The low frequency and fixed pulse width of burst mode increases the tolerance factor for patients using the stimulator for extended periods. -For acute pain achieve sustained analgesia, relief deep or diffuse pain. Burst mode may access inhibitory pain centers within the brain and spinal cord which release endogenous opiates or other neurotransmitters. Intensity Output:
Low intensity / high frequency ( enkephalin release ), Moderate intensity / burst frequency ( gate-control) High intensity / low frequency ( endorphin release )
The endorphin effect lasts longer than the enkephalin or dynorphin effect. Endorphin release is a powerful tool to reduce pain, more powerful than the gate-control. As individual pain syndromes differ, the controls are adjusted by the patient to a setting, which gives optimal comfort and pain relief. There is no benefit in painful stimulation. Frequency:
High pulse rates are used for blocking pain ( sedation ) and low pulse rates are used for treating pain ( tonification ). Burst setting ( 2-10 Hz ) which is reported to aid in the release of beta endorphin and which is said to produce longer residual pain relief. The higher conventional frequencies (10-99 Hz) has been reported to relieve pain more quickly. Low Rate mode uses high intensity pulses to relieve deep or diffuse pain which has proven resistant to conventional treatment. It is frequently applied to treatment points. Brief, Intense mode requires high patient tolerance and clinical supervision. It is frequently used for relief of spasm, myofacial pain or deep joint pain. Pulse width:
50-250 μsec ( milli output ), 20 msec ( micro current ) The wider the pulse width the
deeper the stimulation. The narrower the pulse width the more shallow the stimulation. Basically, large areas of deep pain require wide pulse widths between 120-200 μsec, shallow surface pain is best treated with narrow pulse widths between 40-120 μsec.
Stimulation thresholds for afferent nerve fibers shows that A and C-fibres can be stimulated with pulse widths larger than 200 μs. According to many studies on the effect of electrical stimulation and endogenous opioids, these fibers should be stimulated to start endorphin release. On the other hand, pulse widths in the 60 μs range should be used only to affect A-fibers to achieve the effect of pain decrease. It may be clear that in this latter situation , optimal use of gate-control mechanism should not trigger any small, pain transporting A-fibers and C-fibers. These two mechanisms of controlling the pain can be used by adjusting the pulse width. It is probably that large pulse widths are also necessary to achieve effects on ATP production. Dosage:
1-2 times or several times per day, 5 to 6 treatment per week, rest 1 to 2 days before another treatment.
Treatment period:
20 to 30 minutes for acute or chronic pain. Long term pain ( chronic ) may take longer treatment time or under supervision of physicians.
Electrode Placement:
On trigger point, painful site, pathology site, relative acupuncture points ( require specific knowledge and experience ).
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