StopMusclePain » Blog Archive » Myofascial Pain|trigger points

Sunday, October 21, 2007

Myofascial trigger point as defined by Travell and Simons includes “a hyperirritable spot, usually within a taut band of skeletal muscle or in the muscle fascia which is painful on compression and can give rise to characteristic referred pain, motor dysfunction, and autonomic phenomena”.

The autonomic phenomenon on palpation of the trigger point consist of skin redness (vasomotor response), sweating (sudomotor response due to pain is characteristically hot and sticky sweat as opposed to thin sweat from nervousness or just being cold ) and goose pimpling (pilomotor response). Usually with pain due to trigger point palpation, the goose pimples do not cross the midline.

When the trigger point is pressed, there is an area of referred pain. This is the feature that differentiates myofascial pain syndrome from fibromyalgia. The tender spots in fibromyalgia do not produce referred pain.This pain is reproduced reliably on palpation of the trigger point in myofascial pain. The referred pain does not coincide with dermatologic or neuronal distributions, but follows a consistent pattern.

Trigger points may develop after an initial injury to muscle fibers. This injury may include a noticeable traumatic event or repetitive microtrauma to the muscles. The trigger point causes pain and stress in the muscle or muscle fiber. As the stress increases, the muscles become fatigued and more susceptible to activation of additional trigger points. When predisposing factors combine with a triggering stress event, activation of a trigger point occurs. This theory is known as the “injury pool theory”.

Gunn’s theory for myofascial pain is that of shortened muscle fibers due to injury to nerve roots leading to denervation of muscle fibers. The denervation is related to aging, blunt trauma insidiously or acutely from whiplash injuries, sports, work and repetitive injuries. The shortened muscle fibers produce pain from compression of intramuscular nerve terminals and small blood vessels. There is also a tugging effect of the tight muscles on its own tendon with a pulling or tugging effect on ligaments, bones and joints. The covering of the bones called periosteum or the annulus fibrosus of the intervertebral discs is painful since they are richly innervated with pain fibers.

Electromyography at the trigger point shows spontaneous electrical activity with presence of endplate potential, and the active loci probably are related closely to motor endplates. T

Treatments used traditionally include spray (freeze) and stretch, physical therapy, transcutaneous electrical stimulation, ultrasound, massage , ichemic compression therapy, trigger point injections with local anesthetics, corticosteroids, botulinum toxin, dry needling and/or acupuncture.

The most effective treatment for myofascial pain syndrome is Electrical Twitch Obtaining Intramuscular Stimulation (eToims). The trigger points have to be systematically searched for and electrically stimulated. The characteristic forceful twitch on trigger point stimulation is strong enough to effect movements of the joint over which the treated muscle crosses. When such twitch forces are elicited, it treats the root cause of the pain which is the shortened muscle. The skin resistance to electrical stimulation is lowest at the trigger point allowing effective stimulation of the intramuscular terminal nerves using the least current. However, the stimulus strength has to be supramaximal to ensure effective stimulation of the trigger point (s).

Pain relief results from the release of the tight muscle fibers on the entrapped intramuscular terminal nerve fibers and blood vessels. The exercise effect which retores circulation to the exercised areas as well as deep stretching effects produce a reduction of the tugging effect on tendons, ligaments, bones and joints.

Unlike medications given orally or through injections, eToims is not a pain suppressant but by treating the root cause of the pain, is curative. There is accompanied increases in range of motion and improvement of function with eToims leading to a better quality of life. There are no side effects from eToims and can be done repetitively over the life time of the patient for treating new trigger points that will continue to be formed due to the presence of ongoing nerve root irritation.

The trigger points that are treated with eToims are permanently gone. However, the ongoing pain is from formation of new trigger points that can occur even with activities of daily living. The regularity of eToims treatments allows the treatments to heal new trigger points as soon as they occur.

When trigger points are allowed to accumulate, it adds to the intensity of the underlying pain. When the muscle tightness is significant and when pain levels are high, the trigger points are difficult to find and stimulate and pain reduction is harder to achieve.

The best time for eToims to achieve maximum effects pain relief or improvement in range of motion and hence function is when the pain levels are low. Many patients who have no pain continue eToims treatments for relieving muscle tightness. Muscle tightness interferes with function and produces discomfort rather than pain. Release of muscle tightness even without pain is an indication for eToims.

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