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Trigger Point Therapy

Trigger Point Therapy involves the injection of procaine (a local anesthetic) into trigger points, with the intention of causing a twitch response, to help relieve pain and tension in muscles. Trigger points are hyperirritable spots in skeletal muscle that are associated with palpable nodules in taut bands of muscle fibers. The palpable nodules are small contraction knots and a common cause of pain. Compression of a trigger point may elicit local tenderness, referred pain, or motor dysfunction.

Janet G. Travell, M.D., was responsible for the most detailed and important work on Trigger Point Therapy and her text books define the practice. Her work treating US President John F. Kennedy’s back pain was so successful that she was asked to be the first female Personal Physician to the President.

The main innovation of Dr. Travell's work was the introduction of the concept of myofascial pain syndrome. Myofascial refers to the combination of muscle and fascia. Fascia is the thin layer of connective tissue covering, supporting, or connecting the muscles or inner organs of the body. Myofascial pain syndrome is described as a focal hyperirritability in muscle that can strongly modulate central nervous system functions. It is distinguished from fibromyalgia, which is characterized by widespread pain and tenderness and is described as a central increase of perception of pain (nociception), giving rise to deep tissue tenderness that includes muscles. Studies estimate that in 75 to 95 per cent of cases, myofascial pain is a primary cause of regional pain. Myofascial pain is associated with muscle tenderness that arises from trigger points. Trigger points are focal points of tenderness, a few millimeters in diameter, found at multiple sites in a muscle and the fascia of muscle tissue. Biopsy tests found that trigger points were hyperirritable and electrically active muscle spindles in general muscle tissue.

Dr. Travell discovered that trigger points have a number of qualities. They may be classified as active or latent, key or satellite and primary or secondary. An active trigger point is one that actively refers pain either locally or to another location. Most trigger points refer pain elsewhere in the body along nerve pathways. A latent trigger point is one that exists, but does not yet refer pain actively, but may do so when pressure or strain is applied to the myofascial structure containing the trigger point. A key trigger point is one that has a pain referral pattern along a nerve pathway that activates a latent trigger point on the pathway, or creates it. A satellite trigger point is one which is activated by a key trigger point. Successfully treating the key trigger point often will resolve the satellite trigger point and change it from being active to latent, or completely resolving it. In contrast, a primary trigger point in many cases will biomechanically activate a secondary trigger point in another structure. Treating the primary trigger point does not treat the secondary trigger point.

The following factors may cause or activate trigger points: acute or chronic muscle overload, activation by other trigger points (key/satellite, primary/secondary), disease, infection, radiculopathy (any disease of a nerve root), direct trauma to the region, homeostatic imbalances, psycho-emotional disorders and unhealthy lifestyle choices.

Trigger points can result when muscular overload causes a prolonged release of Ca2+ ion (calcium) from the sarcoplasmic reticulum (storage unit for the muscle cell) which results in a sticking of the untrained or overloaded cells. This leads to a compression of capillaries (tiny blood vessels) and results in an increased local energy demand and local ischemia (loss of blood circulation) to the area. This "energy crisis" causes the release of chemicals that augment pain activity. Since an involved muscle is weakened by this sustained shortening, surrounding muscles themselves may develop trigger points in a compensatory fashion.

Trigger points can appear in many myofascial structures including muscles, tendons, ligaments, skin, joint capsules, periosteum (membrane that covers the bones) and scar tissue. When present in muscles there is often pain and weakness in the associated structures. These pain patterns in muscles follow specific nerve pathways or zones of referred pain and have been mapped for identification of the causative pain factor. Many trigger points have pain patterns that overlap, and some create reciprocal cyclic relationships that need to be treated extensively to remove them.

Trigger points are diagnosed by examining signs, symptoms, pain patterns and by manual palpation. Usually there is a taut band in muscles containing trigger points, and a hard nodule can be felt. Pressing on an affected muscle can often refer pain. Clusters of trigger points are not uncommon in some of the larger muscles. Often a twitch response can be felt in the muscle by running your finger perpendicular to the muscle's direction. This twitch response often activates the "all or nothing" response in a muscle that causes it to immediately contract followed by relaxation.

Traditionally, Trigger Point Therapy involved injecting procaine into the trigger points with the intention to elicit a twitch response to resolve the trigger point. Also, procaine can optimize the bioelectric charge across cell walls and this improves movement of nutrients into the cell and waste products out. Treating trigger points may also be accomplished by injecting other substances (saline, lidocaine) into the trigger point, inserting a needle into the trigger point without injecting anything (dry-needling), deep massage (myofascial release) and by spray and stretch techniques in which a topical refrigerant is sprayed to temporarily numb the skin surface at a specific area, after which the muscles of the area are methodically stretched.