Trigger Point Injection

What are trigger points?

Trigger points are discrete hyperirritable spots located in a taut band of skeletal muscle. They produce pain locally and in a referred pattern and often accompany chronic musculoskeletal disorders. Acute injury or repetitive small injuries (overuse) may lead to the development of stress on muscle fibers and the formation of trigger points. They can be caused by muscle injuries, poor posture, or secondarily from joint injuries as the surrounding muscle tries to ‘protect’ the injured joint.

People with trigger points may have regional, persistent pain resulting in a decreased range of motion in the affected muscles. These include muscles used to maintain body posture, such as those in the neck, shoulders, and pelvic girdle (hips and buttocks), as well as the leg muscles in runners.

Trigger points and their resulting pain can greatly affect sleep and overall quality of life, and may predispose athletes/active people to injury if they are not resolved. The chronically spasmed muscle becomes deprived of blood and becomes even more irritated and damaged. Trigger points are sustained in a cycle as the spasm causes pain, which in turn causes more spasm, and on and on.

Trigger points may also manifest as tension headache, ringing in the ear, TMJ (jaw) pain, decreased range of motion in the legs, and low back pain.

Location of a hypersensitive bundle or nodule of muscle fiber of harder than normal consistency is the physical finding typically associated with a trigger point. Pressing on the trigger point with fingers will elicit pain directly over the affected area and/or cause radiation of pain toward a zone of reference and a local twitch response.

Trigger point injection

Trigger point injection is one of the most effective treatment modalities to inactivate trigger points and provide prompt relief of symptoms.

Trigger points can be rapidly inactivated by introducing a small needle into the center of the irritable muscle band; at this time a very small amount of a local anesthetic (procaine) is injected. This process serves two purposes:

1. The needle is thought to physically interrupt the spasmed muscle, inducing it to relax.

2. The procaine is thought to assist the irritated muscle in relaxing; it lowers the threshold at which the muscle is able to contract, keeping it from spasming again. Procaine is also a painkiller which lessens post-injection soreness.

Minor discomfort in the form of muscle twitching or unpleasant sensation as the needle contacts the taught muscle may occur. A coolant spray is applied to the skin prior to injecting to numb the skin against needle pain, making this a relatively painless experience. Trigger points and their resulting pain can be resolved in 3-4 sessions, typically.

If you have tight, painful muscles or specific areas of pain on your body, chances are you have trigger points.