Trigger Point Injections

Trigger point injections (TPI) may be an option in treating pain for some patients. TPI is a procedure used to treat painful areas of muscle that contain trigger points or knots of muscle that form when muscles don't relax. The term "trigger point" was coined in 1942 by Janet Travell, M.D., who was President John Kennedy's physician. Travell's pioneering work introduced the concept the introduction of myofascial pain (referring to the combination of both muscle and fascia) and referred pain.  Her monumental work also established "trigger point maps" for the entire human body to help to guide practitioners in using her therapy.

Myofascial pain is associated with muscle tenderness that arises from trigger points, which are focal points of tenderness or knots  found at multiple sites in the muscle and  fascia. These tender knots can almost alwaysbe felt under the skin. Trigger points may irritate the nerves around them and cause referred pain, which is felt in another part of the body.

What Happens During Trigger Point Injection?

In the TPI procedure, a needle is inserted directly into the patient's trigger point. The injection contains a local anesthetic, usually procaine.  In this clinic only preservative-free procaine is used. Sometimes homeopathic medications are injected with the procaine to relieve muscle spasm, inflammation, lymphatic congestion and impaired cellular metabolism. The injection inactivates the trigger point and the pain and spasm are alleviated. Usually, a brief course of treatment will result in sustained relief. Several sites may be injected in one visit. Generally if an upper back muscle is treated, it is done on both sides and not just the painful side to keep things in balance and for other reasons. If a patient is allergic to local anesthetics then normal saline or a dry-needle technique (involving no medications) can be used.

Why are Trigger Points injected?

TPI is used to treat muscle pain, which can involve many different muscle groups, especially those in the neck, upper back, shoulders and low back. TPI can also be used to treat headaches and fibromyalgia. Sometimes knee pain is caused by referred pain from trigger points in one or more of the anterior thigh muscles (quadriceps).

There are a few more than 620 potential trigger points possible in human muscles. These trigger points, when they become active or latent, show up in the same places in muscles in every person. That is, trigger point maps can be made that are accurate for everyone.

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). Latent trigger points may not yet refer pain actively, but may do so when pressure or strain is applied to the structure containing the trigger point. Latent trigger points can influence muscle activation patterns, which can result in poor muscle coordination and balance. Active and latent trigger points are also known as "Yipe" points, for obvious reasons.

Activation of trigger points may be caused by a number of factors, including acute or chronic muscle overload,  direct trauma to the region (such as a car accident which stresses many muscles and can cause multiple trigger points), musculoskeletal imbalances, poor posture, being "round shouldered" and activation by other trigger points.

Trigger points form only in muscles. They form as a local contraction in a small number of muscle fibers in a larger muscle. These in turn can pull on tendons and ligaments associated with the muscle and can cause pain deep within a joint where there are no muscles.  When muscle fibers contract they use biochemical energy, which can result in the accumulation of metabolic byproducts such as lactic acid. The tightened muscle fibers constrict capillaries and prevent them from carrying off metabolic acids, which further increases pain and muscle dysfunction.

When trigger points are present in muscles there is often pain and weakness in the associated structures. These pain patterns in muscles follow specific pathways that have been readily mapped. Many trigger points have pain patterns that overlap and some create reciprocal cyclic relationships that need to be treated extensively to remove them.