Trigger Point Injections (TPI) is a procedure used to treat irritable, painful, taut areas of muscle that contain trigger points, or knots of muscle that form when muscles do not relax. Pressing on the trigger point will “trigger” pain at the area of pressure and often in other areas. Many times, such knots can be felt under the skin. Trigger points may irritate the nerves around them and cause referred pain, or pain that is felt in another part of the body. They can occur from direct muscle injuries, poor posture, stress, repetitive strain, or secondary from spine conditions such as a herniated disc.

Types of Trigger Points

The Active Type: An active trigger point is an area of hyperirritability in a muscle or its surrounding tissue that causes the patient pain. An active trigger point causes pain and tenderness at rest or with motion that stretches or strains the muscle. It prevents full lengthening of the muscle, as well as fatigue and decreased strength. Pressure on an active trigger point induces and reproduces some of the patient’s pain complaint and is recognized by the patient as being some or all of his or her pain.

The Latent Type: A latent trigger point does not cause pain during normal activities. It is locally tender, but causes pain only when palpated. It also refers pain on pressure. It can be associated with a weakened shortened more easily fatigued muscle.

When Is Trigger Point Injection Used?

TPI is used to treat many muscle groups, especially those in the arms, legs, lower back, and neck. Myofascial pain syndrome is a chronic pain condition in which there may be several trigger points limited to a particular area of the body. The pain and spasm associated with trigger points can lead to a vicious pain cycle in which pain causes more spasm and spasm causes more pain.

Myofascial pain syndrome is not to be confused with fibromyalgia. Myofascial pain syndrome is a regional or localized pain syndrome in contrast to FMS (fibromyalgia syndrome) which is a widespread musculoskeletal pain syndrome. In addition, TPI can be used to treat fibromyalgia and tension headaches.

What Happens During the Procedure?

In the TPI procedure, a health care professional inserts a small needle into the patients trigger point. The injection typically contains a local anesthetic (numbing) medication, saline, and/or natural substances. The basis for a TPI is to relax the area of intense muscle spasm. By relaxing the muscle spasm, blood flow to the area is improved thus allowing the washout of irritating metabolites. With the injection, the trigger point is made inactive and the pain is alleviated. Usually, a brief course of treatment will result in sustained relief. Injections are given in office and usually take just a few minutes. Several sites may be injected in one visit. If a patient has an allergy to a certain medication, a dry-needle technique (involving no medications) can be used. You may also experience some numbness over the pattern of referral of the muscle injected for about an hour after the injection. There may be some stiffness and soreness, which should not last longer than 24 hours. Within two or three days you should experience a decrease in pain.

How often will I need injections?

Most patients receive an initial series of injections, which are repeated two to three weeks later. Your response to these injections will guide your physician as to whether or not additional injections are indicated.

How do I prepare for the injections?

Before you receive a trigger point injection, it is beneficial if you know how to perform exercises to stretch the involved muscles. Then, after the injections, you should immediately perform the exercises once per hour for the remainder of that day. Moist heat may also be recommended over the area of the trigger point injections to maximize the benefit from the injections

How long do the benefits of the injections last?

Trigger point injections are just one component of your overall treatment program, which may also include physical therapy and regular home exercise. If those regimens are faithfully followed, a single series of injections is more likely to provide long-lasting benefit. Some people, however, no matter how diligent they are, will require additional injections.

Are there any risks to the procedure?

Generally, trigger point injections are quite safe. No procedure is totally without risk, however, and possible complications include temporary muscle soreness, infection, bleeding and bruising. Quite rare are weakness in the injected muscles (up to 45 minutes) or puncture of the lung.