FAQ’s on Trigger Point Injections (TPI) in Philadelphia

Trigger point injection (TPI) is used for the treatment of painful muscle regions. A trigger point is a tight, ropy band of muscle that forms when a muscle cannot relax. This knot may twitch under the skin when touched.

How does a trigger point cause pain?

The trigger point will trap and irritate surrounding nerves. This leads to referred pain, which is discomfort felt in a nearby body region. Trigger points can lead to loss of range of motion, scar tissue, and muscle weakness.

What conditions cause trigger points?

Situations that cause development of trigger points include poor posture, placing stress on a muscle, emotional stress, sitting at a chair, grasping a mouse, sports injuries, and a chair with little back support.

What conditions are treated with TPI?

Trigger point injections are used to alleviate myofascial pain syndrome, which is chronic pain involving tissue that surrounds the muscle. The muscle groups most involved include those of the arms, legs, neck, and lower back.

What causes trigger points?

Trigger points often develop due to injury to muscle tissue. This occurs related to overuse of a muscle group, whiplash, and post viral syndrome. Spinal abnormalities also are associated with trigger points, such as degenerative disc, postural problems, scoliosis, osteoarthritis, and herniated discs.

Are trigger points common?

The prevalence rate of myofascial trigger points is not exactly known. However, one report estimated that 30% of people develop these muscle knots at some time during their lives.

How does the doctor detect a trigger point?

Trigger points are discovered through physical examination. The doctor will palpate the muscles for knots, tight bands, and tender areas. There is no laboratory or diagnostic test used to diagnose trigger points.

How is the trigger point injection procedure done?

The doctor may inject more than one trigger point during the procedure. The skin over the region is cleansed with an antiseptic solution. The needle is inserted, and a long-acting anesthetic, with or without a corticosteroid agent, is instilled into the tissue. The procedure only takes a few minutes. A band-aid is applied to the injection site.

What happens after the TPI procedure?

The patient may experience mild bruising, soreness, or an increase of pain at the injection site. These side effects are temporary and resolve within 1-2 days. Heat and stretching exercises are recommended to ease this discomfort.

What risks and side effects are associated with trigger point injections?

The TPI procedure is very safe. Most patients enjoy immediate pain relief due to the injection and the long-acting anesthetic. It usually takes 2-4 days for the effectiveness of the corticosteroid to take effect.

How long do the effects of TPIs last?

There is no definitive answer to this question. The local anesthetic numbs the areas for 1-3 hours. The major benefit of trigger point injections is that they improve mobility, decrease pain, and allow the patient to participate in a rehabilitative program. TPIs are proven to loosen tight muscle groups so joint mobilization is increased.

How many TPIs will I need?

This depends on your response to treatment, your health conditions, and the doctor’s choice of treatment. Trigger point injections are often repeated in 1-2 weeks if necessary. The pain management specialist may recommend a series of injections, or one session may be all that is necessary.

Does trigger point injections work?

Many clinical studies support the effectiveness of trigger point injections for pain relief. According to one study, an anesthetic TIP has an efficacy rate of approximately 85%. Botox TPIs were found to have a 90% success rate.


Esenyel M, Caglar N, & Aldemir T (2000). Treatment of myofascial pain. Am J Phys Med Rehabil, 79: 48-52.

Garvey TA, Marks MR, & Wiesel SW (1989). A prospective, randomized, double-blind evaluation of trigger-point injection therapy for low-back pain. Spine, 14:962-964.

Wong CSM & Wong SHS (2012). A new look at trigger point injections. Anesthesiol Res Pract: 492452.