What are Trigger Point Injections?
Trigger point injections (TPI) are a simple procedure widely performed to relieve myofascial pain. It involves injection of medications into trigger points, or knots that form when muscles do not relax.
A myofascial trigger point, or knot, is a hyperirritable spot, usually located within a taut band of skeletal muscle, which feels painful upon compression and can give rise to characteristic pain, motor dysfunction, and autonomic phenomena. Trigger points produce local and referred pain and often accompany chronic musculoskeletal disorders.
Knots can be felt as nodules or bands in the muscle. Stimulation of a knot may elicit a twitch response and pain, which may radiate in a distribution consistent with the affected muscle.
Conditions Treated with Trigger Point Injections
Trigger point injections are used to treat a wide variety of pain syndromes and other painful conditions. A common application for TPI is treatment of myofascial pain syndrome, a chronic musculoskeletal pain condition in which painful trigger points develop within muscle and fascia, resulting in local and referred pain, restricted range of motion, and autonomic nervous system dysfunction. A number of studies suggest that TPIs may improve quality of life in patients who experience pain as a result of myofascial pain syndrome ,,,,. For example, a study in 91 patients with myofascial pain in different locations reported pain relief in 93.3% of the patients following ultrasound-guided TPI without medications. Further, a clinical trial in patients with active myofascial trigger points of the upper trapezius muscle found TPI improved their pain and range of motion. And the authors of a randomized, controlled clinical trial reported 12-week comprehensive treatment of trigger points in shoulder muscles reduced the number of muscles with active trigger points and was effective in reducing symptoms and improving shoulder function in patients with chronic shoulder pain.
Another pain syndrome commonly treated with trigger point injections is fibromyalgia, a chronic condition involving widespread pain, fatigue, sleep abnormalities, and often distress. The authors of a controlled study in fibromyalgia patients concluded the overall spontaneous fibromyalgia pain pattern can be reproduced by mechanical stimulation of active trigger points located in different muscles, suggesting fibromyalgia pain arises largely from muscle pain and spasm. According to another study in fibromyalgia patients, tender points located at examination sites specified by American College of Rheumatology criteria are almost universally myofascial trigger points. And two recent reviews concluded local extinction of trigger points in patients with fibromyalgia produces significant relief of fibromyalgia pain, and improves range of motion.
Trigger point injections are also used to treat chronic pelvic pain syndrome, which involves lower urinary tract symptoms, chronic pelvic pain, sexual dysfunction, interstitial cystitis, painful bladder syndrome in women, and chronic prostatitis in men. There may be an association between myofascial trigger points and reported painful sites in individuals with this syndrome, and concentrating therapy on clusters of trigger points inside and outside the pelvic floor may help relieve symptoms. A 2011 Stanford University study found men with chronic pelvic pain refractory to traditional treatment benefitted from intensive myofascial trigger point therapy and concomitant paradoxical relaxation training. And another study found application of the trigger point release/paradoxical relaxation training protocol in men was associated with significant improvement in pelvic pain, urinary symptoms, libido, ejaculatory pain, and erectile and ejaculatory dysfunction.
Patients with chronic headaches sometimes receive trigger point injections to assist in controlling the pain. One theory is that referred pain from trigger points in head, neck, and shoulder muscles produces head pain,. According to a survey conducted by the International Headache Society, the most common indications for the use of TPIs in headache patients are chronic tension-type headache and chronic migraine. Further, a 2008 study in chronic cluster headache patients found trigger point injections were associated with significant improvement in 7 of 8 chronic cluster headache patients.
Additionally, trigger point injections are being investigated as a treatment for whiplash, an acute condition involving neck pain after sudden backwards and forwards motion, as may occur in an automobile accident. According to the authors of a preliminary study, trigger points are considered a primary cause of pain in whiplash injured patients. A controlled study in 17 whiplash patients with chronic and intractable neck pain showed several beneficial effects in individuals who received TPI. The study subjects were evaluated for cervical range of motion, pressure pain thresholds, sensitivity to light (photophobia) and perception of pain using a visual analog scale (VAS) before and after injections. Immediate (within 1 minute) alterations in cervical range of motion and pressure pain thresholds were observed following an average of 3.8 injections with 1% lidocaine into carefully identified trigger points. Cervical range of motion increased by an average of 49%, and pressure pain thresholds were found increased by 68%, 78%, and 64% over three different affected body areas, respectively. Among 11 subjects with photophobia, only 2 remained sensitive to light after the TPIs, and average VAS dropped by 57%.
Trigger Point Injections Procedure
In a trigger point injections procedure, a health care professional exerts gentle pressure upon a trigger point to observe muscle twitch and evaluate the patient’s pain. This may be accomplished using a hand or a special device. The purpose of this examination is to allow the provider to identify muscles causing pain that could benefit from injections.
When the painful area has been identified, the practitioner uses a small needle to inject medications into the trigger point. Common treatment sites include the arms, legs, low back, and neck. Typically, TPI medications include a local anesthetic (painkiller) and a synthetic steroid (corticosteroid). These medications work in concert to lower inflammation and disperse the trigger point. Injection of botulinum toxin A (botox) into trigger points has also been reported as effective,,. In some cases, no medications are injected; this is called a dry needling technique and is effective in certain patients. For example, a 2010 study of dry needling in elite volleyball players with painful shoulder injuries produced significant improvements in range of movement, strength and pain. Normally, a brief course of TPIs results in sustained pain relief. The injections are given in the doctor’s office and take only a few minutes to administer. Several sites may be injected in one session.
Trigger point injections are a preferred means of treating pain disorders and other painful conditions because it is a minimally invasive treatment. Less invasive procedures provide compelling advantages over more invasive procedures such as open surgery. These advantages include quicker recovery time, lower risk of infection and other complications, minimal scarring, and outpatient setting.
Since myofascial pain conditions can profoundly affect quality of life, TPI provides an effective, quick, safe and minimally invasive solution to pain management in certain patients.
As with any medical procedure, trigger point injections are associated with various risks. A review of medical literature for documented complications associated with interventional pain management, specifically those associated with joint, tendon, and muscle injections, found the most common complication appears to be infection, including spondylodiscitis, septic arthritis, epidural abscess, necrotizing fascitis, and osteomyelitis.. Other reported complications include spinal cord injury and peripheral nerve injuries, pneumothorax, air embolism, pain or swelling at the site of injection, chemical meningism, and tendon and fascial ruptures. In addition, one case study reported a patient who received TPI developed myositis ossificans, an inflammatory condition that causes calcification of soft tissues, or abnormal bone formation within muscle, tendons, and ligaments. As noted by the authors of the review, many of these complications may be preventable by choosing an experienced practitioner who adheres strictly to aseptic techniques, has refined the procedure, and who is exceptionally familiar with the relevant anatomies.
Trigger points can cause recurrent pain and inactivity, and can significantly lower quality of life. Fortunately, the doctors at Wake Spine & Pain Specialists understand the burden of living with pain and are highly experienced in the treatment of pain syndromes. Schedule a consultation today to learn about the numerous interventions available to help manage chronic pain.
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