Trigger point injection (TPI) is
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
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.
TPI is 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
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 TPIs 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.
TPI is 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
Patients with chronic headaches
sometimes receive TPIs 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
patients found TPIs were associated with significant improvement in 7 of 8
chronic cluster headache patients.
Additionally, TPI is 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%.
In the TPI procedure, a health
care professional exerts gentle pressure upon a trigger point to observe muscle
twitch and evaluate the patientís 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 doctorís office and take only a few minutes to
administer. Several sites may be injected in one session.
TPI is 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,
TPI is 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 Louisiana 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.