CERVICAL MYOFASCIAL PAIN
Descriptions of myofascial pain date back to the mid 1800s when Froriep described muskelschwiele, or muscle calluses. He described these calluses as tender areas in muscle that felt like a cord or band associated with rheumatic complaints.
In the early 1900s, Gowers first used the term fibrositis to describe muscular rheumatism associated with local tenderness and regions of palpable hardness. In 1938, Kellgren described areas of referred pain associated with tender points in muscle. In the 1940s, Janet Travell, MD, began writing about myofascial trigger points.
PATHOPHYSIOLOGY
Pain attributed to muscle and its surrounding fascia has been termed myofascial pain. The diagnosis of this syndrome in clinical, with no confirmatory laboratory tests available.
Thus, myofascial pain in any location is characterized on examination by the presence of trigger points located in skeletal muscle. In the cervical spine, the muscles most often implicated in myofascial pain are the trapezius, levator scapulae, rhomboids, supraspinatus, and infraspinatus.
A trigger point is defined as a hyperirritable area located in a
palpable taut band of muscle fibers.
According to Hong and Simon's review on the pathophysiology and electrophysiologic mechanisms of trigger points, the following observations help to define them further :
Trigger points are known to elicit local pain and/or referred pain in a specific recognizable distribution.
Palpation in a rapid fashion (ie, snapping palpation) may elicit a local twitch response (LTR), a brisk contraction of the muscle fibers in or around the taut band. The LTR also can be elicited by rapid insertion of a needle into the trigger point.
Restricted range of motion (ROM) and increased sensitivity to stretch of muscle fibers in a taut band are noted frequently.
The muscle with a trigger point may be weak because of pain. Usually, no atrophic change is observed.
Patients with trigger points may have associated localized autonomic phenomena (eg, vasoconstriction, pilomotor response, ptosis, hypersecretion).
An active myofascial trigger point is a site marked by generation of spontaneous pain or pain in response to movement. This phenomenon is in contrast to the case of latent trigger points, which may not produce pain until they are compressed.
FREQUENCY
Myofascial pain is thought to occur commonly in the general population.
As many as 21% of patients seen in general orthopedic clinics have myofascial pain.
Of patients seen at specialty pain management centers, 85-93% has a myofascial pain component.
SEX
While fibromyalgia occurs more commonly in women than in men, cervical myofascial pain occurs in both sexes, also with predominance among women.
AGE
Myofascial pain seems to occur more frequently with increasing age until midlife. Incidence declines gradually after middle age.
CLINICAL
HISTORY
Typical findings reported by the patient with myofascial pain may include the following:
v The patient may present with a history of acute trauma associated with persistent muscular pain. In contrast, myofascial pain also manifests insidiously, without a clear antecedent accident or injury. It may be associated with repetitive tasks, poor posture, stress, or cold weather.
v Cervical spine ROM is often limited and painful.
v The patient may describe a lumpiness or painful bump in the trapezius or cervical paraspinal muscles.
v Massage is often helpful, as is superficial heat.
v The patient's sleep may be interrupted because of pain. The cervical rotation required for driving is difficult to achieve.
v The patient may describe pain radiating into the upper extremities, accompanied by numbness and tingling and making discrimination from radiculopathy or peripheral nerve impingement difficult.
v Dizziness or nausea may be a part of the symptomatology.
v The patient experiences typical patterns of radiating pain referred from trigger points.
PHYSICAL
Common findings noted upon physical examination may include the following:
Patients with cervical myofascial pain often present with poor posture. They exhibit rounded shoulders and protracted scapulae.
Trigger points frequently are noted in the trapezius, supraspinatus, infraspinatus, rhomboids, and levator scapulae muscles.
The palpable taut band is noted in the skeletal muscle or surrounding fascia. An LTR often can be reproduced with palpation of the area.
Cervical spine ROM is limited, with pain reproduced in positions that stretch the affected muscle.
While the patient may complain of weakness, normal strength in the upper extremities is noted on physical examination.
Sensation typically is normal when tested formally. No long tract signs are observed on examination.
CAUSES
Cervical myofascial pain is thought to occur following either overuse or trauma to the muscles that support the shoulders and neck.
Common scenarios are that the patient recently was involved in a motor vehicle accident or that he or she performed repetitive upper extremity activities.
Trapezial myofascial pain commonly occurs when a person with a desk job does not have appropriate armrests or must type on a keyboard that is too high.
Other issues that may play a role in the clinical picture include endocrine dysfunction, chronic infections, nutritional deficiencies, poor posture, and psychological stress.
LABORATORY STUDIES
Myofascial pain traditionally does not produce abnormalities in the results of the patient's lab work. Travell and Simons describe a study looking at lactate dehydrogenase (LDH) isoenzymes.
A shift was noted in distribution of the isoenzymes, with higher levels of LDH1 and LDH2, while the total LDH remained within normal limits. In clinical practice, myofascial pain is diagnosed by way of a thorough physical examination in conjunction with an adequate medical history.
Depending on the clinical presentation, it may be reasonable to check for indicators of inflammation, assess thyroid function, and perform a basic metabolic panel to rule out a concomitant medical illness.
IMAGING STUDIES
Imaging studies often reveal nonspecific change only and typically are not helpful in making the diagnosis of cervical myofascial pain; however, radiographs and a cervical spine magnetic resonance imaging (MRI) scan may be helpful in ruling out other pathology that may be present at the same time.
OTHER TESTS
Several research articles have attempted to identify changes on electromyograms/nerve conduction velocity studies that may be unique to patients with myofascial pain. The research has been somewhat contradictory, with some studies finding no real Electromyographic activity and others finding nonspecific electrical activity.
TREATMENT
PHYSICAL THERAPY
The primary goal of physical therapy is to restore balance between muscles working as a functional unit.
The physical therapist may progress toward that goal initially by attempting to diminish pain.
This goal can be accomplished using a modality-based approach performed in conjunction with myofascial release techniques and massage.
Cervical stretch and stabilization are integral parts of the approach as well.
Postural retraining is crucial in cervical myofascial pain.
An ergonomic evaluation may be indicated if overuse in the work setting is contributing to the patient's symptoms.
OTHER TREATMENT
Several treatment options for cervical myofascial pain are discussed in the literature.
Trigger point injection probably is one of the most accepted means of treating myofascial pain besides physical therapy and exercise.
Injection is performed most commonly with local anesthetic, although dry needling has been shown to be equally effective.
Palpate the trigger point in the taut band, and place the muscle in a slightly stretched position to prevent it from moving.
Hold the trigger point between 2 fingers while injecting with the other hand. Then redirect the needle in the area to assure widespread infiltration of the anesthetic.
Instruct the patient to be aggressive about compliance with stretching protocols, because they increase the injection's effectiveness.
Production of an LTR helps to confirm the diagnosis. This approach, therefore, generally is the most helpful technique for reducing myofascial pain.
Stretch and spray is another method of treating cervical myofascial pain.
This technique is performed using a vapocoolant spray applied to the affected muscle after it has been placed in passive stretch.
Apply the vapocoolant spray to the region around the trigger point and the area of referred pain using parallel strokes in the same direction.
Ischemic compression involves application of sustained pressure on the trigger point. Have the patient place the muscle in a fully stretched position. Press firmly on the trigger point with a thumb. Gradually increase the pressure as the pain lessens.
Botulinum toxin injection therapy has gotten mixed reviews in the literature. Injection directly into the trigger point produces inconsistent results. The best use of botulinum toxin may be for correcting abnormal biomechanics that incite a myofascial response.
MEDICATION
The goals of pharmacotherapy are to reduce morbidity and prevent complications.
NONSTEROIDAL ANTI-INFLAMMATORY DRUGS
IBUPROFEN (Motrin, Advil)
Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis. Used to provide relief of cervical myofascial pain.
Adult: 400-600 mg PO tid with food; 800 mg if pain is severe and patient has no history of gastric ulceration
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy
TRICYCLIC ANTIDEPRESSANTS
AMITRIPTYLINE (Elavil)
Inhibits reuptake of serotonin and/or nor epinephrine at presynaptic neuronal membrane, which increases concentration in CNS.
May increase or prolong neuronal activity since reuptake of these biogenic amines is important physiologically in terminating transmitting activity.
Adult: 30-100 mg PO qhs
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Caution in cardiac conduction disturbances and history of hyperthyroidism, renal or hepatic impairment; avoid using in the elderly
MUSCLE RELAXANTS
CYCLOBENZAPRINE (Flexeril)
Acts centrally and reduces motor activity of tonic somatic origins, influencing both alpha and gamma motor neurons. Structurally related to TCAs.
Skeletal muscle relaxants have modest short-term benefit as adjunctive therapy for nociceptive pain associated with muscle strains and, used intermittently, for diffuse and certain regional chronic pain syndromes.
Long-term improvement over placebo has not been established.
Often produces a "hangover" effect, which can be minimized by taking the nighttime dose 2-3 h before going to sleep.
Adult: 10 mg PO tid with a range of 20-40 mg/d in divided doses; not to exceed 60 mg/d
Pregnancy
B - Usually safe but benefits must outweigh the risks.
Precautions
Caution in angle closure glaucoma, and urinary hesitance
TIZANIDINE (Zanaflex)
Centrally acting muscle relaxant metabolized in liver and excreted in urine and feces.
Adult: 4-8 mg PO q8h prn; not to exceed 36 mg/d
Pregnancy
C - Safety for use during pregnancy has not been established.
Precautions
Caution in renal impairment
NON-NARCOTIC ANALGESICS
TRAMADOL (Ultram)
Analgesic probably acting over monoaminergic and opioid mechanisms. Monoaminergic effect shared with TCAs. Tolerance and dependence appear to be uncommon.
Adult: 100-400 mg PO qd shown to be effective in diabetic neuropathic pain
ANTICONVULSANTS
GABAPENTIN (Neurontin)
Membrane stabilizer, a structural analogue of inhibitory neurotransmitter GABA, which paradoxically is thought to not exert effect on GABA receptors. Appears to exert action via the alpha(2)delta1 and alpha(2)delta2 auxiliary subunits of voltage-gaited calcium channels.
Used to manage pain and provide sedation in neuropathic pain.
Adult: 300 mg on day 1, 300 mg bid on day 2, and 300 mg tid on day