Identifying and Treating Myofascial Pain Syndrome

Elizabeth W. Fomby, MD; Morris B. Mellion, MD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 25 - NO. 2 - FEBRUARY 97

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In Brief: Though common, myofascial pain syndrome can be difficult to recognize and distinguish from underlying entities. It is often confused with fibromyalgia. Diagnosis hinges on the identification of painful muscle trigger points that, when palpated, create local twitch responses and refer pain in predictable patterns. With appropriate treatment, such as stretch and spray, trigger point injections, or massage therapy, prognosis is good. Perpetuating factors, such as poor posture or workplace ergonomics, also need to be addressed.

Myofascial pain is a common, though poorly understood, source of discomfort and disability for many patients. Janet Travell, MD, developed the concept of myofascial pain syndrome in the 1950s. According to Simons and Travell (1), the syndrome is defined by the presence of trigger points. These taut bands of muscle fibers are "ropy" and tender to the touch and, when palpated, create a local twitch response (also known as a "jump sign") that is an involuntary shortening of the fibrous muscle band (2).

Trigger points usually occur longitudinally along the axis of the muscle at sites that are reproducible from one patient to another. They are most common in the axial muscles, especially those used to maintain posture (3). Patients commonly have trigger points in more than one location.

Trigger points cause referred pain in specific pain reference zones that are predictable, consistent, and usually distal. These reference zones do not follow any dermatomal or myotomal pattern. The referred pain is often described as dull, aching, and deep, and it can be constant or sporadic. Palpating a trigger point elicits referred pain. If the patient has constant pain, palpation can worsen the pain.

Trigger points can be classified as either active or latent. Active trigger points cause ongoing, persistent pain; latent trigger points are silent until palpated. Both create a local twitch response when palpated and can be associated with decreased range of motion, weakness in the affected muscle group, and decreased ability of the muscle to stretch actively and passively (3). Often, active trigger points can activate "satellite," or secondary, trigger points in the reference zone that respond because of the increased stress to the involved muscle groups (4).

Focal or regional autonomic dysfunction may occur with palpation of a trigger point. Skin temperature decreases have been noted at trigger points, and skin temperature can decrease in pain reference zones.

Prevalence

Myofascial pain syndrome is common. In one study (5) of patients with pain complaints, 31% had acute trigger points. Trigger points have been described in all age-groups and in both sexes. The syndrome most often occurs between the ages of 30 and 60 years; prevalence declines with advancing age (6). A 1950s study (7) of asymptomatic Air Force recruits found tender spots indicative of latent trigger points in 54% of the women and 45% of the men. The study also noted referred pain with palpation in 5% of the recruits.

Trigger Point Diagnosis

To accurately diagnose myofascial pain syndrome, a thorough history and physical evaluation are essential. The history should include a detailed pain history, including when and how the pain started, the exact location of the pain, what it feels like, which treatment modalities have been attempted (and their results), and any history of trauma, overuse, or concurrent illness. The patient should point to the exact location of the pain, rate the pain on a scale of 0 to 10, and review what makes the pain better or worse (8).

A thorough physical examination should be performed, with a focus on the area of pain and discomfort. The physician should start by observing the patient's movements and posture, looking for poor posture, muscle strain, pain that increases guarding, and increased pain in other muscle groups. Trigger points cause muscle shortening with secondary weakness and decreased range of motion; therefore, a complete musculoskeletal exam with strength testing and relevant neurologic assessment is essential. Tension and spasm in muscle groups should be assessed.

To facilitate the identification of trigger points, the patient should be as relaxed as possible. Trigger points can be felt by palpating the muscles; trigger points will consist of tender, hard (or ropy) knots or nodules surrounded by what feels like normal muscle tissue. Once a trigger point has been found, the local twitch response may be elicited as muscle or skin twitching. Next, the patient should be evaluated for referred pain. Knowledge of reference zones (table 1) is essential to the diagnosis.

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Table 1. Reference Zones and Symptoms Associated With Common Muscle Trigger
Points
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                        Referred Pain              
Muscle                  Location                       Associated Symptoms
__________________________________________________________________________________

Head and Neck Splenius
Splenius cervicis,      Occiput                        Headache behind eyes 
semispinalis cervicis, 
rotatores, multifidi 

Upper trapezius 	    Back of neck, temporal region  — 

Sternocleidomastoid                                    Ataxia, otalgia, dizziness; 
                                                       increased lacrimation, 
                                                       coryza,scleral congestion

  Clavicular           	Across forehead, in and 
                        behind ear 

  Sternal               Occiput, cheek, periorbital	   Can mimic sinus pain 
                        area, down toward sternum 

Splenius capitis        Retro-orbital or temporo-      Vertex headache 
                        orbital region 

Temporalis, masseter,   Teeth, jaw	                    — 
medial and lateral 
pterygoid 

Shoulder, Thorax, 
and Arm
Anterior serratus	    Side of chest to border of     Decreased maximum 
                        scapula                        chest expansion, shortness
                                                       of breath 

Pectoralis major        Breast, ulnar aspect of arm    — 
and minor 

Levator scapulae        Base of neck                   Neck stiffness; can 
                                                       follow cervical whiplash 
                                                       injury; seen with anxiety 
                                                       and depression 

Infraspinatus           Glenohumeral joint, down	   Can mimic cervical 
                        upper arm                      radiculopathies 

Supraspinatus           Middle deltoid, elbow          Can mimic cervical 
                                                       radiculopathies 

Back and Buttock
Quadratus lumborum      Low back                       — 

Iliocostalis 		    Lower quadrant abdomen to      — 
                        buttocks 

Gluteus maximus         Sacrum, inferior surface of    — 
                        buttock

Thigh, Leg, and Foot
Quadriceps femoris                                     —
  Rectus femoris        Kneecap, distal half of 
                        anterior thigh 
  Vastus intermedius    Upper part of thigh 
  Vastus medialis       Medial aspect of knee 

Biceps femoris          Calf                           — 

Gastrocnemius           Over calf to instep of foot    — 

Soleus                  Heel, ipsilateral sacroiliac   —
                        joint 
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Differential Diagnosis

To diagnose myofascial pain syndrome accurately, other potential sources of myofascial and skeletal pain should be considered and eliminated. The presence of myofascial trigger points does not preclude a tumor or other hidden cause of ongoing pain.

Myofascial pain syndrome is often confused with fibromyalgia, a common syndrome that represents 16% of all rheumatologic visits (9). However, they are distinct entities. In 1990, the American College of Rheumatology established diagnostic criteria (10) for fibromyalgia: 11 of 18 specific points must be tender, and widespread pain must be present for at least 3 months. Like trigger points, the tender points of fibromyalgia are tender to palpation and may have taut bands of muscle fibers; however, they do not exhibit local twitch responses. Fibromyalgia tends to be more global and is more prevalent in women than men. Myofascial pain syndrome, in contrast, is more regional and affects men and women equally (10-12). In addition, unlike myofascial pain syndrome, fibromyalgia has a poor prognosis.

Certain neurologic conditions such as multiple sclerosis, entrapment neuropathies, and radiculopathies should also be considered in the differential diagnosis, as well as rheumatologic conditions such as rheumatoid arthritis and systemic lupus erythematosus.

Contributing Factors

A large part of managing myofascial pain syndrome is recognizing underlying problems that might influence the patient's pain by increasing tension and irritability in a muscle or group of muscles. This often poses a diagnostic challenge because myofascial pain can occur in association with many other conditions. For example, whiplash trauma or an overuse injury in athletes can cause myofascial pain as a secondary phenomenon that persists after the original injury has healed.

Some neurologic pain syndromes can mimic or cause myofascial pain syndrome. Tension-vascular headaches can create trigger points in the temporalis, suboccipital, posterior cervical, scalene, and sternocleidomastoid muscles. Trigger points in the scalene and pectoralis minor muscles occur in thoracic outlet syndrome (13). Fricton et al (6) describe trigger points in the temporalis, masseter, and posterior cervical muscles in patients with temporomandibular joint dysfunction.

The physician should review possible contributing factors, such as exercise habits, posture, body mechanics, work ergonomics, and stress. Often, individuals with fibromyalgia and myofascial pain syndrome will be sedentary or only mildly active. Among athletes, however, Bonci and Oswald (13) note "barrier," or latent, trigger points that are painless unless touched; create weakness, fatigue, and stiffness; and often occur in athletes experiencing performance slumps. Other situations that may lead to sports-related myofascial pain include a tennis player serving repeatedly and a baseball pitcher with poor technique.

Mechanical factors can cause or contribute to myofascial pain by increasing stress and strain on the musculoskeletal system. For example, patients with poor posture (ie, excessive lumbar lordosis) increase strain on their spine and supportive muscles. Leg-length discrepancy due to an anatomically short limb or a locked sacroiliac joint can lead to significant myofascial back pain. Short upper arms often perpetuate trigger points in the shoulder elevator muscles.

Poor work ergonomics can also create mechanical stress. A receptionist cradling a phone all day, a student leaning forward for many hours each day while studying, or a construction worker who is constantly bending or lifting heavy objects all experience increased musculoskeletal stress and strain.

Travell and Simons (14) suggested that deficiencies of vitamins B1, B6, B12, folic acid, and vitamin C contribute to trigger point pain, but their contention is not proven.

Finally, psychosocial factors may play an important role. Anxiety and depression, by increasing muscle tension, can cause myofascial pain syndrome. They can also accompany the syndrome as comorbidities or develop as sequelae of chronic pain and disability.

Treatment Approaches

Many approaches can be used to treat myofascial pain syndrome. Often, a combination is necessary to obtain pain relief and full functional recovery. Treatment should begin with the least invasive and least traumatic approaches.

Stretch and spray. The stretch and spray technique for relief of muscle pain was introduced in the 1940s by Simons and Travell (1). Using an anesthetic spray as a distraction, the clinician passively stretches the muscle containing the trigger point to its normal maximum length, creating mild discomfort. For best results, the patient should be in a comfortable, relaxed position and the stretch should be performed with a fluid motion.

The recommended anesthetic spray is 15% dichlorodifluoromethane and 85% trichloromonofluoromethane (Fluori-Methane, Gebauer Co, Cleveland). It has replaced ethyl chloride because it is neither combustible nor potentially lethal. To obtain optimal cold stimulation, Fluori-Methane should be used at 10°C to 12°C while the muscle is being stretched. The spray should be directed at a 30° to 60° angle in sweeps parallel to the muscle fibers and toward the pain reference zone. Two to three sprays covering approximately 10 cm/sec are typically sufficient. Concern has arisen regarding Fluori-Methane's potential as a biohazard affecting the ozone layer, but because of its limited usage, it continues to be considered appropriate for medical treatment.

After using the stretch and spray technique, moist heat should be applied to the muscle for 10 to 20 minutes, followed by active movement of the muscle several times through its full range of motion. The stretch and spray treatment may be repeated daily if improvement occurs and the pain has not resolved. Patients can see immediate results with this technique, which is typically applied for 1 to 2 weeks. However, if the muscle becomes sore, treatments should be stopped for 2 or 3 days and then their effectiveness reassessed.(1)

Most patients respond well to this technique. However, Travell and Simons (14) note that in patients who have hyperirritable trigger points and other perpetuating factors, the treatment may cause increased local and referred pain.

Trigger point injections. Injections are recommended for more chronic myofascial pain but should be avoided in the acute setting. Goldman and Rosenberg (4) report that 75% to 80% of acute myofascial pain can be treated with less invasive methods, such as stretch and spray and nonsteroidal anti-inflammatory drugs (NSAIDs).

Technique is critical because it appears that pain relief is caused not by the medication but by the mechanical disruption of the trigger point. Dry needle injections (injections without medication, or "needling") are effective but more painful and not as well tolerated by the patient (15-17).

As with stretch and spray, it is essential that the patient be in a comfortable position during the procedure. The clinician should locate the most tender spot in the taut muscle-fiber band, fix it between his or her fingers, and inject it directly using sterile technique. Often, inserting the needle causes a local twitch response with some referred pain: This confirms that the injection is well placed. Pain relief may also occur in the absence of a twitch response. Injecting near the trigger point, instead of into it, may irritate the trigger point rather than quiet it.

Because of its low side-effect profile, the recommended injection solution is procaine hydrochloride 0.5% dilution, which is prepared by mixing 1 part of 2% procaine with 3 parts of sterile normal saline. Only small amounts are needed: 0.5 to 1 mL per trigger point (1). Corticosteroids provide no additional benefit because trigger points are not inflammatory lesions.

Injection therapy may be repeated. However, if pain persists after two or three injections, underlying perpetuating factors may exist.

Massage therapy. Massage by a massage therapist may be a valuable primary or adjunct therapy. Deep massage of the trigger point and surrounding tissue with 20 to 30 lb of force often provides relief. Prudden (18) attributes the therapeutic effect to locally induced ischemia, but scientific validation is lacking.

Exercise. Exercise is critical for long-term recovery. A rehabilitation program should include stretching, postural and strengthening exercises, and aerobic conditioning. Stretching reduces the potential for trigger point reactivation. It should be both passive and active. Posture-enhancing exercises improve musculoskeletal alignment, thereby enhancing balance and promoting relaxation (5). Strengthening and aerobic conditioning improve not only strength and endurance, but also blood circulation in the muscles.

Medication. The use of medication for myofascial pain syndrome is somewhat debatable. NSAIDs are beneficial as analgesics, especially to make the patient more comfortable while exercising and returning to activities of daily living. There is no evidence, however, for an anti-inflammatory effect for NSAIDs in myofascial pain syndrome. Muscle relaxants are not particularly effective. If the patient suffers from sleep disturbance, low-dose tricyclic antidepressants may be effective in restoring sleep duration and quality (19). They may also diminish the pain.

Address Contributing Factors

Often, treatment for myofascial pain syndrome fails because underlying problems go untreated. Thus, the physician should pay special attention to other factors as well. For example, posture exercises, revamped workplace ergonomics, and heel or buttock lifts can dramatically improve myofascial pain by addressing contributing factors. Psychosocial issues also need to be addressed. The best outcomes often involve diverse professionals working together. A comprehensive treatment plan can help ensure a positive prognosis for myofascial pain syndrome.

References

Simons DG, Travell JG: Myofascial origins of low back pain: 1: principles of diagnosis and treatment. Postgrad Med 1983;73(2):66-73
Simons DG: Electrogenic nature of palpable bands and 'jump sign' associated with myofascial trigger points, in Bonica JJ, Albe-Fessard DG (eds): Advances in Pain Research and Therapy, vol 1. New York City, Raven Press, 1986, pp 913-918
Campbell SM: Regional myofascial pain syndromes. Rheumat Dis Clin North Am 1989;15(1):31-44
Goldman LB, Rosenberg NL: Myofascial pain syndrome and fibromyalgia. Semin Neurol 1991;11(3):274-280
Simons DG: Myofascial pain due to trigger points, in Goodgold J (ed): Rehabilitation Medicine. St Louis, CV Mosby Co, 1988, pp 686-723
Fricton JR, Kroening R, Haley D, et al: Myofascial pain syndrome of the head and neck: a review of clinical characteristics of 164 patients. Oral Surg Oral Med Oral Pathol 1985;60(6):615-623
Sola AE, Rodenberger ML, Gettys BB: Incidence of hypersensitive areas in posterior shoulder muscles: a survey of two hundred young adults. Am J Phys Med 1955;34(6):585-590
Rachlin ES: History and physical examination for regional myofascial pain syndrome, in Rachlin ES (ed): Myofascial Pain and Fibromyalgia: Trigger Point Management. St Louis, CV Mosby Co, 1994, pp 159-172
Goldenberg DL: Fibromyalgia, chronic fatigue, and myofascial pain syndromes. Curr Opin Rheumatol 1992;4(2):247-257
Wolfe F, Smythe HA, Yunus MB, et al: The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the multicenter criteria committee. Arthritis Rheumatol 1990;33(2):160-172
Bennett RM (ed): The fibrositis/fibromyalgia syndrome: current issues and perspectives, symposium. Am J Med 1986;81(3A):1-115
Bennett RM: Myofascial pain syndromes and the fibromyalgia syndrome: a comparative analysis, in Fricton JR, Awad EA (eds): Myofascial Pain and Fibromyalgia: Advances in Pain Research and Therapy, vol 17. New York City, Raven Press, pp 43-65
Bonci AS, Oswald S: Barrier trigger points and muscle performance. N Stren Condit Assoc J 1993:15(6):39-43
Travell JG, Simons DG: Myofascial Pain and Dysfunction: The Trigger Point Manual. Baltimore, Williams & Wilkins, 1983
Gunn CC, Milbrandt WE, Little AS, et al: Dry needling of muscle motor points for chronic low back pain: a randomized clinical trial with long-term follow-up. Spine 1980;5(3):279-291
Hong CZ: Lidocaine injection versus dry needling to myofascial trigger point: the importance of the local twitch response. Am J Phys Med Rehabil 1994;73(4):256-263
Lewit K: The needle effect in the relief of myofascial pain. Pain 1979;6(1):83-90
Prudden B: Pain Erasure: The Bonnie Prudden Way. New York City, Evans, 1980
Gerwin RD: Myofascial aspects of low back pain. Neurosurg Clin North Am 1991;2(4):761-784

Dr Fomby is a family physician at Scripps Clinic in the San Diego area. Dr Mellion is medical director of the Sports Medicine Center in Omaha, clinical associate professor of family practice and orthopedic surgery (sports medicine) at the University of Nebraska Medical Center in Omaha, and medical director of Blue Cross and Blue Shield of Nebraska. He is team physician for men's and women's sports at the University of Nebraska and a past president of the American Academy of Family Physicians. Address correspondence to Morris B. Mellion, MD, Sports Medicine Center, 2255 S 132nd St, Omaha, NE 68144.

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