Thursday, April 9, 2009

Cervical Myofascial Pain

BackgroundDescriptions 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. Her text, written in conjunction with David Simons, MD, continues to be viewed as the foundational literature on the subject of myofascial pain.
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. 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.
Cross-sectional drawing shows flat palpation of a taut band and its trigger point. Left: A. Skin is pushed to one side to begin palpation. B. The fingertip slides across muscle fibers to feel the cord-line texture of the taut band rolling beneath it. C. The skin is pushed to other side at completion of movement. This same movement performed vigorously is snapping palpation. Right: A. Muscle fibers are surrounded by the thumb and fingers in a pincer grip. B. The hardness of the taut band is felt clearly as it is rolled between the digits. C. The palpable edge of the taut band is sharply defined as it escapes from between the fingertips, often with a local twitch response.
Longitudinal schematic drawing of taut bands, myofascial trigger points, and a local twitch response. A: Palpation of a taut band (straight lines) among normally slack, relaxed muscle fibers (wavy lines). B: Rolling the band quickly under the fingertip (snapping palpation) at the trigger point often produces a local twitch response that usually is seen most clearly as skin movement between the trigger point and the attachment of the muscle fibers.
Longitudinal schematic drawing of taut bands, myofascial trigger points, and a local twitch response. A: Palpation of a taut band (straight lines) among normally slack, relaxed muscle fibers (wavy lines). B: Rolling the band quickly under the fingertip (snapping palpation) at the trigger point often produces a local twitch response that usually is seen most clearly as skin movement between the trigger point and the attachment of the muscle fibers.

Frequency
United States
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% have a myofascial pain component.
Mortality/Morbidity
Increased mortality is not associated with cervical myofascial pain.
Race
No studies clarify whether racial differences exist in frequency of cervical myofascial pain.
Sex
While fibromyalgia occurs more commonly in women than in men, cervical myofascial pain occurs in both sexes, also with a 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:
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.
Cervical spine ROM is often limited and painful.
The patient may describe a lumpiness or painful bump in the trapezius or cervical paraspinal muscles.
Massage is often helpful, as is superficial heat.
The patient's sleep may be interrupted because of pain. The cervical rotation required for driving is difficult to achieve.
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.
Dizziness or nausea may be a part of the symptomatology.
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.