Repetitive Strain Injury and Myofascial Pain Syndrome
By Hal S. Blatman, MD

During the last few years I have followed the postings to online Repetitive Strain Injury (RSI) discussion lists with considerable interest, and have occasionally offered some suggestions for myofascial pain sufferers. Scott Wright encouraged me to write this FAQ to assist in understanding myofascial pain, a syndrome that is still quite a mystery to many people including physicians, chiropractors, and other healthcare practitioners.

When muscles are overused, fatigued, and strained, knots called trigger points form in the muscle and its associated fascia. Fascia is the connective tissue of variable thickness that holds muscle fibers together, attaches muscles to bone, and holds bones together. These trigger points can be felt as small knots within taught and ropy bands of muscle. The trigger point causes the tightness along the muscle fibers, thereby forming the taught or ropy band.

Each trigger point generates two pain patterns, whether the person is conscious of it or not. One pain pattern is localized, causing local soreness and tenderness, while the other may be local or distant. The distant or referred pain pattern will be interpreted by the brain as numbness, tingling, burning or aching. All trigger points may generate some degree of these pain patterns all of the time. Trigger points may also cause the muscle to cramp.

Trigger points may be classified as active, latent, or satellite. An active trigger point is a focus of hyperirritability in the muscle or its fascia that generates pain. It will usually cause more pain with use of the muscle.

A latent trigger point is less tender than an active trigger point, commonly producing pain with applied pressure. It will generally restrict motion, prevent full lengthening of the muscle and cause weakness without atrophy (atrophy: muscle thinning or getting smaller). A latent trigger point tends to cause weaknessdoes rather than a noticeable level of pain.

A satellite trigger point develops within the zone of referred pain from an active trigger point somewhere else in the body. When a trigger point is active and refers a strong level of pain to another area of the body, muscles in this other area develop "satellite" trigger points. In this fashion a localized pain pattern may spread to other and larger areas of the body.

Repetitive strain injury causes formation of new trigger points and activation of latent trigger points within the injured muscles. Sustained muscle contraction to maintain a position (sustained, posture) will also activate trigger points.

Common repetitive strain diagnoses that have a strong myofascial component include tennis elbow, golfer's elbow, hip bursitis, and shoulder bursitis.

During medical and other therapy training programs, medical professionals are taught that repetitive strain injuries cause inflammation of the overused tissues. This can indeed occur. In the extreme circumstance, there can be physical evidence of an inflammatory condition—called crepitus. Crepitus is the "creaking" that occurs as not-so-well-lubricated tendons fail to glide smoothly. It can sometimes be felt in the swollen and injured tissues. This inflammation can be very serious.

Unfortunately medical professionals are usually only aware of the "inflammation model" or theory for the cause and treatment of pain due to repetitive strain. In addition, the makers of non-steroidal anti-inflammatory drugs (NSAIDs) continue to educate the public about inflammation in order to promote products like Naprosyn and Motrin. Unfortunately, these drugs can be dangerous: there were a reported 100,000 hospitalizations and 15,000 deaths last year in the USA alone, due to side effects of NSAIDs.

Most of the time, however, the primary pathology resulting from repetitive strain injury is not inflammation, but rather it is myofascial pain generated primarily from trigger points in the injured muscles. Later, satellite and latent trigger points also contribute to the larger pain pattern.

Therefore, treatment of the myofascial component of the condition will generally result in greater therapeutic success. The treatment for myofascial pain is to first minimize the factors that can perpetuate or worsen the pain condition. In order to do this, the following must be balanced and maintained:

• diet
• nutrition
• ergonomics
• stress reduction
• hormonal balance
• other factors which must be identified

Then the trigger points need to be made smaller. This is done mostly by physical techniques, including:

• maintaining pressure on a trigger point (acupressure)
• stretching the involved muscles to a more normal resting length
• use of fluori-methane or other vapo-coolant spray
• massage therapy
• trigger point injections (local anesthetic only and not cortisone)
• dry needling (generally more painful in my experience than trigger point injection)
• myotherapy
• chiropractic adjustment
• other forms of body work

Mental work such as relaxation therapy and biofeedback may also be contribute positively.

Additional information on this topic is featured in is the two volume medical text by Travell and Simons: Myofascial Pain and Dysfunction, The Trigger Point Manual, available through Amazon.com or your local medical library or bookstore.