PALM SPRINGS, CA—Myofascial pain syndrome affects up to 95% of people with chronic pain disorders and approximately 9 million Americans suffer from myofascial pain, with underlying factors that include overuse syndromes, trauma, and spinal pathologies, Mehul J. Desai, MD, MPH, George Washington University Hospital, Washington, DC, told attendees during the 2012 American Academy of Pain Medicine Annual Meeting.

Treatment options for myofascial pain include the nonsteroidal antiinflammatory drug diclofenac, tramadol, antidepressants (with concomitant sleep disturbance), the alpha-2 adrenergic agonist tizanidine, anticonvulsants, and muscle relaxants. Other therapies, for which varying levels of data are available to support their use, include postural, mechanical and ergonomics approaches, therapeutic ultrasound, stretching, needling and injections (including dry needling and acupuncture), botulinum toxin, and laser.

Describing muscle as the “orphan organ”—in that no specialty claims muscle as its organ, despite the fact that muscle is half of the body, Jay P. Shah, MD, National Institutes of Health, Bethesda, MD said clinicians generally therefore focus primarily on treating the symptoms of myogenic pain, not the cause of the pain. Unique characteristics of muscle pain include an aching cramping pain that is difficult to localize and referred to deep and distant somatic tissues and activation of unique cortical structures; in addition, activation of muscle nociceptors is much more effective at inducing neuroplastic changes in dorsal horn neurons.

“Myofascial trigger points (MTrPs) are a very common, complex and overlooked cause of nonarticular musculoskeletal pain whose pathophysiology is unknown,” said Dr. Shah, in explaining the “myofascial conundrum.” Currently, there are no accepted criteria, such as biomarkers, electrodiagnosis, or imaging, that can diagnose MTrPs—hard, palpable nodules in taut bands of skeletal muscle—or that can assess the clinical outcome of treatments.

In addition, several controversies exist about MTrPs and myofascial pain: etiology and pathophysiology; the mechanisms by which the pain state begins, evolves, and persists; how a tender nodule evolves to a myofascial pain syndrome; lack of consensus about which soft tissues are involved; that physical findings are not always discernible; lack of consensus about objective measures for therapeutics outcomes; lack of consensus about whether myofascial pain is a disease, process, or syndrome; and lack of consensus about physical findings except the MTrP.