Dr C Chan Gunn
Institute for the Study of Pain, Vancouver, Canada
Chronic myofascial pain – or pain that occurs in the musculoskeletal system without any obvious cause – often defies treatment. Medications and commonly available physical therapies usually give only temporary relief. Many patients therefore wander from therapist to therapist in a vain quest for relief.
This presentation explains Intramuscular Stimulation (IMS), a comprehensive, alternative system of diagnosis and treatment which was first developed and proven at the Worker’s Compensation Board of British Columbia. IMS is now employed at the University of Washington’s Multidisciplinary Pain Center in Seattle and iSTOP.
IMS training is recommended for general practitioners, orthopedic and sports medicine physicians, anesthesiologists and rheumatologists, and others who seek a more effective physical modality for the management of chronic myofascial pain.
Myofascial pain is typically accompanied by sensory, motor and autonomic manifestations that indicate some functional disturbances and/or pathological changes in the peripheral nervous system – that is, neuropathy. A large number of chronic pain syndromes belong to this category of pain. This is called “neuropathic pain” but because neuropathy occurs almost invariably at the nerve root, “radiculopathic pain” is a more accurate term.
Myofascial pain syndromes can occur in any part of the body and are customarily considered as distinct and unrelated local conditions (eg. “lateral epicondylitis”, “bicipital tendonitis”, and so on). But since pain and neuropathic manifestations in all of these conditions respond to the same type of treatment regardless of the location of the pain, the underlying mechanism is the same, wherever the syndrome may be present. Thus, there may be hundreds of “conditions”, but only one cause – radiculopathy. In radiculopathy, signs are found in the distribution of both primary rami of the segmental nerve. Frequently, pain persists unless muscles belonging to both rami – especially paraspinal muscles – are treated.
The causes of neuropathy are numerous, but spondylosis is the most common cause. A crucial ingredient of myofascial pain is muscle shortening from contractures. In fact, myofascial pain does not exist without shortening. Prolonged muscle shortening not only causes pain in muscles, it can also pull on tendons, thereby mechanically straining them and distressing the joints they act on. The increased wear and tear in joints eventually leads to degenerative changes (eg. “osteoarthritis”).
The goal of treatment is to release muscle shortening. Unfortunately, commonly used physical therapies are often ineffective in chronic conditions; a needle technique is then necessary. Medications may be injected, but the use of a needle without injected substances, or “dry needling,” is just as effective. Intramuscular stimulation is a special application of dry needling.
Our system is IMS is based on neurophysiologic concepts, but the technique and implements for needling are borrowed from traditional acupuncture. Unlike acupuncture however, IMS requires a medical examination and diagnosis and treats points that are specific anatomic entities selected according to physical signs.
In recent years, the injection of “trigger points” has become widely used. Our system has features in common with the trigger point approach but differs in concept and objectives. The trigger point approach regards painful points primarily as localized phenomena – foci of hyperirritable tissue (myofascial, cutaneous, fascial, ligamentous, and periosteal) occurring as the result of compensatory overload, shortened range, or response to activity in other trigger points. Instead, we view pain as only one of several possible manifestations or epiphenomena of radiculopathy. (Dysfunction occurs also in the other components of the segmental nerve – motor, sensory and autonomic). In trigger point therapy, focal sources of noxious input are eliminated by therapy directed primarily to the affected muscles. In our concept, needling not only produces local inflammation which is the necessary prelude to healing, but also influences distant components of the segmental nerve by reflex stimulation. Fox example, it can relax shortening in smooth muscles (in blood vessels and viscera). Furthermore, because neural dysfunction occurs as the result of radiculopathy, a prime purpose of IMS treatment is to relieve shortening in paraspinal muscles that entraps the nerve root and perpetuates pain.
IMS is safe in qualified hands, and has few iatrogenic side effects.
- IMS is a total system for the diagnosis and treatment of myofascial pain syndromes.
- IMS treats nerve dysfunction and supersensitivity in the peripheral nervous system (neuropathic pain).
- IMS applies Cannon and Rosenblueth’s law of denervation to explain the supersensitivity that occurs with peripheral neuropathy.
- IMS has introduced an examination technique that shows neuropathy to occur almost invariably at the nerve root, causing radiculopathic pain. Because there is no satisfactory laboratory or imaging test for neuropathy, IMS’s clinical examination is indispensable for diagnosis.
- IMS’s radiculopathy model explains many apparently different and unrelated pain syndromes – from headache to low back pain, from tennis elbow to trigeminal neuralgia – and places them all into one classification.
- IMS borrows its needle technique from traditional Chinese acupuncture, but advances and enhances it with anatomy and neurophysiology. IMS is simple to learn for doctors and therapists who have had training in anatomy. Results are predictable and superior to acupuncture because treatment is based on physical signs.
IMS and the radiculopathy model was developed from clinical observation and research carried out over a period of more than 30 years, first at the Worker’s Compensation Board of British Columbia and subsequently at iSTOP.
IMS differs from traditional acupuncture in that it:
Requires a medical examination using our early signs of radiculopathy
Requires a medical diagnosis that implicates spondylosis
Uses neuroanatomic points that are found in a radicular or segmental pattern, instead of using traditional acupuncture points
Determines the points to be treated; the effects of needling can appear very quickly and progress can be monitored through objective physical signs.
Muscle shortening, autonomic changes, and sometimes pain, are natural occurrences and epiphenomena of radiculopathy, and they all occur according to Cannon and Rosenblueth’s law of denervation. The radiculopathy model is able to explain many puzzling chronic pains that are not caused by injury or inflammation, such as low back pain, tennis elbow, whiplash and fibromyalgia.