Intramuscular Stimulation

What is Chan Gunn Intramuscular Stimulation (IMS)?


IMS treatment is an effective treatment for chronic pain and best suited to treat soft tissue pain that shows no obvious sign of ongoing tissue damage or inflammation, such as many forms of: neck/back pain, whiplash, repetitive strain, jaw pain, tennis elbow, frozen shoulder and fibromyalgia, amongst others. It is often effective when other forms of therapy have failed. IMS is a very effective treatment for painful Trigger Point Syndrome as well. The concept of “neuropathic pain” can help to explain this type of pain. Typically this occurs when nerves malfunction following minor irritation. Nerves and nerve endings become extremely sensitive and cause normal, harmless signals to be exaggerated and misperceived as painful ones. This is known medically as “supersensitivity”, and results in pain and shortening in the muscles supplied by the involved nerve(s). Chronic muscle shortening can then produce pain elsewhere e.g. by pulling on tendons and straining them or by distressing the joints they move and contribute to many degenerative conditions such as “tendonitis” or “osteoarthritis”. 

How does Chan Gunn IMS work?

The immediate benefit of IMS is related to its mechanical effect. The inserted needle breaks up the tight muscle fibers, “muscle knots” or “trigger points” and allows the muscle to lengthen immediately. The needle induces a small injury in the muscle; this will cause in increasing blood flow and initiating natural body’s response for healing and repair. The healed muscle fibers now have normal healthy alignment and structure.


As the Secondly, the needle also stimulates the stretch receptors in the muscle, which produces a reflex relaxation resulting in lengthening of the muscle and desensitizes the supersensitive areas such as trigger points. Shortened muscles can pull on peripheral and spinal joint. Shortened muscles in the spine can compress the disk and impinge on the nerve roots, the irritated nerve root will affect the muscles supplied by it and cause shortening and dysfunction that will cause further irritation. The lengthening of the muscle will release the compression applied to the joints they surround. Therefore, IMS has been found very helpful in treating disk degeneration and herniation, and in prevention of osteoarthritis.


Thirdly, the insertion of the needle and the twitching response will create an electrical potential within the muscle fibers that make the nerve function normally again. This is referred to as planting a battery inside the muscle that can function long after the needle is removed.

Research has shown that Intramuscular stimulation has a remarkable success rate at decreasing dysfunction related to chronic conditions such as low back pain, cervical pain, whiplash, tennis elbow, and temporomandibular pain.

What is the Chan Gunn IMS procedure like?

During an IMS treatment, your physiotherapist will use thin needles to ‘dry needle’ to penetrate deep within muscle tissue targeting tightened and shortened muscle fibers. This is performed without the injection of any substance into the muscle.  In a healthy muscle with a healthy nerve IMS needles can not be felt, however, when the needle enter a tight muscle band or a trigger point, the patient will feel a cramping or twitching sensation which shows the tightened muscle is relaxing. Depending on your injury, your physiotherapist can needle anywhere from muscles in the upper or lower limbs or muscles around the spine. The procedure takes just a few minutes and needles will be removed right away after a twitch response is achieved. The muscle relaxation response is mostly immediate; however, you might feel some discomfort for 24 to 48 hours days that will subside gradually. Many people describe the post-treatment sensation as “feeling bruised”, which is similar to sensation of delayed onset muscle soreness after intense exercise. This sensation will subside gradually within one to two days. The IMS treatment should result in improved pain, and better movement, and in many cases full recovery from the injury and return to normal daily and sport activities.

What is the goal of IMS?

The goal of IMS is to release muscle shortening that further presses on and irritates the nerves. Supersensitive areas can be desensitized and the persistent pull of shortened muscles reduced with IMS. The effects of IMS are cumulative – each needling session stimulates a certain amount of healing, until eventually the condition can more fully recover and pain dissipates as muscles loosen.

What is the difference between IMS and acupuncture?

While the IMS procedure uses the same needles as traditional Chinese acupuncture, the technique is very different.

IMS is a technique developed and used in western medicine, scientifically proven method for diagnosing and treating of chronic pain.  Acupuncture was developed in ancient china and is a traditional way of treatment with holistic approach aiming to balance energies in the body (yin and yang). For more information on acupuncture, please refer to “Acupuncture” in services section on this website.

The IMS technique involves inserting tiny needles only into the area of the muscle most affected by the nerve problem and is based on physical signs of pain. In acupuncture, needles are placed on specific predetermined points on the body called meridian points.

In acupuncture needles remain placed on meridian points for 15-20 minutes, whereas in IMS needles are removed immediately after a twitch response in the muscle is produced. The acupuncture needles are mostly inserted more superficially as compared to IMS as in IMS the aim is to reach the tight and sensitized muscle fibers that might be located in deeper layers of the muscle.

How many sessions of IMS will I need?

The number of treatments you require will vary depending upon several factors such as the duration and extent of your condition. If the pain is of recent origin, one or two treatments may be all that is necessary. More chronic problems will probably require more treatments. In published studies of patients with low back pain, the average number of IMS treatments required was 8.2.

How frequent should I get IMS done?

 Treatments are usually once per week to allow for tissue healing. Patients may experience a deep achy feeling following treatment for 24-36 hours. This is normal, and considered a good reaction. Patients can use heat or warm baths to help with soreness.

What is the history behind Chan Gunn IMS?

Intramuscular Stimulation was developed by Dr. Chan Gunn in the 70’s in Vancouver, British Columbia. Dr. Gunn was physician at the Worker’s Compensation Board of British Columbia. Working with many chronic patients that did not respond to any conventional treatment methods, he developed the neuropathic model, based on scientific research and neurophysiological studies. Dr. Gunn worked as clinical professor at the University of Washington’s Multi Disciplinary Pain Centre in Seattle and the president of the Institute for the Study and Treatment of Pain. During his career Dr. Gunn trained many physiotherapists and physicians how to evaluate, assess, and treat chronic pain conditions using Chan Gunn IMS method. He has been awarded the Order of British Columbia and the Order of Canada, the nation’s highest honour, for his contribution towards solving chronic pain. Currently Dr. Gunn is retired living in Vancouver, BC.

Who can do IMS?

 Dr. Gunn had a unique system for assessing and treating chronic pain conditions. Physiotherapists and physicians who are certified to perform Chan Gunn Intramuscular Stimulation technique can perform this technique properly. This certification is issued by the Institute for the Study and Treatment of Pain, founded by the developer of the IMS technique, Dr. Chan Gunn M.D.

What are the contraindications of IMS treatment?

IMS is not recommended for during pregnancy (mostly first trimester), recent surgery, local infection, and hemophilia. If you have phobia of needles, you can discuss other treatment methods with your physiotherapist.

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