IMS or intramuscular stimulation is a form of dry needling technique that uses thin acupuncture needles to directly release painful, high tone muscles. It was developed locally in Vancouver, BC in 1973 by Dr. Chan Gunn.

The Significance of Dr. Chan Gunn’s Work

Dr. Gunn noticed some musculo-skeletal injuries would not respond to traditional treatments in a typical time frame and found that these types of cases often exhibit a nervous system component.

Understanding Neuropathic Pain in IMS

Dr.Gunn’s research at the time demonstrated that many cases of what were thought to be musculoskeletal injuries – tennis elbow for example, were accompanied by sensitive, painful trigger points and issues with the associated nerve and nerve root level at the spine. We would call this a peripheral nerve dysfunction. This scenario is an example of a well known law from researchers Canon and Rosenbleuth that states this aforementioned sensitivity and pain can occur when there is a peripheral neuropathy present. The specific type of pain felt in this scenario is called “neuropathic pain” and this is what IMS is meant to alleviate. There are many possible causes of neuropathic pain but IMS more commonly treats cases that arise from an issue at the spine such as osteoarthritis. There are also situations where repetitive sprains/strains and overuse in the extremities can affect a peripheral nerve near this area of stress – for example, carpal tunnel syndrome.

Symptoms and Treatment in IMS

If there is something irritating a peripheral nerve or nerve root, the individual will often show signs and symptoms in one or even all of the three components of the nerve: motor, sensory and autonomic. These can include: hyperalgesia or increased sensitivity, abnormally tight bands of muscle, and even increased sweating in the distribution of the nerve root. Please keep in mind it’s not abnormal to have some tight bands of muscle in certain areas, BUT if they are significantly more tense and tender than the other side, this could be a sign of neuropathy.

Physiological Response and Benefits of IMS

There are several documented responses of the body to IMS. When a dry needle is introduced into a tight band of muscle it “stimulates” the nerve endings in the area. This can often, but not always, elicit a local twitch response which is a reflex of the muscle causing it to briefly contract. This local twitch response can lead to a reduction of pain and sensitivity in the area. This change in pain and sensitivity is brought on by mechanical, electrical and chemical changes around the treated muscle. The effects can certainly be felt locally, but have even been shown to cause positive changes in other regional muscles that were not even needled. Often these muscles would share a common nerve root innervation. There can also be a reduction in pain through the body’s release of endogenous opiods. These are molecules that are naturally produced by our own body to modulate and decrease pain levels.

Your IMS Appointment: What to Expect

When you arrive for an IMS appointment, the physiotherapist will go through a detailed history to determine if this treatment modality is both suitable and safe. If this is the case, and you agree to proceed, there would also be a detailed physical assessment to determine what muscles are most suitable to dry needle. Very thin acupuncture needles are inserted into the muscle for only a few seconds and then removed. A twitch response may be felt, and there could be some temporary deep achiness. Any lasting achiness usually only persists for 24-48 hours and is often alleviated with heat. Many of the aforementioned positive effects of IMS can be felt within this time frame as well. The number of treatments required typically depends on how long the neuropathic pain and muscle tone has persisted. Usually, the physiotherapist will also provide education and a home exercise program to help you maintain the positive benefits of the treatment and work towards a more functional and pain-free state.

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