Gunn Intramuscular Stimulation, or IMS for short, is a technique used by physiotherapists since it was developed in the 1970s in Vancouver by the pain specialist Dr. Chan Gunn. IMS is a total system for the assessment and treatment of chronic musculoskeletal pain that has a neuropathic cause. It is grounded in western medical science and there is a growing body of evidence to support its efficacy.