Complex Regional Pain Syndrome

What is Complex Regional Pain Syndrome?

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy (RSD), is a chronic pain condition that may result in extreme sensitivity and pain to the hands and elbows or knees and legs, in particular, without an obvious cause that would explain the degree of pain. Usually diagnosed through a process of elimination, it occurs rarely but has historically been challenging to treat. In addition to creating pain in a certain region of the body, the syndrome is complex because the patient’s affected area may appear swollen, change color, feel hot or cold, or exhibit other unusual qualities.

What Occurs in CRPS?

CRPS appears to arise after an initial injury (although its pain level bears no relationship to the original injury or surgical operation). Perhaps 1% of injuries or surgeries lead to CRPS. One theory is that the original injury creates an inflammation that spreads from tissues and inflames peripheral nerves (nerves beyond the spinal cord). In turn, that process may trigger the spinal column to amplify pain signals sent to the brain, in a fashion that is not well understood.

CRPS has been classified as Type I (formerly known as RSD), or Type II, which is characterized by the presence of nerve injury as a contributing cause – and was formerly known as causalgia. If diagnosed and treated within the first three months, the condition may resolve. Left untreated, symptoms of burning pain and swelling may rarely spread. Patients tend to avoid moving the affected area. Disuse and other aspects of the condition can eventually harm the muscle, nerves and bones of the painful area if treatment is delayed.

How is This Pain Condition Treated?

Treatment for CRPS generally consists of physical, occupational, or rehabilitation therapy, along with counseling to help combat the fear and anxiety that accompany the disorder and may increase pain sensations. A healthy lifestyle, such as avoiding tobacco and getting good rest, seems to help.

Although the body’s disordered pain signals spur patients to guard the affected area and not use it, the painful part of the body is not damaged and does not need to heal. Treatment approaches will try to lower the intensity of the pain and any associated muscle spasms. Treatment does appear most effective when the condition is treated early. Patients are most often diagnosed with the condition around middle age, although it can strike at any age, affecting women about three times as often as men.

Has Neuromodulation Been Used for CRPS?

In addition to physical therapy, counseling, and rehabilitation training, a treatment option for some patients may be spinal cord stimulation (SCS). SCS delivers electrical stimulation to nerves at the spinal cord through electrical leads that are placed under the skin, above the protective covering of the spinal column. After a trial period of about seven days, patients who experience significant pain reduction can go on to have a small pulse generator or radiofrequency unit implanted in a pocket created in a fleshy area under the skin of the abdomen, or the upper buttock or chest. A thin extension wire is threaded under the skin to the leads. With programming by a physician, an external control unit is used at home to stimulate the nerves by triggering the power supply to send an electrical impulse to the nerves beneath the leads. Clinical evidence shows appropriately selected CRPS patients have benefited from SCS to manage chronic pain symptoms of the condition.

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Complex Regional Pain Syndrome (CRPS) is a perplexing, rare syndrome that typically occurs after surgery, and causes pain out of proportion to the cause . . .

Complex Regional Pain Syndrome and Neuromodulation (2-minute video, 2018)


1. Poree L, Krames E, Pope J, Deer TR, Levy R, Schultz L. Spinal cord stimulation as treatment for complex regional pain syndrome should be considered earlier than last resort therapy. Neuromodulation. 2013 Mar-Apr;16(2):125-41

Reviewed Nov. 16, 2017
Executive Officer, International Neuromodulation Society, 2011-2017
Hunter Pain Clinic, Broadmeadow, NSW Australia

Last Updated on Monday, November 22, 2021 11:00 AM