Research Article - CRPS

Lessons from the Front
Questions for Lt. Col Chester C. Buckenmaier, III

In the February, 2005 issue of Wired, Lt. Col Chester C. Buckenmaier, III talks about casualties in Iraq. He believes “the future of wartime pain control is a new form of anesthesia called a continuous peripheral nerve block, which takes a more targeted approach by switching off only the pain signals coming from the injured limb, leaving patients' vital signs and cortical functions unimpaired.” Further in the article, it says, “Pioneered in experimental programs at Duke University and St. Luke's-Roosevelt Hospital in New York City, continuous peripheral nerve blocks could transform civilian medicine in the next few years by reducing the incidence of chronic pain…" Further, this technique "will enable patients to take control of their own pain relief at home, with less dependence on addictive pharmaceuticals.” [1]

We were intrigued by this, and asked Lt. Col Buckenmaier, an acute pain specialist at Walter Reed Army Medical Center (WRAMC), about this technique and its potential use for people with CRPS.

Q: Could physicians use regional anesthesia, continuous peripheral nerve blocks, for peoples who have complex regional pain syndrome?
Yes. It is a technique we use at WRAMC to provide patients with a 'pain free interval.' We believe this temporary adjustment in the afferent pain input from the affected CRPS area allows the brain to 'reset,' often resulting in improvement in symptoms when the block is resolved. Currently, this treatment is purely investigational and has not been formally studies to my knowledge. Again, it is a treatment option we employ at WRAMC.

Q: What about using it for other neuropathic pain syndromes?
Regional anesthesia blocks for a variety of chronic pain syndromes are common in chronic pain practice. Though I practice chronic pain medicine, my specialty is acute pain and perioperative medicine. Chronic pain is a clinical, outpatient activity while acute pain is an inpatient hospital activity. We have a close working relationship with chronic pain but our focus is different.

Q: Could this be used as a preventative measure, to keep acute pain from becoming chronic pain?
We know that uncontrolled pain has a number of ill effects on the body- depressed immune function, increased stress response to surgery, up-regulation of inflammatory mediators, to name just a few. We believe that true preemptive pain control (pain management before, after, and long after the surgical insult) has a positive impact on patient recovery and possibly limits the development of chronic pain. You have essentially hit on the fundamental question for regional anesthesia and advanced pain control. Do we impact on morbidity and chronic pain states? We are hoping our Regional Anesthesia Combat Casualty database will help us begin to answer this question. We have the largest cohort of wounded soldiers, many with amputation, who have been exposed to regional anesthesia during their care. We plan to compare these soldiers to other databases with soldiers who did not receive this intervention. This is a fundamental question that the Army Regional Anesthesia & Pain Management Initiative is trying to answer.

Q: Is it appropriate for chronic pain patients? With any modifications?
It is appropriate for a variety of chronic pain patients as one of a variety of therapies. Because it is an invasive technique, it is usually reserved for the most difficult cases.

Q: Have any studies have been conducted on this procedure for long-term pain relief?
Studies are available that have tried to define an impact of regional anesthesia on phantom limb pain following amputation. Results have been mildly encouraging. The biggest problem with these studies in the 'n' number (sample size) of participants is usually very small. Considerable work remains to be done in this field of study. I am hopeful our database will help clarify some of these issues.

Q: Are you seeing many soldiers returning from the war with symptoms of CRPS?
No, CRPS is a rare condition that strikes patients with a variety of injuries. Some people with CRPS have the condition begin with something as simple as an ankle strain. The use of regional anesthesia for the management of CRPS is an interesting footnote; it is not the focus of our organization. We are specifically interested in how pain adversely affects recovery from major surgery (an improvised explosive device that blows off a soldier's leg for example) and how we can improve on pain management in general after surgery. While regional anesthesia is a focus of our organization because it is so effective, it is just a slice of the whole pain management pie. We are the Army Regional Anesthesia & Pain Management Initiative, we are also interested in innovative uses of narcotics, ketamine (and other NMDA receptor antagonists), new nanotechnology pain medications on the horizon, NSAIDS, drug combinations, and true multimodal pain therapy. We are working very hard to improve the experience of our soldiers in the current war to ease the strain of the very successful but difficult evacuation realities facing them after wounding.

[1] Silberman S, The Painful Truth, Wired Magazine, February 2005.13;02:accessed http://www.wired.com/wired/archive/13.02/pain.html?pg=6

http://rsds.org/5/news/2005/buckenmaier.htm