Free Access: Predictors of Pain Relieving Response to Sympathetic Blockade in CRPS Type 1

Good Thursday, Dear Readers.
Happy Solstice!


I almost passed over the notice I received about this article's publication, irritated by what seemed a blithe acceptance of sympathetic blocks as an always appropriate first-line response in treating CRPS.  If you're a regular here, you know I'm a tad touchy about medicos who don't update their knowledge, who continue old ways based on old understandings.

Good thing I looked closer and saw this was from the good people at TREND (Trauma Related Neuronal Dysfunction), "a knowledge consortium that integrates research on complex regional pain syndrome type 1, and supported by a Dutch government grant."

Better, they address my concern upfront, and first thing. They even manage to be polite about it. So long as folks persist in waltzing down the yellow brick road proclaiming "sympathetic nervous system dysfunction" as the crux of the matter, there will be people subjecting themselves to (no kidding) hundreds of sympathetic blocks, whether they "work" or not. This culture of treatment is crucial to the support of pain management clinics that rake in cash -- hand over fist -- for procedures, procedures, procedures.

I would love to see an undercover investigative report of one of these procedure factories, where many patients are told they will not receive pain medication unless they submit to procedures, procedures, procedures.

Though I had not teased out all the details, this was roughly my situation early on in my CRPS treatment saga. Newly diagnosed, I had been suffering from CRPS for two years at that point. Delay in diagnosis and treatment is too normal, unfortunately. The anesthesiologist in question told me blatant lies about various medications, as well as telling me to stop taking the narcotic pain regimen in the manner of frozen fowl, cold turkey. "Oh, you can just stop taking it. No problem." A few seizures later... Ha! He would not condone taking Baclofen, saying "it's for crazy people." (We've yet to figure that out.) And nuts I must be, because today, seven years later, Baclofen may be all that keeps me from permanent installation at the psych hospital.

[Hell, I no longer look upon my potential for Funny Farm residence as something to be ashamed of... Today, I daydreamed about the relief that might be inherent in going insane, so long as that journey involved immunity to pain, as well as the elimination of the lies and good manners necessary to the oh-so-civilized suffering of pain. Maybe I wouldn't be so obsessed with wanting to bitch slap the sweet people brave enough to stay in my life.]

Anyway, after the Nth sympathetic lumbar block to no effect, as I lay prone waiting for Nth-plus-one, it occured to me to ask why we were continuing, arduously continuing, to do them.

He was scrubbing at the sink, back to me, and had laughter in his voice: "I guess it doesn't make much sense to you, huh?"

I wonder how differently I might have behaved had I missed that joyful (ka-ching ka-ching) tone; Had he been facing me, his serious doctor-face might have made me doubt myself. Because no, it did not make sense to me, that I was being bankrupted for treatments that weren't in the least helpful.

Sympathetic block Nth-plus-one never happened. Fred was grinning from ear-to-ear.

The next pain management guru is the one I am still with, though I believe he'd be happy were I to leave. He turned out to be from the opposite end of the spectrum and believes me so far gone with the disease that the only appropriate modality is pharmaceutical management. Please note that I have tried to soldier on, revisiting physical therapies, going daily to the gym (until my bones started snapping), riding the Ketamine train, et cetera.

There just are not many pain management doctors/clinics that happily marry appropriate procedures with judicious drug maintenance. The procedure joints are like factories without the predictable factory outcomes; The places that just hand out prescriptions are, hands down, best at killing hope.

Back to these good TREND researchers! Their purpose is cleanly delineated -- how to ensure that patients receiving blocks are the patients most likely to have relief from them. And as I said, they immediately address the whole "sympathetically maintained pain" thang -- not dogmatically, but clearly enough.  Emphases are, of course, mine:

Complex regional pain syndrome exhibits some signs and symptoms that may indicate sympathetic autonomic dysfunction, yet sympathetic blockade produces inconsistent improvement in this condition.

In a prospective series of patients with complex regional pain syndrome type 1, the success rate with sympathetic blockade was moderate (31%), and no signs or symptoms predicted block success.


The use of a sympathetic block (SB) for diagnostic and therapeutic purposes in the management of complex regional pain syndrome type one (CRPS-1) is based on previous hypotheses concerning the involvement of the sympathetic nervous system in the pathophysiologic mechanism of this disease. The nociceptive afferent input was believed to cause hyperactive spinal neuron activity, which stimulated the sympathetic neurons to induce arterial spasms, ischemia, and edema.

In certain cases of CRPS-1, the pain may be attributable to a sympathetically maintained form of pain that is classically defined as pain relieved by SB with local anesthetics. Consequently, SB frequently is performed for the management of CRPS. Current treatment guidelines for CRPS-1 limit the role of SB to selected cases that are refractory to conservative treatment with pharmacologic therapy and physical rehabilitation. When a single SB with a local anesthetic (diagnostic block) proves successful (50% or more pain reduction for the duration of action of the local anesthetic), repeated blocks or a more definitive sympathetic blockade using radiofrequency lesions may be considered. A review of the literature shows that SB with a local anesthetic in patients with CRPS resulted in pain relief in approximately one third of patients. Predicting which patients would benefit from SB would assist physicians in patient selection and reduce the number of unsuccessful invasive SB procedures, along with their potential complications and side effects.

Anesthesiology:
January 2012 - Volume 116 - Issue 1 - p 113–121
doi: 10.1097/ALN.0b013e31823da45f
Pain Medicine

Predictors of Pain Relieving Response to Sympathetic 
Blockade in Complex Regional Pain Syndrome Type 1

van Eijs, Frank M.D.*; Geurts, José M.Sc.†; van Kleef, Maarten M.D., Ph.D.‡; Faber, Catharina G. M.D., Ph.D.§; Perez, Roberto S. Ph.D.‖; Kessels, Alfons G.H. M.D., M.Sc.#; Van Zundert, Jan M.D., Ph.D.**


ABSTRACT

Background: Sympathetic blockade with local anesthetics is used frequently in the management of complex regional pain syndrome type 1(CRPS-1), with variable degrees of success in pain relief. The current study investigated which signs or symptoms of CRPS-1 could be predictive of outcome. The incidence of side effects and complications of sympathetic blockade also were determined prospectively.

Methods: A prospective observational study was done of 49 patients with CRPS-1 in one extremity only and for less than 1-yr duration who had severe pain and persistent functional impairment with no response to standard treatment with medication and physical therapy.

Results: Fifteen (31%) patients had good or moderate response. The response rate was not different in patient groups with cold or warm type CRPS-1 or in those with more or less than 1.5°C differential increase in skin temperature after sympathetic blockade. Allodynia and hypoesthesia were negative predictors for treatment success in CRPS-1. There were no symptoms or signs of CRPS-1 that positively predicted treatment success. A majority of patients (84%) experienced transient side effects such as headache, dysphagia, increased pain, backache, nausea, blurred vision, groin pain, hoarseness, and hematoma at the puncture site. No major complications were reported.

Conclusions: The presence of allodynia and hypoesthesia are negative predictors for treatment success. The selection of sympathetic blockade as treatment for CRPS-1 should be balanced carefully between potential success and side effect ratio. The procedure is as likely to cause a transient increase in pain as a decrease in pain. Patients should be informed accordingly.

This article may be accessed for personal use at no charge through the Journal Web site, www.anesthesiology.org.




Author Information
* Consultant Anesthesiologist, Department of Anesthesiology and Pain Management, St. Elisabeth Hospital, Tilburg, The Netherlands. † Research Associate, ‡ Professor, Department of Anesthesiology and Pain Medicine, § Associate Professor, Department of Neurology, Maastricht University Medical Centre, Maastricht, The Netherlands. ‖ Associate Professor, Department of Anesthesiology and Institute for Health and Care Research, VU University Medical Centre, Amsterdam, The Netherlands. # Biostatistician, Epidemiologist, Department of Clinical Epidemiology and Medical Technology Assessment, University Hospital Maastricht, Maastricht, The Netherlands. ** Consultant Anesthesiologist, Department of Anesthesiology and Multidisciplinary Pain Centre, Hospital Oost-Limburg, Genk, Belgium.


Address correspondence to Dr. van Eijs: Department of Anesthesiology and Pain Medicine, Maastricht University Medical Centre, Mailbox 5800, 6202 AZ Maastricht, The Netherlands. f.v.eys@elisabeth.nl.