Dear Karen -

Sorry for getting in late here, but how long has it been since you have first had onset of RSD/CRPS symptoms? The reason I ask is because it's pretty well established that they loose their usefulness the farther out you go. Check out the following piece, written for patients, on the always useful site of the RSDSA:

Clinical Q & A: Can there be too many sympathetic nerve blocks for the treatment of CPRS?
By William E. Ackerman, III, MD

Yes and no. Not all CRPS patients respond to this therapy. If patients get transient relief, allowing them to participate in physical therapy or not have to increase their medications, sympathetic nerve blocks are indicated. If no relief is noted after two blocks, then why repeat them? The results will not be favorable. Sympathetic blocks must be performed early in this disease to be effective. At that time, 2 to 3 blocks are usually effective.

The longer the duration from the onset of CRPS until the first injection, the worse the results. For example, a patient with CRPS for 12 months will have poor results with a sympathetic block. However, if a patient receives an injection within the first 2.5 to 3 months, the results should be good. This is why an accurate diagnosis of CRPS must be made in a timely fashion. Failure to do so may condemn a patient to life-long severe pain.

A sympathetic nerve blockade, however, is not a totally benign procedure, with side effects that include elevated blood sugars, rash, itching, weight gain, soreness at the injection site, bleeding, seizures, and death. Blockades are also more efficacious with decreased vasomotor activity, but become less effective with increased vasoconstriction. Therefore, the effectiveness of a sympathetic nerve blockade is based on the duration of the symptoms and blood perfusion in the affected area.

RSDSA Review, Winter 2008

http://www.rsds.org/publications/Ack...inter2008.html

For Dr. Ackerman’s more technical analysis, see, Ackerman WE, Zhang JM, Efficacy of Stellate Ganglion Blockade for the Management of Type 1 Complex Regional Pain Syndrome, South Med J. 2006 Oct;99(10):1084-8, FULL ONLINE TEXT @ http://www.rsds.org/pdfsall/Ackerman...lion_block.pdf:

Abstract
INTRODUCTION: The purpose of this study was to examine the efficacy of stellate ganglion blockade (SGB) in patients with complex regional pain syndromes (CRPS I) of their hands.

METHODS: After IRB approval and patient informed consent, 25 subjects, with a clinical diagnosis of CRPS I of one hand as defined by the International Association for the Study of Pain (IASP) criteria, had three SGB's performed at weekly intervals. Laser Doppler fluxmetric hand perfusion studies were performed on the normal and CRPS I hands pre- and post-SGB therapy. No patient was included in this study if they used tobacco products or any medication or substance that could affect sympathetic function. The appropriate parametric and nonparametric data analyses were performed and a p value <0.05 was used to reject the null hypothesis.

RESULTS: Symptom onset of CRPS I until the initiation of SGB therapy ranged between 3 to 34 weeks. Following the SGB series, patient pain relief was as follows: group I, 10/25 (40%) had complete symptom relief; group II, 9/25 (36%) had partial relief and group III, 6/25 (24%) had no relief. The duration of symptoms until SGB therapy was: group I, 4.6 +/- 1.8 weeks, group II, 11.9 +/- 1.6 weeks and group III, 35.8 +/- 27 weeks. Compared with the normal control hand, the skin perfusion in the CRPS I affected hand was greater in group I and decreased in groups II and III.
DISCUSSION:

The results of our study demonstrate that an inverse relationship exists between hand perfusion and the duration of symptoms of CRPS I. On the other hand, a positive correlation exists between SGB efficacy and how soon SGB therapy is initiated. A duration of symptoms greater than 16 weeks before the initial SGB and/or a decrease in skin perfusion of 22% between the normal and affected hands adversely affects the efficacy of SGB therapy.

Comment in South Med J. 2007 Apr;100(4):411-2; author reply 412.

PMID: 17100029 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed/17100029

I hope this information is useful.

Mike