INTRAVENOUS REGIONAL SYMPATHETIC BLOCKADE FOR PAIN RELIEF IN REFLEX SYMPATHETIC DYSTROPHY - A SYSTEMATIC REVIEW AND A RANDOMIZED, DOUBLE-BLIND CROSSOVER STUDY

The first aim was a systematic review of intravenous regional sympathe tic blocks (IRSBs) in patients with reflex sympathetic dystrophy (RSD) . Randomized controlled trials (RCTs) of IRSBs in patients with RSD we re identified by MEDLINE search (1966 to May 1993) and by hand search of 30 journals (1950 to May 1933). Authors of eligible trials were ask ed for information on additional trials and for unpublished data. Seve n RCTs of IRSBs in RSD were found. Four used guanethidine; none showed significant analgesic effect in IRSBs to relieve pain due to RSD. Two reports, one using ketanserin and one bretylium, with 17 patients in total, showed some advantage of IRSBs over control. RCT results were n ot combined because of the variety of different drugs and outcome meas ures and because of methodological deficiencies in most of the reports . The second aim was a randomized, double-blind, crossover study to as sess the effectiveness of IRSBs with guanethidine. Patients fulfilling diagnostic criteria for RSD and who had reported pain relief after an open IRSB with guanethidine received IRSBs with guanethidine high dos e, guanethidine low dose, and normal saline. Pain intensity and relief adverse effects, mood, duration of analgesia, and global scores were recorded. Sixteen patients with diagnosis of RSD were recruited, but o nly nine entered the double-blind phase. The trial was stopped prematu rely because of the severity of the adverse effects. No significant di fference was found between guanethidine and placebo on any of the outc ome measures. Patients in all groups reported less than 30% of the max imum possible relief during the first week after the injections, and o n only two occasions (one saline and one guanethidine low dose) was re lief reported for longer than a week. There was no evidence of a dose response for guanethidine. The use of guanethidine in IRSBs for patien ts with RSD was not supported by the systematic review or by the doubl e-blind study.