Intravenous regional sympathetic blockade for pain relief in reflex sympathetic dystrophy: A systematic review and a randomized, double-blind crossover study

Abstract

The first aim was a systematic review of intravenous regional sympathetic blocks (IRSBs) in patients with reflex sympathetic dystrophy (RSD). Randomized controlled trials (RCTs) of IRSBs in patients with RSD were identified by MEDLINE search (1966 to May 1993) and by hand search of 30 journals (1950 to May 1993). Authors of eligible trials were asked for information on additional trials and for unpublished data. Seven 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 not combined because of the variety of different drugs and outcome measures and because of methodological deficiencies in most of the reports. The second aim was a randomized, double-blind, crossover study to assess 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 dose, 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 only nine entered the double-blind phase. The trial was stopped prematurely because of the severity of the adverse effects. No significant difference was found between guanethidine and placebo on any of the outcome measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Causalgia and reflex sympathetic dystrophy: Does the sympathetic nervous system contribute to the generation of pain?

“…Five placebo-controlled studies using guanethidine IVRS have been performed. 14,65,77,133,139 Only one demonstrated a significantly better acute effect (1 h after the block). 65 One potential criticism of these guanethidine data is that four studies used only one IVRS, but multiple blocks may be necessary for treatment of RSD and causalgia.…”

Assessment of the Peripheral Microcirculation Using Computer-Assisted Venous Congestion Plethysmography in Post-Traumatic Complex Regional Pain Syndrome Type I

“…Until recently, an increased efferent sympathetic response following the initial injury was an often formulated hypothesis. Current placebo-controlled studies on the efficacy of therapeutic sympathicolysis [5]and the finding of diminished concentrations of norepinephrine in CRPS-I-affected extremities versus the unaffected side refute the hyperactive sympathetic theory [6]. By contrast, there is evidence of an upregulated sensitivity of α-adrenoceptors for catecholamines in the affected extremity inducing CRPS-I.…”

Letter to the Editor of Pain on Jørum et al: Catecholamine-induced excitation of nociceptors in sympathetically maintained pain; Pain 2007;127:296–301

“…But in absence of placebo control, the SMP assumption is scientifically invalid because too many chronic pain patients communicate temporary relief that is demonstrably due to inert or active placebo effect (Verdugo and Ochoa, 1994a;Verdugo et al, 1994;Ramamurthy et al, 1995;Jadad et al, 1995;etc. ) and recent work ratifies this (unpublished).…”