Twenty-six studies (n=788) concerning treatment modalities were identified: there were 18 (15 RSD, 3 CRPS I) placebo-controlled RCTs (n=473) and 8(6 RSD, 2 CRPS I) active-controlled RCTs (n=315). Two placebo-controlled RCTs (n=194) concerning the prevention of RSD or CRPS I were identified.
RSD.
Sympathetic ganglion block.
One 'high quality' trial concluded that epidural clonidine (700 and 300 microg) decreased pain significantly more than placebo. Another high-quality study demonstrated no benefit for either intravenous phentolamine or phenylephrine over placebo for the treatment of RSD. One study evaluated intravenous reserpine and intravenous guanethidine, and another only intravenous guanethidine. Both high-quality studies found no benefit for these interventions over placebo.
No benefit over placebo was observed for intravenous droperidol in one high-quality study. Of the two studies that evaluated intravenous ketanserin against placebo, one found a significant improvement with ketanserin, and the other found no difference between the groups in terms of improvement in pain intensity.
One high-quality crossover study found bretylium in combination with lidocaine significantly reduced pain compared with lidocaine alone, and another found no significant differences between intravenous guanethidine alone or in combination with lidocaine. Another high- quality crossover trial comparing various doses of guanethidine and lidocaine found no significant differences between the intervention groups.
A low-quality crossover study found no difference in pain reduction between guanethidine plus lidocaine, reserpine plus lidocaine, or lidocaine alone. There was also no difference between bupivacaine and guenethidine when compared in a single low-quality study.
Calcium regulating drugs.
One high-quality study found a significant improvement in pain reduction in patients receiving clodronate when compared with a placebo group. Another high-quality trial significantly favoured 3 days of intravenous alendronate (7.5 mg) over placebo.
Two high-quality placebo-controlled studies used intranasal calcitonin as a therapeutic intervention. One of these (the higher quality trial) of calcitonin 100 IU (thrice daily for 3 weeks) found calcitonin to significantly improve pain intensity; the second study found no significant difference between calcitonin 200 IU (twice daily for 5 days) and placebo.
Radical scavenging.
A high-quality trial found no benefit for topical DMSO over placebo for the reduction of pain. There was also no difference found in a low-quality study that compared dermal application of DMSO against sympathetic blockade.
Corticosteroids.
A single low-quality trial found 12 weeks of treatment with prednisolone significantly improved clinical scores in comparison with placebo.
Complementary therapies.
Two trials (of low quality) found 3 weeks of acupuncture to be superior to sham acupuncture, although this difference was not significant.
CRPS I.
Sympathetic block.
One 'high quality' study found a slight improvement after treatment with lidocaine, though this improvement was not significant when compared with saline. Another study, of low quality, reported lidocaine to be significantly more effective than diphenhydramine.
Complementary therapies.
One high-quality study reported that 4 weeks of qigong exercises resulted in significantly greater improvements than in a sham exercise group. One low-quality study found no difference in the efficacy of acupuncture and sham acupuncture in CRPS I patients. A single high-quality study reported no difference in outcome between lymph drainage combined with exercise, compared with exercise alone.
Prevention of CRPS I.
Two high-quality studies were identified. One reported that the incidence of RSD in patients who had received 50 days of vitamin C (500 mg) was significantly lower than in patients who had received placebo. In the other study, patients undergoing faciectomy for Duputyren's disease received either saline or intravenous guanethidine (20 mg). The study authors concluded that it is not possible to prevent RSD by giving intravenous guanethidine pre-operatively.