Evaluating the efficacy of botulinum toxin in treating complex regional pain syndrome: A systematic review

Complex Regional Pain Syndrome (CRPS) is characterized by pain, swelling, limited range of motion, skin changes, vasomotor instability, and bone demineralization. This study aims to assess the efficacy of botulinum toxin type A (BoNT-A) in the treatment of CRPS. We conducted a systematic literature review following the PRISMA guidelines, using the PICO strategy (Patient, Intervention, Comparison and Outcome) with the following criteria: P = Patients with CRPS; I = Botulinum toxin; C = Placebo or active drug; and O = Pain relief. Three randomized controlled trials with placebo controls were included, involving a total of 64 patients, 36 of whom received BoNT-A in doses ranging from 40U to 200U. The studies examined both lumbar sympathetic block and local application methods. Botulinum toxin shows promise in alleviating pain associated with CRPS, particularly when used as an adjunct to lumbar sympathetic blockade. However, the limited number of studies and small sample sizes impede reaching definitive conclusions regarding its efficacy and safety. Notably, local applications (intradermal or subcutaneous) require further investigation, as current evidence is insufficient and reports indicate patient discomfort. While preliminary findings suggest potential benefits of BoNT-A in managing CRPS, larger randomized trials are necessary to confirm its efficacy and safety.