Botulinum toxin therapy in amputee pain management

Background: Post-amputation pain is common, occurring in up to 85% of patients. The pain can be related to the etiology of amputation, post-surgical healing, or prosthetic use. Pain syndromes may arise from a variety of tissue pathologies and can be broadly categorized into residual limb pain (RLP) or phantom limb pain (PLP). Botulinum toxin (BTX) has been found to be effective in treating a variety of neuropathic pain conditions. This scoping review summarizes the use of BTX in RLP and PLP management of patients with a major extremity amputation. Methods: A literature search was conducted using PubMed, Web of Science, Cochrane Library, Scopus, and Google Scholar. Sixteen studies were included. Most studies excluded did not address BTX use in amputee pain management. Extracted data were categorized by either RLP or PLP. Results: Two randomized controlled trials (RCTs), 10 case series, and 4 case reports were included (total 68 patients, 82 amputations). Seven studies addressed BTX use in both RLP and PLP, 5 studies address RLP exclusively, and 5 additional studies exclusively addressed PLP. Toxin types, injection techniques, and dosages varied between the studies. Negative results were reported in 2 RCTs and 2 case series showing 30% of patients with RLP and 50% patients with PLP did not benefit from BTX. Conclusion: Literature for BTX in PLP and RLP is broad but lacking rigour for definitive conclusions to guide usage. There were more positive results for BTX use in RLP than in PLP. Case reports and patient series show promising results for both PLP and RLP, indicating future research should be directed at adequately-powered prospective trials.