Efficacy and safety of botulinumA toxin for the treatment of chronic peripheral neuropathic pain: A systematic review of randomized controlled trials and meta-analysis.

Abstract

Botulinum toxin type A (BTX-A)is a recently developed treatment for the management of peripheral neuropathic pain. The objective of this study was to provide a synthesis of the evidence concerning the efficacy and safety of subcutaneous botulinum toxin type A injections. We searched the MEDLINE, EMBASE, LILACS, Cochrane, and Clinical Trial Register databases for randomized controlled trials comparingsubcutaneousBTX-A to placebo injections for treating chronic peripheral neuropathic pain. The primary endpoint was the assessment of pain 1month after the injection. The secondary outcomes were the assessment of pain at 3months, neuropathic pain intensity andquality of lifeat 1 and 3months, and adverse effects. A random-effect meta-analysis was performed on the combined data. Evidence quality was rated by the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) method. Ten randomized controlled trials including 505 patients were included in this review (registration number CRD42021239108). At 1 and 3months after injection,theBTX-A groups had a lower mean difference (MD) in pain score (MD -1.87 (confidence intervals [CIs] -2.91; -0.83) and -1.38 (CI -1.95; -0.81), respectively).Subgroup analysis showed greater efficacy for diabetic polyneuropathy (MD -2.48, [-3.22; -1.74]).We found no impact ofBTX-A onquality of life and no difference in adverse effect betweenBTX-A andplacebo.The evidencewasconsideredof moderate quality. The pooled data suggest that subcutaneousBTX-A injections have aclinicallysignificant effect, decreasing pain for threemonths after the injection, but nobenefit in terms of quality of life has yet been demonstrated. We found that botulinum toxin is efficient and safe for the treatment of neuropathic pain, especially for diabetic polyneuropathy. Botulinum toxin type A, used for years in neurology, rehabilitation and physical medicine, has proved innocuous and effective, and should be considered as a serious alternative for pain treatment.