Chaichanavichkij P, Vollebregt P F, Scott S M, Knowles C H
National Bowel Research Centre and GI Physiology Unit (Colorectal Services), Centre of Neuroscience, Surgery and Trauma, Blizard Institute, Queen Mary University of London, London, UK.
Colorectal Dis. 2020 Dec;22(12):1832-1841. doi: 10.1111/codi.15120. Epub 2020 Jun 11.
Dyssynergic defaecation (DD) is characterized by inappropriate coordination of the pelvic floor muscles during defaecation, resulting in impaired stool expulsion. The mainstay of treatment is biofeedback and alternative therapies are limited in those who do not respond. This systematic review evaluated botulinum toxin type A injection (BTXA) as a treatment option for dyssynergia.
PubMed, Embase and Cochrane Central Register of Controlled Trials were searched for studies evaluating adult patients with DD treated with BTXA injection into the puborectalis and/or external anal sphincter. All study designs, except case reports, were included in the review with no language restriction. Studies limited to patients with specific neurological diagnoses or with a follow-up period under 1 month were excluded. Study selection, assessment and data extraction were performed by two reviewers and results were synthesized narratively.
Eleven studies (three randomized control trials) involving 248 participants were included. All studies used the transanal approach to deliver the injection, most commonly at the 3 and 9 o'clock positions using digital palpation for guidance. The most commonly used patient position was left lateral, and most studies did not use any anaesthesia. The dose of BTXA varied (Botox 12-100 units, Dysport 100-500 units), and outcomes measured were heterogeneous (global rating ± up to five investigations). Symptomatic improvement varied between 29.2% and 100% and adverse effects occurred in 0% to 70%.
The evidence to support using BTXA for DD is poor and only covers a transanal approach. Future studies should redress these limitations: heterogeneity of design, dose and outcome measures.
