Botulinum toxin type-A infiltration of the external anal sphincter to treat outlet constipation in motor incomplete spinal cord injury: pilot cohort study

Abstract

Abstract Background Outlet constipation is a major problem in spinal cord injury (SCI) patients. We aimed to study the efficacy of external anal sphincter (EAS) infiltration with type-A botulinum toxin (BTX-A) in motor incomplete SCI patients with outlet constipation. Methods Double blind, randomized, placebo controlled, comparative study in 16 motor incomplete SCI subjects. Patients were randomly assigned toreceive100 UI of BTX-A (n\u2009=\u20099) or physiologic serum infiltration (n\u2009=\u20097) in the EAS under electromyographic guidance. Outcome measures included a questionnaire for clinical bowel function evaluation, colonic transit time and anorectal manometry. All assessments were done at baseline, 1 and 3 months after treatment. Results Fourteen patients completed the study. In the BTX-A group we observed an improvement of subjective perception of bowel function (p\u2009=\u20090.01), constipation (p\u2009=\u20090.02) and neurogenic bowel dysfunction score (p\u2009=\u20090.02). The anorectal manometry revealed are duction of EAS voluntary contraction pressure (p\u2009=\u20090.01). No changes were observed in the placebo group. No significant side effects were observed in none of the groups. Conclusion BTX-A infiltration of the EAS is a safe technique that in motor incomplete SCI, decreases the EAS contraction and the anal canal pressure during straining, and improves outlet constipation symptoms. Future studies in larger populations are needed.