Suprapubic Catheter-Associated Defecatory Outlet Dysfunction in a Decompressed Bladder: An Integrated Mechanistic Framework and Empirical Validation A Synthesis of Viscerovisceral Cross-Talk, Sacral Spinal Reflex Arc Modulations, Pharmacological Interventions, and Diagnostic Protocols

Abstract

Bruce H. Knox

Background: Suprapubic catheterisation (SPC) provides continuous urinary drainage and leaves the urinary bladder substantially decompressed. Nevertheless, an indwelling suprapubic catheter remains a persistent mechanical stimulus within the bladder. Catheter-related bladder discomfort, trigonal irritation, and detrusor spasm occur even when the bladder is not filled. The urinary bladder, pelvic floor, and anorectal outlet are linked through shared sacral, spinal, and supraspinal neural networks, raising the possibility that persistent catheter-generated afferent input influences anorectal motor behaviour. Hypothesis & Integrative Synthesis: This paper establishes an expanded mechanistic framework proposing that continuous mechanical contact between an SPC/balloon and the decompressed bladder wall triggers persistent urothelial/suburothelial afferent firing (Aδ and C fibres). Through sacral spinal cord convergence (S2–S4) and the vesico-anal reflex arc, this afferent activity induces central sensitization and a protective pelvic-floor motor guarding reflex. Consequently, impaired relaxation of the puborectalis muscle and external anal sphincter during attempted defecation produces acquired anorectal outlet obstruction despite preserved colonic transit.