Programmed bladder cycling before renal transplantation: A scoping review of definitions, protocols and functional outcomes

Low-capacity or defunctionalised bladder is a recurring urological dilemma before renal transplantation (RT), but the definitions, indications and protocols for programmed bladder cycling (PBC) remain poorly standardised. This scoping review aims to map bladder dysfunction definitions, patient populations, cycling protocols, urodynamic endpoints, adverse events and transplant-related outcomes.

This scoping review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping review guidelines (PRISMA-ScR). All studies assessing bladder cycling before Renal Transplantation up to 11^th March 2026 were included. Findings were synthesized descriptively. PBC was defined as protocolised repeated or continuous bladder filling, retention and drainage before transplantation for assessment or conditioning.

A total of 1,673 records were identified, of which 13 studies met inclusion criteria. Study designs were predominantly observational, with small sample sizes and substantial heterogeneity in patient selection, definitions of defunctionalised bladder, cycling protocols, and outcome reporting. Definitions varied from anuria, urinary diversion and low urine output to bladder capacity or pressure-based thresholds. Most studies reported increased measured bladder capacity (BC) after PBC and, in a subset of patients, improvements in urodynamic parameters. However, clinically relevant urological and transplant-related outcomes were infrequently reported. Only one study included a comparator group and demonstrated no significant difference in BC, compliance, or renal function between patients undergoing PBC and those managed without it.

PBC may increase measured bladder capacity in selected renal transplant candidates, but current evidence does not establish which patients require it, what endpoint should define adequate lower urinary tract optimisation, or whether it improves transplant-relevant outcomes. Future studies should distinguish adult disuse-related low-capacity bladder from paediatric congenital, neurogenic or reconstructed lower urinary tract dysfunction. In addition, the focus should shift from reporting of bladder capacity to clinically meaningful endpoints.