Urodynamic investigations in reversed ileal seromuscular enterocystoplasty: an experimental study in a rabbit model

To investigate the efficacy of the reversed ileal seromuscular enterocystoplasty (RISMEC) technique and assess the urodynamic findings.

A large bladder defect was created in 12 New Zealand White rabbits: in six the bladder was closed primarily (control group) and in the remaining six the bladder was augmented using the RISMEC technique combined with omentoplasty. The results were assessed using intravenous pyelography (IVP), voiding cysto-urethrography (VCUG), histopathological investigations and urodynamic studies after 4 and 12 weeks.

The IVP and VCUG revealed an apparently normal urinary system and voiding pattern in both groups. Histopathologically, in all rabbits undergoing RISMEC, the serosal surface of the reversed ileum was lined with transitional urinary epithelium; there was no evidence of severe fibrosis, inflammation, stone or mucus-production. Urodynamic studies showed a significant decrease in the mean bladder capacity in the controls, but no significant change in the RISMEC group. The mean bladder compliance decreased from 5.85 to 1.36 mL/cmH2O in the controls (P < 0.02) but there was no significant decrease in compliance in the RISMEC group.

The results suggest that in this rabbit model, the RISMEC technique combined with omentoplasty increases bladder capacity with minimal graft shrinkage; the peritoneal surface is rapidly covered with transitional epithelium and the integrity of the kidneys preserved. Urodynamic investigations showed neobladders with adequate storage capacity, low intravesical pressures and improved compliance rates.