Comparison of different bladder autoaugmentation techniques in a rabbit model.

Abstract

OBJECTIVE: To compare the urodynamic, radiological and histopathological findings of a bladder autoaugmentation method combined with different seromuscular enterocystoplasty (mucosectomized) techniques and the rectus abdominis muscle-flap (RAMF) technique, and thus devise a method that may eliminate the potential risks of bladder autoaugmentation. MATERIALS AND METHODS: The study comprised 20 male New Zealand White rabbits in four groups. In group 1 (control), an autoaugmentation model was created by incising the detrusor muscle of the bladder, forming a large wide-mouthed bladder diverticulum. In group 2, a full-thickness RAMF with an intact vascular supply was used to cover the augmented bladder wall. In groups 3 and 4, besides the autoaugmentation procedure, a 5 cm ileal segment with an intact vascular supply was prepared and the muscosal layer of the segment removed. In group 3, the mucosectomized surface of the ileal graft was used to cover the autoaugmented bladder (seromuscular ileocystoplasty, SMEC) and in group 4, the serosal surface of the pedunculated ileal graft was used in reverse to cover the autoaugmented bladder wall (reversed SMEC, RSMEC). All groups were followed using intravenous pyelography (IVP), voiding cysto-urethrography (VCUG), urodynamic investigations and histopathological analysis for 2 months post-operatively. RESULTS: In all groups except 2 (RAMF), a diffuse bulging of the bladder wall was detected on IVP and VCUG. In groups 1, 3 and 4, there was a significant increase in mean bladder capacity and the compliance also increased. However, in group 2 there was a significant reduction in bladder capacity and compliance, and the histopathological analysis showed severe fibrosis. The fibrotic changes were moderate in groups 1 and 4 and mild in group 3. CONCLUSIONS: The urodynamic studies, IVP, VCUG and histopathology suggested that the SMEC technique decreased the potential risks of bladder autoaugmentation, had minimal side-effects and was the most appropriate coat over the uroepithelium after bladder autoaugmentation.