Bladder augmentation using acellular collagen biomatrix: a pilot experience in exstrophic patients

A preliminary experience on in vivo bladder wall regeneration in a subset of patients born with exstrophy-epispadias complex is reported. The objective was to improve bladder capacity and compliance without bowel augmentation. Five patients (3 males, 2 females), mean age 10.4 years, presenting poor bladder capacity and compliance after complete exstrophy repair, underwent bladder augmentation using small intestinal submucosa (SIS) scaffold. Ultrasonography, cystoscopy with cystogram, assessment of bladder volume and compliance and bladder biopsy were performed before surgery (T0), at 6 (T1) and 18 months (T2) follow-up. Histology was compared with normal bladder specimens. Wilcoxon test was adopted for statistics. Bladder capacity and compliance resulted increased (+30%) at T1 (p < 0.05) and remained stable at T2, despite dry intervals did not changed significantly. Bladder biopsy at T1 showed no evidence of SIS, but normal transitional mucosa and sero-muscular layer containing smooth muscle fascicles, small nerve trunks and vessels within abundant type-3 collagen. Muscle/collagen ratio was decreased compared with controls at T1 and T2 (p < 0.05). No kidney damage, bladder diverticula, or stones were observed at 3 years follow-up. Bladder regeneration was feasible in these patients, but bladder capacity and compliance was poorly increased to obtain significant clinical benefit. Histology showed poor muscle components. The acellular matrix grafting failed to provide long-term effective results in terms of continence achievement.