Laparoscopic augmentation cystoplasty with different biodegradable grafts in an animal model

Purpose: Recently a variety of biodegradable organic materials have been us ed for bladder wall replacement. We sought to study the effectiveness of 4 different types of biodegradable materials for bladder augmentation using l aparoscopic techniques. Materials and Methods: Thirty one minipigs underwent successful transperito neal laparoscopic partial cystectomy and subsequent closure (6 control) or patch augmentation (25): porcine bowel acellular tissue matrix (ATM) (6), b ovine pericardium (BPC) (6), human placental membranes (HPM) (6) or porcine small intestinal submucosa (SIS) (7). An intracorporeal suturing technique with the EndoStitch device (U.S, Surgical, Norwalk, CT) and Lapra-Ty clips (Ethicon, Enodsurgery Inc. Cincinnati, OH) was used to anastomose the graf t to the bladder wall. Postoperatively, a urethral catheter was left for on e week. Bladders were evaluated by cystoscopy at 6 and 12 weeks and harvest ed at 12 weeks. Results: Grafts remained in place in all groups except for the BPC group, w here all grafts failed to incorporate. For the ATM and SIS groups, at 6 wee ks, there was mucosal coverage of the grafts without evidence of encrustati on. In the control group, at 12 weeks, the bladder capacity was 23% less th an preoperatively. In the ATM, HPM and SIS groups, at 12 weeks, the bladder capacities were larger than preoperatively by 16%, 51% and 43% respectivel y; also the grafts had contracted to 70%, 65%, and 60% of their original si zes, respectively. Histologically, there was patchy epithelialization of AT M and SIS grafts with a mixture of squamoid and transitional cell epithelia . The graft persisted as a well-vascularized fibrous band in HPM, ATM, and SIS without evidence of significant inflammatory response. Conclusion: A laparoscopic technique for partial bladder wall replacement u sing a free graft is feasible. The biodegradable grafts of ATM, HPM and SIS are tolerated by host bladder and are associated with predominantly only m ucosal regeneration at 12 weeks post-operatively.