Patch grafting the renal pelvis and ureteropelvic junction. A comparative study in pigs using lyophilized dura mater and free peritoneum.

Lyophilized dura mater (Lyodura) and autogenous free peritoneum were compared in the replacement of the partially resected renal pelvis and uretero-pelvic junction (UPJ) in the pig. The Lyodura and peritoneum grafts were both progressively resorbed, and replaced by fibroblasts which formed a mature scar lined by transitional epithelium, but without smooth muscle regeneration. Lyodura was found to be superior to free peritoneum with a longer time before resorption of the graft, less intense inflammatory reaction, absence of metaplastic bone formation, less risk of urine leak and greater ease of surgical manipulation.