Long-term complications arising from bowel interposition in the urinary tract.

After radical cystectomy or pathologies affecting the ureter(s), bowel segments can be employed to restore the natural urine flow or to create an external urinary diversion. Nevertheless, the interposition of bowel segments in the urinary tract is not devoid of complications. In fact, bowel's microstructure differs from the urothelium; specifically its mucosa is aimed at reabsorption, rather than storage. The aim of this paper is to revise the pathophysiology of complications related to bowel's mucosal properties. Those are: metabolic imbalance, malabsorption of vitamins, cholelitiasis, nephrolitiasis and infections. Their entity varies according to the segment used and to its length, which reflects the surface in contact with urine. Mostly, they occur on the long-term, but metabolic imbalances might occur soon after surgery as well.