[Urinary calculi in an intestinal loop used for ureteral substitution. A case report]

The authors report the case of large urinary calculi formed inside the ileal conduit diversion in a patient who underwent radical surgery for an ovarian carcinoma involving the right ureter. Two ureter stents were left to ensure drainage and were endoscopically removed after six months. Renal function and ureteral canalization were normal. However, because of a knot in the proximal end of stents, a piece 5 cm-long-was left inside the diversion. After six months the patient developed recurrent renal colics: plain abdomen X-ray and urography showed a large urinary stone around the stents fragment and several smaller stones nearby. They all were removed surgically. The pathogenesis of such complications was considered: even though the slow flux of urine in the diversion, the abnormal mucus production from the ileal mucosa and the excessive and chronic bicarbonate loss played an important role in the developing of urinary calculi, the authors believe that in this case the main responsible for the stone formation was the foreign body in the urinary diversion.