[Hydronephrosis caused spontaneous evacuation of many small calculi in a caliceal diverticulum: a case report]

We experienced a curious case that hydronephrosis had caused spontaneous evacuation of calculi in a caliceal diverticulum. A 50-year-old woman was visited to our department complaining of right lower abdominal pain. Several right ureteral stones, right hydronephrosis and a great numbers of small round-shaped calculi in a right caliceal diverticulum were diagnosed. Many of the calculi moved from the diverticulum to ureter, and were evacuated spontaneously. The month after, the right hydronephrosis had already subsided and almost all of the calculi had disappeared. It was supposed that a hydronephrosis had widened the narrow channel between the diverticulum and the calyx and enabled the small calculi to pass through. Recent reports show that effectiveness of ESWL for symptomatic caliceal diverticular calculi is doubtful, because the narrow channel hinders the passage of stone fragments. However, this case suggests that an artificial hydronephrosis created by retrograde occlusion ureteral balloon catheter may lead to good drainage of gravel and better stone-free rate of caliceal diverticular calculi treated by ESWL.