Lithotripsy of urinary concrement in the sigmoid after ureterosigmoidostomy.

A urinary concrement which appeared in the sigmoid of a 63-year-old man after ureterosigmoidostomy was extracted by endoscopy. The stone was situated proximal to a radiogenic stenosis. Because of the disproportion between the stone and the sigmoidal stenosis, mechanical lithotripsy had to be done before the concrement could be completely extracted.