STONE GRANULOMA - A CAUSE OF URETERAL STRICTURE

Ureteral stricture is a recognized complication of ureteroscopy and ur eteral stone fragmentation. Although most strictures are either asympt omatic or easily dilated, there are some strictures that result in pro gressive ureteral obstruction, do not respond to ureteral dilation and require operative intervention. A review of 125 percutaneous nephrost olithotomies for staghorn stone disease and 652 ureteroscopic stone fr agmentations revealed 5 cases in which refractory ureteral strictures developed, requiring operative intervention. In 4 patients a ''stone g ranuloma,'' embedded particles of calcium oxalate associated with macr ophages and foreign body giant cells, was found with surrounding fibro sis and ureteral obstruction. In the remaining patient a suture granul oma from a recent ureterolithotomy was the source of the stricture. In each instance of stone granuloma the particles of calcium oxalate had become embedded in the wall as a consequence of ureteroscopic stone f ragmentation and partial ureteral wall disruption. During ureteroscopy and intracorporeal lithotripsy every effort should be made to prevent calcium oxalate particles from becoming embedded in the ureteral wall . They are not inert and may cause irreversible stricture formation. T o our knowledge, stone granuloma is a previously undescribed phenomeno n and should be suspected when ureteral strictures that occur followin g ureteroscopy do not respond to endourological methods of management.