The use of a cystoscopically placed cobra catheter for directed irrigation of lower pole caliceal stones during extracorporeal shock wave lithotripsy.

As the general experience with extracorporeal shock wave lithotripsy (ESWL) for renal calculi broadens, it is increasingly evident that the clearance of stone fragments in lower pole calices needs to be improved. The stone-free rate after treatment for lower caliceal stones is consistently less than that for other upper tract locations. Use of a cystoscopically placed cobra catheter for directed irrigation during ESWL resulted in an increase of our lower caliceal stone-free rate at 1 and 3 months of followup to 71% (15 of 21) compared to 33% (8 of 24) of randomly selected controls at 1 month and 54% (13 of 24) at 3 months. We conclude that pre-ESWL placement of a cobra catheter into the lower pole calix and intermittent irrigation during the procedure are potentially useful adjuncts in the successful treatment of lower caliceal calculi.