[Analysis and clinical course of residual lithiasis after shock wave renal treatment]

Although residual lithiasis after the application of shock waves is a situation that coexists with the procedure, in some cases it can be considered to be a failure of ESWL. The natural history and outcome of 244 cases of residual renal stone followed over a 5-year period are analyzed, and the approach based on a pre-established classification is discussed.

Of 1,407 patients treated by ESWL for renal lithiasis during 1995, 244 cases with a renal calculus larger than 3 mm were followed for a period of 5 years after treatment and evaluated by clinical, radiological, ultrasound and analytical methods.

At 3 months post-ESWL, 1,013 cases (72%) were completely stone-free and 394 (28%) showed residual stone; of these, 244 (62%) had residual stone fragments greater than 3 mm. At 5 years, 190 (78%) remained stable and the remaining 54 (22%) showed stone regrowth that warranted additional treatments: 52 ESWL, 1 PNL and 1 partial nephrectomy. Despite the retreatments, only 42% became completely stone-free.

A classification of residual renal stone can be established based on the data obtained to orient the approach in each case, although the frequency of residual stone can be reduced by the appropriate indication of ESWL. Once a renal stone has formed retreatments with ESWL cannot ensure complete elimination of the stone.