The efficacy and safety of synchronous bilateral extracorporeal shock wave lithotripsy

Bilateral renal calculi have traditionally been managed by staged extracorporeal shock wave lithotripsy (ESWLdagger) due to concern about bilateral obstruction. We evaluated the safety and efficacy of synchronous bilateral ESWL in a large series of patients treated at our institution to determine the safety and efficacy of this controversial technique in what is to our knowledge the largest series to date.

We retrospectively evaluated the records of 120 patients with a mean age of 48 years who underwent bilateral synchronous ESWL between 1987 and 1996. Of the patients 71 (59%) were male. Average followup was 21 months. ESWL was performed using a Dornier HM3 lithotriptor in all cases. Intraoperative technique and postoperative factors were analyzed using the Pearson product moment correlation, the 2-tailed t test and multiple regression analysis.

Mean stone size was 13 and 15 mm. on the left and right sides, respectively. There was an average of 1.7 stones per renal unit. After 1 treatment 72 of the 120 patients (60%) were stone-free bilaterally, while 72% and 73% of left and right renal units, respectively, were also stone-free. Mean creatinine was similar preoperatively and postoperatively (1.46 and 1.41 mg./dl., respectively, p = 0.73). There was 1 or more complications in 18 cases. The majority of complications were minor with no long-term morbidity or death and there was no case of bilateral obstruction or renal failure. Additional procedures were required in 19 patients (16%) due to significant residual stone disease or obstruction during followup. Multiple regression analysis revealed that only patient age, a right ureteral stent and the number of shocks correlated with the complication rate. Stone size and number independently increased the probability of treatment failure and a repeat procedure (p <0.05). Patients with stones 20 mm. or greater were at particularly high risk for treatment failure and additional procedures. A total of 27 of the 35 patients (77%) with residual calculi and 13 of the 19 (68%) requiring additional procedures were in this high risk subgroup.

Bilateral synchronous ESWL is safe and effective monotherapy for bilateral urolithiasis. No patient had bilateral obstruction or renal failure and no deterioration of renal function was detected at followup. Knowing which patient populations are at higher risk for failure or complications may guide decision making.