Prospective Randomized Evaluation of Antimicrobial Prophylaxis in Patients Undergoing Extracorporeal Shock Wave Lithotripsy*

Clear guidelines that address the appropriate use of prophylactic antibiotics in patients undergoing extracorporeal shock wave lithotripsy (ESWL) are not available. The purpose of this study was prospectively to evaluate the role of such antibiotics.

Fifty-two patients with sterile urine (tested 3 days prior to ESWL or stent placement and not receiving antibiotics) were randomly assigned (double-blind) to receive oral placebo or norfloxacin 400 mg every 12 hours beginning 48 hours prior to ESWL, with the last dose at 6 am on the morning of the procedure. Urine cultures obtained on the first postoperative day were considered to be significant if the pure colony count exceeded 10,000/ml. No patients had perioperative sepsis. Although statistical evaluation showed no difference between the 24 evaluable norfloxacin-treated and the 25 evaluable placebo-treated patients in the frequency of urinary infection (p = 0.28), two of the patients in the placebo group, both of whom had other manipulations at the time of ESWL, had significant bacteriuria the day after treatment, and one of them was rehospitalized 4 days after ESWL for febrile urinary infection. In contrast, all patients in the norfloxacin group had sterile urine postoperatively. Although the data suggest that antimicrobial prophylaxis is not necessary in ESWL patients with sterile urine preoperatively, it is our impression that patients with a significant history of urinary infection who will have manipulations during ESWL may well benefit from prophylactic antibiotics. Further study on a larger cohort of patients will be necessary to corroborate this belief.