Post-percutaneous nephrolithotomy systemic inflammatory response: a prospective analysis of preoperative urine, renal pelvic urine and stone cultures.

Purpose: Prior studies suggest that renal pelvic urine culture is a more accurate predictor of urosepsis. We prospectively determined the correlation between preoperative bladder urine cultures, intraoperative renal pelvis cultures and stone cultures in patients undergoing percutaneous nephrolithotomy. We also examined post-procedure risk factors for systemic inflammatory response syndrome.

Materials And Methods: From February 2009 to February 2011 urine samples from the bladder and renal pelvis were collected from patients undergoing percutaneous nephrolithotomy. Extracted stones were also sent for culture analysis. Postoperatively patients were closely monitored for any signs of systemic inflammatory response syndrome. The concordance of urine and stone cultures across different sites was examined. Regression analysis was done to identify clinical variables associated with systemic inflammatory response syndrome.

Results: A total of 204 percutaneous nephrolithotomies were done in 198 patients, of whom 20 (9.8%) had evidence of systemic inflammatory response syndrome postoperatively, including 6 (30%) requiring intensive care. The concordance among stone, renal pelvic and preoperative cultures was 64% to 75% with the highest concordance between renal pelvic urine and stone cultures. In a multivariate model multiple access tracts and a stone burden of 10 cm(2) or greater were significant predictors of systemic inflammatory response syndrome postoperatively.

Conclusions: Even appropriately treated preoperative urinary infections may not prevent infected urine at percutaneous nephrolithotomy. Renal pelvic urine and stone cultures may be the only way to identify the causative organism and direct antimicrobial therapy. We recommend collecting pelvic urine and stone cultures to identify the offending organism in patients at risk for sepsis, particularly those with a large stone burden requiring multiple access tracts.