How do increasing stone surface area and stone configuration affect overall outcome of percutaneous nephrolithotomy?

Abstract

Background and purpose: Studies reporting the outcome of percutaneous nephrolithotomy (PCNL) in relation to stone burden and configuration are limited. We analyzed our stone-free and complication rates of PCNL with regard to stone surface area and configuration.

Patients and methods: Data of 234 patients who underwent PCNL were analyzed retrospectively. Patients were stratified into six groups according to stone burden and into four groups in relation to stone configuration. Groups were compared with respect to the number of tracts, success of therapy, complications, requirement for secondary procedures, drop in hematocrit, and blood transfusion requirement.

Results: The overall stone-free rate was 78.6% with a complication rate of 34.6%. Stone-free rates decreased with increasing stone size (P = 0.001) and with increasing caliceal component in complex stones (P = 0.01). The total number of complications rose with increasing stone surface area (P = 0.0001); however, stone distribution within the kidney did not affect the complication rate (P = 0.2). The mean operative time rose with increasing stone burden (P < 0.05) and increasing caliceal involvement by complex stones (P < 0.01). The need for multiple tracts also rose with increasing stone burden (P < 0.05).

Conclusion: There is a decrease in the overall stone-free rate, as well as an increase in the complication rate, the secondary procedure rate, the mean operative time, and the need for multiple tracts, with increasing stone surface area with PCNL. With regard to stone configuration, there is a decrease in the stone-free rate, as well as an increase in the operative time, with increasing caliceal component in complex renal stones.