Interventional stress in renal stone treatment

To compare current minimally invasive strategies in renal stone treatment-shockwave lithotripsy (SWL), retrograde intrarenal surgery (RIRS), and minimally invasive percutaneous nephrolitholapaxy-with regard to interventional stress, measured by changes in interleukin (IL)-6 and C-reactive protein (CRP) serum levels during treatment.

143 patients underwent stone therapy for renal pelvic stone (SWL, n=40, mean age±standard error of the mean [SEM]: 48.3±3.1 years; RIRS, n=74, 54.5±1.8; and minimally invasive percutaneous nephrolitholapaxy (MIP), n=29, 54.6±2.7) between 2006 and 2007. Blood samples were prospectively collected 24 hours before and 24 hours after the procedure. Interventional stress was analyzed by changes of the acute phase proteins IL-6 and CRP.

Mean IL-6 (ng/L) difference (±SEM; 95% confidence interval [CI]) before and after therapy was +8.7 (±10.5; -13.9-31.2), +7.3 (±3.2; 1.5-13.1), and +20.5 (±8.1; 4.0-36.0) in the SWL, RIRS, and MIP groups, respectively (P=0.20). Differences in mean CRP (mg/dL) levels (±SEM; 95% CI) ranged between +0.9 (±1.6; -2.3-4.1) in SWL, +1.6 (±0.5; 0.6-2.5) in RIRS, and +1.8 (±,0.3, 1.2-2.5) in MIP patients (P=0.79). Mean stone sizes (mean/median mm(2)±SEM) differed significantly between SWL (27/20±3), RIRS (70/16±36), and MIP groups (346/160±104, P<0.0005).

Contrary to common opinion that SWL is the least invasive therapy, the reported stress parameters did not show significant differences between SWL, RIRS, and MIP, although significantly bigger stones were treated with MIP.