COMPARATIVE EFFICACY OF EXTRACORPOREAL SHOCKWAVE LITHOTRIPSY AND RETROGRADE INTRARENAL SURGERY IN THE TREATMENT OF CALCIUM OXALATE NEPHROLITHIASIS

Abstract

Objective To evaluate the results of extracorporeal shockwave lithotripsy (ESWL) versus retrograde intrarenal surgery (RIRS) for the treatment of calcium oxalate nephrolithiasis, as well as the damaging effects on renal function, taking into account the dynamics of blood cystatin C and urine beta2-microglobulin.Material and Methods Of 94 patients with calcium oxalate nephrolithiasis aged 23–78 included in the study,  42 patients were classified as having undergone ESWL (group I) and 52 patients as having undergone RIRS (group II). Group II patients were then stratified into subset 2A (n = 32) as having undergone RIRS through rigid ureteroscope and subset 2B (n = 20) as having undergone RIRS through flexible ureteroscope. We performed plain urography and nephrosonography at 24–48 hours postoperatively and unenhanced computed tomography 4–6 weeks after surgery. We measured concentrations of serum cystatin C and urinary beta2-microglobulin as a marker for kidney damage. In group I, samples of peripheral blood andurine were taken before and after the first, third sessions and 30 days after the last ESWL session. In group  II, samples were analyzed before surgery, on the first and 30th postoperative days.Results The average size of calculi in the group with RIRS was 16.91 ± 2.79 mm, in the group with ESWL  12.31 ± 2.27 mm. The need for reoperation after RIRS was 19.2%, which was lower than after ESWL. Stone-free effect (no stones, or residual stones less than 3 mm) was observed in 95% of cases in patients with RIRS, and in 78% with ESWL. Group I patients demonstrated an increase in the blood leukocytes total number more often than subsets 2A (rigid RIRS) and 2B (flexible RIRS) patients. Leukocyturia was also a more common complication in group I. In the RIRS group, there was no statistically significant change in the level of blood cystatin C and urine beta2-microglobulin, on the contrary, a moderate increase in the endogenous marker of cystatin C was noted after one ESWL session. The increase in urine beta2-microglobulin levels in patients after the first and third ESWL sessions was significantly higher than after RIRS.Conclusion Flexible RIRS may be suggested as the preferred procedure for patients requiring additional protection of renal function in the treatment of renal stones less than 20 mm. ESWL of stones less than 20 mm can be used as an alternative treatment, since it is characterized by a rather long period of stone eradication from the urinary tract, a high frequency of residual calculi after the procedure, and also has a damaging effect on the renal tissue.