Authors' Response to Lingeman

To the Editor:

We thank Dr. Lingeman ¹ for his thoughtful comments. The patients in this study included a heterogeneous group in which 32 patients had a stone volume of more than 2 cm and 123 patients had a stone size of 1.5 to 2 cm. Therefore, our results cannot be equated with stones <2 cm only.

Although urolithiasis is a global phenomenon, the treatment modality has to take into consideration the socioeconomic status as well as the geographic condition of the native area, which influence patient preferences. At our center, shockwave lithotripsy (SWL) offers a clearance rate of 88.02% at first sitting ² ; however, it necessitates stringent follow-up for repeated sittings for residual stones. Our subgroup of patients is unable to follow up because of socioeconomic conditions. Although retrograde intrarenal surgery (RIRS) achieves comparable stone-free rates, ³ it remains a costlier option and, hence, not preferred by our patients.

The European Association of Urology guidelines state that SWL, RIRS, and percutaneous nephrolithotomy (PCNL) can be offered as options for stones <10 mm, 10–20 mm, as well as >20 mm. RIRS, however, is less commonly used as a first choice for stones >15 mm.

We agree with the comment that miniperc has value in the pediatric age group in such sized stones; however, we would disagree with the opinion expressed that SWL and RIRS are “less invasive.” The present study of miniperc noted that Clavien-Dindo grade I and grade II complications occurred in 4.4% and 0.3% patients, respectively. There were no higher grades of complications in this miniperc study, whereas another study suggested that ureteral wall injury was seen in 46.5% of the patients after use of an access sheath during RIRS. Severe injury involving smooth muscle layers of the ureter was seen in 13.3% patients. ⁴ A prospective randomized study comparing RIRS and miniperc suggested that both RIRS and miniperc are associated with high stone-free rates (100% with miniperc and 96.88% with RIRS) and minimal complication rates. RIRS had lesser blood loss and postoperative pain at the cost of increased operative time. ³ A prospective randomized multicentric clinical trial comparing SWL and PCNL for lower-pole calculi suggested that the complication rates with SWL (12%) and PCNL (23%) were not significantly different (P=0.087). ⁵

Last but not least, we agree that the case in this debate can be rested only with large multicentric randomized trial comparing RIRS vs SWL vs miniperc for stones <2 cm.