PROSPECTIVE COMPARATIVE STUDY OF MINIPERC AND STANDARD PNL FOR TREATMENT OF 1 TO 2 CM SIZE RENAL STONE

Abstract

Sir, We read with great interest the above article by Mishra et al. [1] on the prospective comparative study of Miniperc and standard percutaneous nephrolithotomy (PNL) for the treatment of medium-sized kidney stones. In the article, the authors concluded the significant advantages of the Miniperc procedure for reduced bleeding leading to a tubeless procedure and reduced hospital stay. The stone-free rates and the complications were similar in both groups. However, we have some questions about this work. Firstly, why was shockwave lithotripsy (SWL) not chosen as a first-line therapy in these patients? At our institution, renal stones of <2 cm are managed by SWL, whereas stones of ≥2 cm are usually managed by PNL. The European Association of Urology and the AUA guidelines for the treatment of intrarenal calculi of <2 cm recommend SWL as the first-line therapy [2,3]. Because of its non-invasive nature, low complication rate, and high level of patient acceptance, SWL is usually the method of choice for the treatment of kidney stones. However, there is a broad consensus that the lowest success rate of SWL occurs with stones located in the lower calyces. The choice of therapy for lower pole stones of 10–20 mm is controversial and based on various stone, patient, and surgeon factors. Secondly, why was no retrograde intrarenal surgery (RIRS) technique used in these patients who had previously failed SWL? Because, despite its effectiveness major complications have been identified from PNL and occur at reported rates of 0.03–10% [4,5]. RIRS for medium-sized renal calculi is an acceptable alternative therapeutic method to PNL [6]. With the advent of the new generation of flexible ureteroscopes, with greater deflection and control, there has been an increase in endoscopic ureteroscopy and laser lithotripsy for renal calculi. Recent studies report stone-free rates of >90% for retrograde ureteroscopic management of renal stones and as high as 85% for the management of lower pole stones [7]. In our clinic, we decide upon the appropriate technique for treating stones of 10–20 mm according to pelvi-calyceal anatomy and patient choice. We prefer the PNL technique in patients who have a narrow lower-pole infundibulo-pelvic angle or infundibular width. And we prefer the RIRS technique in patients who have bleeding diathesis, musculoskeletal deformities, chronic obstructive pulmonary disease, morbid obesity or abnormal renal anatomy (horseshoe, pelvic, and malrotated kidneys, ectopic pelvic fusion anomaly).