Micropercutaneous nephrolithotomy (microperc) vs retrograde intrarenal surgery for the management of small renal calculi: a randomized controlled trial

Abstract

Objective: To compare micropercutaneous nephrolithotomy (microperc) and retrograde intrarenal surgery (RIRS) for the management of renal calculi <1.5 cm with regard to stone clearance rates and surgical characteristics, complications and postoperative recovery.

Patients and methods: Seventy patients presenting with renal calculi <1.5 cm were equally randomized to a microperc or a RIRS group between February 2011 and August 2012 in this randomized controlled trial. Randomization was based on centralized computer-generated numbers. Patients and authors assessing the outcomes were not blinded to the procedure. Microperc was performed using a 4.85-F (16-gauge) needle with a 272-μm laser fibre. RIRS was performed using a uretero-renoscope. Variables studied were stone clearance rates, operating time, need for JJ stenting, intra-operative and postoperative complications (according to the Clavien-Dindo classification system), surgeon discomfort score, postoperative pain score, analgesic requirement and hospital stay. Stone clearance was assessed using ultrasonography and X-ray plain abdominal film of kidney, ureter and bladder at 3 months.

Results: There were 35 patients in each group. All the patients were included in the final analysis. The stone clearance rates in the microperc and RIRS groups were similar (97.1 vs 94.1%, P = 1.0). The mean [sd] operating time was similar between the groups (51.6 [18.5] vs 47.1 [17.5], P = 0.295). JJ stenting was required in a lower proportion of patients in the microperc group (20 vs 62.8%, P < 0.001). Intra-operative complications were a minor pelvic perforation in one patient and transient haematuria in two patients, all in the microperc group. One patient in each group required conversion to miniperc. One patient in the microperc group needed RIRS for small residual calculi 1 day after surgery. The decrease in haemoglobin was greater in the microperc group (0.96 vs 0.56 g/dL, P < 0.001). The incidence of postoperative fever (Clavien I) was similar in the two groups (8.6 vs 11.4%, P = 1.0). None of the patients in the study required blood transfusion. The mean [sd] postoperative pain score at 24 h was slightly higher in the microperc group (1.9 [1.2] vs 1.6 [0.8], P = 0.045). The mean [sd] analgesic requirement was higher in the microperc group (90 [72] vs 40 [41] mg tramadol, P < 0.001). The mean [sd] hospital stay was similar in the two groups (57 [22] vs 48 [18] h, P = 0.08).

Conclusions: Microperc is a safe and effective alternative to RIRS for the management of small renal calculi and has similar stone clearance and complication rates when compared to RIRS. Microperc is associated with higher haemoglobin loss, increased pain and higher analgesic requirements, while RIRS is associated with a higher requirement for JJ stenting.

Keywords: laser lithotripsy; microperc; retrograde intrarenal surgery; small renal calculi.