BJUI BJU INTERNATIONAL E346 © 2 0 1 2 B J U I N T E R N A T I O N A L | 11 0 , E 3 4 6 – E 3 4 9 | doi:10.1111/j.1464-410X.2012.11089.x What’s known on the subject? and What does the study add? Miniperc and RIRS are commonly used modality for treating non-bulky renal urolithiasis. Both the treatment options are invasive and are associated with inherent complications. There are only a few studies that compare these two treatment modalities. Both the modalities are effective to render patient stone free with minimal complications. Immediate stone free rate is higher with miniperc but comparable in both the modalities at 1 month. RIRS is associated with favourable pain scores and lower hemoglobin drop. OBJECTIVE • To plan a prospective comparative case–control designed study aiming to compare minipercutaneous (miniperc) and retrograde intrarenal surgery (RIRS) for a renal calculus of size 1–2 cm. PATIENTS AND METHODS • A total of 64 cases (32 in each arm) underwent miniperc and RIRS during the study period from March 2009 to April 2011. • The primary and secondary outcome objective was stone-free rate and retreatment rate, complications, operation duration, patient visual pain scores, analgesic requirement, haemoglobin drop and hospital stay, respectively. RESULTS • Miniperc and RIRS had stone clearance rates of 100% and 96.88%, respectively. • In the RIRS group, one patient required retreatment at 1 month. • Hospital stay (0.24) and intra-operative (0.99) and postoperative complications (0.60) were similar in both groups. • Operation duration ( P = 0.003) was lower in the miniperc group. • Haemoglobin drop ( P < 0.001), patient pain and visual analogue scale score (each P < 0.001) at 6, 24 and 48 h, as well as analgesic requirement ( P < 0.003), were all lower in the RIRS group. CONCLUSIONS • The stone clearances in both modalities are high and complications are low. • RIRS requires a larger operation duration, although it is associated with favourable pain scores and a lower haemoglobin drop. KEYWORDS miniperc, RIRS, prospective, renal stone 1–2 cm Study Type – Therapy (pattern of practice survey) Level of Evidence 2b Treating renal calculi 1–2 cm in diameter with minipercutaneous or retrograde intrarenal surgery: a prospective comparative study Ravindra B. Sabnis, Jitendra Jagtap, Shashikant Mishra and Mahesh Desai Muljibhai Patel Urological Hospital – Urology, Nadiad, Gujarat, India INTRODUCTION The management of urinary stones is evolving rapidly. The past few years have seen significant advances in endoscopic instrumentation and laser technology, facilitating quick and minimally invasive stone extraction. Simultaneously, because of patients’ growing reluctance for repeated treatments and hospitalizations, together with the low stone-free rate of ESWL for stones of 1–2 cm [1,2], questions are being raised about the use of this conservative non-invasive approach. As a result, there is renewed interest in minimally invasive approaches, such as minipercutaneous (miniperc) and retrograde intrarenal surgery (RIRS). Currently, there is no prospective comparative study investigating RIRS and miniperc for stone sizes of 1–2 cm. PATIENTS AND METHODS We planned a prospective comparative case–control designed study aiming to compare miniperc and RIRS for a renal calculus of size 1–2 cm. The institutional ethics committee approved the present clinical study. Patients were informed regarding the investigational nature of the procedure in evolution and the limitations of miniperc. The inclusion criterion was a renal stone (single or multiple) of no greater than 1–2 cm in diameter. The exclusion criteria were patients undergoing any other surgical procedure during same admission, concomitant stones at other sites, pregnancy, children, renal malformation, uncorrected coagulopathy and withdrawal of consent. Patients withdrawing their consent were excluded Accepted for publication 10 November 2011