Minimally Invasive Percutaneous Nephrolithotomy in Management of Lower Pole Renal Stones 2cm or Less

Background: The best management of lower calyceal stones remains debatable. Small lower calyceal stones are usually managed with SWL, RIRS or PNL. Aim of Study: This study aims to assess the safety, efficacy and complications of minimally invasive percutaneous nephrolithotomy (mini PNL) in lower calyceal stones. Patients and Methods: Patients with lower calyceal radioopaque unilateral stones ≤2cm were enrolled and underwent mini PNL between February 2014 and January 2016 using a semi rigid ureteroscope through a 16Fr sheath and holmium laser lithotripsy. Patients were considered stone free when no stones or residuals <3mm were found on plain X-ray UT or non contrast CT. Result: Thirty patients with mean age of 40±9.2 years underwent mini PNL for lower calyceal stones ranging in size from 10-20mm (16.1 ± 1.8). A single tract was used (16Fr). Six patients (20%) had a nephrostomy tube (12F) at the end of the procedure. Mean hospital stay was 2±0.15 days. Twentyfive (83.3%) of our patients had no or mild post-operative pain that required no analgesia. Minor complications occurred in 4 patients (13.3%) in the form of post-operative fever and was treated conservatively. Conclusion: Mini PNL is a safe and effective treatment option for lower calyceal stones 2cm or less. Mini PNL is limited by longer operative time than standard PNL. It has similar safety profile as of standard PNL with the advantage of causing significantly less pain and shorter hospital stay. Stone Free Rate (SFR) is comparable to PNL and is significantly better than SWL and possibly RIRS.