Outcomes in Lower Pole Kidney Stone Management Using Mini-Percutaneous Nephrolithotomy Compared With Retrograde Intra Renal Surgery: A Randomized Controlled Trial

Background Because of the anatomical properties of the inferior calyx, lower pole stones are difficult to remove through the ureter, even if the stones are fragmented. Retrograde intra-renal surgery (RIRS) is typically employed to treat the smaller lower pole stones (1.0-2.0 cm) while percutaneous nephrolithotomy (PCNL) is primarily used to treat the larger diameter stones or when RIRS has failed to clear the stones. This study was conducted to compare mini-PCNL and RIRS for the management of lower pole kidney stones in terms of stone clearance. Material and methods This randomized control trial was conducted in the Department of Urology, Shaikh Zayed Hospital, Lahore from October 2020 to December 2022. A total of 150 patients between the ages of 18 and 80 years with a kidney stone size of 10-20 mm at the lower pole were included. Patients with positive urine culture, anatomical abnormalities, uncontrolled diabetes (hemoglobin{Hb}A1c >9%), and undergone previous renal surgery were excluded. Group A patients were treated with mini-PCNL, while group B patients were managed with RIRS. Follow-up visits were planned four weeks postoperatively with CT KUB (computed tomography of kidneys, ureters, and bladder) plain to assess stone clearance. Results The mean age in group A was 43.27 ± 13.86 years, while in group B was 45.32 ± 14.14 years. Out of 150 patients, 102 (68.0%) were males and 48 (32.0%) were females. Mean size of the stone was 15.30 ± 2.21 mm. Stone clearance after mini-PCNL was found in 69 (92.0%) patients and after RIRS in 59 (78.67%) patients (p-value = 0.021). Mean hospital stay after RIRS was 1.1 ± 0.09 days, while it was 2.3 ± 0.64 days after mini-PCNL (p-value < 0.001). Two (2.67%) patients in the mini-PCNL group developed bleeding postoperatively. The stone clearance rate in older patients (51 to 80 years) was significantly higher in the mini-PCNL group than RIRS group. Similarly, the stone clearance rate in female patients and in patients with larger stones (16 to 20 mm) was found to be higher in mini-PCNL group as compared to the RIRS group. Conclusion This study concluded that both mini-PCNL and RIRS are safe and efficient techniques for treating lower pole kidney stones with a size of 11-15 mm. However, mini-PCNL has a higher stone clearance rate compared to RIRS in the treatment of stones larger than 15 mm in size. This study further suggested that patients treated with mini-PCNL had a longer hospital stay compared to patients treated with RIRS.