Mini-percutaneous nephrolithotomy for stones in anomalous-kidneys: a prospective study

To evaluate safety and efficacy of minipercutaneous nephrolithotomy (Mini-PNL) in management of stones in different types of renal anomalies. Patients with stones ≥2 cm or SWL-resistant stones in anomalous-kidneys treated by Mini-PNL between March 2010 and September 2012 were included prospectively. Mini-PNL was done under regional anesthesia in prone position with fluoroscopic guidance through 18 Fr sheath using semirigid ureteroscope (8.5/11.5 Fr) and pneumatic lithotripter. All patients were followed-up for 2-3 years. Stone-free rate was defined as absence of residual fragments ≥2 mm. Student-T, Mann-Whitney, Chi square (χ ²), Fisher-exact, one way ANOVA or Kruskal-Wallis test were used for analysis. Mini-PNL was performed for 59 patients (20 horseshoe, 15 malrotated, 7 polycystic, 13 duplex and 4 ectopic pelvic-kidneys). Mean age was 40.18 ± 12.75 (14-78) years. Mean stone burden was 31.72 ± 21.43 (7.85-141.3) mm². Two tracts were required in 7 (11.9 %) patients. Tubeless Mini-PNL with double-J insertion was performed in all patients except two. Operative time was 50.17 ± 18.73 (15-105) min. Hemoglobin loss was 0.44 ± 0.30 (0-1.4) g/dL. Complications were reported in 15 (25.4 %) patients. No pleural injury, sepsis, perinephric-collection or renal-pelvis perforation were reported. Stone-free rate was 89.8 % (converted to open-surgery in one patient, second-look PNL in two patients, auxiliary SWL in three patients). Stone-free rate improved to 98.3 % after retreatment and auxiliary SWL. Site of puncture was mostly upper calyceal in horseshoe-kidney (80 %), mid calyceal in polycystic-kidney (85.7 %) and lower calyceal in duplex-kidney (46.2 %). Punctures were also significantly infracostal in horseshoe-kidney (100 %) and supracostal in both duplex (53.8 %) and malrotated-kidneys (66.7 %). Mini-PNL is safe for management of stones in anomalous-kidney with SFR comparable to standard-PNL but with less complications.