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To compare the effectiveness and safety of standard percutaneous nephrolithotomy (sPCNL) and super-mini PCNL (SMP). Patients and MethodsA total of 150 patients presenting with renal calculi of <2 cm were randomised to either sPCNL (Group 1) or SMP (Group 2). Randomisation was based on centralised computer-generated numbers. Variables studied included: stone-free rates (SFRs), operative time, intra-and postoperative complications, postoperative pain score, analgesic requirement, and hospital stay. Statistical analysis was performed using a t-test or Mann-Whitney U-test for continuous variables and chi-squared test or Fisher's exact test for categorical variables. ResultsBetween September 2018 and April 2019, 75 patients were included in each group. The SFRs of the groups were similar (97.33 vs 98.66%, P = 0.56). The mean (SD) operative time was significantly longer in Group 2, at 36.40 (14.07) vs 23.12 (11.96) min (P < 0.001). The mean (SD) decrease in haemoglobin was significantly less in Group 2, at 3.0 (4.9) vs 7.5 (6.5) g/L (P < 0.001). The mean (SD) pain score at 24 h was significantly lower in Group 2, at 0.3 (0.46) vs 0.75 (0.53) (P < 0.001). The mean (SD) analgesic requirement was significantly less in Group 2, at 67 (22.49) vs 91.5 (30.56) mg tramadol (P < 0.001). The mean (SD) hospital stay was significantly less in Group 2, at 28.38 (3.6) vs 39.84 (3.7) h (P < 0.001). ConclusionsSMP is equally as effective as sPCNL for managing renal calculi of <2 cm, with improved safety. Although SMP is associated with a longer operative time, it has a significantly lower incidence of bleeding and postoperative pain, and a shorter hospital stay.

Acute Kidney Injury (AKI) after percutaneous nephrolithotomy (PNL) is a significant complication, but evidence on its incidence is bereft in the literature. The objective of this prospective observational study was to analyze the incidence of post-PNL AKI and the potential risk factors and outcomes. Demographic data collected included age, gender, body mass index (BMI), comorbidities (hypertension, diabetes mellitus), and drug history—particularly angiotensin converting enzyme inhibitors (ACE inhibitors), angiotensin II receptor blockers and beta blockers. Laboratory data included serial serum creatinine measured pre- and postoperation (12, 24, and 48 h), hemoglobin (Hb), total leucocyte count (TLC), Prothrombin time (PT), serum uric acid and urine culture. Stone factors were assessed by noncontrast computerized tomography of kidneys, ureter and bladder (NCCT KUB) and included stone burden, location and Hounsfield values. Intraoperative factors assessed were puncture site, tract size, tract number, operative time, the need for blood transfusion and stone clearance. Postoperative complications were documented using the modified Clavien–Dindo grading system and patients with postoperative AKI were followed up with serial creatinine measurements up to 1 year. Among the 509 patients analyzed, 47 (9.23%) developed postoperative AKI. Older patients, with associated hypertension and diabetes mellitus, those receiving ACE inhibitors and with lower preoperative hemoglobin and higher serum uric acid, had higher incidence of AKI. Higher stone volume and density, staghorn stones, multiple punctures and longer operative time were significantly associated with postoperative AKI. Patients with AKI had an increased length of hospital stay and 17% patients progressed to chronic kidney disease (CKD). Cut-off values for patient age (39.5 years), serum uric acid (4.05 mg/dL) and stone volume (673.06 mm3) were assessed by receiver operating characteristic (ROC) curve analysis. Highlighting the strong predictors of post-PNL AKI allows early identification, proper counseling and postoperative planning and management in an attempt to avoid further insult to the kidney.