Over-dilatation versus under-dilatation in percutaneous nephrolithotomy (pcnl): a comparative study of 200 patients

Objective: To evaluate the clinical outcomes of over-dilatation versus under-dilatation during PCNL in a cohort of 200 patients, analyzing its impact on operative time, stone-free rates, complications, and renal function. Methods: A prospective, randomized study was conducted on 200 patients undergoing PCNL for renal calculi. Patients were divided into two groups: Group A (over-dilatation, n=100) and Group B (under-dilatation, n=100). Primary outcomes included stone clearance rates, intraoperative and postoperative complications, and renal function preservation. Secondary outcomes included operative time and hospital stay duration. Randomization was performed using a computer-generated sequence, and all procedures were standardized with experienced surgeons. Statistical analyses included chi-square tests for categorical data and t-tests for continuous variables. Results: Over-dilatation was associated with a higher stone-free rate (85% vs. 72%, p<0.05) but increased risk of bleeding requiring transfusion (10% vs. 4%, p<0.05). Under-dilatation resulted in longer operative times (78 min vs. 64 min, p<0.05) and a higher rate of residual fragments requiring auxiliary procedures (22% vs. 12%, p<0.05). No significant difference in long-term renal function deterioration was observed between groups. Conclusion: Over-dilatation in PCNL provides superior stone clearance but comes at the cost of increased bleeding risk. Under-dilatation prolongs operative time and increases the likelihood of secondary procedures. A balanced approach to tract dilation is recommended to optimize outcomes.