Surgery · Medical Literature
Comparing the outcomes of non-papillary versus papillary mini-percutaneous nephrolithotomy for treatment of multiple renal stones: a prospective randomized study.
Abstract
Papillary puncture is commonly recommended in percutaneous nephrolithotomy (PCNL) because it is thought to reduce the risk of vascular injury. In patients with multiple renal stones, however, calyceal anatomy and stone distribution can make a strict papillary approach difficult. Non-papillary access may be a practical alternative during mini-PCNL, but its safety and effectiveness remain debated. This study compared non-papillary and papillary access in mini-PCNL for multiple renal stones. This prospective randomized study enrolled 108 patients with multiple renal calculi. Patients were allocated to non-papillary access (n = 53) or papillary access (n = 55). All procedures were performed as mini-PCNL using an 18-Fr tract and holmium: YAG laser lithotripsy. Study outcomes included operative time, hemoglobin drop, stone-free rate (SFR), and perioperative complications. The non-papillary group had a significantly shorter operative time (49 ± 11 min vs. 58 ± 11 min; p < 0.001) as well as shorter fluoroscopy time (median 2.5 vs. 3.3 min; p < 0.001). Single access was achieved in 100% of non-papillary cases compared to 78.2% of papillary cases (p < 0.001). Hemoglobin drop was comparable (mean difference 0.10 g/dL; 95% CI: - 0.24 to 0.45) demonstrating non-inferiority. SFR was higher in the non-papillary group (69.8% vs. 54.5%; p = 0.102). The complication rates of the groups were low and comparable: transfusion (3.8% vs. 3.6%), fever (3.8% vs. 5.5%), hematuria (3.8% vs. 3.6%), bowel injury (0% vs. 1.8%). In mini-PCNL for multiple renal stones, non-papillary access was non-inferior to papillary access in terms of hemoglobin drop and was associated with shorter operative and fluoroscopy times, with a similar complication profile.
Clinical relevance
Papillary access has long been the standard for percutaneous nephrolithotomy (PCNL) due to its presumed vascular safety advantage, yet in patients with multiple renal calculi, complex calyceal anatomy frequently renders strict papillary puncture technically challenging or suboptimal. This prospective randomized trial directly addresses the clinical equipoise around non-papillary mini-PCNL access in this specific stone burden population, where no robust comparative data previously existed. Urologists managing patients with multiple renal stones need evidence-based guidance on access strategy to optimize stone clearance while minimizing bleeding risk and operative morbidity.
Key findings
1. Operative time was significantly shorter in the non-papillary group (49 ± 11 min vs. 58 ± 11 min; p < 0.001), representing an approximately 16% reduction in procedural duration. 2. Fluoroscopy time was significantly lower with non-papillary access (median 2.5 vs. 3.3 min; p < 0.001), implying reduced radiation exposure to patient and surgical team. 3. Single-access tract sufficiency was achieved in 100% of non-papillary cases versus only 78.2% of papillary cases (p < 0.001), indicating superior anatomical access versatility with the non-papillary approach. 4. Hemoglobin drop was non-inferior between groups (mean difference 0.10 g/dL; 95% CI: −0.24 to 0.45), directly refuting the presumption that non-papillary access carries a meaningfully higher hemorrhagic risk in an 18-Fr mini-PCNL context. 5. Stone-free rate (SFR) trended higher in the non-papillary group (69.8% vs. 54.5%; p = 0.102), though this difference did not reach statistical significance, suggesting a potential efficacy benefit that warrants confirmation in a larger, adequately powered trial. 6. Perioperative complication rates were low and statistically comparable across both groups: transfusion (3.8% vs. 3.6%), postoperative fever (3.8% vs. 5.5%), hematuria (3.8% vs. 3.6%), and bowel injury (0% vs. 1.8%), with no significant between-group differences reported.
Practice implications
For urologists performing mini-PCNL (18-Fr tract with holmium:YAG laser lithotripsy) in patients presenting with multiple renal calculi, non-papillary access should be considered a safe and efficient alternative to the papillary approach, particularly when calyceal anatomy or stone distribution makes strict papillary puncture technically demanding or would necessitate multiple access tracts. The demonstrated non-inferiority in hemoglobin drop, combined with significantly shorter operative and fluoroscopy times and a higher rate of single-tract sufficiency, supports adopting a flexible access strategy rather than mandating papillary puncture in this patient population. Given that the SFR improvement with non-papillary access did not reach statistical significance in this sample of 108 patients, clinicians should await larger confirmatory trials before concluding superiority in stone clearance, and should continue individualized intraoperative decision-making based on stone burden, collecting system anatomy, and surgeon experience.