Comparison of the efficacy between modified prone split-leg position and lithotomy position in retrograde intrarenal surgery for upper urinary tract calculi
Year: 2026
Type: article
Study design: Observational Study
Abstract: Purpose To compare the efficacy and safety of the modified prone split-leg position versus the lithotomy position in retrograde intrarenal surgery (RIRS) for upper urinary tract calculi. Methods We retrospectively analyzed 270 patients undergoing RIRS for upper urinary tract calculi (November 2024–March 2026): modified prone split-leg ( n = 103) and lithotomy ( n = 167). After 1:1 propensity score matching (84 per group), operative time, hospital stay, day-1 stone-free rate (KUB), fever, renal function, and inflammatory markers were compared; subgroup, multivariable regression, and interaction analyses were performed. Results After matching, baseline characteristics were balanced. The immediate radiographic stone-free rate (SFR), assessed by KUB on postoperative day 1, was 94.05% vs. 85.71% ( P = 0.073). Operative time was longer with the modified prone split-leg position (54.00 vs. 38.50 min, P < 0.001), as was hospital stay ( P = 0.012); the fever rate was 1.19% in both groups. In the 10–20 mm subgroup, SFR was significantly higher in the modified prone split-leg group (95.12% vs. 78.05%, P = 0.023). The renal stone subgroup showed a numerically higher SFR (92.31% vs. 42.86%, P = 0.031) but was hypothesis-generating owing to the small sample size. No SFR difference was found for ureteral stones ( P = 0.290), and renal function and inflammatory markers did not differ between groups. Multivariable regression showed that the lithotomy position was associated with a higher risk of residual stones (OR = 5.327, P = 0.013) and shorter operative time (B = −10.295, P = 0.009). Interaction analyses were not significant ( P for interaction: stone size 0.999, BMI 0.946, stone location 0.059). Conclusion In the unadjusted analysis, the immediate radiographic SFR did not differ significantly between the two positions. After adjustment for residual confounders, the modified prone split-leg position was independently associated with a lower risk of residual stones. It was also associated with a higher SFR for 10–20 mm stones; however, the interaction was not significant, and this finding should be interpreted cautiously. In the renal stone subgroup, a numerically higher SFR was observed, but this hypothesis-generating finding requires validation in larger studies.
Source: Frontiers in Surgery
Language: English
Subfield: Urology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7223064530