Comparison of the efficacy between modified prone split-leg position and lithotomy position in retrograde intrarenal surgery for upper urinary tract calculi
- 1Department of Urology, The Second Affiliated Hospital of Chongqing Medical University , ,
- 2Department of Urology, Chamdo People’s Hospital , , ,
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.
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BibTeX
@article{li2026comparison,
title = {{Comparison of the efficacy between modified prone split-leg position and lithotomy position in retrograde intrarenal surgery for upper urinary tract calculi}},
author = {Hongfei Li and Chao Li and Jiahang Liu and Xudong Yang and Yanjun Lin and Shengjie Yu},
journal = {Frontiers in surgery},
year = {2026},
month = oct,
doi = {10.3389/fsurg.2026.1959157},
url = {https://europepmc.org/article/PMC/PMC13727563},
note = {CC BY},
}
RIS
TY - JOUR
TI - Comparison of the efficacy between modified prone split-leg position and lithotomy position in retrograde intrarenal surgery for upper urinary tract calculi
AU - Hongfei Li
AU - Chao Li
AU - Jiahang Liu
AU - Xudong Yang
AU - Yanjun Lin
AU - Shengjie Yu
PY - 2026
DA - 2026/10/20
JO - Frontiers in surgery
DO - 10.3389/fsurg.2026.1959157
UR - https://europepmc.org/article/PMC/PMC13727563
AB - 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.
SN - 2296-875X
ER -