Intelligent versus flexible negative-pressure aspiration sheath for ureteroscopic lithotripsy: a single-center retrospective study with systematic review and meta-analysis.
- 1Department of Urology, Xiangxi Tujia and Miao Autonomous People's Hospital, Jishou, China.
Abstract
Negative-pressure aspiration ureteral access sheaths (NP-UAS) outperform traditional sheaths in retrograde intrarenal surgery (RIRS), but whether the two designs-the intelligent pressure-controlled type (real-time intrarenal pressure monitoring) and the flexible negative-pressure type (steerable tip)-differ in clinical outcomes is unknown. Three head-to-head comparisons exist, all using clinically insignificant residual fragment (CIRF)-based stone-free rate (SFR) definitions, with no systematic synthesis. This study aimed to determine whether the two designs differ in clinically relevant outcomes after RIRS. This study combined a single-center retrospective cohort (264 patients; 147 intelligent, 117 flexible NP-UAS) with a meta-analysis of all published head-to-head comparisons (4 studies, 539 patients). The primary outcome was SFR, defined as zero residual fragments on 1-mm computed tomography (CT) within 48 hours to maximize sensitivity to between-group differences. Confounding by indication was addressed with multivariable regression, propensity score matching (PSM), inverse probability of treatment weighting (IPTW), Firth penalized likelihood, and E-value analysis; the meta-analysis used a restricted maximum likelihood (REML) random-effects model. Certainty was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Crude SFR was 24.5% (intelligent) versus 14.5% (flexible) [odds ratio (OR) 1.91, 95% confidence interval (CI): 1.02-3.68, P=0.047], attenuating to non-significance after sequential adjustment (operative time excluded: OR 1.72, 95% CI: 0.83-3.68, P=0.15), with consistent results across PSM (OR 1.67), IPTW (OR 1.49), and Firth regression (OR 1.65); E-values were 3.23 (crude) and 2.83 (adjusted). Operative time was shorter with the flexible sheath (crude -25.9 min), but mediation analysis showed it did not mediate the sheath-SFR relationship [average causal mediation effect (ACME) P=0.30]. Postoperative infection did not differ between groups. In the exploratory meta-analysis, subgrouping by SFR definition reduced I2 from 75.7% to 0.7%, though confounded with study center. GRADE certainty was very low for all outcomes. Across five analytical methods and meta-analysis, the evidence is insufficient to establish a clinically meaningful SFR difference between intelligent and flexible NP-UAS. The flexible sheath is associated with shorter operative time, but without differential stone clearance, and GRADE certainty is very low. A non-inferiority randomized controlled trial (RCT) (approximately 500 patients) with standardized zero-fragment CT SFR is required.
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BibTeX
@article{xiao2026intelligent,
title = {{Intelligent versus flexible negative-pressure aspiration sheath for ureteroscopic lithotripsy: a single-center retrospective study with systematic review and meta-analysis.}},
author = {Wenyang Xiao and Nanyang Luo and Junyu Yan and Xiuhong Huang and Qi Huang},
journal = {Translational andrology and urology},
year = {2026},
month = sep,
doi = {10.21037/tau-2026-0611},
url = {https://europepmc.org/article/MED/42997147},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Intelligent versus flexible negative-pressure aspiration sheath for ureteroscopic lithotripsy: a single-center retrospective study with systematic review and meta-analysis.
AU - Wenyang Xiao
AU - Nanyang Luo
AU - Junyu Yan
AU - Xiuhong Huang
AU - Qi Huang
PY - 2026
DA - 2026/09/28
JO - Translational andrology and urology
DO - 10.21037/tau-2026-0611
UR - https://europepmc.org/article/MED/42997147
AB - Negative-pressure aspiration ureteral access sheaths (NP-UAS) outperform traditional sheaths in retrograde intrarenal surgery (RIRS), but whether the two designs-the intelligent pressure-controlled type (real-time intrarenal pressure monitoring) and the flexible negative-pressure type (steerable tip)-differ in clinical outcomes is unknown. Three head-to-head comparisons exist, all using clinically insignificant residual fragment (CIRF)-based stone-free rate (SFR) definitions, with no systematic synthesis. This study aimed to determine whether the two designs differ in clinically relevant outcomes after RIRS. This study combined a single-center retrospective cohort (264 patients; 147 intelligent, 117 flexible NP-UAS) with a meta-analysis of all published head-to-head comparisons (4 studies, 539 patients). The primary outcome was SFR, defined as zero residual fragments on 1-mm computed tomography (CT) within 48 hours to maximize sensitivity to between-group differences. Confounding by indication was addressed with multivariable regression, propensity score matching (PSM), inverse probability of treatment weighting (IPTW), Firth penalized likelihood, and E-value analysis; the meta-analysis used a restricted maximum likelihood (REML) random-effects model. Certainty was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Crude SFR was 24.5% (intelligent) versus 14.5% (flexible) [odds ratio (OR) 1.91, 95% confidence interval (CI): 1.02-3.68, P=0.047], attenuating to non-significance after sequential adjustment (operative time excluded: OR 1.72, 95% CI: 0.83-3.68, P=0.15), with consistent results across PSM (OR 1.67), IPTW (OR 1.49), and Firth regression (OR 1.65); E-values were 3.23 (crude) and 2.83 (adjusted). Operative time was shorter with the flexible sheath (crude -25.9 min), but mediation analysis showed it did not mediate the sheath-SFR relationship [average causal mediation effect (ACME) P=0.30]. Postoperative infection did not differ between groups. In the exploratory meta-analysis, subgrouping by SFR definition reduced I2 from 75.7% to 0.7%, though confounded with study center. GRADE certainty was very low for all outcomes. Across five analytical methods and meta-analysis, the evidence is insufficient to establish a clinically meaningful SFR difference between intelligent and flexible NP-UAS. The flexible sheath is associated with shorter operative time, but without differential stone clearance, and GRADE certainty is very low. A non-inferiority randomized controlled trial (RCT) (approximately 500 patients) with standardized zero-fragment CT SFR is required.
SN - 2223-4691
ER -