Ureteral Access Sheath Use and Infection-Related Hospitalizations: Practice Patterns and Outcomes

UAS used in 59% of kidney stone surgeries, but practice rates range from 4% to 99%—and 30-day infection hospitalizations are the same either way

Journal: Urology Practice | Published: 2025-12-15 | Type: Journal Article | PMID: 41397097 Authors: Becker et al., University of Michigan; multi-institutional Michigan collaborative Funding/COI: Not listed for either

Summary

A registry study of 6,142 kidney stone surgeries across 34 Michigan practices found that ureteral access sheath (UAS) use during ureteroscopy varies by a factor of 24 across practices—from 4.1% to 99.5%—yet has no detectable effect on 30-day infection-related hospitalization rates. The actual predictors of post-operative infection were all patient-level: comorbidity burden, recurrent UTI history, stone size, and preoperative bacteriuria. The tool's adoption appears to be driven by surgeon preference, not evidence of infectious benefit.

Claims

• 6,142 patients underwent single-stage unilateral ureteroscopy for renal stones, performed by 233 urologists across 34 practices
• UAS was used in 59% of cases overall; practice-level usage ranged from 4.1% to 99.5% (P < .001)
• 30-day infection-related hospitalization: 2.5% overall; 2.6% with UAS vs. 2.3% without (P = .5)
• Multivariable OR for UAS: 0.8 (95% CI 0.6–1.2) — not significant
• Charlson Comorbidity Index 1 vs. 0: OR 1.9 (95% CI 1.2–2.9)
• CCI 2+ vs. 0: OR 2.3 (95% CI 1.4–3.6)
• History of recurrent UTI: OR 2.4 (95% CI 1.4–4.0)
• Stone size: OR 1.1 per 5 mm increase (95% CI 1.0–1.3)
• Positive preoperative urinalysis or culture: OR 1.8 (95% CI 1.2–2.7)

Study Quality

This is a retrospective analysis of a prospective clinical registry (Michigan Urological Surgery Improvement Collaborative), which provides better data granularity than claims-based administrative datasets but falls short of a randomized trial. The 6,142-patient sample is large for a single-state registry and the multivariable logistic regression model adjusts appropriately for the main confounders. However, selection bias is a legitimate concern: surgeons may preferentially use UAS for anatomically complex cases, which could mask a real infection effect in both directions. No randomization means residual confounding is unavoidable.

The study uses "infection-related hospitalization" as its endpoint, an administrative composite that captures severe outcomes but misses outpatient infections, antibiotic prescriptions, and ED visits—potentially undercounting the true infection burden.

Red Flags

• Observational design cannot rule out indication bias: UAS may be used preferentially in harder, higher-risk cases, partially masking protective or harmful effects
• Funding and conflict of interest are both unlisted — a gap for a paper that implicitly challenges widespread tool adoption
• No measurement of intrarenal pressure, which is the leading mechanistic hypothesis for how UAS could affect infection risk; the authors themselves call for prospective studies on this
• Single-state data (Michigan) limits generalizability; practice patterns elsewhere may differ
• Administrative endpoint ("infection-related hospitalization") likely undercounts infectious complications, particularly less severe ones

Strengths

• Large, multi-institutional sample from a well-established collaborative registry
• Captures real-world variation in a way single-center studies cannot
• Identifies clinically actionable patient-level risk factors (comorbidity, preop bacteriuria, stone size)
• Honest about the study's limitations and explicitly calls for the RCT-level evidence it cannot provide

Verdict

This is a competent registry study that does something useful: it quantifies how dramatically UAS adoption varies across practices and demonstrates that this variation doesn't translate into detectable differences in serious infectious outcomes. The 24-fold practice variation is the paper's most provocative number—it signals that a device used in the majority of kidney stone surgeries has no evidentiary consensus behind it. The null finding on infection hospitalizations doesn't resolve whether UAS affects intrarenal pressure or mild infections, but it does shift the burden of proof. Worth reading for urologists and for anyone tracking the gap between surgical device adoption and outcome evidence.