Association of a 0.85 Ratio of Endoscope-Sheath Diameter Threshold with Infectious Complications after Retrograde
Han Kyu Chae1, Dongrul Shin2, Hyun Cheol Jeong1
1Department of Urology, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea.
Purpose:
To evaluate the clinical impact of the ratio of endoscope-sheath diameter (RESD) on postoperative infectious complications after retrograde intrarenal surgery (RIRS) and to assess whether a prespecified RESD threshold of 0.85 provides better risk discrimination than the conventional target (<0.75).
Materials And Methods:
We retrospectively evaluated consecutive adults who underwent RIRS at two academic institutions. The RESD was defined as the outer diameter of the ureteroscope divided by the inner diameter of the ureteral access sheath (UAS). The primary outcome was postoperative infectious complications graded according to the Clavien-Dindo classification. Infection rates were assessed across ordered RESD categories (<0.75, 0.75 to <0.85, and >0.85), with a p for trend from ordinal logistic regression, and compared using prespecified dichotomous thresholds (0.75 and 0.85). Predictors of infectious complications were assessed using univariable and prespecified multivariable Firth's penalized logistic regression.
Results:
Among the 243 patients, 20 (8.2%) experienced infectious complications. Infection rates increased stepwise across RESD categories (<0.75, 0.75 to <0.85, and >0.85; 2.6%, 4.6%, and 14.6%, respectively; p for trend = 0.009). Using the prespecified 0.85 threshold, infection occurred in 14.6% (14/96) of patients with RESD >0.85 vs 4.1% (6/147) with RESD ≤0.85 (p = 0.007), whereas dichotomization at 0.75 did not significantly discriminate infection risk (2.6% [1/39] vs 9.3% [19/204]; p = 0.214). In multivariable Firth's penalized logistic regression, both RESD >0.85 (adjusted odds ratio [aOR] 3.73, 95% confidence interval [CI] 1.41-9.88; p = 0.008) and positive stone culture (aOR 3.50, 95% CI 1.33-9.22; p = 0.011) remained independently associated with infectious complications.
Conclusions:
RESD >0.85 was independently associated with post-RIRS infectious complications. A threshold of 0.85 provided more clinically useful risk stratification than the conventional RESD <0.75 target, while highlighting the importance of infected stone assessment.
Insights
A higher ratio of endoscope-sheath diameter (RESD) greater than 0.85 is linked to increased infectious complications after retrograde intrarenal surgery (RIRS). This RESD threshold offers better risk assessment than the standard <0.75 target.
Area of Science:
- Urology
- Surgical Innovation
- Infectious Disease
Background:
- Postoperative infectious complications are a concern after retrograde intrarenal surgery (RIRS).
- The ratio of endoscope-sheath diameter (RESD) is a potential factor influencing these complications.
- Current practice often uses a RESD target of <0.75.
Purpose of the Study:
- To evaluate the clinical impact of RESD on infectious complications following RIRS.
- To compare the risk discrimination of a RESD threshold of 0.85 versus the conventional target of <0.75.
Main Methods:
- Retrospective analysis of 243 adult patients undergoing RIRS at two academic institutions.
- RESD calculated as ureteroscope outer diameter divided by ureteral access sheath inner diameter.
- Infection rates analyzed across RESD categories (<0.75, 0.75-<0.85, >0.85) and dichotomous thresholds (0.75, 0.85) using logistic regression.
Main Results:
- Infection rates increased with higher RESD categories (2.6% for <0.75, 4.6% for 0.75-<0.85, 14.6% for >0.85; p=0.009).
- RESD >0.85 was significantly associated with higher infection rates (14.6% vs 4.1%; p=0.007), unlike the 0.75 threshold (p=0.214).
- RESD >0.85 (aOR 3.73) and positive stone culture (aOR 3.50) were independent predictors of infectious complications.
Conclusions:
- An RESD greater than 0.85 is independently associated with increased infectious complications after RIRS.
- The RESD threshold of 0.85 provides superior risk stratification compared to the <0.75 target.
- Assessing for infected stones is crucial in managing post-RIRS infectious risk.
