Related Experiment Video
Updated: Oct 16, 2026
Vessel-sparing Excision and Primary Anastomosis
Published on: January 7, 2019
Global Direct In-scope Suction Study: An EAU-endourology Multicenter Prospective Collaboration (DISS-study)
Vineet Gauhar1,2,3, Daniele Castellani2,4,5, Olivier Traxer2,6
1Department of Urology, Ng Teng Fong General Hospital, Singapore, Singapore.
Background:
Direct in-scope suction (DISS) facilitates continuous stone dust evacuation during flexible ureteroscopy (FURS), but prospective evidence validating its clinical efficacy and safety remains limited.
Objective:
To evaluate the stone-free rates (SFRs), perioperative outcomes, and limitations of DISS during successfully completed FURS for renal and ureteric stones in real-world practice, with the primary outcome being 30-d computed tomography (CT)-determined SFR.
Design Setting And Participants:
A prospective, multicenter, investigator-led registry was conducted across 16 centers in 14 countries (NCT05297331). Adults undergoing FURS with the Pusen 7.5-Fr DISS scope for any-sized renal/ureteric stones were included.
Outcome Measurements And Statistical Analysis:
The primary outcome was 30-d postoperative noncontrast CT SFR, classified as grade A (zero residual fragments [ZRF]) and grade B (single ≤2-mm fragment). Multivariable logistic regression identified predictors of ZRF status.
Results And Limitations:
A total of 540 patients (median age 55 yr; 57% male) were enrolled. Anomalous kidneys were present in 12% (horseshoe 5.0% and malrotation 3.9%). Median stone volume was 590 mm3. Overall SFR (grades A and B) was 93% (501/540; 95% confidence interval [CI] = 90%-95%), with grade A achieved in 71% (386/540). Major complications were rare: no sepsis requiring intensive care unit admission, no transfusions, and only 2.6% ureteral access sheath (UAS)-related injuries (all Traxer grade 1). Postoperative fever >38°C occurred in 6.7% of the patients (36/540). On multivariable analysis for renal stones, stone volume (adjusted odds ratio [OR] 0.56, 95% CI = 0.39-0.79; p = 0.001) predicted lower odds of grade A status, whereas prestenting (adjusted OR 1.32, 95% CI = 0.76-2.33; p = 0.3) and UAS use (adjusted OR 0.76, 95% CI = 0.46-1.26; p = 0.3) were not statistically significantly associated with grade A status.
Conclusions:
Flexible ureteroscopy for kidney and ureteral stones using the 7.5-Fr DISS achieves high SFR with low morbidity in real-world practice. Stone burden remains a key determinant of complete renal stone clearance using DISS.
