Access Sheaths With Aspiration for Renal RetrOgrade Surgery, Randomized CompArative Outcomes
Trial statusNot yet recruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18+
SponsorHospitales Universitarios Virgen del Rocío
About this trial
The goal of this clinical trial is to learn whether the ClearPetra ureteral access sheath (Coloplast) is more effective than the Navigator ureteral access sheath (Boston Scientific) in treating intrarenal kidney stones of 1-3 cm in adult patients undergoing flexible ureteroscopy (RIRS). The main questions it aims to answer are:
Does ClearPetra achieve a higher stone-free rate at 1 month post-intervention compared to Navigator, as assessed by non-contrast abdominal-pelvic CT scan?
Does ClearPetra reduce total surgical time compared to Navigator?
Does ClearPetra lower the retreatment rate at 3 months compared to Navigator?
Does ClearPetra present a rate of clinically significant complications (Clavien-Dindo ≥ II) that is lower than or similar to Navigator?
Researchers will compare flexible ureteroscopy using the ClearPetra vacuum-assisted flexible ureteral access sheath to flexible ureteroscopy using the Navigator standard rigid ureteral access sheath, to see if ClearPetra leads to higher stone clearance rates while maintaining a comparable safety profile.
Participants will:
Undergo flexible ureteroscopy (RIRS) using one of two randomly assigned ureteral access sheaths (ClearPetra or Navigator), determined by computer-generated randomization immediately before surgery
Have a non-contrast abdominal-pelvic CT scan at 1 month post-intervention to assess stone-free status
Have a non-contrast abdominal-pelvic CT scan at 3 months post-intervention to evaluate residual fragments and the need for retreatment
Attend follow-up visits at 1 month and 3 months post-surgery for clinical assessment and complication recording
The study will be conducted at the Urology Department of Hospital Universitario Virgen del Rocío (Seville, Spain), a tertiary reference centre. A total of 156 patients will be randomized in a 1:1 ratio (78 per group), with pre-defined subgroup analyses stratified by stone size (1-2 cm vs. \>2 cm). The outcome assessor evaluating CT images for stone-free rate will be blinded to treatment allocation (single-blind).
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Age ≥18 years
Diagnosis of intrarenal lithiasis with maximum stone diameter of 1-3 cm on preoperative non-contrast abdomino-pelvic CT scan
Candidate for treatment by flexible ureteroscopy (RIRS) as indicated by the treating urologist
Attended at the Department of Urology, Hospital Universitario Virgen del Rocío (Seville, Spain)
Disqualifiers
Active urinary tract infection or urosepsis at the time of the planned intervention
Known ureteral stricture precluding passage of a ureteral access sheath
Pregnancy
Prior urinary diversion incompatible with transurethral access (e.g., urinary conduit, neobladder)
Trial design
Design model
Parallel
Treatments tested in this trial
ClearPetra ureteral access sheath
DeviceTip-flexible ureteral access sheath with integrated continuous vacuum aspiration system (Coloplast). Placed transurethrally prior to flexible ureteroscopy to maintain stable ureteral access and actively evacuate stone fragments and irrigation fluid throughout the RIRS procedure. Used in combination with laser lithotripsy (Holmium:YAG or Thulium) for fragmentation of intrarenal stones of 1-3 cm. Accessory instruments (retrieval basket, stone cone) employed per standardised intraoperative protocol.
Navigator ureteral access sheath
DeviceStandard rigid ureteral access sheath without active aspiration mechanism (Boston Scientific). Placed transurethrally prior to flexible ureteroscopy to maintain stable ureteral access during the RIRS procedure. Used in combination with laser lithotripsy (Holmium:YAG or Thulium) for fragmentation of intrarenal stones of 1-3 cm. Accessory instruments (retrieval basket, stone cone) employed per standardised intraoperative protocol.
Treatment groups
156 Participants
are divided into 2 treatment groupsGroup A: ClearPetra Vacuum-Assisted Ureteral Access SheathExperimental treatment 1 intervention
Group B: Navigator® Standard Rigid Ureteral Access SheathActive comparator 1 intervention
Trial outcomes
Primary outcomes
1
Stone-Free Rate (SFR) at 1 Month Post-Intervention
Proportion of patients with complete absence of residual lithiasis or presence exclusively of fragments ≤2 mm on non-contrast abdomino-pelvic CT scan performed at 30 ±7 days post-intervention. Assessed by a blinded outcomes assessor using standardised multiplanar CT reconstruction. Dichotomous variable: stone-free (yes/no). A sensitivity analysis will apply a stricter definition (0 mm, complete absence of any fragment).
Time frame
30 days (±7 days) after surgical interventionSecondary outcomes
1
Stone-Free Rate (SFR) at 3 Months Post-Intervention
Proportion of patients with complete absence of residual lithiasis or presence exclusively of fragments ≤2 mm on non-contrast abdomino-pelvic CT scan at 3 months. Assessed by a blinded outcomes assessor. Dichotomous variable (yes/no).
Time frame
90 days (±14 days) after surgical intervention2
Stone Volume Reduction Rate at 1 Month
Percentage of stone volume eliminated, calculated as \[1 - (residual postoperative volume / preoperative volume)\] × 100. Pre- and post-operative stone volumes measured by volumetric CT software on blinded multiplanar reconstruction. Expressed as percentage (0-100%).
Time frame
30 days (±7 days) after surgical intervention3
Immediate Endoscopic Stone-Free Rate
Surgeon's qualitative assessment of the absence of visible stone fragments at the end of the endoscopic procedure. Dichotomous variable (yes/no stone-free), recorded on the intraoperative registration form immediately after procedure completion.
Time frame
Intraoperative (at procedure completion, Day 0)4
Immediate Fluoroscopic Stone-Free Rate
Absence of residual stone visible on fluoroscopic assessment at the end of the procedure. Dichotomous variable (yes/no), recorded on the intraoperative registration form immediately after procedure completion.
Time frame
Intraoperative (at procedure completion, Day 0)Other outcomes
1
Subgroup Analysis of SFR at 1 Month by Stone Size
Pre-specified subgroup analysis of the primary outcome (SFR at 1 month) stratified by maximum stone diameter: Subgroup 1 (1-2 cm) and Subgroup 2 (≥2 cm). Formal interaction test between sheath type and stone size category will be performed using logistic regression to evaluate consistency of treatment effect across stone size strata.
Time frame
30 days (±7 days) after surgical interventionSponsors and contacts
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Source ClinicalTrials.gov
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