Access Sheaths With Aspiration for Renal RetrOgrade Surgery, Randomized CompArative Outcomes

Summary

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).

Conditions

• Urolithiasis
• Nephrolithiasis
• Kidney Calculi
• Ureteroscopy

Interventions

DEVICE

ClearPetra ureteral access sheath

Tip-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.

DEVICE

Navigator ureteral access sheath

Standard 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.

Sponsors & Collaborators

• Hospitales Universitarios Virgen del Rocío

  lead OTHER

Principal Investigators

• Paula Rodríguez-Marcos, MD · Department of Urology. Unit of Urolithiasis. Virgen del Rocio University Hospital, Seville, Spain

• Rafael A Medina-López, PhD · Department of Urology. Unit of Uro-Oncology. Virgen del Rocio University Hospital, Seville, Spain

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-09-15

Primary Completion

2029-09-30

Completion

2030-05-31

Countries

• Spain

Study Locations