Flexible and Navigable Suction Ureteral Access Sheath (FANS) vs Conventional Access Sheaths in RIRS: A Prospective Randomized Study.

This was a prospective, single-center, randomized controlled trial conducted at a tertiary referral endourology center. Adult patients (≥18 years) with renal stones measuring 10 mm or greater and scheduled to undergo retrograde intrarenal surgery (RIRS) under general anesthesia were eligible for inclusion.

Participants were randomized in a 1:1 ratio to undergo RIRS using either a flexible and navigable suction ureteral access sheath (FANS group) or a conventional ureteral access sheath (control group). Randomization was performed using a computer-generated sequence with allocation concealment via sealed opaque envelopes. Blinding of the operating surgeon was not feasible due to the nature of the devices used.

All procedures were performed by experienced endourologists using standardized surgical techniques. Flexible ureteroscopy was performed with a digital ureteroscope, and stone fragmentation was achieved using a Holmium:YAG laser in dusting mode. In the suction access sheath group, negative pressure suction was applied through the sheath according to manufacturer guidelines. Irrigation parameters were standardized across both study arms.

The primary outcome measure was operative time, defined as the interval from insertion of the first endoscopic instrument through the urethra to removal of the final instrument at the end of the procedure. Secondary outcome measures included intraoperative and postoperative complications (classified using the Clavien-Dindo system), ureteral wall injury, length of hospital stay, stone migration, and stone-free rate. Stone-free status was defined as the absence of residual fragments greater than 2 mm on postoperative imaging.

Preoperative assessment included non-contrast computed tomography to evaluate stone size, location, and burden. Postoperative imaging was performed using kidney-ureter-bladder radiography or renal ultrasound approximately two weeks after surgery.

The study was approved by the Institutional Review Board of Barzilai University Medical Center, and all participants provided written informed consent prior to enrollment.

Inclusion criteria

Age 18 years or older

Presence of single or multiple renal stones measuring 10 mm or greater

Eligible for retrograde intrarenal surgery under general anesthesia

Ability to provide written informed consent

Exclusion criteria

Pregnancy

Active urinary tract infection at the time of surgery

Known bleeding disorders

Solitary kidney

Anatomical abnormalities of the urinary tract that could affect ureteroscopic access