Tip Bendable Suction Ureteral Access Sheath vs. Traditional Ureteral Access Sheath in Retrograde Intrarenal Stone Surgery

Immediate stone-free rate

Nephrolithiasis is the most common chronic kidney condition and affecting approximately one
 in every 10-17 people in the world[1,2]. Flexible ureteroscopy (f-URS) has become one of the
 most common treatments for ureteral and renal stones with minimal complications. The
 development of ureteral access sheath (UAS) is a significant advance in flexible
 ureteroscopic management of urinary stones. The UAS has two major advantages: 1) facilitating
 multiple entries into the renal collecting system without causing recurrent trauma to the
 ureter and permit expeditious basketing of multiple stone fragments, 2) improving the
 irrigation with better fluid outflow, thereby reducing the renal pelvic pressure (RPP) and
 risk of infectious complications.
 
 The tip bendable suction ureteral access sheath (S-UAS) is a novel UAS that has good
 flexibility and deformability at the tip, which can passively bend (bend 90°) with the
 bending of f-URS and can connect to a vacuum suction device. Preliminary study showed that
 S-UAS can follow f-URS to cross the UPJ and into the renal pelvis and calices. S-UAS close to
 the stone can achieve complete stone-free status in RIRS. However, further clinical studies
 and comparisons with available techniques are required. This prospective, single-blinded,
 single-center, randomized control trial will evaluate the stone free rates, operative time,
 postoperative complications following RIRS with S-UAS. To the best of our knowledge, this is
 the first study to compare the clinical benefits of RIRS with S-UAS and traditional UAS.