INTRODUCTION
During the past decades, the surgical treatment of kidney stones has
undergone many technological advances and retrograde intrarenal surgery
(RIRS) became one of the standard treatments for patients with renal
stones. The ureteral access sheath (UAS) was developed in 1974 by Hisao
Takayasu&Yoshio Aso [1] and it is often used during RIRS to
facilitate entry of flexible ureteroscopes into the renal collecting
system. Additionally it facilitates easy re-entry into the collecting
system, consequently shortens the operating time, improve vision,
decrease intrapelvic pressure and increases the flexible ureteroscope’s
life span [2-5]. Currently, UASs are produced with various
characteristics, including various lengths, diameters, materials,
dilator tip designs, radiopaque markers and stiffness [6].Selection
of the UAS among the choices of manufacturers and models typically
depends on physician familiarity, cost, and size of ureteroscope.
Despite their advantages, there are some important misgivings concerning
to UAS use. UAS usage entails a risk of ureteral damage including
involving the smooth muscle layer after insertion [7]. Additionally
to the over distention created by a UAS may decrease ureteral blood flow
and theoretically induce long-term ureteral stricture formation [8].
In addition to that, a previous study reported that a large sized UAS
had a more effect on ureteral blood flow [9]. Therefore, a UAS with
a small outer diameter and large inner diameter is considered to be
ideal in clinical practice.
To our knowledge; there is no prospective study in the international
literature has evaluated the effect of UAS related ureteral injury and
possible ischemia on the development of ureteral stricture. In the
current study, we aim to analyze intraoperative, postoperative
complications and the incidence of ureteral injury with using smallest
diameter UAS on the market and the effect of injuries and possible
ischemia/inflammatory changes on the risk of ureteral stricture
development in the long term.