Introduction
The most desirable conditions following a successful retrograde
intrarenal surgery (RIRS) procedure are a complete flush-out of all
stone fragments and diminish stone related events (SRE)1,2. One of the primary metrics used to measure the
outcome of RIRS is the stone-free rate (SFR). Residual stone fragments
(RSF) of 4 mm or less after RIRS are accepted as clinically
insignificant 3. RIRS studies have shown that in
almost 20% of cases, clinically insignificant RSFs are observed
postoperatively 4; however, these RSF may grow and
cause stone-related events (SRE) such as pain and infection5,6.
RSFs were detected by ultrasonography (USG), kidneys, ureters, bladder
(KUB) radiography, or computed tomography (CT) 7. The
most accurate imaging technique is the CT scan, which may show stones as
small as 1 mm, although concerns about radiation exposure limit its use8. Also, for economic reasons, CT is underutilized for
imaging RSFs; therefore, a wide range of SFRs are reported following
RIRS 9-12.
Various techniques and methods have been reported in the literature to
achieve an utterly stone-free status and to reduce radiation exposure,
including artificial intelligence algorithms 13,14.
This study investigates the effectiveness of second-look flexible
ureterorenoscopy (URS) to achieve a true stone-free status and decrease
stone-related events. To the best of our knowledge, the use of routine
second-look flexible URS for this purpose has not been studied
previously.