Surgical procedure
All patients were placed in the lithotomy position and all operations
were performed under the general anesthesia. Among all patients, 421
cases were indwelled F6 double J stent for 2 weeks before FURSL
procedure. At first, the double J tubes were removed if the double J
tubes were placed, then under the guideline of safety wire, the F9.8
semi-rigid ureteroscope were used to access to ureter. If ureteric
calculi were observed, lithotripsy was performed using a Holmium laser
with a 365μm fiber at an energy range of 0.8-1.2W and a frequency of
20-25Hz. After confirming the clearance of stone from the ureter, a
F12/14 ureter access sheath (UAS) was inserted into the proximal ureter
with the guide wire. Then, a F7.5 flexible ureteroscope was passed
through the UAS, and the front end of the UAS was placed in the
pyeloureteral junction under direct view of the flexible ureteroscope.
The perfusion flow was set to 60-100mL/min. When entering the renal
pelvis, the renal pelvis and calyces were observed and the stones were
found accurately. Lithotripsy was performed using a holmium:yttrium
aluminum garnet (Ho:YAG) laser with a 200μm fiber at an energy range of
1.0-2.5W and a frequency of 15-25Hz. According to the actual situation
of the operation, three types of lithotripsy were used: fragmentation
(high energy, low frequency), dust (low energy, high frequency), and
popcorn effect (high energy, high frequency). The stone should be
powdered as much as possible (the maximum diameter of the stone is less
than 0.4cm), and the larger stone should be taken out with the help of
reticular basket for the analysis of stone composition. In order to
avoid the damage of flexible ureteroscope, the stones which located at
the lower renal calyceal could be put into the middle or upper renal
calyceal and renal pelvis through the reticular basket, and then
lithotripsy could be carried out. At the end of the operation, all renal
calices were checked to confirm satisfied fragmentation before the F6
double J stent was placed routinely.