Methods
After obtaining the approval of the ethics committee (01/04/2021.05-25),
the data of 129 patients who underwent f-URS on renal and proximal
ureteral stones in two centers between 2015 and 2020 were prospectively
recorded in a database and retrospectively analyzed. All the patients
were evaluated preoperatively using 64-detector non-contrast computed
tomography (NCCT). The renal pelvis Hounsfield units (HU) of the
patients with hydronephrosis were measured and recorded using the
technique described by Basmacı et al. [14]. Wall thickness at the
location of the stones in the proximal ureter and pelvis was measured
and recorded as defined by Sarica et al. [15]. Stone parameters
evaluated consisted of number, size (measured as the longest diameter of
the stone in NCCT in axial or reconstructed coronal planes), and CT
attenuation value. Patient data obtained included age, gender, body mass
index (BMI), history, physical examination findings, and specific
comorbidities.
PBUC and RPUC were performed using 5% sheep blood agar and
eosin-methylene blue agar and incubated at 37 °C for 18-24 h. The
results were quantitatively evaluated [16,17]. The bacterial growth
of ≥ 10 5cfu/ml was determined as positive.
PBUC was taken from all the patients preoperatively, and if negative,
intravenous cefazolin was administered as PAP with the induction of
anesthesia according to the EAU guidelines [9]. In case of a
positive PBUC before f-URS, the operation was not performed until a
negative PBUC was achieved with appropriate antibiotherapy. Patients
with a previous history of urological operation, urinary system
catheterization or congenital urinary system anomalies, cases in which a
double-J stent was placed for passive dilation at the time of the first
operation and the operation was delayed, steroid users, and pregnant
women were not included in the study.
All operations were performed with the patients in the lithotomy
position under general anesthesia. First, ureteroscopy was performed
with a semirigid ureteroscope (8 Fr; Karl Storz, Tuttlingen, Germany) to
provide active dilatation and place a guidewire. At this stage,
approximately 10 cc of available urine sample was taken from the renal
pelvis for the RPUC analysis. Then, according to the surgeon’s
preference, a ureteral access sheath (UAS) (Flexor 9.5/11.5Fr or
12/14Fr, Cook Medical Bloomington, IL, USA, Navigator 11/13Fr, Boston
Scientific, Natik, MA, USA) was placed under fluoroscopic inspection
over the guidewire. If UAS could not be placed, the operation was
performed without a sheath. In all patients, f-URS was performed using
flexible ureteroscopes (Flex-X2, Karl Storz Endoscope, Tuttligen,
Germany) and a 200/273 micron Holmium laser lithotriptor. The procedure
was terminated after stone-free status was confirmed by both
ureteroscopic inspection and fluoroscopy (leaving only ungraspable
gravel or fragments <2mm), in cases of bleeding, or if deemed
necessary by the surgeon. At the end of the operation, a double-J stent
or a ureteral catheter was placed according to the surgeon’s preference.
On the first postoperative day, the patients were discharged if there
was no hematuria or fever.