Materials and Methods
We performed a retrospective analysis of 949 patients who were underwent
f-URS and laser lithotripsy for renal stones in two institutions (HSU
Izmir Bozyaka Training and Research Hospital, HSU Ankara Diskapi
Training and Research Hospital) between March 2015 and June 2020.
Preoperative evaluation of the patients included medical history,
physical examination, complete blood count, urine analysis and culture,
serum biochemistry and non-contrast computed tomography (NCCT). All
patients were given antibiotic prophylaxis according to current
guidelines. Stone characteristics and renal anatomical characteristics
were evaluated on NCCT. Stone size was determined by measuring the
longest axis at NCCT; in case of multiple stones the sum of each stone
size was calculated. Stone surface area and lower pole
infindibulo-pelvic angle (IPA) was measured as defined before [6,7].
All procedures were performed by experienced surgeons by using different
size and brand ureterorenoscopes (7.5F Flex –X2™ (Karl Storz,Tuttlingen
Germany), Olympus URF P-5™ (Olympus, Tokyo, Japan), 9.5F Pusen™ (Zhuhai
Pusen Medical Technology Co, Ltd., Zhuhai, China). Patients with missing
data and/or lacking of 1st month post-operative NCCT were excluded from
the study. All procedures were performed under general anesthesia in
lithotomy position. A diagnostic ureteroscopy with a semi-rigid
ureterorenoscope was always performed at the beginning of surgery both
to dilate the ureter and pass a safety guidewire. A ureteral access
sheath (9,5-11,5; 12-14 Fr) was placed according to surgeon’s
preferences. The stones were fragmented by using a holmium: YAG laser.
If needed some fragments were removed with tipless nitinol stone
baskets. At the end of procedure, a D-J stent was placed according to
surgeon’s decision. All patients were evaluated with NCCT at 1st month
for stone-free status. Residual fragments <2mm were accepted
as insignificant.
The RUSS, modified S-ReSC, Ito’s nomogram and R.I.R.S. scores were
calculated for each patient by same surgeon on imaging methods. Results
were compared for their predictive capability of stone-free status and
complications.