Materials and Methods
After receiving the ethics board approval of Amasya University (decision
no. 2/25/2021), patients that underwent fURS for the treatment of renal
and ureteral stones between January 2017 and January 2020 were
retrospectively evaluated. Patients that completed ureteral stone
treatment with semi-rigid URS, those with ureteral or renal anomalies or
calyceal diverticula, and those with unavailable data were excluded from
the study.
All operations were started by entering the ureter through a guide wire
(0.035 inch, Microvasive; Boston Scientific Corp., Natick, MA) with
semi-rigid URS. Active dilatation was applied with URS.
Ureterorenoscopic lithotripsy was performed using fURS (7.5F; Karl Storz
Flex-X2, Tutlingen, Germany and Olympus P-5TM, Olympus, Tokyo, Japan)
and 270-350 μm Holmium laser (AMS; Sureflex). Ureteral access sheath
(12/14 or 14/16 F, Cook Medical, Bloomington, IN or 11/13 or 13/15 F,
Boston Scientific, Natick, MA, USA) was utilized to facilitate the
removal of stones and reduce intrarenal pressure in both renal and
ureteral stones. All operations were performed by experienced surgeons.
In all patients, 1.5 F-2.2 F tipless nitinol baskets were used for
removal of residual stones. Preoperative D-J placement was applied in
cases with treatment-resistant renal colic, pyelonephritis, and a narrow
ureter that could prevent access to stone. A postoperative D-J stent or
ureteral catheter was placed according to the surgeon’s preference and
clinical necessity. if no clinically significant stones were shown by
KUB, uretral catheter was removed at POD 1. D-J stent was removed 2
weeks after the procedure.
The presence of residual stones was investigated using non-contrast
computed tomography at the first postoperative month (POM1). SFS was
defined as no evidence of stone.
As a result of the retrospective examination, the clinical
characteristics of the patients [age, gender, body mass index (BMI),
American Society of Anesthesiologists (ASA) score, stone side, ESWL
history, preoperative stent requirement, and degree of
hydronephrosis], stone characteristics (localization, number, density,
and size), and perioperative findings (operation time, length of
hospital stay, SFS, and development of complications) were noted.
Complications were graded according to the Clavien-Dindo classification.
The degree of hydronephrosis was measured according to the Society For
Fetal Urology Hydronephrosis Grading System Stone length was measured as
the longest diameter and stone width as the shortest diameter in the
reconstructed coronal section.17 Stone area was
calculated using the formula, length x width x π x 0.25, where π is a
mathematical constant equal to 3.14.18 The mean HU
measurement was performed in the longest diameter of the stone with bone
window and large magnification. The burden and HU value of multiple
stones were calculated as described in the original T.O.HO.
study.16 The T.O.HO. scoring system does not specify
how to grade multi-calyceal stones. Therefore, the stone localization
with the highest score was used in the presence of multi-calyceal stones
at different localizations.