Materials and Methods
With the approval of the local ethics committee (approval number
2020.193.08.02), patients who underwent RIRS for the treatment of
proximal ureter stones between 2014 and 2020 at 4 referral centres were
retrospectively included in the study. The proximal ureter was defined
as the ureteral portion between the ureteropelvic junction and the upper
border of the iliac crest. Patients younger than 18 years of age;
patients with a renal anatomical anomaly, bleeding tendency, solitary
kidney, multiple stones (even at the proximal ureter); and patients who
had undergone previous ipsilateral ureteric or renal surgery were
excluded from the study.
The patients in the study population were divided into 2 groups. Group 1
was composed of patients who had undergone ESWL for proximal ureter
stone before RIRS, and Group 2 was composed of patients who directly
underwent RIRS without any prior ESWL. RIRS was performed by urologists
from the 4 centres who had a minimum of 5 years’ experience. The
clinical and demographic properties of the patients, including age,
gender, body mass index, preoperative serum creatinine level,
preoperative renal hydronephrosis, number of ESWL sessions, duration
between the last ESWL session and RIRS and stone-related parameters,
such as stone volume, stone density and location, were analysed at our
database. All patients underwent preoperative evaluation, which included
a detailed anamnesis, physical examination and routine laboratory
studies, including serum creatinine, urinalysis and a urine culture, and
a preoperative radiologic evaluation with non-contrast computed
tomography (NCCT). The stone volume was calculated based on the NCCT
images using the formula as follows: length × width × height × 0.523
(mm3). Stone density was measured by the mean value of
three Hounsfield unit (HU) measurements that were taken from the centre,
sub-centre and peripheral regions of the maximum stone length in the
axial NCCT image. The operative outcomes (operation time and fluoroscopy
time), peroperative complications, postoperative complications,
hospitalization time and the stone-free rates after RIRS were compared
between the groups. The stone-free status was defined as: no evidence of
residual stones or remaining residual fragments of <3 mm on
the first month postoperative NCCT images.