Materials and Methods
Patients with renal calculi detected on imaging, who underwent RIRS in
the urology clinic of a tertiary hospital between January 2013 and May
2020, were included in the study. Preoperative and postoperative data of
681 patients were obtained from the hospital information system. During
the preoperative period, all patients underwent physical examination,
had their demographic data and medical history evaluated and underwent a
hemoglobin along with analysis of serum urea, creatinine and white blood
cell levels. Radiological imaging including kidney, ureter, and bladder
(KUB) radiography, ultrasonography (USG) and abdominopelvic computed
tomography (CT) was also performed.
Stone laterality (right-left), number (single and multiple),
localization, stone density, stone size, presence of hydronephrosis,
preoperative double-j (DJ) stent, congenital kidney anomaly and solitary
kidney were evaluated preoperatively using imaging methods. Stone size
was determined by measuring the longest axis on preoperative
radiological examination. In cases with multiple stones, stone size was
defined as the sum of the longest axis of each stone. Stone burden was
defined as the two-dimensional area determined by multiplying the
longest diameter by the perpendicular diameter of the stone.
Infundibular length (IL) was measured as the distance from the farthest
point below the calyx containing the stone to the midpoint of the lower
edge of the renal pelvis. Infundibuloureteropelvic angle (IUPA) was
measured as the internal angle formed at the intersection of the
ureteropelvic axis and the central axis of the lower infundibular pole.
In RUSS, 4 parameters were evaluated for the patient with urinary system
stone disease. For each parameter, 1 point was given to patients and the
patients were scored with a score between 0-4. These parameters were the
stone size > 20 mm, the IUPA < 45 degree for
lower pole stones, stone number in different calyces and abnormal kidney
anatomy such as horseshoe kidney or pelvic kidney.5The modified S-ReCS is scored according to the localization of the stone
in the kidney.6 In R.I.R.S., all parameters are
calculated using computed tomography images. In this system, the
parameters of stone density (Houndsfield Unit (HU)), IUPA, IL, stone
burden (mm) and precence of lower pole stone were
checked.7 The patients were divided into two groups
according to RUSS (0 points, 1-4 points), and three groups according to
the modified S-ReCS score (low score: 1-2 points, medium score: 3-4
points, high score 5- 12 points) and four groups according to R.I.R.S.
(low score: 4-5 points, medium score: 6-8 points, high score 9-10
points).
Preoperative urine cultures of all patients were sterilised. Prophylaxis
with 2 g of cefazolin was administered intravenously to all patients
within 1 hour before surgery. RIRS was performed in all patients under
general anaesthesia in the lithotomy position. Ureterorenoscopy was
performed with a 9.5 F rigid ureterorenoscope (Karl Storz, Tuttingen,
Germany) before RIRS. In cases where ureteral dilatation was sufficient,
after the access sheath reached the collecting system, the collecting
system was reached by entering through the access channel with a 7.5 F
flexible ureterorenoscope (Karl Storz, Flex X2, GmbH, Tuttlingen,
Germany). In cases where the access sheath could not be delivered to the
collecting system due to insufficient ureteral dilatation, a DJ stent
was placed and RIRS was postponed for two weeks. The stone was
fragmented using a holmium-yttrium-aluminum-garnet laser (200–365 μm)
sent from the working channel of the flexible ureterorenoscope. The DJ
stent and urethral catheter were used in all cases at the end of the
operation. The patients were evaluated with KUB radioraphy, USG or CT in
the postoperative first month. Success was defined as the absence of
stones in the urinary system or the presence of asymptomatic residual
stones ≤2 mm in size.
Infective complications after RIRS were defined as fever (body
temperature >38°C continuing for 48 hours during hospital
stay), urinary infection (urinary and/or blood culture positivity),
sepsis (urinary infection) and presence of ≥2 Sequential Sepsis-related
Organ Failure Assessment (SOFA) score and septic shock (sepsis
accompanied by serum lactate level >2 mmol/L and
vasopressor need for mean arterial pressure >65
mmHg).8