ABSTRACT
Aim: The guidelines propose optical dilatation before
retrograde intrarenal surgery (RIRS), but there are no evidence-based
studies concerning the impact of optical dilatation with semirigid
ureteroscopy (sURS) in the literature. The aim of this study was to
evaluate the effect of optical dilatation through sURS prior to the
procedure on the success and complications of RIRS.
Methods: In a multicentre retrospective study, 422 patients
were included in the study. The patients were divided into two groups
according to whether sURS was to be performed. Patients’ demographics,
stone parameters and operative outcomes were compared. Surgical success
was defined as no or up to 3-mm residual stone fragments without the
need for additional procedures. The independent predictors for surgical
success were determined with a multivariable logistic regression model.
Results: Of the 422 patients, 133 (31.5%) were in the sURS
group and 289 (68.5%) were in the non-sURS group. Stone characteristics
and patients’ demographics were similar among the groups. Operation time
in the sURS group was significantly long (p<0.0001 ). A
ureteral access sheath (UAS) could not be placed in four (3.0%)
patients in the sURS group, nor in 25 (8.7%) patients in the non-sURS
group (p=0.03 ). Compared with the non-sURS group, the
intraoperative complication rate was low in the sURS group (14 (4.8%)
vs 1 (0.8%), p=0.04 ). The surgical success rate was higher in
the sURS group (p=0.002 ). Nevertheless, sURS had no independent
effect on surgical success. We have found two independent predictors for
surgical success rate: stone number (p<0.0001, OR:2.28)
and failed UAS placement (p=0.035, OR:3.49)
Conclusions: Optical dilatation with sURS before RIRS increases
surgical success by raising the rate of UAS placement and reducing the
rate of intraoperative complications. We suggest that this method can be
routinely applied in the group of patients who have not been passively
dilated with a JJ stent.
Keywords: Flexible ureteroscopy; optical dilatation; retrograde
intrarenal surgery, semirigid ureteroscopy, ureteral access sheath.
INTRODUCTION
Improvements in surgical techniques and endourological devices over
recent years have led to significant changes in treatment modalities for
kidney stones. Among these, retrograde intrarenal surgery (RIRS) is now
considered one of the first-line treatment options, with high stone-free
rates and lower morbidity for renal calculi, especially up to 2 cm
[1,2]. In the classical application of RIRS, the use of a ureteral
access sheath (UAS) may provide significant advantages by decreasing
intra-renal pressure, improving visibility, and allowing easy insertion
of the endourological equipment into the collecting system [1,3].
However, in some patients, the placement of a UAS is quite difficult.
Several strategies are suggested to allow easy insertion of a UAS during
RIRS. Some authors defend routine stent placement before RIRS to provide
passive ureteral dilatation [1,4]. Despite its effectiveness and
reliability, this method requires a two-stage procedure. The other
option, known as active ureteral dilatation performed by balloon or
coaxial dilator before UAS, may cause significant ureteral injury
[1,5]. On the other hand, for the past ten years EAU guidelines have
recommended doing optical dilatation with semirigid ureteroscopy (sURS)
before RIRS to facilitate the process [6,7].
Semirigid ureteroscopy provides optical ureteral dilatation with easier
ureteral access and inspection of upper urinary tract anatomy for
possible pathologies such as stones, strictures, or tumours. In
addition, ureteral diameter and compliance can be evaluated to select
the proper UAS size [5,8]. However, the effects of optical
dilatation on RIRS success and complications have not yet been
investigated. In this multicentre study, we aimed to evaluate the
effects of optical dilatation through sURS on the surgical success and
complication rates of RIRS.
METHODS:
The present study conducted in accordance with the tenets of the
Declaration of Helsinki and with the approval of Ethics Committee of
Onsekiz Mart University School of Medicine (Approval number:
26.02.2020/2019-04). A total of 515 patients who had undergone RIRS for
renal and upper ureteral stones between February 2016 and January 2020
at four referral centres in Turkey were included in this study. All
operations were carried out by senior surgeons with a minimum of five
years of experience at these centres. Patients’ characteristics,
including age, gender, the side and size of the stone, body mass index,
previous stone treatment history, and operative outcomes, were entered
into each centre’s database retrospectively. The patients with
incomplete records and/or known renal anatomical abnormalities were
excluded from the study. Patients requiring preoperative or
intraoperative active or passive ureteral dilatation and undergoing
ipsilateral ureteral surgery were also excluded. The remaining 422
patients were included in this study.
All patients underwent a preoperative radiologic evaluation with
non-contrast computed tomography (NCCT). The stone characteristics were
recorded from NCCT findings. Stone size was determined by the largest
diameter of the main stone. The mean Hounsfield unit was calculated
using the elliptical region of interest incorporated into the largest
stone area in an axial image of NCCT [9].
The patients were divided into two groups based on the use of sURS or
not. Patients’ demographics and operative outcomes were compared between
groups. The intraoperative and postoperative surgical complications were
noted. The primary outcome was to define whether optical ureteral
dilatation with sURS before the procedure provides high surgical success
along with a low complication rate. The secondary outcome was to
evaluate independent predictors that could affect surgical success.