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.