Retrograde Intrarenal Surgery For Kidney Stones Research Articles

External validation of the R.I.R.S. scoring system to predict stone-free rate after retrograde intrarenal surgery

BackgroundThe R.I.R.S. scoring system is defined as a novel and straightforward scoring system that uses the main parameters (kidney stone density, inferior pole stones, stone burden, and renal infundibular length) to identify most appropriate patients for retrograde intrarenal surgery (RIRS). We strived to evaluate the accuracy of the R.I.R.S. scoring system in predicting the stone-free rate (SFR) after RIRS.MethodsIn our medical center, we retrospectively analyzed charts of patients who had, between September 2018 and December 2019, been treated by RIRS for kidney stones. A total of 147 patients were enrolled in the study. Parameters were measured for each of the four specified variables.ResultsStone-free status was achieved in 105 patients (71.43%), and 42 patients had one or more residual fragments (28.57%). Differences in stone characteristics, including renal infundibulopelvic angle, renal infundibular length, lower pole stone, kidney stone density, and stone burden were statistically significant in patients whether RIRS achieved stone-free status or not (P < 0.001, P: 0.005, P < 0.001, P < 0.001, P: 0.003, respectively). R.I.R.S. scores were significantly lower in patients treated successfully with RIRS than patients in which RIRS failed (P < 0.001). Binary logistic regression analyses revealed that R.I.R.S. scores were independent factors affecting RIRS success (P = 0.033). The area under the curve of the R.I.R.S. scoring system was 0.737.ConclusionsOur study retrospectively validates that the R.I.R.S. scoring system is associated with SFR after RIRS in the treatment of renal stones, and can predict accurately.

Size is Not Everything That Matters: Preoperative CT Predictors of Stone Free After RIRS

To define computed tomography (CT) predictors of residual fragments after retrograde intrarenal surgery (RIRS) for kidney stones up to 20 mm in patients never submitted to surgical procedures for stone removal. From August 2016 to August 2017, symptomatic adult patients with kidney stones less than 20 mm treated by RIRS had their pre- and postoperative CT prospectively evaluated in search for predictors of residual stone fragments. Stone size, stone volume, number of stones, stone density, and location were evaluated in preoperative CT and analyzed as predictors for residual stone fragments on 90 POD CT. Stone location was represented by the infundibulopelvic angle (IPA) measured for each stone on preoperative noncontrast CT using multiplanar reconstruction. Ninety-two patients were successfully submitted to RIRS. Bilateral procedures were performed in 23 patients (25%) resulting in 115 renal units operated. Operative time was 54.5 ± 26.7 minutes (mean ± SD) and 96.7% (89/92) of the patients were discharged up to 12 hours after the procedure. Postoperative CT demonstrated stone-free in 86 of 115 (74.8%), 0-2 mm in 10 of 115 (8.7%), and > 2 mm residual fragments in 19 of 115 (16.5%) procedures. Logistic regression analysis revealed steep IPA was a predictor for any residual stone fragment after RIRS for kidney stones < 20 mm (P= .012). ROC curve showed that IPA < 41° was associated with a higher chance of residual fragments after RIRS. IPA < 41° is associated with a higher chance of residual fragments after RIRS for kidney stones up to 20 mm.

Evaluation of ureteral lesions in ureterorenoscopy: impact of access sheath use

Objective: The aim of this study was to evaluate the incidence of ureteral lesions in retrograde intrarenal surgery (RIRS) with and without the use of a 10/12 Fr ureteral access sheath (UAS). A further objective was to search for preoperative factors that could influence the risk of ureteral damage.Materials and methods: Data were collected from a clinical database on 180 consecutive adult patients undergoing RIRS for kidney stones with or without a 10/12 Fr UAS. The primary outcome measure was ureteral lesions endoscopically identified at the end of surgery using the Post-Ureteroscopic Lesion Scale (PULS) classification system.Results: The use of 10/12 Fr UASs resulted in less severe lesions than reported previously with larger diameter UASs. There was a higher risk of superficial lesions in the UAS group, with a calculated crude odds ratio (OR) of 1.84 [95% confidence interval (CI) 1.00–3.37]. When adjusting for age and gender, the OR was 1.68 (95% CI 0.90–3.13; p = 0.10) and thus was not significant. The only factor that remained significant was age (OR =1.02/year, 95% CI 1.00–1.04).Conclusion: There was a trend towards a higher risk of ureteral lesions in RIRS with a 10/12 Fr UAS compared with an endoscope alone, but when adjusting for age and gender the incidence of ureteral lesions was comparable between RIRS with and without the use of a 10/12 Fr UAS.