Comparison of scoring systems for predicting stone-free status and complications after retrograde ıntrarenal surgery

Comparison of clinical effectiveness and safety of 272 µm and 365 µm holmium lasers in retrograde intrarenal surgery

INTRODUCTION

Surgeons typically prefer 270 µm and 272 µm laser probes in retrograde intrarenal surgery (RIRS) due to the reduced deflection capacity of flexible ureterorenoscopes when using larger probe diameters. This study aims to investigate the effects of 272 and 365 µm holmium laser probes on operative time, clinical efficacy, and complication rates in RIRS.

MATERIALS AND METHODS

A total of 285 patients with proximal ureteral or kidney stones who met the inclusion criteria were enrolled in the study. Patients were divided into two groups based on laser probe thickness: 272 µm and 365 µm. Stone-free rates, operative time, and complication rates were compared between the groups. Factors affecting stone-free rates were analyzed using multivariate logistic regression analysis.

RESULTS

Patient and stone characteristics were similar between the two groups. No significant differences were found in stone-free or complication rates. However, operative time was significantly shorter in the 365 µm probe group. In univariate analysis, risk factors for postoperative residual stones included multi-calyceal stones, lower pole stones, high Hounsfield unit (HU) values on non-contrast computed tomography, and larger stone size. In multivariate analysis, independent prognostic factors for residual stones were identified as multi-calycal stones, lower pole stones, and high HU values.

CONCLUSION

Compared to 272 µm laser probes, operative time was shorter in surgeries performed with 365 µm laser probes. The 365 µm holmium laser can be effectively and safely used in the treatment of proximal ureteral and renal stones, demonstrating high clinical efficacy and safety.

Novel scoring system for predicting stone-free rate after flexible ureteroscopy lithotripsy

This study aims to investigate the factors affecting the stone-free rate (SFR) of flexible ureteroscopy and laser lithotripsy (fURSL) for renal stones and establish predictive models by identifying their prognostic factors. We retrospectively examined 252 patients with renal stones who were treated with fURSL between July 2020 and April 2022. We analyzed the relationship between the patient's clinical data (sex, age, and body mass index), stone status (side, size, location, stone/transverse process pixel ratio [STPR], and the CT value of stone [SCTV]), and SFR to determine the relevant factors and analyze their influence. Additionally, a nomogram was constructed based on these prediction results. A total of 252 patients were enrolled based on the inclusion and exclusion criteria. They were reviewed 7, 30, and 90 days postoperatively, with 46, 23, and 10 patients failing to discharge stones, respectively. Univariate Cox proportional hazard regression results revealed that the SFR was correlated with stone location, diameter (D1, diameter of stone measured by computed tomography [CT]; D2, diameter of stone measured by kidney-ureter-bladder abdominal radiography), SCTV, STPR, and operation time. Multivariate Cox proportional hazard regression was used to develop 2 predictive models for the SFR. The influencing factors of model 1 included D1, location, and SCTV, whereas those of model 2 were D2, location, and STPR. The results are shown in the nomogram. Receiver operating characteristic curves showed no significant difference between models 1 and 2 (P = .498), indicating that the nomogram was highly predictive. After 1000 resamples and internal self-validation, the C-indices of models 1 and 2 were 0.924 and 0.895, respectively, showing that the stone clearance predicted by the nomogram matched the actual situation. Stone location, size, and density (SCTV and STPR) were significant predictors of SFR after fURSL. The scoring system based on these factors may be used to guide optimal treatment strategy selection.

Comparative analysis of scoring systems for patients undergoing retrograde intrarenal surgery with isolated lower calyx stones

PURPOSE

It is critical to provide patients with accurate information on potential surgical outcomes during the preoperative phase. Several scoring systems have been developed for this specific purpose. This study aimed to examine the predicted efficacy of scoring systems in patients with isolated lower calyx stones who underwent retrograde intrarenal surgery (RIRS).

METHODS

We performed a retrospective analysis of 85 patients who underwent RIRS for lower calyx stones between 2016 and 2023. The study computed each participant's Resorlu-Unsal Stone score (RUSS), R.I.R.S. scoring system score, Modified Seoul National University Renal Stone Complexity (S-ReSC) score, S.T.O.N.E. score, Ito's nomogram, and T.O.HO score. Residual stones less than 4 mm were classified as clinically insignificant residual fragments (CIRFs) and regarded as successful. Following that, we used receiver-operating characteristic (ROC) curves to compare various scoring systems' success predictions.

RESULTS

The median scores for RUSS, R.I.R.S. scoring system, Modified S-ReSC, S.T.O.N.E., Ito's nomogram, and T.O.HO score were 1 (1), 7 (2), 2 (0), 11 (1), 18 (4), and 7 (1), respectively. When CIRF cases were included, the stone-free rate increased to 80%. Only Ito's nomogram from scoring systems has a statistically significant cut-off value for success in ROC analysis (p = 0.021). In multivariate analysis, stone volume and preoperative hydronephrosis were associated with success (p = 0.004 and p = 0.035, respectively).

CONCLUSION

In the multivariate analysis, none of the scoring systems were significantly associated with success. Hence, a new scoring system must be developed exclusively for patients with isolated lower pole stones undergoing RIRS.

The relationship between stone-free and patient position in retrograde intrarenal surgery: a randomized prospective study

PURPOSE

Residual fragments not removed with urinary stone surgery may become symptomatic. In this context, this study was carried out to investigate the effect of performing retrograde intrarenal surgery, which is conventionally performed in the lithotomy position, in the modified lithotomy position (Trend-side) on stone-free rates following the surgery.

METHODS

This prospective study consisted of 100 patients with a single kidney stone smaller than 2 cm between 2021 and 2023. These patients were randomized into two groups of 50 patients each to be operated on in the conventional lithotomy and Trend-side positions. Variables were compared using independent t test for continuous variables and chi-square test for categorical variables.

RESULTS

There was no significant difference between the lithotomy and Trend-side position groups in terms of preoperative size, density, location of the stone, and hydronephrosis degree. Stone-free rate was 72% (n = 36) in the lithotomy group and 92% (n = 46) in the Trend-side group. Hence, there was a significant difference between the groups in the stone-free rate in favor of the Trend-side group (p = 0.009). Fragmentation time was statistically significantly shorter in the Trend-side group than in the lithotomy group (34 ± 17 min vs. 43 ± 14 min; p = 0.006). There was no significant difference between the groups in postoperative complication rates.

CONCLUSION

Performing retrograde intrarenal surgery in the Trend-side position shortened the duration of fragmentation compared to the lithotomy position and was associated with higher stone-free rates. In conclusion, the Trend-side position can be safely preferred in patients undergoing retrograde intrarenal surgery due to kidney stones.

Prediction of percutaneous nephrolithotomy outcomes and flexible ureteroscopy outcomes using nephrolithometry scoring systems

BACKGROUND

Kidney stones account for a high proportion of urological emergencies. The main objective of this paper is to evaluate the predictive ability of five scoring systems for overall stone-free status and postoperative complications after percutaneous nephrolithotomy and retrograde ureteroscopy.

MATERIALS AND METHODS

This study retrospectively analysed 312 cases of kidney stone patients between January 2021 and May 2022 at our centre. Multivariate logistic regression as well as ROC curves were applied to determine the ability to evaluate each scale to predict stone-free rates and postoperative complications.

RESULTS

179 patients have undergone PCNL. After multivariate logistic regression, the S.T.O.N.E score and history of ipsilateral renal surgery were predictive of stone-free status, and the predictive power of the S.T.O.N.E score was higher than that of history of ipsilateral renal surgery. Grade 1 complications were considered to be related to Guy's score and grade 2 complications were considered to be related to history of diabetes mellitus. 133 patients have undergone f-URS. After multivariate logistic regression analysis, the modified S-ReSC score, RUSS score, and R.I.R.S score were predictive of stone-free status, with the R.I.R.S score being the strongest predictor. Evidence of grade 2 complications was considered to be related to abnormal renal function.

CONCLUSION

For PCNL, the S.T.O.N.E score had the best efficacy in predicting stone-free status, and the Guy's score had the best efficacy in predicting postoperative complications; for f-URS, the R.I.R.S score had the best efficacy in predicting stone-free status, and no scoring system predicted postoperative complications.

New infundibulopelvic angle measurement method can predict stone-free rates following retrograde intrarenal surgery

To enhance the accuracy of predicting stone-free rates after retrograde intrarenal surgery, we devised a novel approach to assess the renal infundibulopelvic angle. We conducted a retrospective review of patient records for those who underwent retrograde intrarenal surgery for renal stones between April 2018 and August 2019. Patient demographics, stone characteristics, and perioperative data were recorded. Subsequently, we introduced a modified angle measurement called the pelvic stone angle and evaluated its predictive performance for stone-free rates by comparing it with the traditional method in scoring systems. A total of 43 individuals were included in this study. Notable differences in stone burden and Hounsfield unit measurements were found between stone-free and non-stone-free patients. The pelvic stone angle demonstrated a good model fit when used in scoring systems, performing equally well as the conventional approach. The area under the receiver operating characteristic curve for the R.I.R.S. scoring system using the pelvic stone angle and the conventional approach did not show a significant difference. In conclusion, the predictive ability of the pelvic stone angle for stone-free rates was comparable to the old measurement method. Moreover, scoring systems using the pelvic stone angle exhibited a better model fit than those using the conventional approach.

Does Moses technology enhance the efficiency and outcomes of regular holmium laser lithotripsy? Results of a pooled analysis of comparative studies

Holmium laser lithotripsy is currently the optimum standard for surgical treatment of upper urinary calculi. This study aims to evaluate the clinical efficacy and safety of Moses compared with conventional holmium laser lithotripsy for the treatment of patients with upper urinary calculi. We conducted a systematic search using multiple databases (PubMed/Medline, Scopus, Web of Science, and ClinicalTrials.gov) until June 2022. Clinical trials comparing Moses and conventional holmium laser lithotripsy were included. Analysis was performed using RevMan version 5.4.4 software. Four studies with 892 patients were included. There were no significant differences regarding stone-free rate (mean difference [MD] 1.19, 95% CI 0.54, 2.64, p = 0.66), operative time (MD - 9.31, 95% CI - 21.11, 2.48, p = 0.12), fragmentation time (MD - 1.71, 95% CI - 11.81, 8.38, p = 0.74), total energy used (MD 1.23, 95% CI - 0.44, 2.90, p = 0.15), auxiliary procedures (MD 0.38, 95% CI 0.08, 1.90, p = 0.24), and overall complications (odds ratio [OR] 0.70, 95% CI 0.30, 1.66, p = 0.42) between the groups. However, the laser working time (MD - 0.94, 95% CI - 1.20, - 0.67, p < 0.001) of Moses technology was shorter than that of conventional technology. Moses technology has similar outcomes to regular technology in terms of safety and efficacy. Given the higher operating costs of the Moses technology, further study is required to determine whether there are benefits to this new technology.

Does unenhanced computerized tomography as imaging standard post-retrograde intrarenal surgery paradoxically reduce stone-free rate and increase additional treatment for residual fragments? Outcomes from 5395 patients in the FLEXOR study by the TOWER group

Background

Assessment of residual fragments (RFs) is a key step after treatment of kidney stones.

Objective

To evaluate differences in RFs estimation based on unenhanced computerized tomography (CT) versus X-rays/ultrasound after retrograde intrarenal surgery (RIRS) for kidney stones.

Design

A retrospective analysis of data from 20 centers of adult patients who had RIRS was done (January 2018-August 2021).

Methods

Exclusion criteria: ureteric stones, anomalous kidneys, bilateral renal stones. Patients were divided into two groups (group 1: CT; group 2: plain X-rays or combination of X-rays/ultrasound within 3 months after RIRS). Clinically significant RFs (CSRFs) were considered RFs ⩾ 4 mm. One-to-one propensity score matching for age, gender, and stone characteristics was performed. Multivariable logistic regression analysis was performed to evaluate independent predictors of CSRFs.

Results

A total of 5395 patients were included (1748 in group 1; 3647 in group 2). After matching, 608 patients from each group with comparable baseline and stone characteristics were included. CSRFs were diagnosed in 1132 patients in the overall cohort (21.0%). Post-operative CT reported a significantly higher number of patients with RFs ⩾ 4 mm, before (35.7% versus 13.9%, p < 0.001) and after matching (43.1% versus 23.9%, p < 0.001). Only 21.8% of patients in the matched cohort had an ancillary procedure post-RIRS which was significantly higher in group 1 (74.8% versus 47.6%, p < 0.001). Age [OR 1.015 95% confidence interval (CI) 1.009-1.020, p < 0.001], stone size (OR 1.028 95% CI 1.017-1.040, p < 0.001), multiple stones (OR 1.171 95% CI 1.025-1.339, p = 0.021), lower pole stone (OR 1.853 95% CI 1.557-2.204, p < 0.001) and the use of post-operative CT scan (OR 5.9883 95% CI 5.094-7.037, p < 0.001) had significantly higher odds of having CSRFs.

Conclusions

CT is the only reliable imaging to assess the burden of RFs following RIRS and urologist should consider at least one CT scan to determine the same and definitely plan reintervention only based on CT rather than ultrasound and X-ray combination.

Computational Analysis of Influencing Factors and Multiple Scoring Systems of Stone Clearance Rate after Flexible Ureteroscopic Lithotripsy

Our research aims at the analysis of various stone scoring systems which are referred to as STONE scoring system (SSS) in this study. GUY's scoring system and RUSS scoring system (RSS) are utilized to predict stone-free status (SFS) after surgery and problems after percutaneous nephrolithotomy (PCNL) for harder stones. The data of 68 patients with renal calculi who received FURL in Ren Ji Hospital from Jan 2020 to Mar 2021 are collected as the study subjects. There were 44 male and 24 female patients, with an average age of 55.6 ± 11.4 years. Reliability analysis of related influencing factors (IF) of stone clearance rate (SCR) and multiple scoring systems after flexible ureteroscopic lithotripsy (FURL) was performed. Relevant factors with statistical significance for postoperative SCR were selected for logistic regression analysis (RA). According to the SSS score, GSS classification, and RUSS score, the SCR after FURL was statistically analyzed. The results showed that the P values corresponding to stone position (lower caliceal), cumulative stone diameter (CSD), urinary tract infection, and external physical vibration lithecbole (EPVL) were less than 0.05. The area under the ROC curve of RUSS score, SSS score, and GSS grading was 0.932, 0.841, and 0.533, respectively. The main IF of SCR after FURL were stone location (lower caliceal), CSD, urinary tract infection, and EPVL. The RUSS score system was the best in the evaluation of SCR after FURL. In the previous research, the score systems such as CROES (CRS), SSS, S-ReS, C, and GSS for the prediction of SFS were compared. In our analysis, we have compared the RUSS scoring system which has proven to be giving better results as compared to SSS and GSS. We also performed the regression analysis and found that the stone location shows the strongest correlation of all the other factors for stone clearing rate.