Does previous open or percutaneous renal stone surgery affect retrograde intrarenal surgery outcomes?

Does prior PCNL affect RIRS? A retrospective analysis of a single center data

PURPOSE

The aim of this study is to investigate the results and safety of retrograde intrarenal surgery (RIRS) in patients who have previously undergone percutaneous nephrolithotomy (PCNL).

METHODS

A retrospective analysis included patients who underwent RIRS for kidney stones between August 2018 and April 2023. Group 1 comprised 396 patients who underwent primary RIRS, while Group 2 included 231 individuals who had RIRS after previous PCNL. Evaluation parameters included preoperative characteristics, stone attributes, operative details, treatment outcomes, stone-free status, and complications. Statistical analysis utilized Student's t test, Mann-Whitney U test, and Pearson Chi-square test (p < 0.05).

RESULTS

The mean age, body mass index, stone number, mean stone burden, and SFS were not statistically different between the groups. Lower pole stones were identified in 144 patients in Group 1 and 88 patients in Group 2 (p = 0.315). In Group 1 and Group 2, the mean operation time and fluoroscopy time were 65.23 ± 18.1 min, 81.32 ± 14.3 min, 26.34 ± 8.31 s, 46.61 ± 7.6 s, respectively, showing statistically significant differences between the groups (p = 0.013, p < 0.001, respectively). Infundibulum stenosis was identified and treated with a laser in 12% of Group 2 cases. Complications occurred in 12 patients in Group 1 and 14 patients in Group 2 (p = 0.136).

CONCLUSION

A history of PCNL may contribute to extended operation times and increased fluoroscopy exposure in subsequent RIRS without significantly affecting postoperative SFS or complication rates.

External validation of the current scoring systems and derivation of a novel scoring system to predict stone free rates after retrograde intrarenal surgery in patients with cumulative stone diameter of 2-4 cm

OBJECTIVE

Our primary aim is to perform the external validation of the current scoring systems in predicting stone-free status (SFS) after retrograde intrarenal surgery (RIRS) for renal stones 2-4 cm and develop a novel scoring system by re-examining possible predictive factors related to SFS.

METHODS

Patients who underwent RIRS due to renal stones with a cumulative stone diameter of 2-4 cm between January 2017 and March 2021 were retrospectively screened. Residual stones ≤2 mm were defined as clinically insignificant, and these cases were considered to have SFS. Possible predictive factors related to SFS were examined using the multivariate logistic regression analysis. A nomogram and a scoring system were developed using independent predictive variables. The prediction ability of the previous and the new scoring system were evaluated with the ROC analysis.

RESULTS

The existing scoring systems were found to be insufficient in predicting SFS (AUC < 0.660 for all). The independent predictors of SFS were identified as stone surface area (OR: 0.991, p < 0.001), stone density (OR: 0.998, p < 0.001), number of stones (OR: 0.365, p = 0.033), and stone localization (p = 0.037). Using these predictive markers, a new scoring system with a score ranging between 4 and 15 was developed. The AUC value for this scoring system was 0.802 (0.734-0.870).

CONCLUSION

The RUSS, S-ReSC and R.I.R.S. scoring systems and Ito's nomogram failed to predict SFS in stones >2 cm. The SFS predictive ability of our new scoring system was higher in >2 cm stones compared to the other scoring systems.