How to estimate stone volume and its use in stone surgery: a comprehensive review.

OBJECTIVE: Current interventional guidelines refer to the cumulative stone diameter to choose the appropriate surgical modality (ureteroscopy [URS], extracorporeal shockwave lithotripsy [ESWL] and percutaneous nephrolithotomy [PCNL]). The stone volume (SV) has been introduced recently, to better estimate the stone burden. This review aimed to summarize the available methods to evaluate the SV and its use in urolithiasis treatment. MATERIAL AND METHODS: A comprehensive review of the literature was performed in December 2022 by searching Embase, Cochrane and Pubmed databases. Articles were considered eligible if they described SV measurement or the stone free rate after different treatment modalities (SWL, URS, PCNL) or spontaneous passage, based on SV measurement. Two reviewers independently assessed the eligibility and the quality of the articles and performed the data extraction. RESULTS: In total, 28 studies were included. All studies used different measurement techniques for stone volume. The automated volume measurement appeared to be more precise than the calculated volume. In vitro studies showed that the automated volume measurement was closer to actual stone volume, with a lower inter-observer variability. Regarding URS, stone volume was found to be more predictive of stone free rates as compared to maximum stone diameter or cumulative diameter for stones >20 mm. This was not the case for PCNL and SWL. CONCLUSIONS: Stone volume estimation is feasible, manually or automatically and is likely a better representation of the actual stone burden. While for larger stones treated by retrograde intrarenal surgery, stone volume appears to be a better predictor of SFR, the superiority of stone volume throughout all stone burdens and for all stone treatments, remains to be proven. Automated volume acquisition is more precise and reproducible than calculated volume.

Preoperative risk factors for complications after flexible and rigid ureteroscopy for stone disease: A French multicentric study.

BACKGROUND: With an increasing prevalence in industrialized countries, lithiasis represents a public health problem with significant economic cost. Ureteroscopy is nowadays the main treatment for kidney and ureteral stones with increasingly broad indications. While this treatment is relatively safe and effective, the complications can be severe. AIM: The aim of this study was to investigate the preoperative risk factors of complication in the 30 days following a rigid or flexible ureteroscopy in a large cohort of patients. METHODS: A retrospective multicenter study was conducted in 5 French centers between January 1st 2017 and 31st December 2018. All flexible and rigid ureteroscopies performed were included. All preoperative and per operative data were collected in an electronic database. Outcomes and complications within 30 days of the procedure were also collected. Univariate and multivariable analyses evaluated for potential predictors of postoperative complications. RESULTS: 1124 procedures were included. According to the occurrence of a postoperative complication, patients were divided into two groups, 109 in the group with complications. The majority of complications were minor, with only 13.7% classified as Clavien 3-4. In univariate analysis, ASA score>2 (odd ratio, OR=1.68, P=0.04), WHO performance status≥1 (OR=1.50, P=0.04) and neurologic disease (OR=2.78, P=0.005) were predictors of postoperative complications. In multivariable analysis, Charlson's score (OR=0.79, P=0.01) and ASA score>2 (OR=1.48, P=0.03) were independents risk factors of postoperative complication. Concerning major complications, in univariate analysis, cardiovascular disease (OR=3.71, P=0.032) and BMI (OR=0.87, P=0.02) were the only predictors of major complications after ureteroscopy. Only BMI was found In multivariable analysis (OR=0.86, P=0.01) CONCLUSION: Baseline characteristics and comorbidities of the patients, especially neurological diseases, were the main risk factors for short-term complications after ureteroscopy. Ureteroscopy remains a relatively safe and effective procedure. However, we advise surgeons to take precautions with fragile patients with multiple comorbidities or neurological disease.