Supine NCCT is not accurate to plan PCNL access in prone position. Prone decubitus is associated with more potential organ injuries in the upper pole. In supine, the kidney situates deeper in the abdomen but the access angle is wider than in prone.

Flexible ureteroscopy is a well-established method for treatment of urinary stones but fl exible ureteroscopes are expensive and fragile devices with a very limited lifetime. Since 2006 with the advent of digital fl exible ureteroscopes a great evolution has occurred. The fi rst single-use fl exible ureteroscope was launched in 2011 and new models are coming to the market. The aim of this article is to review the characteristics of these devices, compare their results with the reusable devices and evaluate the cost-benefi ts of adopting single-use fl exible ureteroscopes in developing countries. Materials and Methods: an extensive review of articles listed at PubMed and published between 2000 and 2021 was performed. Results: Single-use fl exible ureteroscopes have a shaft with 65 to 68cm length and weight between 119 and 277g. Their defl ection goes up to 300 degrees. Their stone-free rates vary between 60 and 95% which is comparable to reusable scopes and operative times ranges from 54 to 86 minutes which are lower when compared to reusable fl exible scopes. Their costs vary between 800 and 3180 US dollars. Conclusion: single-use fl exible ureteroscopes are lighter and have superior quality of image when compared to fi beroptic ones. There are no defi nite data showing a higher stone-free rate or less complications with the use of single-use fl exible ureteroscopes. Each institution must perform a cost-benefi t analysis before making the decision of adopting or not such devices depending on the local circumstances.

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Introduction: We performed a multicentre validation of a nomogram to predict uric acid kidney stones in two populations. Methods: We reviewed the kidney stone database of two institutions, searching for patients with kidney stones who had stone composition analysis and 24-hour urine collection from January 2010 to December 2013. A nomogram to predict uric acid kidneys stones based on patient age, body mass index (BMI), and 24-hour urine collection was tested. Receiver-operating curves (ROC) were performed. Results: We identified 445 patients, 355 from Cleveland, United States, and 90 from Sao Paulo, Brazil. Uric acid stone formers were 7.9% and 8.9%, respectively. Uric acid patients had a significantly higher age and BMI, as well as significant lower urinary calcium than calcium stone formers in both populations. Uric acid had significantly higher total points when scored according to the nomogram. ROC curves showed an area under the curve of 0.8 for Cleveland and 0.92 for Sao Paulo. The cutoff value that provided the highest sensitivity and specificity was 179 points and 192 for Cleveland and Sao Paulo, respectively. Using 180 points as a cutoff provided a sensitivity and specificity of 87.5% and 68% for Cleveland, and 100% and 42% for Sao Paulo. Higher cutoffs were associated with higher specificity. The main limitation of this study is that only patients from high volume hospitals with uric acid or calcium stones were included. Conclusion: Predicting uric acid kidneys stone based on a nomogram, which includes only demographic data and 24-hour urine parameters, is feasible with a high degree of accuracy.

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Introduction Excessive dietary sodium (Na) consumption is a major health care issue in the developed world and linked to many poor health outcomes. Elevated urinary Na may lead to hypercalciuria and an increase in urinary stone risk. Our study aimed to assess the impact of targeted dietary counseling, and its effect on normalizing urinary Na levels in hypercalciuric stone patients. Methods A retrospective analysis of a prospectively collected metabolic stone clinic database was performed. Patients with hypercalciuria and elevated urine Na on 24-hour urine collection (24-HUC) were counselled by the attending nephrologist, urologist or a registered dietician to limit their intake of dietary Na to < 2g/day in addition to receiving general dietary advice. Repeat metabolic testing was performed at least 6 months later. Logistic regression was used to determine correlations between elevated urinary Ca and Na to other urinary abnormalities and to evaluate the effect of normalizing urinary Na on other urinary parameters. Results Metabolic evaluations from 1184 patients were analyzed. The ninety-eight patients with concomitant hypercalciuria and hypernatriuria were predominantly male (67.3%) and had a higher median BMI than the entire cohort. The presence of elevated urinary Na was also associated with hyperuricosuria (p < 0.001) and hyperphosphaturia (p < 0.001). In follow-up, 59.4% corrected their urinary Na, and 43.8% also had their urinary Ca corrected. Patients who corrected their urinary Na were also more likely to have normal urinary values for volume (p = 0.045), oxalate (p = 0.004), and urate (p = 0.008). Conclusions Targeted dietary counseling can be effective in normalizing both elevated urinary Na and Ca levels in stone patients and may obviate the need for pharmacotherapy for the treatment of hypercalciuria in some patients.