Single-Use Digital Flexible Ureteroscopes as a Safe and Effective Choice for the Treatment of Lower Pole Renal Stones: Secondary Analysis of a Randomized-Controlled Trial.

Objective: To compare the efficacy and safety of a single-use digital flexible ureteroscope (FURS) and a reusable FURS for the treatment of lower pole stones (LPS) smaller than 20 mm. Patients and Methods: We analyzed the data of 49 patients with LPS from our previous multicenter, randomized, open-label clinical trial in four hospitals in China. All patients underwent FURS for LPS with a single-use FURS ZebraScope™ (trial group) or a reusable FURS URF-V (control group). The efficacy endpoints assessed were the 1-month postsurgical stone-free rate (SFR), operative time, length of postoperative hospital stay, and mean reduction in hemoglobin level. The safety outcomes assessed were the presence of adverse events (AEs), severe AEs (SAEs), and postoperative complications. Results: The demographic and preoperative parameters were comparable between the two groups. The 1-month SFR was 84.00% for the ZebraScope group and 58.33% for the reusable flexible ureteroscope (URF-V) group (p < 0.05). There was no difference between the two groups in the operative time (p = 0.665), length of hospital stay (p = 0.308), presence of postoperative complications (p = 0.307), presence of AEs (p = 0.483), and the presence of SAEs (p = 0.141). Conclusions: This study demonstrates that single-use digital FURS is a safe and effective option and can offer higher SFR than the reusable FURS in the treatment of LPS smaller than 20 mm. We recommend single-use digital FURS as an alternative to reusable FURS for the treatment of LPS. The Clinical Trial Registration number: ChiCTR1900021615.

Reevaluation of metanephric stromal tumor two decades after it was named: A narrative review.

OBJECTIVE: The aim of this narrative review is to provide an overview and update of metanephric stromal tumor (MST). MATERIALS AND METHODS: All English language studies published from January 1, 2000 to December 31, 2019 in PubMed, EBSCO, Elsevier ScienceDirect, Springer Link and Taylor & Francis databases were searched with the search terms "metanephric stromal tumor" for this review. RESULTS: Seventeen eligible case reports representing 47 patients according to inclusion and exclusion criteria were included in this study. The average age of the patients was under 4 years (range from 2 d to 56 y) and over half of the cases (52.1%, 25/47) are were diagnosed as MST by accident or during examinations for other diseases. Morphologically, tumor specimens of almost all cases presented concentric "onion-skin cuffing" or characteristic collarettes around renal tubules under low power. There were 79.2% (18/25) of patients exhibited BRAF V600E mutations. Immunohistochemistry (IHC) is characterized by CD34 (+), Vimentin (+), Desmin (-), S-100 (-), SMA (-). Most patients underwent surgeries, and no metastasis or recurrence was found except for one case. CONCLUSION: MST is a rare benign pediatric renal tumor with surgical treatment as the first choice. CT examinations and ultrasonography are two widely accepted techniques for the diagnosis of MST. Percutaneous renal biopsy (PRB) is an effective and accurate way of preoperative diagnosis, however, it is not recommended for children under 10 years or with a cystic mass in CT images. The relationship between BRAF V600E mutations and mild clinical manifestations of MST is in need of further verification by biological experiments and clinical studies.