METHODS: Prospectively data of 115 adult patients with bilateral kidney stone disease undergoing SSB-RIRS across 14 global centers between July 2023 and March 2024 were analyzed. Patient demographics, stone characteristics and operative outcomes were recorded. A low-dose non contrast CT scan was performed at 30 days to assess the stone-free rate and clinical outcomes.

RESULTS: Overall bilateral zero residual fragment(ZRF) was 42.6%; unilateral ZRF was 75.7%. Only two patients were noted to have residual fragments > 4 mm. 1.7% experienced Traxer-Thomas grade 1 ureteric injury which was managed with a ureteral stent for four weeks. No pelvicalyceal injury occured. Postoperative mean loin pain score was 1.7 ± 1.0. None had sepsis nor required blood transfusion. 4.3% required readmission within 30 days of surgery. Multivariate analysis indicated longer total operation time correlated with lower odds of achieving a 100% bilateral stone-free (ZRF) (OR 0.978, 95%CI = 0.959-0.994, p = 0.013).

METHODS: This study retrospectively analyzed patients who underwent RIRS for renal stones from January 2018 to August 2021 within the multicentric FLEXOR registry. Demographics, stone characteristics, perioperative findings, results and complications were analyzed and compared between gender groups.

METHODS: Our prospective, multicenter study enrolled 704 adult patients from 21 centers who underwent FURS with FANS between August 2023 and October 2024. IO-SFS was categorized into three groups: (1) 100% SFR (no dust or fragments), (2) only dust remaining, and (3) both dust and fragments remaining. PO-SFS was assessed via 2 mm non-contrast computed tomography (NCCT) at 30 days and categorized into four grades: Grade A (100% stone-free), Grade B (single ≤ 2 mm residual fragment), Grade C (single 2.1-4 mm), and Grade D (multiple or any > 4 mm). Primary outcome was correlation between intraoperative and postoperative 100% SFS. Secondary outcomes included perioperative complications, reintervention rates, and predictors of residual fragments and perioperative complications.

METHODS: Data for adults undergoing fURS in 25 centers worldwide were prospectively collected (August 2023 to January 2024). Exclusion criteria were abnormal renal anatomy and ureteral stones. All patients had computed tomography scans before and within 30 d after fURS with a FANS ureteral access sheath. SFS was defined as follows: grade A, zero fragments; grade B, a single fragment ≤2 mm; grade C, a single fragment 2.1-4 mm; and grade D, single/multiple fragments >4 mm. Data for continuous variables are presented as the median and interquartile range (IQR). Multivariable logistic regression was performed to evaluate predictors of grade A SFS.

KEY FINDINGS AND LIMITATIONS: The study enrolled 394 patients (59.1% male) with a median age of 49 yr (IQR 36-61). The median stone volume was 1260 mm3 (IQR 706-1800). Thulium fiber laser (TFL) was used in 45.9% of cases and holmium laser in the rest. The median lasing time was 18 min (IQR 11-28) and the median operative time was 49 min (IQR 37-70). One patient required a blood transfusion and 3.3% of patients had low-grade fever. No patient developed sepsis. Low-grade ureteral injury occurred in eight patients (2%). The grade A SFS rate was 57.4% and the grade A + B SFS rate was 97.2%, while 2.8% of patients had grade C or D SFS. Eleven patients underwent repeat fURS. Multivariable analysis revealed that a stone volume of 1501-3000 mm3 (odds ratio 0.50) and of >3000 mm3 (odds ratio 0.29) were significantly associated with lower probability of grade A SFS, while TFL use was associated with higher SFS probability (odds ratio 1.83). Limitations include the lack of a comparative group.

CONCLUSIONS AND CLINICAL IMPLICATIONS: fURS using a FANS ureteral access sheath resulted in a high SFS rate with negligible serious adverse event and reintervention rates.