Acute kidney injury following retrograde intrarenal surgery (RIRS) with flexible and navigable suction ureteral access sheath (FANS): results from a prospective multicenter study.

BACKGROUND

Flexible and navigable suction ureteral access sheaths (FANS) have proven to be effective in reducing operative time and infectious complications and in increasing stone-free rate during retrograde intrarenal surgery (RIRS). FANS may reduce intrarenal pressure, thus reducing parenchymal renal damage. The aim of the present study was to assess acute kidney injury (AKI) rate following RIRS with FANS.

METHODS

This was a prospective multicenter study. Patients were enrolled between August 2023 and March 2024. Inclusion criteria were: patients aged ≥18 years with normal urinary anatomy who successfully underwent RIRS using FANS for renal stones. Complete baseline and perioperative data were collected. AKI was assessed at postoperative day 1 or 2 according to the KDIGO criteria. Intra and early postoperative complications, readmissions, and reinterventions up to 30 days post-surgery were documented. Univariable logistic regression (UVA) analysis was performed to identify predictors of AKI.

RESULTS

Two hundred an ten patients were eligible for analysis. The median stone volume was 1320 mm3. Median preoperative serum creatinine and eGFR were 0.94 mg/dL and 84 mL/min, respectively. The commonest FANS size used was 11-13 Ch (47%). A disposable scope was used in 55%, and TFL in 53% of surgeries. Median total laser time, ureteroscopy time, and operative times were 16.5, 31, and 49 minutes, respectively. At the end of the surgery, a double-J ureteral stent was placed in 84% of patients. AKI occurred in 13 (6.2%) patients. All cases were stage 1 AKI. At UVA, none of the preoperative or intraoperative variables were statistically associated with the occurrence of AKI (all P>0.05).

CONCLUSIONS

AKI following RIRS with FANS is a not neglectable event and endourologist should be aware of this eventuality. However, all AKI episodes were mild. This study findings should be validated with a randomized controlled trial comparing outcomes of RIRS with and without FANS.