The Neutrophil Gelatinase-Associated Lipocalin (NGAL) as a Biomarker for Monitoring Renal Function in Patients with Solitary Kidney Stones: A Single-Center, Retrospective Analysis of 23 Cases.

Purpose: To assess the efficacy of flexible ureteroscopy (F-URS) in treating single kidney stones and the role of Neutrophil Gelatinase-Associated Lipocalin (NGAL) in detecting early renal function abnormalities in patients with solitary kidney stones.

Materials And Methods: We retrospectively analyzed 23 patients with solitary kidney nephrolithiasis who underwent F-URS at the Sichuan Science City Hospital between January 2017 and November 2020. We collected data on the following variables: Age, gender, stone size, surgery time, perioperative outcomes, and complications; Stone-free rates (SFRs) were calculated using computed tomography (CT). Serum creatinine (SCr) and NGAL levels were tested before surgery and at one-day and one-month postoperatively.

Results: The average size of the stones was 1.53 ± 0.57 cm. The average operating time was 59.28 ± 21.25 minutes. For urethral stricture, three patients (13.0%) required second-stage F-URS. The SFRs were 91.3% following the first and second treatments. The mean NGAL levels were significantly increased at one-day postoperatively compared to baseline (768.91 ± 514.50 ng/mL vs. 173.39 ± 147.94 ng/mL, respectively, < 0.001). Minor complications, including gross hematuria (n = 5) and mild fever (n = 3), occurred in 34.8% of cases (n = 8), who recovered quickly.

Conclusions: F-URS is a safe and efficient therapeutic approach for patients with solitary kidney nephrolithiasis, and NGAL has huge prospects as an indicator of early-stage renal injury in this patient population.