Beyond BMI: A Clearer Choice of Flouroscopic Guided PCNL Over USG-PNL in Cases of Central Obesity

Purpose: This study aimed to investigate the effect of waist circumference (WS) on Percutaneous Nephrolithotomy (PCNL) compared with body mass index (BMI) in different access techniques: fluoroscopy (FPNL), and ultrasonography (UPNL). Methods: 109 patients were enrolled in the study in two different centers (63, FPNL-46, UPNL). After investigating the basic 24 parameters, Subgroups were analyzed based on WS ≥ 90 cm and BMI ≥ 30. CT scans determined the stone-free rate (SFR); less than 4 mm stones were accepted as relative SFR. The difficulty level of access was determined using the number of attempted access (NAA) and access times (AT). Results: Success rates were similar between the groups. In the UPNL group, X-ray time and NAA were lower, but AT was higher (p: 0.018, p: 0.012, p: 0.005, respectively). In the UPNL group, having a BMI ≥30, only prolonged AT, p: 0,029, but having WS ≥ 90 prolonged AT, NAA, and operation time, p< 0.01. In FGPNL, however, WS and BMI did not affect access parameters. In a linear regression analysis, WS and dilatation level predict access time and NAA (p: 0,003 and p: 0,015). Absolute SFR was similar between the groups, with 44,4 % for FPNL and 41,3 % for UPNL, without being affected by BMI and WS. Conclusion: Even if UPNL is safer regarding radiation exposure, it can be challenging in central obesity. Waist circumference may be a more reliable predictor of this issue than BMI. Despite having similar success rates, FGPNL might be preferable for these patients.