Percutaneous Nephrolithotomy With X-Ray Free Technique in Morbidlyobese Patients: Outcomes and Skills From A Large High-Volume Stone Management Center

Objectives This study was performed to investigate the feasibility and safety of complete ultrasound (US)-guided percutaneous nephrolithotomy (PNL) in morbidly obese patients and to introduce the US skills used in a high-volume stone management center. Methods We retrospectively reviewed consecutive patients with a body mass index (BMI) of ≥ 40 kg/m2 who underwent X-ray-free PNL for treatment of upper urinary tract stones from October 2013 to March 2020. The patients’ demographic information and intraoperative and postoperative parameters were collected and analyzed. Surgical complications were recorded and classified according to the modified Clavien classification system. Results In total, 52 patients were included. Their mean BMI was 45.5 kg/m2 (range, 40.3–61.6 kg/m2), and their mean age was 46 years (range, 28–58 years). The mean stone burden was 2.8 cm (range, 2.1–8.8 cm). Thirty-nine patients underwent surgery in the prone position, and the remaining 13 underwent surgery in the lateral position. All procedures were completed successfully with no major intraoperative complications. The mean operative duration was 68 min (range, 38–97 min). The mean time required for establishment of each access was 6.6 min (range, 3.5–14.7 min). No blood transfusion or embolization was needed for any patient. The initial stone-free rate was 80.8% (42/52 patients). Five patients required second-look PNL. Two patients underwent flexible ureteroscopic lithotripsy. The final stone-free rate was 90.4% (47/52 patients). Conclusions Complete US-guided PNL was technically feasible and safe in morbidly obese patients. The stone-free rate and complication rate were acceptable and comparable with those in non-obese patients.