Supine versus prone percutaneous nephrolithotomy: A comparison of efficacy and safety in obese patients

Abstract

Objective: To compare prone and supine percutaneous nephrolithotomy (PNL) in obese patients with respect to efficacy and safety.Material and Methods:  Individuals with kidney stones larger than 2 cm undergoing either prone or supine position PNL were included in the study based on the World Health Organization (WHO) classification of body mass index (BMI) ≥30 kg/m2 between January 2011 and September 2020 retrospectively. Demographic characteristics, intraoperative, postoperative data, and complications according to Modified Clavien Grading System were listed. Patients were followed for 3 months, documenting their stone-free status. Results: Out of the total 156 obese patients, 74(47.4%) underwent supine PNL (group 1), and 82 (52.6%) were prone to PNL (group 2). There was no statistically significant difference between the groups concerning hemoglobin drop, the number of pelvicalyceal access, blood transfusion, length of hospital stay, complications rates, and stone-free status (p>0.05). The location of pelvicalyceal access (upper, middle, lower calyces) was significantly different (18.9%, 32.4%, 42.6% in group 1, 3.2%, 19.3%, 77.5% in group 2, respectively) (p<0.001). Mean operative times were statistically different between the groups (97.2 ± 18.1 minutes in group 1, 119.5 ± 18.9 minutes in group 2, respectively) (p<0.001).Conclusion: In the prone or supine position, PNL is a safe and effective method for managing kidney stones in obese patients. Access through the upper calyx may be favored in the supine position considering to patient’s characteristics. Additionally, the supine position has the greatest advantage over the prone position due to shorter operative times.