PERCUTANEOUS NEPHROLITHOTOMY IN OBESE PATIENTS: COMPARISON BETWEEN THE PRONE AND TOTAL SUPINE POSITION

Abstract

OBJECTIVE: We compared the outcomes of obese patients(BMI > 30) submitted to Percutaneous Nephrolithotomy (PCNL) in the prone or in the complete supine position. METHODS: Patients were randomly divided and all had a non-contrast computed tomography (CT) before and after the procedure. Stones were graded according to the Guy’s score and complications according to the Clavien grading. The stone-free rates, operative time, hospital stay and surgical complications were evaluated. RESULTS: 56 PCNL were performed (24 in the prone and 32 in the supine position). Mean stone area was 11.28 cm2 and 10.2 cm2 for patients in the prone and supine position (p=0.43). Overall stone-free rate after one procedure and the final result were 54.2% and 83.3% in the prone and 68.8% and 78.1% in the supine position, respectively (p=0.28 and 0.64). Stone-free rate was 100 and 88.9% for Guy’s I (p=0.84), 62.5 and 62.5% for Guy’s II (p=1.0), 75 and 54.5% for Guy’s III (p=0.6) and 20 and 75% for Guy’s IV (p=0.09) in the prone and supine positions, respectively. Mean operative time was 164.6 and 120.3 minutes in the prone and supine position (p=0.0017) and hospital stay 4.38 and 2.68 days, respectively (p=0.01). The transfusion rate was 20.8% in the prone group and zero in the supine group (p=0.01). Surgical complications rates were 33.3% and 31.3 % in the prone and supine positions, respectively (p=0.77). CONCLUSIONS: PCNL in the complete supine position in obese patients achieved similar results but complete supine position requires less transfusion, shorter operative time and hospital stay.