Percutaneous nephrolithotomy in obese patients: comparison between the prone and total supine position

Percutaneous nephrolithotomy (PCNL) can be performed in the prone or in the supine position. Comparisons between the two techniques in obese patients are rare in the current literature.

The records of obese patients (body mass index >30) who underwent PCNL in the prone or complete supine positions were reviewed. All patients had a noncontrast CT before and after the procedure. Stones were graded according to the Guy stone score and complications according to the Clavien grading. The stone-free rates, operative time, surgical complications, and hospital stay were analyzed.

A total of 56 PCNL were performed in 42 patients. Twenty-four PCNL were performed in the prone and 32 in the total supine position. Stone-free rate on the first postoperative day was 50% in the prone and 46.9% in the supine position (P=1.0). Final stone-free rates were 83.3% and 78.1%, respectively (P=0.74). Mean operative time was 164.6 minutes in the prone and 120.3 minutes in the supine position (P=0.0017), and hospital stay was 4.38 and 2.68 days (P=0.014), respectively. The transfusion rate was 20.8% in the prone and zero in the supine position patients (P=0.01). Excluding Guy IV stones, transfusion rate was 8.3% in the prone position (P=0.1). Significant surgical complications rate was 12.5% in the prone and 3.1% in the supine position (P=0.302).

PCNL performed in the prone or in the complete supine position in obese patients presents similar outcomes. The supine decubitus position has the advantages of a significantly shorter operative time and hospital stay.