Supine versus Prone Percutaneous Nephrolithotomy for Complex Stones: A Multicenter Randomized Controlled Trial

Abstract

High-quality evidence comparing supine to prone percutaneous nephrolithotomy (PCNL) for the treatment of complex stones is lacking. This study aimed to compare the outcomes of supine (SUP) and prone (PRO) PCNL. Materials and Methods:A non-inferior randomized controlled trial was performed according to the CONSORT criteria. The inclusion criteria were patients over 18 years of age with complex stones. SUP was performed in the Barts flank-free modified position. Except for positioning, all the surgical parameters were identical. The primary outcome was the difference in the success rate on the first postoperative day (POD1) between groups. The secondary outcome was the difference in the stone-free rate on the 90 th postoperative day (final SFR). A noninferiority margin of 15% was used. Demographic, operative, and safety variables were compared between the groups.Statistical significance was set at p<0.05.Results: Overall, 112 patients were randomized, and their demographic characteristics were comparable. The success rate on POD1 was similar (SUP:62.5% vs. PRO:57.1%, p=0.563). The difference observed (-5.4%) was lower than the predefined limit. The final SFR was also similar (SUP:55.4% vs. PRO:50.0%, p=0.571). SUP had a shorter operative time (117.9±39.1 vs. 147.6±38.8; p<0.001, minutes) and PRO had a higher rate of Clavien ≥ 3 complications (14.3% vs. 3.6%; p=0.045).

This Month in Adult Urology

“…Perrella et al (page 647) in a multi-institutional study report the first randomized, noninferiority trial comparing positioning with a primary outcome of success rate on the first postoperative day. 4 Their results illustrate similar early success rates but also describe some interesting secondary findings such as operative times and complications. The authors conclude that positioning during PCNL for complex kidney stones did not dramatically impact success, suggesting that advancing the less frequently utilized supine position may be worthwhile given some potential advantages.…”

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“…Similarly, Perella et al found comparable outcomes for both prone and supine positioning in PCNL. Supine position was also associated with lower high-grade complication rates [ 27 ]. The downwardly orientated access sheath could have provided better drainage and prevented high intrarenal pressures, thus lowering infections in supine position [ 28 ].…”

Reply by Authors

“…Along with that, another advantage provided by supine position is the reduced operative time that might render mPCNL also more cost-effective. 5…”