Purpose: To assess efficacy and safety of prone- and supine percutaneous nephrolithotomy (PCNL) for the treatment of lower pole kidney stones.
Methods: Data from patients affected by lower pole kidney stones and treated with PCNL between December 2005 and August 2010 were collected retrospectively by seven referral centres. Variables analysed included patient demographics, clinical and surgical characteristics, stone-free rates (SFR) and complications. Statistical analysis was conducted to compare the differences for SFRs and complication rates between prone- and supine PCNL.
Results: One hundred seventeen patients underwent PCNL (mean stone size: 19.5 mm) for stones harboured only in the lower renal pole (single stone: 53.6%; multiple stones: 46.4%). A higher proportion of patients with ASA score ≥ 3 and harbouring multiple lower pole stones were treated with supine PCNL (5.8 vs. 23.1%; p = 0.0001, and 25 vs. 81.5%; p = 0.0001, respectively, for prone- and supine PCNL). One-month SFR was 88.9%; an auxiliary procedure was needed in 6 patients; the 3-month SFR was 90.2%. There were 9 post-operative major complications (7.7%). No differences were observed in terms of 1- and 3-month SFRs (90.4 vs. 87.7%; p = 0.64; 92.3 vs. 89.2%; p = 0.4) and complication rates (7.6 vs. 7.7%; p = 0.83) when comparing prone- versus supine PCNL, respectively.
Conclusions: The results confirm the high success rate and relatively low morbidity of modern PCNL for lower pole stones, regardless the position used. Supine PCNL was more frequently offered in case of patients at higher ASA score and in case of multiple lower pole stones.