Learning of percutaneous nephrolithotomy in supine position. An observational multicenter study

To prospectively study the post-operative results and complications of percutaneous nephrolithotomy (PNL) in supine position to assess difficulty of learning it and how experience affects the results. To establish a relative comparison with the data published in the literature on the prone position. A prospective observational multicenter study on PNL in Valdivia position or in its Galdakao variant was performed. Demographic variables and specific variables related to the lithiasis were collected. Technical aspects, surgery time, success rate and complications according to the Clavien-Dindo classifications were assessed. A total of 335 PNL in supine position conducted in 13 Spanish centers were registered from September 2008 to June 2011. The man:woman ratio was 1:1.28 and mean age 51.3+14.5 years. 211 (63%) cases were performed by urologists with experience in >50 cases and 124 (37%) by urologists with less experience. Mean operation time was 113.3 ± 46.4 min, 106.6 ± 38.2 for the experienced ones vs. 124.9 ± 56.2 in the novice ones (P