E-Mail karger@karger.com Original Paper Urol Int 2014;92:444–448 DOI: 10.1159/000356562 Skin-to-Stone Distance Has No Impact on Outcomes of Percutaneous Nephrolithotomy Umut Gonulalan a Murat Akand c Gokcen Coban b Tufan Cicek a Murat Kosan a Serdar Goktas c Hakan Ozkardes d Departments of a Urology and b Radiology, Başkent University, and c Department of Urology, Selçuk University, Konya; d Department of Urology, Başkent University, Ankara, Turkey retrospective review of patients undergoing PCNL, we found that SSD has no impact on operative and postoperative out- comes. These results were in accordance with the safety of PCNL in obese patients. © 2014 S. Karger AG, Basel Introduction Percutaneous nephrolithotomy (PCNL) has been used for stones >2 cm, complicated or staghorn stones in the upper urinary tract since it was first described in 1976 by Fernström and Johansson [1–3]. In the treatment of renal stones in obese patients, extracorporeal shock wave litho- tripsy (ESWL) is being used restrictedly due to both weight limitation of the device and larger skin-to-stone distance (SSD), and PCNL is preferred more commonly [4]. Studies evaluating the effect of obesity on the out- comes and complications of PCNL with high caseloads have reported that obesity does not affect the safety of this technique but lowers the stone-free rates [5, 6]. SSD increases due to localization of the stone, increase in subcutaneous and visceral adipose tissue, and thick- ness of the renal parenchyma. The association between renal parenchymal thickness and the efficacy and safety Key Words Obesity · Percutaneous nephrolithotomy · Skin-to-stone distance · Success Abstract Objective: Skin-to-stone distance (SSD) is a stronger factor than body mass index in predicting the success of shock wave lithotripsy. We aimed to evaluate the impact of SSD on outcomes of percutaneous nephrolithotomy (PCNL). Mate- rials and Methods: The medical records of 1,280 patients who had undergone PCNL between April 2007 and February 2012 were evaluated retrospectively. 192 patients who had had preoperative non-contrasted computed tomography and single renal access were included the study. According to this median SSD value, patients were divided into two groups: group 1 (SSD ≤94 mm) (n = 92) and group 2 (SSD >94 mm) (n = 90). The groups were compared according to operative and postoperative parameters. Results: We found no significant differences between the two groups with re- gard to stone-free rate, operation time, fluoroscopy time, hospitalization time, visual analog score of pain, stone bur- den, transfusion rates and complication rates. On the other hand, the mean body mass index of group 1 was significant- ly lower than that of group 2 (p < 0.05). Conclusions: In this Received: August 23, 2013 Accepted after revision: October 22, 2013 Published online: January 29, 2014 Internationalis Urologia Umut Gonulalan, MD Başkent University School of Medicine Konya Research and Training Hospital Saray Street, No: 1 Selçuklu, Konya (Turkey) E-Mail drugonulalan  @  yahoo.com © 2014 S. Karger AG, Basel 0042–1138/14/0924–0444$39.50/0 www.karger.com/uin