WCE 2018: Prospective Evaluation of Kidney Displacement During Supine Mini Percutaneous Nephrolithotomy: Incidence, Significance and Analysis of Predictive Factors

Paris, France (UroToday.com) During percutaneous nephrolithotomy, it is essential to obtain percutaneous access safely and in an optimal location. This step may be complicated by kidney displacement due to patient positioning. Given that little is known about the effects of and associations with kidney displacement, the authors sought to identify the rate of kidney displacement and its impact on achieving successful puncture, and any parameters associated with kidney displacement during supine mini-PCNL.

The investigators studied 98 patients, of whom 34 were displacement-positive and 64 were displacement-negative. Importantly, the authors specified that displacement was measured by capturing fluoroscopy images and holding upscaled graph paper on the fluoroscopy machine monitor in order to quantify kidney positioning.

There was no significant association between displacement-positive versus displacement-negative groups in regards to age, gender, BMI, stone size, stone-free rate, and complication rate. There was, however, a significantly longer fluoroscopy time in the displacement-positive group. Moreover, multivariate analysis revealed that less perirenal fat, significantly longer renal arteries, and significantly higher rates of lower pole puncture were independently associated with the displacement-positive group.

Based on these data, the authors concluded that surgeons can perhaps use these parameters during preoperative planning. For example, if the surgeon noted a longer renal artery and less perirenal fat, then he or she could anticipate the potential for kidney displacement during the operation. However, one audience member asked how this could actually change the surgical approach, and asked if these parameters, when identified preoperatively, call for the expertise of a more experienced surgeon, for example. Dr. Gökce responded by saying that, depending on the stone position, the surgeon could attempt to gain percutaneous access through a more suitable calyx, but he also noted that more data are needed in order to determine how these identified predictive variables can aid in preoperative planning.

Presented by: Mehmet Gökce, MD, Associate Professor, Ankara Uuniversity School of Medicine Department of Urology, Ankara, Ankara, Turkey
Co-Authors: Başak Gülpınar, Aykut Akıncı, Evren Süer, Adem Sancı, Muammer Babayiğit, Yaşar Bedük, Sümer Baltacı
Author Affiliation: Department of Urology, Ankara University School of Medicine, Ankara, Turkey., Ankara, Ankara, Turkey

Written by: Frank Jefferson, Department of Urology, University of California-Irvine, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France