Category: Clinical Stones: PCNL

MP12-2 - Prospective evaluation of kidney displacement during supine mini percutaneous nephrolithotomy: Incidence, significance & analysis of predictive factors

Fri, Sep 21
2:00 PM - 4:00 PM

Introduction & Objective : Percutaneous access is the most important step of percutaneous nephrolithotomy and kidney displacement may alter renal puncture.  The aim of this study was to identify the rate of kidney displacement, its significance on achievement of a successful puncture, and parameters associated with kidney displacement in patients operated in modified supine position.


Methods :

The data of 98 consecutive patients that underwent mini-PNL was collected prospectively. The patients were grouped as displacement positive vs. displacement negative based on kidney movement measurements on fluoroscopic screen. The parameters collected were age, gender, body mass index, side of the kidney, punctured calyx, fluoroscopy time to successful puncture and tract dilation, stone free and complication rates, stone diameter, length of the renal artery, quantity of perirenal and abdominal fat. Groups were compared for the above listed parameters and logistic regression analysis was performed to identify factors associated with kidney displacement.


Results :

There were 34 and 64 patients in the displacement positive and negative groups respectively. Groups were similar for age, gender, BMI, stone size, stone free, and complication rates. Fluoroscopy time to puncture and tract dilation were longer in the displacement positive group. Groups were different for renal artery length and perirenal fat measurements (table 1). In multivariate analysis, lower pole puncture, renal artery length, and perirenal fat measurement were found to be independent predictors of kidney displacement (table 2).


Conclusions :

Kidney displacement can occur in up to 1/3 of the PNL cases operated in supine position. Although, it does not alter the success and complication rates, it is associated with longer fluoroscopy times and therefore more difficult access. Puncture through a lower calyx, longer renal artery, and lesser perirenal fat measurement were identified as factors associated with significant displacement. These parameters can be evaluated in preoperative NCCT studies and we recommend the surgeons to taken in to account these parameters during preoperative planning.

Mehmet I. Gökce

associate professor
ankara university school of medicine department of urology
Ankara, Ankara, Turkey

Mehmet İlker Gökce, MD, Associate Professor of Urology
Ankara University School of Medicine Department of Urology, Ankara, Turkey
Special interest on Supine PNL & ECIRS, RIRS

Başak Gülpınar

ankara university school of medicine department of radiology
Ankara, Ankara, Turkey

Aykut Akıncı

ankara university school of medicine department of urology
Ankara, Ankara, Turkey

Evren Süer

ankara university school of medicine department of urology
Ankara, Ankara, Turkey

Adem Sancı

ankara university school of medicine department of urology
Ankara, Ankara, Turkey

Muammer Babayiğit

Department of Urology, Ankara University School of Medicine, Ankara, Turkey.
Ankara, Ankara, Turkey

Yaşar Bedük

ankara university school of medicine department of urology
Ankara, Ankara, Turkey

Sümer Baltacı

ankara university school of medicine department of urology
Ankara, Ankara, Turkey