PD19-09 ULTRASOUND-GUIDED RENAL ACCESS REDUCES RADIATION EXPOSURE DURING PERCUTANEOUS NEPHROLITHOTOMY COMPARED TO FLUOROSCOPIC GUIDANCE

Abstract

INTRODUCTION AND OBJECTIVES: In the United States, renal access for percutaneous nephrolithotomy (PCNL) is most commonly performed using fluoroscopic guidance. Fluoroscopy provides good structural visualization of the collecting system but requires the use of ionizing radiation. Ultrasonography (US) is an alternative imaging modality for achieving percutaneous renal access and provides both collecting system and visceral imaging compared to fluoroscopy. The purpose of this study is to compare radiation exposure and surgical outcomes for PCNL between cases performed with USversus fluoroscopy-guided renal access. METHODS: This prospective cohort study enrolled 118 PCNL cases from the UCSF hospital system between May 2014 and May 2015, of which 48 were performed with fluoroscopic guidance (group 1) and 70 with US guidance (group 2) for percutaneous renal access. USguided cases were those for which US was utilized for all or the majority of renal access, while fluoroscopy-guided cases were those done purely using fluoroscopy. The main variables measured included radiation dose, total operative time, residual stone status, serum creatinine change, hematocrit change, perioperative transfusion rate, surgical complication rate (Clavien class >2), and hospital length of stay. RESULTS: Groups 1 and 2 were comparable, having mean ages of 53.9 13.8 vs. 54.2 12.2, percent male patients of 43.8% vs. 41.4%, mean BMI of 30.9 8.1 vs. 29.3 9.8, and mean ASA physical status classification of 2.1 0.6 vs. 2.3 0.7, respectively. Patients in group 2 received less total mean radiation dose (18.5 mGy vs. 46.0 mGy, P<.01) and fluoroscopic screening time (68.9 sec vs. 169.5 sec, P<.01) compared to group 1. An average radiation dose reduction of 27.5 mGy (95% CI 7.8 to 47.3) was observed. There were no statistically significant differences in mean values for total operative time (156 vs. 159 min P1⁄4.77), change in serum creatinine (.03 vs .03, P1⁄4.95), change in hematocrit (-2.8 vs. -4.1, P1⁄4.16), transfusion rate (2.1% vs. 1.4%, P1⁄41.0), complication rate (4.2% vs. 4.3%, P1⁄41.0), residual stone status (16.7% vs. 21.4%, P1⁄4.23), and hospital length of stay (2.9 days vs. 3.1 days, P1⁄4.62). CONCLUSIONS: Ultrasound guidance for percutaneous renal access results in reduced radiation exposure for patients during PCNL and has no negative effects on surgical outcomes or efficacy of the procedure when compared to fluoroscopic guidance.