Presentation Authors: Manuel Armas-Phan*, David Tzou, David Bayne, Scott Wiener, Tim Liang, Marshall Stoller, Tom Chi, San Francisco, CA
Introduction: Reducing radiation exposure to patients & staff during medical procedures is a growing area of importance. Ultrasound (US)-guided percutaneous nephrolithotomy (PCNL) is becoming increasingly adopted by American urologists. The aim of this study was to compare the clinical outcomes between fluoroscopic & non-fluoroscopic guided tract dilation for PCNL.
Methods: A prospective cohort study enrolled successive patients undergoing PCNL between 7/2015 & 3/2018. Included were those with a successful US-guided renal puncture. Patients were divided based on whether tract dilation was performed with fluoroscopy or not. The outcomes of interest were complications, EBL, & stone clearance. Differences were compared using Welch&[prime]s t-test, Fisher&[prime]s exact test, and regression modeling with Stata v15.1.
Results: 177 patients underwent PCNL including those with successful US-guided renal puncture. 38 & 139 underwent renal tract dilation with & without fluoroscopic guidance, respectively. There were no differences in age, gender, BMI, presence of hydronephrosis, stone size, procedure laterality, number of dilated tracts, & calyx puncture location. There was a larger proportion of modified dorsal lithotomy positions (49% v. 24%) & a shorter operative time (117min v. 138min) among non-fluoroscopic tract dilations. With multivariate regression analysis, only modified dorsal lithotomy remained statistically significantly different between the two groups. There were no differences in postoperative stone clearance, complications, or intraoperative EBL. For the entire cohort, a 5-unit increase in BMI had 30% greater odds of more severe Clavien-Dindo complications (p < 0.05) & 5mm decrease in the stone burden had 10% greater odds of achieving stone clearance (p < 0.05). No variables were predictive of EBL.
Conclusions: Renal tract dilation can be safely performed in the absence of fluoroscopic guidance. Compared to using fluoroscopy, our study demonstrated that ultrasound-guided dilations can be safely performed without higher complication or bleeding rates. This can be performed using a variety of surgical positions, & future studies centered on improving dilation techniques could be of impactful clinical value.
Source of Funding: NIH P20-DK-116193, NIH R21-DK-109433, NIH TL1-TR-001871, & Urology Care Foundation Medical Student Fellowship