Electromotive Drug Administration in the Porcine Ureter: First In Vivo A pplication for Ureteral Dilation

Abstract

Objective:

Retrograde intrarenal surgery is limited by the narrow caliber of the human ureter, resulting in both reluctance to deploy larger ureteral access sheaths and, at times, failed primary ureteral access, requiring placement of a ureteral stent and a delayed second procedure. In this study, we sought to evaluate the application of electromotive drug administration (EMDA) to deliver smooth muscle relaxants to the porcine ureter to facilitate acute ureteral dilation.

Methods:

Eighteen juvenile female Yorkshire pigs were randomized into three treatment groups (alfuzosin, aminophylline, or isoproterenol; n = 6 per group). Within each animal, one ureter received an intraureteral drug infusion with EMDA, while the contralateral ureter served as a control, receiving 0.9% normal saline (NS). Ureteral size was assessed before and after treatment by passing sequentially larger urethral dilators starting at 10 Fr, with a maximum insertion force of 3.5 N.

Results:

Only alfuzosin with EMDA increased ureteral size compared with NS alone (alfuzosin vs NS, 0.8 Fr vs 0.1 Fr, p = 0.031). Neither aminophylline nor isoproterenol with EMDA resulted in a significant increase in ureteral size compared with their respective NS controls (aminophylline vs NS, 0.3 Fr vs −0.6 Fr, p = 0.344; isoproterenol vs NS, 0.1 Fr vs −0.4 Fr, p = 0.125).

Conclusion:

In this first report, EMDA-mediated in vivo delivery of alfuzosin into the porcine ureter acutely increased ureteral distensibility.