Radial dilation of ureteral balloons : Comparative in vitro analysis

The dynamics of ureteral balloon expansion may differ with increasing extrinsic compressive forces and inflation pressures. This study compared the ability of ureteral balloons to expand under different conditions. The balloons tested were the Cook Accent, Ascend, Ascend AQ, and Pursuit; the Bard 195503 and UroForce; and the Boston Scientific Microvasive UroMax Ultra. When available, multiple balloon diameters and lengths were tested. With a guidewire in place, the balloon tip was secured by elevated vise grips on either side of the balloon. A string was wrapped around the balloon center once, and incremental increases in load were added (2 g, 42 g, 82 g, 122 g) to represent increasing extrinsic compression. The balloon was inflated with contrast medium, and circumference changes were measured at increments of 2 atm up to burst pressure. Balloons were tested in triplicate for each weight. The majority of the balloons were unable to reach 90% of their expected diameter with larger constrictive loads (122 g) at low inflation pressure (4 atm). The only balloons that achieved a diameter at 4 atm that was at least 90% of the expected diameter with a coefficient of variance (CV) of