Abstract: PD30-10
Sources of Funding: none

Introduction

Tipless nitinol baskets are commonly used during ureteroscopic procedures for urinary calculi manipulation and retrieval. We aimed to evaluate and compare 5 commercially available tipless nitinol stone baskets(2.2F): 2.2F Coloplast Dormia No-Tip®, 1.5F Sacred Heart Medical Halo®, 2.2F Cook NCircle Nitinol Tipless Stone Extractor®, 1.9F Bard SkyLite Tipless Nitinol Basket® and the 1.9F Boston Scientific Zero Tip® Nitinol Stone Retrieval Basket for penetration force, radial dilation force, opening dynamics and resistance towards deflection.

Methods

Each of the 5 baskets were tested for penetration force (safety metric) - 5 repetitions with 2 baskets tips of each model) with a motorized sliding stage model and digital force gauge to assess perforation of a piece of aluminum foil with the basket tip. Radial force (functional metric for ureteric calculi) was tested by measuring maximal force of an opened basket between two blocks on a digital scale (10 repetitions for each basket). Opening/closing dynamics for each basket were measured by determining the width of the basket at 0.5 mm increments of basket length with digital calipers and light microscopic visualization. Limitation of deflection (functional metric) was tested by measuring the difference in maximal upward and downward angle of deflection of a ureteroscope with and without a basket in place.

Results

The Sacred Heart Halo 1.5F basket had the highest mean force required to perforate the foil at 0.676N +/- 0.117 (p<0.0001). The Coloplast No-Tip Dormia 2.2F basket required the lowest mean force required to perforate at 0.105N +/- 0.043 (p<0.0001). The Sacred Heart Halo 1.5F basket had the highest mean radial dilation force at 3.04 g +/- 0.15 (p<0.0001). The Cook NCircle 2.2F basket had the lowest mean radiation dilation force at 1.24 g +/- 0.084 (p<0.0001). The Cook NCircle 2.2F had the most linear pattern of opening, while the Coloplast No-Tip Dormia 2.2F and the Sacred Heart Halo 1.5F exhibited exponential opening dynamics. The Cook NCircle 2.2F limited scope deflection the most with a decrease in 4° downward and 10° upward (net 14° of lost deflection). The Sacred Heart Halo 1.5F had the least influence on deflection with a decrease in 3° downward and 5° upward (net 8° of lost deflection)

Conclusions

The penetration force, radial dilation force, opening dynamics and resistance to deflection varied between 5 commonly available tipless nitinol stone baskets. A small diameter 1.5F basket is capable of providing optimal performance, while sacrificing linear opening.

Funding

none