Design and preparation of a flexible ureteroscope sheath with variable diameter and its application on pigs

Abstract

Objective To prepare a sheath with variable diameter which can achieve catheterization with small diameter while operation with large diameter, and evaluate its effect of catheterization in animals. Methods With reference to ureter data, a new sheath was designed and made by computer-aided procedure. Then 12 female Chinese pigs were randomly divided into experimental group (new sheath) and control group (12Fr conventional sheath) to undergo sheath insertion and extraction experiments. The time of tube extubation and catheterization, total time of operation, sheath diameter during catheterization, success rate of catheterization, and morphology of ureteral injury were observed and recorded, and the results were compared between the 2 groups. Results The water-balloon ureteral access sheath was successfully prepared. The experimental group had significantly shorter insertion time (1.58±0.41 vs 3.53±1.09 min) and total operation time (9.59±2.95 vs 13.74±3.72 min), smaller outer diameter of sheath during catheterization (2.15±0.25 vs 4.00±0.08 mm), higher catheter success rate (100% vs 80%), and milder ureteral injury when compared with the control group (P 0.05). Conclusion Our newly-designed sheath can establish the similar operation channel as the conventional sheath, with the advantages of smaller outer diameter, shorter operation time and milder ureter damage, and has a favorable application prospect.

Keywords

• flexible ureteroscope
• variable diameter sheath
• operation time
• ureteral injury