In vitro evaluation of ureteral stent compression

Area of Science:

• Biomedical Engineering
• Urology
• Materials Science

Background:

• Ureteral stents are essential for maintaining urine flow and preventing obstruction.
• Extrinsic compression can compromise stent function, impacting patient outcomes.
• Understanding stent mechanical properties is vital for selecting appropriate devices.

Purpose of the Study:

• To quantify the radial compression force required for various ureteral stents.
• To assess the impact of compression on stent performance across different sizes and manufacturers.
• To identify stent designs offering superior resistance to extrinsic compression.

Main Methods:

• Evaluated 14 ureteral stents (6F-10.3F) using a universal testing machine for radial compression.
• Measured compression increments and recorded stress relaxation over time.
• Calculated Young's Modulus (E) and, for one stent, measured simultaneous saline flow rates.

Main Results:

• Cook C-Flex, Microvasive Percuflex Plus 6F, Cook EndoSof, and Fossa Open Lumen showed highest compression resistance (E > 28,000 Pa).
• Cook Amplatz 10.2F and Microvasive Percuflex Plus 10.3F exhibited the lowest resistance (E < 12,000 Pa).
• Flow through the Cook Amplatz stent decreased linearly with compression (R² = 0.95).

Conclusions:

• Stent resistance to radial compression is critical for managing extrinsic ureteral obstruction.
• The Cook C-Flex ureteral stent provided the best resistance to compressive forces.
• Larger lumen stents, often preferred clinically, were found to be more susceptible to compression.