Hydraulically Steerable Micro Guidewire Capable of Distal Sharp Steering.

Area of Science:

• Biomedical Engineering
• Medical Devices
• Fluid Dynamics

Background:

• Current steerable catheters and guidewires face limitations in accessing small-diameter vessels due to size and steering constraints.
• Effective navigation within narrow and tortuous vascular networks remains a significant challenge in minimally invasive procedures.

Purpose of the Study:

• To develop and evaluate a novel hydraulically steerable guidewire with a 400 μm diameter for enhanced vascular access.
• To enable navigation into vessels as small as 1 mm diameter, including those with wide bifurcation angles (>90 degrees).

Main Methods:

• Design of a steering mechanism using a flexible eccentric tube with micro patterns, capable of bending into two distinct curvatures via hydraulic pressure.
• Fabrication via a template-based method using 3D printing, stamping, and silicone coating, avoiding adhesion or division.
• Performance evaluation in a custom-built blood circulatory system mimicking arterial conditions (viscosity, pressure, flow velocity, and bifurcation geometry).

Main Results:

• The 400 μm guidewire successfully accessed 1 mm diameter vessels.
• The guidewire demonstrated the ability to navigate bifurcations with angles up to 128 degrees.
• The steering mechanism's dual curvature design (2 mm distal sharp curve, 9 mm proximal gradual curve) facilitates access in both confined and larger diameter vessels.

Conclusions:

• The hydraulically steerable guidewire offers a promising solution for accessing challenging small-diameter vessels.
• The novel design and fabrication method provide improved steering capacity and access in complex vascular anatomies.
• The use of biocompatible materials ensures safety for potential clinical applications.