1. Design of a Steerable Catheter Steeratheter
Cherry R. Abenojar
Eric D. Benson
Advisor: Dr. Ted Larson
BME 273
Oral Report #3
22 March 99

2. Project Goal
Reference: US Patent 5,817,057
The goal of this project is to design a steerable catheter for use within the carotid bifurcation and its extensions.

3. Significance Easy access to the brain via carotid artery
Treatment of aneurysms
Improvement of current methods
inefficient trial and error methods
problem with “hooked catheter”
artery
branch
“hooked” catheter tip

4. Catheter Specifications
Demands
Diameter  1 mm
Ability to turn/bend
Controllable
Safe
Wishes
Simple
Flexible
Bend at any angle
Inexpensive

5. Carotid Parameters Laminar flow Carotid extensions: 2 - 3 mm diameters
Reference: Turitto, 147

6. Artery Geometries Best case geometry Acute angle 90 angle
Worst case geometry
Obtuse angle
flow
flow
flow

7. Analyses of Current Designs I
Reference: US Patent 5,824,031
One guide wire design
Size of stylet: 0.35 mm
One guide wire - push or pull to straighten or bend catheter tip
Problem
Stiff and rigid
Hook dislodges plaque

8. Analyses of Current Designs II
Two guide wire design
Size of catheter: 5 mm
Bending radius: 37* 4
Very flexible
Two guide wires with electrodes
Problem
Large diameter
Reference: US Patent 5,779,669

9. Analyses of Current Designs III
Fluid propulsion design
Size of catheter: 0.5 mm - 3 mm
Balloon tip with portholes on side walls
Problem
Blood flow into portholes
Additional channels limit flexibility
Reference: US Patent 5,817,057

10. Steeratheter Design Maximum diameter size: 1 mm (3 Fringes)
Simple and Flexible
One channel
Design catheter tip
Bernoulli’s Equation

11. Future Work Continue analysis of current design
Continue brainstorming other designs
Observe surgical procedures within the carotid performed by Dr. Larson
Prepare poster presentation

12. References
Berenstein et al. “Fluid Propulsion Steerable Catheter and Method.” United States Patent 5,817,057: October 6,
Cookston et al. “Apparatus and Method for Deflecting a Tip of a Lead or Catheter.” United States Patent 5,824,031: October 20, 1998.
Haissaguerre et al. “Steerable Catheter with Fixed Curve.” United States Patent 5,779,669: July 14, 1998.
Motomiya M and Karino T. “Flow Patterns in the Human Carotid Artery Bifurcation.” Stroke 1984; 15:50.
Turitto VT and Goldsmith HL. “Rheology, Transport, and Thrombosis in the Circulation.” Vascular Medicine. Boston: Little, Brown and Company, 1996;