Steerable Introducer Sheath With Pull Wire Deflection
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Solution Overview
Problem
Steerable endoluminal devices face challenges in design and manufacturing due to complex steering mechanisms, which increase catheter wall thickness, require larger access vessels, and elevate costs, while fixed guide catheters lack the necessary control and adaptability for precise anatomical access, leading to potential damage and increased procedural risks.
Innovation Solution
A steerable introducer sheath system with a tubular member featuring a distal deflection portion and a main body portion, utilizing a pull wire mechanism and a combination of polymers and metal braid/coil construction to maintain a thin wall thickness while providing torque transmission and kink resistance, allowing for precise deflection and control within the vasculature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex steering mechanisms are used to enable real-time deflection control, then adaptability and control precision are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the steering function from complex mechanical mechanisms and implements it through a simple pull wire system. The pull wire mechanism removes the need for complex steerable introducers or guide catheters, achieving deflection control through a minimalistic approach that reduces device complexity while maintaining adaptability.
Solution Approach 2:
The patent replaces complex mechanical steering mechanisms with a tension-based pull wire system. Instead of using complex articulation mechanisms or steerable components, the invention uses simple tensile forces applied through pull wires to achieve catheter deflection, significantly reducing mechanical complexity.
2Strength
If thicker catheter walls are used to provide structural support and torque transmission, then strength and torque transmission are improved, but access vessel size requirement increases
Solution Approach 1:
The patent employs composite construction combining polymers with metal braid or coil. This composite structure provides enhanced torque transmission and structural support while maintaining thin wall thickness. The metal reinforcement elements embedded in the polymer matrix enable effective torque transmission without increasing overall catheter diameter, allowing access through smaller vessels.
Solution Approach 2:
The patent applies reinforcement selectively at specific locations and orientations. The metal braid or coil is configured to provide torque transmission primarily, while other regions maintain flexibility. This localized quality approach ensures sufficient strength for torque transmission without uniformly thickening the catheter walls throughout.
3Ease of operation
If pre-formed curved catheters are used to match anatomical pathways, then ease of navigation is improved, but control flexibility and adaptability are reduced
Solution Approach 1:
The patent transforms the catheter from a static pre-formed shape to a dynamic, adjustable configuration. The pull wire mechanism enables real-time modification of the catheter's distal shape, allowing the operator to adapt the catheter curvature to match various anatomical pathways. This dynamic capability provides both navigation ease and shape adaptability.
Solution Approach 2:
The patent incorporates a pre-formed curve in the catheter that provides initial navigation ease, while retaining the capability for real-time adjustment. The pre-formed shape facilitates initial insertion and navigation, and the pull wire system allows subsequent customization to achieve precise positioning and adaptability for different anatomical variations.
4Adaptability or versatility
If multiple device exchanges are performed to achieve proper access, then adaptability to anatomy is improved, but procedural time and risk increase
Solution Approach 1:
The patent creates a universal catheter design that can adapt to multiple anatomical configurations through real-time shaping. The single catheter with pull wire control can be configured to match various anatomical pathways, eliminating the need to exchange between multiple pre-formed catheters. This multi-functionality reduces procedural time while maintaining adaptability.
Solution Approach 2:
The dynamic shaping capability allows a single catheter to replace multiple static catheters with different pre-formed shapes. By enabling real-time curvature adjustment, the invention allows operators to achieve proper anatomical access with one catheter device, reducing the time and risk associated with multiple device exchanges.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables more controlled and safer access to vascular regions with reduced procedural time and costs, minimizing manipulation and risk of arterial wall damage, and supports a wide range of interventional procedures with improved trackability and pushability.
Implementation Method 1
a pull wire extending between the proximal end and the distal end of the tubular member and having first and second ends, the first end being secured to the distal deflection portion to control deflection of the distal deflection portion of the tubular member
Implementation Method 2
the tubular member further including a stiff portion extending along the distal deflection portion, the tubular member comprising polymeric material circumferentially adjacent to the stiff portion, and the stiff portion comprising a material that has an elastic modulus that is greater than the elastic modulus of the polymeric material circumferentially adjacent thereto
Data Source
Figure 1~3C
Figure 3
Figure 3D1~3D2
AI summary
A steerable endoluminal device adapted for delivery into a patient's vasculature. The device includes a tubular member having a distal deflection portion that extends to the distal end and a main body portion that extends from the deflectable portion to the proximal end, the tubular member further including a stiff portion extending along the distal deflection portion, and being formed of polymeric material, which is disposed circumferentially adjacent to the stiff portion. The stiff portion is made of a material that has an elastic modulus greater than the elastic modulus of the polymeric material. A pull wire extends between the proximal end and the distal end of the tubular member and is attached to the distal deflection portion to control deflection of the distal deflection portion of the tubular member.