Steerable Endoluminal Catheter with Stiff Distal Segment
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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, limiting their adoption in procedures like carotid and coronary interventions where precise anatomy alignment is crucial.
Innovation Solution
A steerable endoluminal device with a tubular member featuring a stiff portion and a pull wire system, utilizing a combination of polymers and a helical coil-braid structure to maintain a thin wall thickness while enabling deflection, allowing for precise anatomy alignment and reduced procedural time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex steering mechanisms are used to enable device deflection, then the device can conform to patient anatomy, but the catheter wall thickness increases
Solution Approach 1:
The catheter is divided into distinct segments: a stiff proximal section for torque transmission and a compliant distal section for deflection. This segmentation allows the device to maintain structural integrity while enabling controlled bending at the distal end, resolving the contradiction between adaptability and wall thickness.
Solution Approach 2:
Different sections of the catheter have different mechanical properties - the proximal section is stiff for torque transmission while the distal section is compliant for deflection. This local differentiation allows each section to perform its specific function optimally without requiring the entire catheter to have increased wall thickness.
2Adaptability or versatility
If complex steering mechanisms are used to enable device deflection, then the device can be steered, but the device complexity increases
Solution Approach 1:
The complex internal steering mechanisms are removed entirely. Instead, the catheter relies on its inherent compliance and the operator's manual manipulation to achieve deflection. This extraction of unnecessary complexity maintains steering capability while significantly simplifying the device structure.
Solution Approach 2:
The catheter's compliant distal section naturally conforms to the vessel anatomy through its inherent flexibility, eliminating the need for complex active steering mechanisms. The device serves itself by passively adapting to the vascular path while the operator provides directional control.
3Strength
If preformed catheters are used, then the device has structural support, but it scrapes the arterial wall during advancement
Solution Approach 1:
The catheter transitions from a static preformed shape to a dynamic configuration that can adapt during advancement. The compliant distal section flexes and conforms to the vessel wall during insertion, preventing scraping and embolization, while the stiff proximal section maintains structural support for torque transmission.
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 device achieves improved control and safety during vascular interventions by maintaining a thin wall thickness, reducing procedural time, and enhancing patient outcomes through precise anatomy alignment without scraping the arterial wall, while also reducing costs by minimizing the need for larger access vessels.
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 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
Implementation Method 3
utilizing a combination of polymers and a helical coil-braid structure to maintain a thin wall thickness while enabling deflection
Data Source
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.