Expandable Medical Sheath Strain Relief for Lower Push Forces
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Solution Overview
Problem
Existing introducer sheaths require high push forces to advance delivery devices due to strain relief portions that resist expansion, posing challenges in user grip strength and risk of vessel injury during sheath insertion.
Innovation Solution
A sheath system with a continuous inner layer and a tubular strain relief layer that locally expands and contracts in response to outward radial forces, reducing the need for high push forces and minimizing vessel trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a strain relief portion is added to the sheath to ensure hemostasis and smooth transition, then sealing performance is improved, but push force resistance increases
Solution Approach 1:
The strain relief layer is designed to dynamically change its expansion resistance based on the operational phase: during insertion it resists expansion to maintain hemostasis, but during device delivery it allows controlled expansion to reduce push forces. This dynamic behavior resolves the contradiction between maintaining sealing performance and reducing resistance to device advancement.
Solution Approach 2:
The patent changes the physical parameters of the strain relief layer by using a material with specific elastomeric properties that allow controlled expansion. The layer transitions from a constrained state during insertion to an expanded state during device delivery, changing its mechanical parameters to resolve the force resistance issue while maintaining hemostasis.
2Adaptability or versatility
If highly elastomeric materials are used for sheath expansion, then vessel dilation capability is improved, but push force requirements increase
Solution Approach 1:
The sheath is segmented into distinct functional layers: an inner sheath layer and an outer strain relief layer. This segmentation allows each layer to perform its specific function - the inner layer provides structural integrity and the outer layer provides elastomeric expansion - while working together to reduce overall push force requirements during device delivery.
Solution Approach 2:
The patent uses a composite structure combining different materials with complementary properties. The strain relief layer uses highly elastomeric materials that can be controlled to expand at specific moments, providing both vessel dilation capability and reduced push force requirements when properly timed.
3Reliability
If the strain relief portion is made stiffer to maintain hemostasis, then sealing performance is improved, but vessel trauma risk increases
Solution Approach 1:
The strain relief layer dynamically adjusts its stiffness during the procedure. During insertion, it maintains a stiffer, constrained state to ensure hemostasis. During device delivery, it becomes more compliant and allows controlled expansion, reducing the risk of vessel trauma from excessive rigidity.
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 sheath system reduces procedural time, minimizes vessel trauma, and prevents sheath damage by allowing for controlled expansion and contraction, thereby reducing the risk of tears and plaque dislodgement.
Implementation Method 1
the strain relief layer is composed of an elastomeric material and restricts expansion of the inner layer
Implementation Method 2
the inner layer includes at least one folded portion and locally expanding the lumen of the sheath causes a length of the folded portion to at least partially unfold
Data Source
AI summary
Various implementations include a sheath system with a strain relief portion. The system includes sheath for delivering a medical device including a continuous inner layer having a folded portion, an outer layer provided over the inner layer. A tubular strain relief layer is provided over the outer layer and positioned at a proximal end of the sheath and extending along at least a portion of the sheath length, the strain relief layer including a longitudinally extending opening. At least a portion of the sheath is configured to locally expand and locally contract. At least a portion of the strain relief layer is configured to locally expand and then locally contract at least partially back to the unexpanded configuration, and where the width of the opening increases as the strain relief layer moves from the unexpanded to the expanded configuration to form a gap between longitudinally extending edges of the opening.