Barbed Suture Stop Element Geometry for Holding Strength
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Solution Overview
Problem
Existing barbed sutures face limitations in achieving increased holding strength without significantly increasing insertion force, stiffness, or palpability, and conventional designs like T-shaped stops are structurally weak under bending moments.
Innovation Solution
A barbed suture with a stop element having a length-to-width ratio greater than 4, varying thickness, and minimal leading edge area, which minimizes palpability and allows for flat positioning in the wound, enhancing holding strength through optimized geometric ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surface area of the stop is increased to provide a larger stopping surface perpendicular to the direction of insertion, then holding strength is improved, but the device becomes more palpable and structurally weaker under bending moments
Solution Approach 1:
The stop element is oriented with its length extending substantially parallel to the longitudinal axis of the suture rather than perpendicular, changing the dimensional orientation from a traditional T-shaped cross-section to a longitudinal configuration. This dimensional change allows the stop to provide holding strength through its length-to-thickness ratio while maintaining a low profile that minimizes palpability.
Solution Approach 2:
The invention changes the geometric parameters of the stop element, specifically requiring a length-to-thickness ratio of at least 4:1. This parameter change optimizes the structural integrity under bending moments while controlling the surface area to reduce palpability, resolving the contradiction between strength and harmful effects.
2Reliability
If the size of the stop is increased to enhance holding strength, then reliability is improved, but the insertion force and stiffness of the suture significantly increase
Solution Approach 1:
The stop element is designed with non-uniform thickness, having a maximum thickness and a minimum thickness, creating local variations in structural properties. This local quality optimization allows the stop to provide sufficient holding strength at critical locations while minimizing overall material usage and reducing insertion force requirements.
Solution Approach 2:
By optimizing the length-to-thickness ratio parameter to at least 4:1 and controlling the surface area of the leading edge, the invention achieves reliable holding strength without requiring excessive size, thereby maintaining acceptable insertion force levels.
3Reliability
If a T-shaped stop configuration is used to increase holding strength, then reliability is improved, but structural strength under bending moments deteriorates
Solution Approach 1:
The stop element transitions from a T-shaped configuration with perpendicular orientation to a longitudinal orientation parallel to the suture axis. This dimensional reorientation fundamentally changes the structural behavior under bending moments, allowing the stop to resist bending more effectively while maintaining holding strength.
Solution Approach 2:
The invention specifies a length-to-thickness ratio of at least 4:1 for the stop element, which optimizes the structural geometry to resist bending moments. This parameter change ensures that the stop maintains structural integrity under the bending forces experienced during wound approximation, unlike traditional T-shaped configurations.
Data Source
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AI summary
A wound closure device (100) is provided. The wound closure device (100) comprises: a filamentary element (102) extending along a longitudinal axis between a proximal end (109) and a distal end (106), the filamentary element having a plurality of projections extending outwardly therefrom along at least a portion of its length; a stop element (108) coupled to the distal end of the filamentary element, the stop element having a length extending substantially parallel to the longitudinal axis of the filamentary element, a width extending substantially perpendicular to the longitudinal axis and a maximum thickness. The ratio of the length to the maximum thickness of the stop element is at least 4.