Variable-Diameter Self-Retaining Suture for Stronger Tissue Anchoring
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Solution Overview
Problem
Existing self-retaining sutures face issues such as fragile or flexible retainers, inadequate tissue anchoring, insufficient contact between retainers and tissue, breakage during tensioning, and rotation or slippage of retainers, which affect their ability to securely hold tissues in place.
Innovation Solution
The development of self-retaining sutures with a variable-dimension filament that has additional material in retainer regions, allowing for enhanced anchoring and tissue holding capabilities, while maintaining the core cross-section and tensile strength, and utilizing specific configurations and manufacturing methods to form and deploy retainers effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retainers are formed on a uniform cross-section filament, then the suture can be manufactured with consistent dimensions, but the retainers become fragile and the tensile strength is reduced
Solution Approach 1:
The filament is designed with variable cross-section where the retainer region has increased diameter compared to the inter-retainer regions. This local variation in geometry provides additional material at retainer locations to enhance retainer strength and reduce fragility, while maintaining appropriate tensile strength in the inter-retainer regions. The non-uniform cross-section allows different parts of the filament to have optimized properties for their specific functions.
2Reliability
If additional material is added to enhance retainer anchoring, then the tissue holding capability is improved, but the filament diameter increases and may affect deployment
Solution Approach 1:
Instead of uniformly increasing the filament diameter throughout, the invention applies additional material only at specific retainer regions where enhanced anchoring is needed. The inter-retainer regions maintain a smaller, more deployable diameter. This localized material distribution achieves improved tissue anchoring without compromising the ability to deploy the suture through tissue.
3Ease of operation
If the filament cross-section is reduced to improve flexibility, then the suture is easier to deploy, but the retainers become more fragile and may break during tensioning
Solution Approach 1:
The variable cross-section filament design ensures that retainer regions have sufficient material thickness to prevent fragility and breakage, while inter-retainer regions have reduced diameter for flexibility and ease of deployment. This spatial differentiation of cross-sectional dimensions allows the suture to simultaneously achieve both deployability and retainer durability.
4Ease of manufacture
If uniform material distribution is used, then the manufacturing process is simpler, but the retainers have insufficient material for effective anchoring
Solution Approach 1:
The invention employs a variable cross-section filament where the retainer regions have increased material volume compared to uniform distribution. This can be achieved through controlled manufacturing processes such as variable aperture extrusion or selective material deposition, allowing retainers to have sufficient material for effective anchoring while maintaining a relatively straightforward manufacturing approach.
Data Source
AI summary
A self-retaining suture comprises a variable-dimension filament which varies in size and/or shape along the length of the filament. The variation in size and/or shape results in a variation in the distribution of filament material from one region of the filament to the next. The filament has retainers formed in the surface such that the filament can engage and retain tissue. The retainers are formed in a manner that makes use of regions of the filament where additional material is distributed. The resulting self-retaining suture has a greater minimum cross-section than would be created using an equivalent uniform filament. The resulting self-retaining suture consequently has a greater tensile strength. Methods for manufacturing the filament and retainers are also described.