MPC-Coated Multifilament Suture Thread for Bendability and Handling
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Solution Overview
Problem
Existing multifilament suture threads coated with a resin layer, such as MPC, suffer from reduced bendability due to friction among ultrafine threads, degrading operability in medical procedures.
Innovation Solution
A medical suture thread design where an inner-filament cover layer of MPC is formed on the outer surface of each ultrafine thread within the multifilament, reducing friction and enhancing bendability, while an outer-filament cover layer is optionally applied to further improve flexibility and operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a resin layer made of MPC is formed on the outer surface of the suture thread to improve slidability and operability, then the ease of operation is improved, but the bendability of the suture thread is reduced due to friction among ultrafine threads
Solution Approach 1:
The patent applies different surface treatments to different locations: the outer-filament cover layer is formed on ultrafine threads at the outer surface of the multifilament, while the inner-filament cover layer is formed on ultrafine threads inside the multifilament. This local differentiation allows the outer surface to have high slidability while the inner threads maintain low friction for bendability.
Solution Approach 2:
The suture thread is segmented into multiple ultrafine threads (6-120 threads) that are assembled into a multifilament structure. This segmentation allows independent treatment of outer and inner threads, enabling the outer threads to be coated for slidability while inner threads remain lightly coated for flexibility and bendability.
2Ease of operation
If the entire suture thread is coated with MPC to enhance ease of tying, then the operability is improved, but the friction among internal ultrafine threads increases, reducing bendability
Solution Approach 1:
The patent implements local quality by forming the inner-filament cover layer with controlled weight (0.01-0.5% per filament) on internal ultrafine threads, which is sufficient to reduce friction and improve ease of tying, while avoiding excessive coating that would increase inter-thread friction and reduce bendability.
Solution Approach 2:
The MPC resin layer acts as an intermediary substance between ultrafine threads. The inner-filament cover layer serves as a thin intermediary coating that reduces friction between threads, enabling easier tying operations while maintaining the flexibility needed for bendability.
3Ease of operation
If a thick resin layer is applied to improve slidability, then the ease of operation is enhanced, but the outer diameter of the suture thread increases, affecting handling characteristics
Solution Approach 1:
The patent applies local quality by differentiating the cover layer thickness and weight between outer and inner ultrafine threads. The outer-filament cover layer provides sufficient slidability with controlled weight (0.01-0.5% per filament), while the inner-filament cover layer uses even lighter weighting to prevent excessive outer diameter increase.
Solution Approach 2:
The patent applies partial action by forming the inner-filament cover layer with a weight within the range of 0.01-0.5% per filament, which is sufficient to reduce friction and improve slidability without being excessive. This partial coating approach achieves the necessary operability enhancement while controlling the outer diameter increase.
Data Source
AI summary
Provided is a medical suture thread as a multifilament, which is formed easily bendable and ensuring favorable operability. The medical suture thread 100 includes a core thread 110 and an outer thread 120. The core thread 110 includes multiple twisted ultrafine threads 111, and is arranged at a center portion of the medical suture thread 100. In the ultrafine thread 111, an inner-filament cover layer 112 made of 2-methacryloyloxyethyl phosphorylcholine (MPC) is formed on an outer surface of a filament 111a. The outer thread 120 is formed to be braided with multiple ultrafine threads 121, and covers an outer surface of the core thread 110. In the ultrafine thread 121, an outer-filament cover layer 122 made of MPC is formed on an outer surface of a filament 121a.