Arthroscopic Suture Cutter Cradle for Untensioned Suture Retention
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Solution Overview
Problem
Conventional suture cutters struggle with effectively capturing and retaining high-strength sutures, especially when they are not tensioned or if tension changes during the cutting process.
Innovation Solution
A suture cutter with a handle, lever, and shaft assembly that includes a biased lever mechanism, a longitudinally movable blade, and a guide assembly with living hinges, allowing for easy loading and retention of tensioned or untensioned sutures, ensuring secure cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional suture cutters are used to cut high-strength sutures, then the cutting function is provided, but the suture cannot be effectively captured and retained, especially when not tensioned or if tension changes
Solution Approach 1:
The device employs a dynamic cradle mechanism that can adapt to different suture states (tensioned or untensioned). The cradle includes a resilient arm that can flex to accommodate suture placement and then springs back to retain the suture securely, providing reliable capture regardless of initial tension state
Solution Approach 2:
The resilient arm acts as an intermediary element between the suture and the cutting blade. It provides a retaining mechanism that holds the suture in place during the cutting process, ensuring the suture remains properly positioned even when not under continuous tension
2Strength
If high-strength suture material is used, then the suture strength increases, but the suture becomes harder to cut
Solution Approach 1:
The device applies preliminary action by first securing the suture in the cradle before cutting. The resilient arm engages with the suture and maintains it in a fixed position, allowing the blade to cut through the suture material more effectively. This preliminary retention step is crucial for cutting high-strength sutures that would otherwise be difficult to sever
Solution Approach 2:
The cutting mechanism is segmented into distinct functional components: the cradle for retention, the resilient arm for securing, and the blade for cutting. This segmentation allows each component to be optimized for its specific function, with the blade designed to cut through high-strength materials once the suture is properly positioned and retained
3Ease of operation
If the suture is not tensioned during cutting, then the handling is easier, but the suture may slip or move during the cutting process
Solution Approach 1:
The resilient arm provides self-service retention by automatically engaging with the suture and maintaining it in place without requiring continuous external tension. The arm's elasticity allows it to flex during placement and then spring back to hold the suture securely, providing position stability while maintaining ease of handling
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 efficiently loads and retains sutures in place, facilitating precise cutting without the need for continuous tension, enhancing suture handling and cutting efficiency.
Implementation Method 1
A resilient arm can flex to accommodate placement of the suture in the cradle and can spring back to retain the suture in place
Implementation Method 2
The pair of opposing members of the guide assembly are coupled together by a pair of living hinges
Data Source
AI summary
A suture cutter that can easily load and retain a tensioned or un-tensioned in place for cutting. The cutter has a handle with a an integral lever and a shaft is coupled to and extending from the handle. A tip has a cutting channel with a cradle for entrapping a suture prior to cutting. A piston in the handle drives a blade pusher to cut the suture in response to movement of the lever. A guide assembly in the body is formed from a pair of members folded together via a living hinge to provide a slot for the head of the piston. The pusher is planar and oriented horizontally within the shaft, while the blade is planar and is oriented vertically at right angles to the pusher. The blade has a tab that is captured by a notch in the pusher to interlock the blade and the pusher.