Bistable Suturing Mechanism for Smooth Needle Penetration and Ejection
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Solution Overview
Problem
Existing suturing devices lack efficient mechanisms for combined motion of effectors that require simultaneous displacement and state switching, particularly in suturing applications where needles need to penetrate and retract smoothly through tissue.
Innovation Solution
A mechanism featuring a bistable effector assembly with a biasing arrangement and a bistable element, allowing displacement and toggling between axial states to manage needle penetration and ejection, utilizing springs for preload forces and tactile feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-state effector mechanism is used, then the device structure is simple, but it cannot achieve both smooth needle penetration and controlled ejection through state switching
Solution Approach 1:
The effector assembly transitions from a static single-state mechanism to a dynamic bistable mechanism that can switch between two stable axial states. This allows the mechanism to adapt its configuration during operation: in a first axial state for smooth needle penetration with effectors aligned, and in a second axial state for controlled needle ejection with effectors in different relative positions. The bistable element enables reliable state switching through tactile feedback without requiring complex control systems.
Solution Approach 2:
The effector assembly is segmented into multiple independent effectors (first effector, second effector, third effector) that can move relative to each other along the axial direction. This segmentation allows each effector to perform specific functions: the first effector holds the needle, the second effector facilitates penetration, and the third effector enables ejection. The biasing arrangement with multiple spring elements provides independent control over each effector's position and movement.
2Ease of operation
If a bistable mechanism with multiple spring elements is implemented, then precise control over needle displacement and ejection is achieved, but the manufacturing complexity increases
Solution Approach 1:
Multiple spring elements (first spring element, second spring element, third spring element) are combined into a single integrated biasing arrangement that controls the relative axial positions of multiple effectors simultaneously. The spring elements work together to provide coordinated biasing forces, ensuring that when the bistable element switches states, all effectors move to their correct positions in a synchronized manner. This merging simplifies the overall control mechanism while maintaining precise positioning capability.
Solution Approach 2:
The biasing arrangement with multiple spring elements is designed to automatically maintain the effectors in their correct relative axial positions during both stable states of the bistable mechanism. The spring elements provide continuous biasing forces that self-adjust to keep the effectors properly positioned without requiring external control systems or complex adjustment mechanisms. The tactile feedback feature allows the operator to intuitively control state transitions without requiring precise force application.
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
Enables precise and reliable suturing operations with enhanced control over needle displacement and ejection, facilitating efficient suturing processes in various medical procedures.
Implementation Method 1
a biasing arrangement including at least a first spring element and a second spring element, the biasing arrangement biasing each of the first and second effectors in a distal direction relative to the bistable element
Data Source
AI summary
A suturing device (10) employs a displaceable bistable mechanism to allow a user to perform successive bidirectional suture passes of a running stitch by successive presses of a single actuation button (14) as the device is rotated. The displaceable bistable mechanism may also be used in other medical and non-medical applications. Also disclosed are aspects of a suture shuttle holder, and a distal shuttle receiver, with retaining structures which generate retaining force profiles optimized for the suturing sequence.