Flexible Endoscopic Stapler With Tension-Gated Staple Ejection
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Solution Overview
Problem
Flexible staplers with suturing mechanisms face issues where staples may unintentionally fall off during use, complicating procedures and increasing time required to remove the stapler from the body for reloading.
Innovation Solution
A medical stapler with a flexible elongated member and a wire system that includes an ejection restriction structure to prevent staple ejection when tension is below a certain threshold, ensuring ease of insertion and reducing staple fallout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is applied to a flexible stapler to prevent staple from unintentionally falling out, then staple retention is improved, but movement of the wire within the flexible member is hindered, reducing ease of insertion into the lumen
Solution Approach 1:
The locking mechanism is designed to dynamically change its state based on wire tension. When tension exceeds the first threshold, the locking part releases to allow staple ejection. When tension is below the threshold, the locking part engages to prevent unintended staple loss. This dynamic behavior resolves the contradiction by adapting the retention strength to the operational state.
Solution Approach 2:
The locking mechanism responds to changes in the physical parameter of wire tension. The first threshold tension value serves as a critical parameter that triggers the transition between locked and unlocked states. This parameter-based control allows the system to maintain reliability during insertion while enabling controlled staple ejection during operation.
2Ease of operation
If the wire path length changes due to the shape of the flexible endoscope, then flexibility and ease of insertion are improved, but pulling force on the wire may cause unintended staple ejection
Solution Approach 1:
The locking mechanism applies a preliminary restraining force on the staple through the locking part, preventing unintended ejection caused by wire tension variations. This preliminary anti-action counteracts the harmful effect of pulling forces that occur when the wire path length changes due to endoscope shaping.
Solution Approach 2:
The system provides mechanical feedback through the locking mechanism that monitors wire tension. When tension exceeds the first threshold, the feedback mechanism triggers staple ejection. This feedback loop ensures that staple ejection only occurs when intentionally initiated by the operator, not due to normal operational tension variations.
3Reliability
If a locking mechanism is added to prevent staple fallout, then staple retention is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is designed as a self-actuating system that automatically engages and disengages based on wire tension without requiring external control mechanisms. The mechanical interaction between the locking part and the wire tension automatically performs the retention and release functions, reducing the need for additional complex control systems.
Data Source
AI summary
A medical stapler is a medical stapler used together with an endoscope and includes a flexible elongated member extending in a length direction of the endoscope, a wire inserted inside the elongated member and movable forward and backward with respect to the elongated member, a suture assembly connected to a distal end of the wire and being able to suture a gripped treatment target with a staple, an operation unit connected to a rear end of the wire and ejecting the staple from the suture assembly by moving the wire forward and backward, and an ejection restriction structure restricting ejection of the staple when a tension applied to the wire is equal to or less than a first tension caused by a change in shape of the elongated member.