Surgical Stapling Instrument Anti-Backup Mechanism
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Solution Overview
Problem
Existing surgical staplers face challenges in preventing the end effector from being articulated after tissue closure, which can apply shear forces to the tissue, and require significant force to extend the return spring, leading to premature return of the cutting member.
Innovation Solution
A surgical instrument with a closure system that locks the end effector in place after closure, preventing articulation and featuring a flexible band and reel mechanism to retract the firing member, along with a brake to control movement and prevent unintended retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return spring is used to retract the cutting member, then the cutting member can be retracted after firing, but the force required to extend the spring is significant and can cause premature return
Solution Approach 1:
The system transitions from a static spring-based return mechanism to a dynamic controlled release mechanism. The surgeon can control the timing and speed of firing member retraction through the release mechanism, allowing the system to adapt to different surgical needs and prevent premature return while reducing extension force requirements.
Solution Approach 2:
A release mechanism is introduced as an intermediary between the surgeon's action and the firing member retraction. This intermediary component allows controlled disengagement of the locked position, enabling smooth retraction without requiring significant force to extend a compressed spring and preventing unintended premature return.
2Adaptability or versatility
If the end effector is articulated after jaw closure, then repositioning is possible, but shear force is applied to the captured soft tissue
Solution Approach 1:
The system applies a preliminary locking action that prevents articulation of the end effector after jaw closure. The lockout mechanism is engaged automatically when the jaws are closed, creating a preventive barrier against any articulation movement that could apply shear force to the captured tissue, while still allowing repositioning through the controlled release mechanism if needed.
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 solution ensures that the end effector remains stable during tissue closure, reducing the risk of shear forces and simplifies the operation by reducing the force required to extend the firing member, while maintaining control over its retraction.
Implementation Method 1
a brake configured to engage the flexible band and thereby control movement of the firing member
Implementation Method 2
Previous surgical staplers have included a return spring which retracts the cutting member relative to the staple cartridge
Data Source
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AI summary
A surgical instrument including a firing drive configured to advance a cutting member and/or staple driver within an end effector, and a brake configured to prevent, or at least partially inhibit, the relative movement of the cutting member and/or staple driver. The surgical instrument can further include a firing member operably engaged with the cutting member, for example, a band connected to the firing member, and a reel, where the band can be configured to be wound around the reel. In various embodiments, the brake can be selectively engageable with the reel and/or band to prevent, or limit, the movement of the band. The brake can include a brake surface where relative movement between the band and the brake surface can generate a friction force therebetween which can hold the firing member in position until a sufficient force is applied to the firing member to overcome the friction force.