Surgical Stapler Locking Mechanism Prevents Tissue Shear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surgical staplers face challenges in preventing the end effector from being articulated relative to the shaft assembly after tissue closure, which can apply shear forces to the soft tissue, and require significant force to extend the return spring for cutting member advancement, often leading to premature return and multiple trigger strokes.
Innovation Solution
A surgical instrument with a locking mechanism that fixes the relative relationship between the shaft assembly and end effector, preventing articulation after closure, and a flexible band with a brake system to manage the cutting member's movement, reducing the need for excessive force and preventing premature return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the end effector is articulated relative to the shaft assembly after jaw members are closed, then the surgeon can reposition the end effector, but shear force is applied to the soft tissue captured between the jaw members
Solution Approach 1:
The locking mechanism is engaged in advance to prevent articulation of the end effector relative to the shaft assembly after the jaw members are closed, thereby preventing shear force from being applied to the captured soft tissue
2Adaptability or versatility
If a release mechanism is activated to pivot the anvil into an open position for repositioning, then the end effector can be repositioned, but the closure system complexity increases
Solution Approach 1:
The locking mechanism is integrated with the closure system such that the actuator for articulating the end effector is coupled to the closure system, allowing the locking and unlocking functions to be combined with the existing closure mechanism rather than adding a separate complex release mechanism
3Ease of operation
If a return spring is used to retract the cutting member, then the cutting member can be retracted automatically, but significant force is required to extend the return spring during advancement
Solution Approach 1:
The return spring is segmented into multiple coils along the longitudinal axis of the cutting member, distributing the force requirements across multiple sections and reducing the peak force needed during advancement while maintaining automatic retraction capability
4Ease of operation
If the return spring applies biasing force to the cutting member during advancement, then automatic retraction is enabled, but the cutting member may return prematurely especially with multiple trigger strokes
Solution Approach 1:
The return spring is configured with varying coil densities or stiffness characteristics at different sections, providing controlled biasing force that increases progressively during advancement, ensuring the cutting member completes its full stroke without premature return while maintaining smooth operation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A surgical instrument including a shaft assembly and an end effector, where the end effector can be moved relative to the shaft assembly. The shaft assembly can include a lock member selectively engageable with the end effector to limit, or prevent, relative movement therebetween. In at least one embodiment, the end effector can include a lock member having a plurality of teeth and/or a plurality of recesses, where the shaft assembly lock member can engage the teeth and/or recesses to fix the relative position between the end effector and shaft assembly. In various embodiments, the teeth can be positioned between first and second surfaces of the end effector lock member to reduce the possibility that the teeth can impinge on soft tissue surrounding the lock member. In other embodiments, the teeth can be beveled in order to allow the teeth to slide relative to the soft tissue.