Surgical End Effector Jaw Stiffness via Nested Asymmetric Design
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Solution Overview
Problem
Prior art surgical end effectors lack sufficient stiffness, leading to inadequate compressive force application during tissue sealing without transection, and are often too wide for minimally invasive procedures.
Innovation Solution
Increasing the height of jaw members to enhance stiffness and surface area for energy delivery while minimizing the overall size of the end effector, achieved by nesting jaw members or using sidewalls to resist deflection and orienting tissue-contacting surfaces transversely for increased energy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the width of jaw members is increased to maximize electrode surface area, then energy delivery capability is improved, but the overall size of the end effector increases making it unsuitable for minimally invasive procedures
Solution Approach 1:
The jaw members are configured to nest within one another when not in use, with the second jaw member positioned inside the first jaw member. This nesting arrangement allows the end effector to maintain a compact overall size suitable for minimally invasive procedures while still providing sufficient electrode surface area when the jaw members are deployed and separated for tissue grasping and sealing.
2Strength
If the height of jaw members is increased to enhance stiffness and resist deflection, then compressive force transmission is improved, but the overall height of the end effector increases
Solution Approach 1:
The jaw members are designed with varying cross-sectional dimensions along their length, with greater height and thickness at the proximal end where stiffness is most needed to resist deflection from closure forces, and reduced dimensions at the distal end where tissue interaction occurs. This local quality variation optimizes the stiffness-to-size ratio, providing sufficient structural strength without excessively increasing the overall end effector height.
3Area of moving object
If symmetrical jaw member design is used to maximize electrode size, then energy delivery surface area is improved, but stiffness and deflection resistance are reduced
Solution Approach 1:
The jaw members are designed with asymmetric cross-sectional dimensions where the height (dimension in the plane of jaw movement) is greater than the width (dimension perpendicular to the movement plane). This asymmetric configuration maximizes the area moment of inertia and stiffness in the critical direction where deflection occurs during closure, while still providing sufficient electrode surface area for energy delivery on the tissue-facing surfaces.
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
This design allows for effective tissue sealing and transection with increased compressive forces and surface area for energy delivery, enabling better tissue welds and seals without the need for larger devices.
Implementation Method 1
increasing a height (measured in the plane defined by the movement of the jaw members) of one or more of the end effector jaw members such that the jaw member possesses an increased area moment of inertia to resist flexing or other deformation
Implementation Method 2
the cutting mechanism can be configured to apply a compressive force to at least one of the jaw members
Implementation Method 3
electrical energy can be applied to the grasped tissue to seal it before tissue transection is completed
Data Source
AI summary
Surgical end effectors with increased stiffness are described herein. Increased stiffness can be accomplished in a variety of manners, including by increasing a height of each jaw member of an end effector. For example, end effector jaw members can include tapered heights that decrease from a proximal end of the jaw member to a distal end thereof. In one embodiment, first and second jaw members can each have a height measured at a proximal end thereof that is greater than half of an overall height of the end effector, while at a distal end thereof a sum of heights of the first and second jaw members can approximately equal the overall height of the end effector. Overlapping or otherwise fitting such jaw members together can create an end effector with greater stiffness that can be used to apply greater compression force to tissue during operation.