Low-Profile Surgical Loading Unit With Double Pushers
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Solution Overview
Problem
Existing surgical instruments with loading units are limited by the size and geometry of their pushers, I-beams, actuation sleds, and fasteners, restricting the diameter of the end effectors and loading units, which hinders their versatility, especially in pediatric surgeries and other tissue locations.
Innovation Solution
A surgical instrument with a low-profile loading unit featuring a novel design of pushers, including double pushers with angled camming members and reduced height, allowing for a smaller diameter and increased pusher stroke, enabling the use of larger fasteners and facilitating insertion through smaller openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional pushers, I-beams, and actuation sleds are used in loading units, then the structural integrity and fastener ejection function are maintained, but the diameter of the end effector and loading unit is limited and cannot be reduced
Solution Approach 1:
The pusher is divided into multiple pusher members (first pusher member and second pusher member) that can be independently actuated. Each pusher member has its own cam surface and interacts with separate actuation features on the sled, allowing the system to maintain functional complexity while reducing the overall diameter of the loading unit by distributing components more efficiently in space.
Solution Approach 2:
The patent utilizes the longitudinal dimension along the firing stroke to accommodate multiple pusher members and their actuation mechanisms. By arranging cam surfaces and actuation features along the length of the sled rather than requiring radial space, the design reduces the diameter of the loading unit while maintaining all necessary functions through extended longitudinal positioning.
2Adaptability or versatility
If the diameter of the loading unit is reduced for smaller incisions, then versatility in pediatric surgeries and natural orifices is improved, but the size of fasteners that can be accommodated is limited
Solution Approach 1:
By segmenting the fastener array into multiple rows with individual pusher members for each row, the system can accommodate larger fasteners in a compact configuration. Each pusher member can be optimized to propel fasteners of specific sizes, allowing the loading unit to maintain a small diameter while supporting larger fastener dimensions through efficient spatial arrangement of multiple smaller fastener elements.
Solution Approach 2:
The patent combines multiple fastener rows and their actuation mechanisms into a single integrated loading unit. By merging the actuation system for multiple pusher members into one sled structure with coordinated cam surfaces, the design achieves a compact diameter suitable for small incisions while maintaining the capability to accommodate and deploy larger fasteners through the combined functionality of multiple rows.
3Productivity
If multiple pusher members are used to eject fasteners in multiple rows, then fastener ejection capability is improved, but the height and complexity of the actuation mechanism increase
Solution Approach 1:
The sled is designed as a universal actuation mechanism that serves multiple functions: it contains actuation features for multiple different pusher members, provides structural support for the entire fastener ejection system, and coordinates the firing sequence for multiple rows of fasteners. This multi-functionality allows the system to achieve improved fastener ejection capability without proportionally increasing complexity, as the same sled structure performs multiple roles.
Solution Approach 2:
Each pusher member has a specific cam surface with particular geometric properties optimized for its row, while the sled provides a standardized platform with corresponding actuation features. This local optimization of cam surfaces for specific rows, combined with a universal sled structure, allows the system to achieve high productivity through specialized fastener ejection for each row while managing overall complexity through the standardized sled design.
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 low-profile design enables the instrument to be used in smaller incisions and natural orifices, accommodating larger fasteners and enhancing versatility, particularly suitable for pediatric surgeries and other tissue locations.
Implementation Method 1
at least a portion of the first and second pushers include a camming member configured to contact the actuation sled and be propelled in a distal direction by movement of the actuation sled
Data Source
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AI summary
A loading unit for engagement with a surgical instrument, and including double pushers and double retention cavities. At least one double pusher includes a first body portion having a first upper surface configured to engage a portion of a first fastener, a second body portion having a second upper surface configured to engage a portion of a second fastener, and a bridge interconnecting the first body portion and the second body portion. Each of the first upper surface and the second upper surface defining an acute angle with respect to a longitudinal axis. At least one double retention cavity includes a first retention guiding surface configured to engage a proximal pusher guiding surface of the first body portion of the double pusher retained therein, and a second retention guiding surface configured to engage a distal pusher guiding surface of the first body portion of the double pusher retained therein.