Rotating Locking Collar for Reusable Circular Stapler Loading Units
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Solution Overview
Problem
Conventional circular surgical stapling instruments are typically disposable after a single use due to a fixedly attached cartridge or shell assembly, lacking a simple and cost-effective method for reuse.
Innovation Solution
A loading unit with a locking collar that securely attaches to the distal end of a surgical instrument, allowing for easy attachment and detachment, enabling the reuse of the instrument by using a flexible tab and cam surfaces to lock and unlock the loading unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixedly attached cartridge or shell assembly is used in circular stapling instruments, then the instrument structure is simple and reliable, but the instrument must be disposed of after single use, increasing cost and waste
Solution Approach 1:
The cartridge assembly is separated from the instrument body into two independent parts: a reusable instrument and a disposable loading unit. This segmentation allows the instrument to be reused while the loading unit is discarded after single use, resolving the contradiction between structural simplicity/reliability and reusability.
Solution Approach 2:
The locking collar and locking mechanism are extracted from the instrument body and integrated into the disposable loading unit. This extraction enables the loading unit to be easily attached and detached, facilitating instrument reuse while maintaining simple and reliable instrument structure.
2Adaptability or versatility
If a replaceable cartridge assembly is implemented in circular stapling instruments, then instrument reuse is enabled, but a complex locking mechanism is required to secure the cartridge
Solution Approach 1:
The locking collar is designed with resilient arms that automatically engage with the annular ring grooves when the loading unit is attached to the instrument. The resilient arms provide automatic locking without requiring additional actuators or complex mechanisms, enabling instrument reuse while keeping the locking mechanism simple.
Solution Approach 2:
The manual locking mechanism is replaced with a resilient arm-based automatic locking system. The resilient arms utilize elastic deformation to provide locking force, eliminating the need for screws, clips, or other complex mechanical fastening devices.
3Ease of manufacture
If a simple and inexpensive locking mechanism is used to secure the loading unit, then manufacturing cost is reduced, but the locking reliability may be compromised
Solution Approach 1:
The resilient arms automatically engage with the grooves in the annular ring through elastic deformation, providing reliable locking without requiring precision machining or expensive materials. The self-adjusting nature of the resilient arms ensures consistent locking reliability while keeping manufacturing costs low.
Solution Approach 2:
The locking mechanism utilizes changes in the elastic properties of the resilient arms to achieve reliable locking. By controlling the material composition and geometric dimensions of the resilient arms, the locking force and reliability can be optimized without increasing manufacturing complexity or cost.
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
Enables the reuse of circular stapling instruments by providing a secure and easy-to-use mechanism for attaching and detaching the loading unit, facilitating multiple uses and reducing disposal costs.
Implementation Method 1
The flexible tab is resilient and is positioned to urge the locking collar to the locked configuration
Implementation Method 2
The lock has a longitudinal cam surface and a radial cam surface. The radial cam surface may be positioned to engage the annular ring to move the lock outward in response to rotation of the body of the locking collar
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A loading unit includes a shell assembly and a locking collar. The shell assembly has an annular ring that defines a locking slot and a proximal opening. The proximal opening configured to receive a distal end portion of the surgical instrument. The locking collar is rotatably disposed about the annular ring. The locking collar has a body including a flexible tab that has an inwardly extending lock. The locking collar is moveable about the annular ring between a locked and unlocked configuration. In the locked configuration, the lock passes through the locking slot and into the proximal opening of the annular ring. In the unlocked configuration, the body of the locking collar is rotated about the annular ring from the locked configuration to move the lock from within the proximal opening.