Disposable Surgical Loading Unit with Cable Tensioning
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Solution Overview
Problem
Existing electromechanical surgical devices are expensive to manufacture, purchase, and operate, necessitating the development of more economical solutions for surgical apparatus that are cost-effective to produce, store, ship, and use.
Innovation Solution
An electromechanical surgical system featuring a housing with a connecting portion for a shaft assembly, including a rotatable drive member and articulation cables, a spur gear mechanism, and a clutch mechanism, which allows for articulation and efficient operation of end effectors with a cable tensioning assembly to maintain tension and prevent slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expensive proprietary drive systems are used in electromechanical surgical devices, then reliability and performance are improved, but manufacturing and operational costs increase
Solution Approach 1:
The device is divided into a reusable handle assembly and a disposable loading unit. The loading unit contains the drive system, end effector, and shaft assembly, which are discarded after a single use. This segmentation allows the expensive proprietary drive system to be contained in a disposable component, reducing the manufacturing cost of the reusable handle assembly while maintaining reliability through proprietary technology in the critical drive components.
Solution Approach 2:
The loading unit is designed as a single-use disposable component that contains the drive system, end effector, and associated mechanisms. After one use, the entire loading unit is discarded rather than sterilized and reused. This approach reduces manufacturing costs for the reusable portions of the device while maintaining high reliability through proprietary engineering in the disposable component, eliminating costs related to sterilization and refurbishment.
2Adaptability or versatility
If complex articulation mechanisms with multiple cables and gears are implemented, then end effector articulation capability is improved, but device complexity increases
Solution Approach 1:
The articulation cables are routed through the shaft assembly and nested within the loading unit structure. The cables pass through guides and channels that are integrated into the shaft and loading unit, creating a compact nested arrangement. This nesting reduces the overall device complexity by organizing multiple cables and mechanical components in a space-efficient manner while maintaining full articulation capability of the end effector.
Solution Approach 2:
The spur gear acts as an intermediary mechanism that converts rotational motion from the drive system into linear motion of the racks, which in turn tensions and releases the articulation cables. This intermediary gear mechanism simplifies the control architecture by providing a single point of mechanical advantage and motion conversion, reducing the complexity of directly controlling multiple cables independently while maintaining precise articulation control.
3Loss of time
If disposable loading units are used instead of reusable components, then sterilization costs and time are reduced, but manufacturing and disposal costs increase
Solution Approach 1:
The loading unit is pre-packaged in sterile condition at the factory before reaching the user. All sterilization processes are completed during manufacturing, and the unit is sealed in sterile packaging that maintains sterility until use. This preliminary action eliminates the need for on-site sterilization processes, reducing time loss in the operating room while the manufacturing cost is offset by eliminating sterilization infrastructure and labor costs at the facility level.
Solution Approach 2:
The loading unit is designed as a single-use disposable component that is discarded after one procedure. This eliminates all sterilization, cleaning, and refurbishment costs and time associated with reusable components. The manufacturing cost is reduced through standardized production processes and the elimination of expensive sterilization infrastructure, while the convenience of immediate sterile readiness provides time savings in the operating room.
4Reliability
If cable tensioning assemblies with screws and biasing members are added, then cable slippage is prevented and articulation reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The biasing member (spring) is integrated into the cable tensioning assembly to automatically maintain cable tension throughout the range of motion. As the end effector articulates and cable lengths change, the spring self-adjusts to maintain optimal tension without requiring external intervention or complex active control systems. This self-service mechanism improves articulation reliability by preventing cable slippage and maintaining consistent force transmission, while adding minimal complexity through a simple spring-loaded 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 system reduces manufacturing and operational costs while maintaining the functionality and efficiency of surgical procedures, providing a cost-effective and convenient solution for end users.
Implementation Method 1
a cable tensioning assembly attached to the spur gear and including a screw and a biasing member between the screw and the clevis
Implementation Method 2
a cable tensioning assembly attached to the spur gear and including a screw and a biasing member between the screw and the clevis
Implementation Method 3
The clutch mechanism can have a plunger member with camming surfaces and a coupling member with camming surfaces
Data Source
AI summary
An electromechanical surgical system having an instrument housing for connecting with a shaft assembly, a shaft assembly, and an end effector. The end effector is an articulating end effector and the system includes a cable tensioning system for tensioning the articulation cables. The system includes a clutch mechanism for preventing slippage of a drive cable.