Trocar Retainer Assembly With Dynamic Pin Locking for Stapling Stability
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Solution Overview
Problem
Existing surgical stapling instruments face challenges in maintaining the precise positioning and stability of the trocar assembly during the anastomosis procedure, particularly in circular anastomosis and hemorrhoid treatment, which affects the accuracy and effectiveness of tissue stapling and cutting.
Innovation Solution
A trocar retainer assembly with a support member having first and second portions that are attachable, allowing the pin to move between inserted and retracted positions, and a ramp with a tapered edge to cammingly engage the pin head, ensuring the trocar assembly's longitudinal repositionability and stability relative to the elongate shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the trocar assembly is made movable for insertion and removal, then ease of operation is improved, but stability and precise positioning during stapling deteriorate
Solution Approach 1:
The retainer assembly employs a dynamic locking mechanism where the pin can transition between locked and unlocked positions. During insertion, the pin is retracted to allow trocar assembly movement. During stapling, the pin engages with the tapered bore to lock the trocar assembly in place, providing stability when needed while maintaining ease of insertion and removal.
Solution Approach 2:
The retainer assembly acts as an intermediary between the trocar assembly and the elongate shaft. It provides a controlled connection that allows the trocar assembly to be securely held during stapling while enabling easy insertion and removal when the pin is in the unlocked position, thus mediating between the conflicting requirements of stability and ease of operation.
2Reliability
If the pin is permanently fixed in the inserted position, then stability of trocar assembly is improved, but ease of operation for repositioning deteriorates
Solution Approach 1:
The pin is designed to be dynamically positionable rather than permanently fixed. The resilient nature of the pin allows it to be pushed into the inserted position for stability during stapling and retracted to the retracted position when repositioning is needed, thus providing both stability and ease of repositioning through dynamic positioning.
Solution Approach 2:
The resilient pin automatically returns to its retracted position when the force applied to it is removed, enabling easy repositioning of the trocar assembly without requiring additional mechanisms. The pin's elasticity provides self-service by automatically resetting to allow trocar repositioning after each stapling operation.
3Ease of operation
If the pin is made resilient to allow movement, then ease of operation for repositioning is improved, but manufacturing precision and structural integrity deteriorate
Solution Approach 1:
The patent replaces complex mechanical positioning systems with a simpler resilient pin mechanism. The pin's elasticity provides the necessary movement capability while tapered surfaces and engagement features ensure precise positioning. This substitution of a complex mechanical system with a resilient element simplifies manufacturing while maintaining positioning precision.
Solution Approach 2:
The pin's material properties are selected to provide optimal resilience, balancing ease of movement with positioning precision. By carefully controlling the elastic properties, dimensional tolerances, and geometry of the pin and its engagement surfaces, the design achieves both easy repositioning and precise positioning without compromising manufacturing precision.
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 solution enhances the stability and precision of the trocar assembly, maintaining its axial and radial position during actuation, thereby improving the accuracy and reliability of tissue stapling and cutting processes.
Implementation Method 1
A ramp has a tapered edge and is located in a proximal region of the support member. The ramp is engageable with a head of the pin to maintain the pin in the orifice of the sleeve.
Data Source
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AI summary
An end effector including an elongate shaft with a lumen has an adapter at one end for coupling with a handle assembly of a surgical instrument. A support member has opposed openings defining a passage. The support member is positionable within the lumen. A trocar assembly has a sleeve and a trocar member. The trocar assembly is insertable into the passage. The sleeve includes an orifice extending through a wall of the sleeve. A pin is disposed in the elongate shaft and is slidable in a direction that is transverse to a longitudinal axis of the elongate shaft. The pin is insertable into the orifice for retaining the trocar assembly longitudinally stationary relative to the elongate shaft that defines an inserted position of the pin. The support member includes a proximal ramp that is engageable with a head of the pin to maintain the pin in the orifice of the sleeve.