Lockable Ball-and-Socket Joint for Quick Polyaxial Surgical Retraction
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Solution Overview
Problem
Existing surgical retractor systems face challenges in achieving polyaxial adjustment and locking of tissue retracting implements relative to retractor bodies, requiring complex operations and multiple rotations to achieve sufficient locking strength, which can lead to unintended movement during actuation.
Innovation Solution
A ball-and-socket joint assembly with a compression member and actuator shaft that allows for quick coupling and decoupling, provisional locking, and selective locking with minimal movement, utilizing a collet and spring mechanism to provide frictional resistance without the need for screw actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screw mechanism is used to lock the expandable element in the socket, then locking strength is achieved, but operational complexity increases and multiple rotations are required
Solution Approach 1:
The patent removes the screw mechanism entirely from the locking system. Instead of using a threaded engagement system, the invention employs a simple expandable element that locks by expanding to contact the socket walls directly, eliminating the complex screw actuation system while maintaining locking strength.
Solution Approach 2:
Instead of using a screw to push the expandable element outward through threading, the invention inverts the mechanism by having the expandable element expand radially outward through frictional engagement or direct contact with the socket walls, reversing the traditional linear-to-radial force conversion approach.
2Strength
If a screw mechanism is used to achieve locking, then locking strength is achieved, but the number of operations required increases
Solution Approach 1:
The patent segments the locking function from the actuation mechanism. The expandable element is designed to provide locking strength through its expanded state contacting the socket, while the actuation method (friction or direct expansion) requires minimal rotational input, separating the locking function from complex multi-rotation actuation.
Solution Approach 2:
The invention allows the expandable element to skip the intermediate steps of multiple screw rotations by using a direct expansion mechanism that achieves locking strength through frictional engagement or wall contact, reducing the actuation process to a single quick motion.
3Ease of operation
If the actuating screw is coupled to the tissue retracting implement, then actuation is achieved, but unintended movement of the implement occurs during actuation
Solution Approach 1:
The patent extracts the actuation mechanism from the tissue retracting implement itself. The expandable element is actuated independently through friction or direct expansion within the socket, separating the actuation function from the implement to prevent unintended movement during the locking process.
4Adaptability or versatility
If a modular retractor system with polyaxial adjustment is used, then versatility is improved, but device complexity increases
Solution Approach 1:
The patent creates a universal socket interface that can accommodate various expandable elements with different polyaxial adjustment capabilities. The basic socket and expandable element design serves multiple functions: providing structural support, enabling polyaxial adjustment, and achieving locking strength, thereby reducing overall system complexity while maintaining versatility.
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 easy assembly and disassembly of surgical instruments, providing improved polyaxial restraint and locking with reduced operational complexity and movement, allowing for efficient tissue manipulation during surgical procedures.
Implementation Method 1
the outer surface of the collet is compressed against the opening of the cavity... such that the spherical portion is compressed between the outer surface of the collet and the opening of the cavity
Implementation Method 2
the spring is configured to urge the collet against the distal opening and impart a drag force on the spherical portion for resisting polyaxial movement of the spherical portion about the collet
Data Source
AI summary
A ball and socket joint assembly is disclosed that includes a body defining a cavity, a collet disposed in the cavity to receive a ball of a connector, and an actuator shaft coupled to the collet for rotating and translating the collet in the cavity. The cavity has a distal opening to accept the ball and an engagement feature extending into the cavity. The collet has an outer diameter larger than the opening in the body when the ball is disposed in the collet, and the collet has a corresponding engagement feature around at least a portion of the outer surface for receiving the engagement feature and converting rotation of the compression member into translation of the compression member along a proximal-distal axis of the body. The collet is compressed against the opening of the cavity when the collet is advanced distally against the opening.