Rotating Saddle Hook for Spinal Fixation
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Solution Overview
Problem
Existing surgical screws and hooks face challenges in achieving optimal placement and strength due to limited space in the spinal column, requiring trade-offs between flexibility during surgery and post-surgical stability, as multi-axial screws provide ease of manipulation but lower strength, while mono-axial screws offer strength but limited flexibility.
Innovation Solution
A surgical hook apparatus with a rotatable saddle and hook member system that allows 360-degree rotation about a common axis, utilizing balls or a gasket for secure attachment and compression, enabling flexible placement while maintaining strength, and a surgical screw system with a receiver member that allows only rotational movement to secure rods without interference during implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multi-axial pedicle screws are used to facilitate surgical manipulation and placement of rods, then ease of operation is improved, but strength is reduced due to the capacity for movement remaining post-surgery
Solution Approach 1:
The saddle member is rotatably mounted to the hook member, allowing dynamic adjustment during surgery for optimal rod placement while maintaining controlled movement capacity. This rotational capability provides surgical flexibility similar to multi-axial screws but with constrained motion that preserves fixation strength.
Solution Approach 2:
The system changes the degree of freedom parameter from multi-axial rotation to single-axis rotation only, maintaining strength by eliminating unwanted movement directions while preserving the necessary rotational capability for surgical manipulation and optimal rod positioning.
2Strength
If mono-axial screws are employed to achieve greater strength, then strength is improved, but flexibility for manipulation to optimally place rods is reduced
Solution Approach 1:
The rotatable saddle member introduces dynamic adjustment capability to the otherwise fixed mono-axial screw system, enabling surgical manipulation and optimal rod placement while maintaining the strength benefits of constrained motion through controlled single-axis rotation only.
3Strength
If cross-connecting devices are used to provide enhanced torsional rigidity, then strength is improved, but device complexity increases due to additional components and installation requirements
Solution Approach 1:
The rotational capability previously requiring separate cross-connecting devices is integrated directly into the hook-rod interface through the rotatable saddle member, eliminating the need for additional cross-connecting components while maintaining torsional rigidity through the constrained rotational mechanism.
4Strength
If implant rods are placed in optimal manner considering pedicle screw depth, placement and angle, then strength is improved, but the trade-off with space requirements and surgical flexibility persists
Solution Approach 1:
The rotatable saddle member provides dynamic adjustment capability that allows optimal rod placement angles and positions to be achieved without compromising fixation strength, enabling surgeons to navigate space constraints while achieving both optimal placement and strong fixation.
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
Facilitates controlled and secure attachment of surgical implants with enhanced flexibility and strength, allowing for complex geometries and optimal placement without compromising stability, mimicking the adaptability of multi-axial systems while maintaining the strength of mono-axial variants.
Implementation Method 1
A compression member may be provided in engagement with at least one of the hook member and the saddle member to compressively retain the balls in the channel so as to rotatably mount the hook member and saddle member to one another
Implementation Method 2
a gasket, and a channel sized to the gasket may be defined within a cavity in one or more of and between the hook member and saddle member. The gasket may be provided within the channel in sliding engagement with the hook member and the saddle member so as to rotatably mount the hook member and saddle member to one another
Data Source
AI summary
Disclosed herein are a hook with rotating saddle and a rotatable mono axial pedicle screw. In an embodiment, the disclosed hook may include at least one body comprising a hook member and a saddle member. The hook member and saddle member may be rotatably mounted to one another so as to rotate with respect to each other only about a common axis, and the saddle member may be configured for connection to an end of a connecting member. A surgical screw system may include receiver and screw members engagable with one another such that when engaged, only rotation of the receiving member about the longitudinal axis of the screw member and restrain against substantially all other translational or rotational movement.