Spinal Hook Articulation for Misaligned Curvature Alignment
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Solution Overview
Problem
Existing spinal implant systems face difficulties in inserting hooks under misaligned spinal curvatures and precisely aligning rod receiving portions without distorting or applying undesired forces.
Innovation Solution
A spinal hook design featuring a hook member with an inner collet and outer portion that transitions between locked and unlocked positions, allowing for easy insertion and removal of connecting rods, utilizing a retaining ring and tapered surfaces to secure the rod in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional hooks are used for spinal implantation, then the hooks can be inserted under the lamina, but it is difficult to precisely align the rod receiving portions with misaligned spinal curvatures without distorting or tilting the hooks
Solution Approach 1:
The hook is designed with a articulation mechanism that allows the rod receiving portion to move relative to the blade portion. This dynamic adjustment capability enables the surgeon to align the rod receiving portion precisely with the spinal curvature without forcing or distorting the hook during insertion, thereby resolving the contradiction between alignment precision and ease of operation.
2Measurement precision
If the hook structure is made more complex to facilitate alignment under misaligned curvatures, then alignment precision improves, but the device complexity increases
Solution Approach 1:
The articulation mechanism provides the necessary alignment capability through a single degree of freedom joint, achieving precise alignment under misaligned curvatures without requiring multiple adjustment mechanisms or complex components. This dynamic solution maintains relative structural simplicity while delivering the required alignment precision.
3Reliability
If the inner collet is designed to securely hold the connecting rod, then fixation reliability improves, but the ease of insertion and removal of the rod decreases
Solution Approach 1:
The inner collet is designed with a tapered bore that automatically guides and centers the connecting rod during insertion. The tapered geometry performs the alignment action preliminarily, allowing the rod to be inserted easily while still achieving secure fixation. The same tapered structure allows for controlled removal by applying force in the opposite direction, thus resolving the contradiction between fixation reliability and ease of operation.
Solution Approach 2:
The inner collet utilizes a tapered geometric parameter that transforms the insertion force into radial expansion of the collet, creating a secure grip on the connecting rod. This parameter change allows the same structure to provide both easy insertion (through the tapered guidance) and secure fixation (through the radial expansion grip), while also enabling controlled removal.
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 precise alignment and secure fixation of spinal hooks without distorting or tilting, enabling effective immobilization of vertebral bodies and reducing the complexity of inserting hooks under misaligned curvatures.
Implementation Method 1
The inner collet includes a tapered surface configured to engage an inner surface of the outer portion. The tapered surface may be spaced apart from the inner surface of the outer portion in the unlocked position to facilitate insertion or removal of the connecting rod.
Data Source
AI summary
A spinal hook includes a hook member, an inner collet, and an outer portion. The hook member includes a head portion and a blade portion. The inner collet includes a base portion configured to rotatably engage the head portion and a pair of engaging portions defining a slot configured to receive a connecting rod therein. The outer portion is movable relative to the inner collet between a locked position in which the outer portion causes the pair of engaging portions to move toward each other and an unlocked position in which the outer portion causes the pair of engaging portions to be spread apart to facilitate insertion or removal of the connecting rod.