Spinal Fixation Holding Device with Internal Locking Mechanism
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Solution Overview
Problem
Conventional spinal fixation holding devices increase the maximum diameter when engaged with spinal fixation tools, leading to a larger range of invasion into the human body during surgery, which increases the surgical burden.
Innovation Solution
A spinal fixation holding device with a cylindrical main body portion and pair of locking pieces that protrude outward from the main body portion, engaging with the head portion and/or rod member, allowing the device to be contained within the outer shape of the spinal fixation tool, preventing protrusion and minimizing the range of invasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional holding device engages with a groove or feature on the outer peripheral surface of the head portion to grip the spinal fixation tool from outside, then the holding device can securely hold the spinal fixation tool, but the maximum diameter of the entire device becomes undesirably larger than the maximum diameter of the spinal fixation tool
Solution Approach 1:
The holding device is designed with a main body portion that fits inside the head portion of the spinal fixation tool, and locking pieces that engage with features within the head portion. This nested configuration allows the holding device to secure the spinal fixation tool while maintaining a compact overall diameter that does not exceed the diameter of the spinal fixation tool itself.
Solution Approach 2:
Instead of gripping the spinal fixation tool from the outside as in conventional designs, this invention inverts the approach by having the holding device engage with the head portion from the inside. The locking pieces protrude inward to engage with engagement features on the inner peripheral surface or rod member, reversing the traditional external gripping method to achieve a more compact profile.
2Area of moving object
If the maximum diameter of the holding device is reduced to fit within the spinal fixation tool dimensions, then the range of invasion into the human body is minimized, but the holding capability and engagement reliability may be compromised
Solution Approach 1:
The holding device employs locking pieces with specific engagement portions designed to engage with corresponding features on the head portion or rod member. The locking pieces have optimized geometries with engagement surfaces, protrusions, and grooves that provide reliable mechanical interlocking within the constrained space, ensuring secure holding capability despite the compact size.
Solution Approach 2:
The locking pieces are designed to engage with pre-formed features on the head portion or rod member before the holding device is fully installed. The engagement portions of the locking pieces interact with engagement features that are already present on the spinal fixation tool, establishing secure connections in advance to ensure reliable holding capability.
Data Source
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AI summary
A holding device includes a cylindrical main body portion having an outer cross-section equal to or less than a cross-section defining the inner wall of an upper portion and a pair of locking pieces protruding outward from the distal end portion of the main body portion in the direction of the central axis along a direction perpendicular to the central axis at the positions of a pair of slots while the main body portion is positioned within the inner wall of the upper portion when viewed from the direction of the central axis. The pair of locking pieces have engagement portions that are engaged with side walls that joins the outer wall and inner wall of the head portion and/or a rod member held in the pair of slots while being positioned within the pair of slots. The pair of locking pieces have such a shape as to be contained within the outer shape of the head portion while being positioned within the pair of slots.