Ratcheting Spinal Bone Plate With Sliding Segments
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Solution Overview
Problem
Conventional spinal fixation plates lack adjustability and do not allow for progressive compression of bone grafts between vertebrae, limiting their ability to fuse effectively over time.
Innovation Solution
A bone plate device with sliding, U-shaped spring members and toothed sections that allow for adjustable length during surgery and post-operative incremental shortening to ensure bone graft compression, using male and female plate members with interlocking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional fixed-length spinal plates are used, then the device structure is simple and easy to manufacture, but the device lacks adaptability to different patient needs and cannot provide progressive compression
Solution Approach 1:
The bone plate device is divided into multiple segments including a first bone plate, a second bone plate, and intermediate sections with toothed surfaces. These segments can move relative to each other along the longitudinal axis, allowing the device to adapt to different patient needs while maintaining a relatively simple overall structure. The segmentation enables progressive compression without requiring complete redesign of the entire device.
Solution Approach 2:
The bone plate device transitions from a static fixed-length structure to a dynamic system where the first and second bone plates can slide relative to each other along the longitudinal axis. This dynamic capability allows progressive compression of the bone graft over time while the ratcheting mechanism prevents reverse movement, providing adaptability without excessive complexity.
2Adaptability or versatility
If variable length fixation plates are used during surgery, then the device allows length adjustment, but the overall length is fixed during surgery and does not change post-operatively
Solution Approach 1:
The device allows length adjustment during surgery by sliding the bone plates relative to each other, and maintains this dynamic capability post-operatively through the ratcheting mechanism. The first bone plate can progressively move toward the second bone plate over time, providing continuous compression while preventing reverse movement, thus extending the useful action duration beyond the surgical procedure.
Solution Approach 2:
The ratcheting mechanism ensures continuous compression action by allowing progressive movement in one direction (compression) while preventing reverse movement. This continuous useful action extends from the surgical procedure through the post-operative healing period, maintaining compression on the bone graft throughout the fusion process.
3Force
If conventional fixed length spinal plates are used, then the device structure is simple, but progressive compression of bone graft beyond initial surgical compression is precluded
Solution Approach 1:
The device is pre-configured with toothed surfaces and ratcheting mechanisms during manufacturing, allowing progressive compression to occur automatically post-operatively without requiring additional surgical intervention. The preliminary arrangement of components enables continuous compression force application as the bone graft heals.
Solution Approach 2:
The ratcheting mechanism automatically provides progressive compression through the relative movement of bone plates without requiring external control or adjustment. As the bone graft heals, the device self-adjusts by allowing controlled sliding of plates while preventing reverse movement, maintaining compression force throughout the healing process.
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 adjustable fixation and progressive compression of bone grafts between vertebrae, enhancing fusion by allowing incremental shortening post-operatively while maintaining initial length adjustment during surgery.
Implementation Method 1
a spring member associated with one bone plate members engages toothed sections on the other bone plate member
Data Source
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AI summary
Devices and methods for spinal fixation employ at least first and second plates that are configured to allow progressive sliding advancement of the plate members toward one another and limit movement of the plate members away from one another after installation. A spring member associated with one bone plate may engage toothed section(s) on the other bone plate. The bone plates may each have arms that are spaced from one another and engaged by corresponding arms on the other bone plate. There may be more than two bone plates, with multiple restricted movement regions.