Dynamic Cervical Plate Ratchet Compression
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Solution Overview
Problem
Existing spinal plate systems for cervical stabilization lack the ability to be dynamically adjusted, locked for compression, and automatically maintain compression post-operatively, especially when used in conjunction with spinal cages for intervertebral spacers.
Innovation Solution
A cervical plate system with an elongated shaft, screw receivers, a locking mechanism, retainer clips, and a ratchet mechanism that allows for manual adjustment and automatic shortening to maintain compression across the intervertebral space, incorporating spinal cages for intervertebral spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed spinal plate is used to stabilize vertebrae, then structural stability is provided, but the ability to accommodate post-operative changes in vertebral alignment is lost
Solution Approach 1:
The spinal plate incorporates a dynamic adjustment mechanism with a ratchet system that allows the plate to be initially set at a specific length for stabilization, then automatically shorten to maintain compression as vertebrae heal and align. This transforms the fixed structure into a dynamically adaptable one that responds to post-operative changes.
Solution Approach 2:
The ratchet mechanism enables the plate to automatically adjust its own length without requiring additional surgical intervention. As the vertebrae heal and the intervertebral space changes, the plate self-adjusts by shortening through the ratchet system to maintain optimal compression force throughout the healing process.
2Strength
If compression force is applied to maintain spinal alignment, then bone fusion is promoted, but the risk of screw backout increases
Solution Approach 1:
A retainer element is introduced as an intermediary component between the compression force and the bone screws. This retainer prevents the screws from backing out by providing a mechanical stop, allowing the compression force to be applied for bone fusion promotion without increasing the risk of screw backout.
Solution Approach 2:
The retainer element is pre-positioned to counteract the potential harmful effect of screw backout before it can occur. By establishing this preventive mechanism in advance, the system allows aggressive compression for fusion while preemptively blocking the failure mode of screw loosening.
3Ease of operation
If the spinal plate length is fixed during surgery, then initial stabilization is achieved, but the ability to maintain compression during healing is lost
Solution Approach 1:
The plate transitions from a fixed length structure to a dynamically adjustable one through the ratchet mechanism. During surgery, the plate is set at the appropriate initial length for stabilization. Over time, as healing progresses and vertebral alignment changes, the plate automatically shortens in discrete increments via the ratchet system to maintain compression force throughout the extended healing period.
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 secure and adjustable spinal stabilization, preventing screw backout and accommodating post-operative changes in vertebral alignment while maintaining compression, facilitating bone growth and fusion.
Implementation Method 1
a ratchet mechanism on the shaft and screw receivers to permit post operative one-way movement shortening the distance between the screw receivers and maintaining compression across the intervertebral space
Implementation Method 2
a locking mechanism that is manually operated simultaneously with the insertion of bone screws into the screw receiver to provide compression across the intervertebral space
Implementation Method 3
a retainer extending over the screw holes to prevent back out of the screws
Data Source
AI summary
Disclosed is a dynamic cervical plate system that may be adjusted to length, locked in place to provide compression, and will automatically shorten its length to maintain compression. The system includes spinal cages coupled to the plate which provide intervertebral spacers for excised discs. The cervical plate system has a flat elongated shaft adapted to span the intervertebral space and has at least two screw receivers spaced along the length of the plate. The screw receivers each have screw holes for accepting the heads of bone screws. The spinal cage is coupled to the plate and interposed between the screw receivers.