Spinal Cage Wedge Mechanism for Rotational Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current spinal deformity treatments, such as those for scoliosis, hyperkyphosis, and hyperlordosis, using long fusion rods and pedicle screws, lack effective mechanisms for controlled rotational correction and stabilization of vertebral alignment.
Innovation Solution
A rotatable spinal cage with a uni-directional rotational pivot and a wedge mechanism, featuring a threaded actuator and biasing device, allows controlled tilting or parallel adjustment of spinal attachment members to correct spinal curvature by wedging between adjacent vertebrae, utilizing articulation joints and enhanced bone-interface surfaces for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If long fusion rods and pedicle screws are used to treat spinal deformity, then spinal stability is improved, but the ability to perform controlled rotational correction is lost
Solution Approach 1:
The spinal cage is divided into multiple functional components: first and second spinal attachment members for stability, a wedge element for rotational correction, and a threaded actuator for controlled adjustment. This segmentation allows each component to perform its specific function while working together as an integrated system.
Solution Approach 2:
The articulation joint between the first and second spinal attachment members provides rotational freedom, allowing the structure to be dynamic rather than fixed. This enables controlled rotational correction while maintaining overall spinal stability through the interconnected components.
2Adaptability or versatility
If a threaded actuator and wedge mechanism are added to enable rotational correction, then adaptability is improved, but device complexity increases
Solution Approach 1:
The wedge element serves as an intermediary component that translates the rotational motion of the threaded actuator into the tilting motion of the spinal attachment members. This intermediary mechanism simplifies the overall system by providing a clear mechanical advantage and straightforward force transmission.
Solution Approach 2:
The biasing device automatically applies a biasing force to the wedge element, eliminating the need for additional actuators or complex control systems. The system uses its own internal components to maintain proper positioning and force application, reducing overall device complexity.
3Adaptability or versatility
If the wedge element is made movable for adjustment, then adaptability is improved, but reliability decreases due to potential slippage
Solution Approach 1:
The wedge element features a curved or inclined surface that interfaces with the spinal attachment members. This curvature creates a self-locking effect through geometric locking, where the wedge shape naturally resists slippage while allowing controlled movement during adjustment.
Solution Approach 2:
The patent replaces reliance on friction-based mechanical holding with geometric locking through the wedge shape and articulation joint. This substitution ensures reliability by using the inherent mechanical advantage of the wedge geometry rather than depending solely on friction forces.
4Reliability
If bone-interface surfaces are enhanced for secure attachment, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The enhanced bone-interface surfaces are applied only to specific localized areas of the spinal attachment members that contact the vertebrae. This localized enhancement provides maximum attachment security where needed while minimizing the overall manufacturing complexity and treatment requirements.
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
The spinal cage effectively corrects spinal deformities by maintaining adjusted positions through geometric locking and biasing forces, promoting osseointegration and reducing wedge slippage, thereby facilitating gradual and sustained spinal alignment correction.
Implementation Method 1
The biasing device applies a biasing force on the wedge element to move the wedge element axially
Implementation Method 2
The actuator includes a threaded member attached to the wedge element and a biasing device positioned between at least one of the first and second spinal attachment members and the wedge element
Implementation Method 3
maintaining adjusted positions through geometric locking and biasing forces, promoting osseointegration and reducing wedge slippage
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A spinal cage (10) includes first and second spinal attachment members (12, 14) attachable to vertebrae, the first and second spinal attachment members (12, 14) articulating with one another by means of an articulation joint (11), and a wedge element (20) arranged for wedging between the first and second spinal attachment members (12, 14). An actuator (22) is linked to the wedge element (20) for moving the wedge element (20) axially with respect to the first and second spinal attachment members (12, 14). The actuator includes a threaded member (24) adjacent the wedge element (20). Upon turning of the threaded member (24), the wedge element (20) is advanced with respect to the articulation joint (11) so that the first and second spinal attachment members (12, 14) are tilted or parallel to each other.