Spinal Implant Controlling Vertebrae Motion
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Solution Overview
Problem
Current spinal instrumentation techniques, such as facet joint capping and arch replacement, fail to effectively mimic the natural function of facet joints, leading to instability, pain, and further damage due to limited anatomical adaptation and motion restrictions.
Innovation Solution
A spinal implant system comprising movable first and second members that allow for controlled flexion, extension, and lateral bending of adjacent vertebrae while preventing axial rotation, utilizing a connecting element with various configurations to accommodate different anatomies and motion requirements, and a spinal prosthesis with an artificial disc to maintain a predetermined envelope of motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional fusion surgery is performed to relieve pain from damaged facet joints, then pain is relieved, but motion between vertebrae is prevented causing additional stress on adjoining levels
Solution Approach 1:
The implant replaces static fusion with dynamic motion control, allowing controlled flexion, extension, and lateral bending through movable members while preventing harmful axial rotation. The connecting element with elongate slot enables dynamic adaptation to physiological motion patterns.
2Shape
If facet joint capping is performed to preserve bony structure, then anatomical structure is preserved, but the pain source in osteoarthritic joints is not removed and caps loosen over time
Solution Approach 1:
The implant divides the facet joint replacement into separate functional components: first and second members that articulate relative to each other, connected by a connecting element. This segmentation allows independent optimization of each component for stability and motion control.
3Adaptability or versatility
If arch replacement is performed to restore facet joint function, then articulating function is replaced, but aligning two articulating rigid surfaces is very difficult due to anatomical variations and motion requirements
Solution Approach 1:
The connecting element with elongate slot provides dynamic alignment capability, allowing the first and second members to self-align during insertion and adjust to anatomical variations. The slot geometry controls motion while accommodating positioning variations.
Solution Approach 2:
The implant design changes the alignment parameter from requiring precise rigid surface matching to allowing positional adjustment within the elongate slot, transforming a complex alignment problem into a more forgiving insertion procedure.
4Ease of operation
If rigid articulating surfaces are used for facet replacement, then articulating function is provided, but difficulty in aligning surfaces increases due to patient anatomy variations
Solution Approach 1:
The articulating system is segmented into first member, second member, and connecting element components. This segmentation allows the connecting element to serve as an alignment buffer, decoupling the rigid articulating surfaces from direct alignment 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 system provides stable and natural-like spinal motion, reducing the risk of further damage by allowing controlled movement and distributing stress evenly, while preventing excessive rotation, thus addressing the limitations of existing techniques.
Implementation Method 1
The second end can, for example, have a hexagonal shape that is adapted to allow limited rotation of the second end within the elongate slot in the second member, thereby controlling lateral bending of the adjacent vertebrae relative to one another.
Implementation Method 2
the first and second members are slidably movable relative to one another
Data Source
AI summary
Various methods and devices for replacing damaged, injured, diseased, or otherwise unhealthy posterior elements, are provided. In one exemplary embodiment, a posterior implant is provided and can be adapted to control movement of two or more adjacent vertebrae. In particular, the implant can be adapted to control extension, flexion, and lateral bending of adjacent vertebrae. The implant can also be adapted to substantially prevent rotation of the adjacent vertebrae. In another exemplary embodiment, the implant can have an envelope of motion that is within an envelope of motion of a disc, either natural or artificial, that is disposed between adjacent vertebrae. In other words, the implant can be configured to allow flexion, extension, lateral bending of the vertebrae to within the amount of flexion, extension, and lateral bending allowed by the particular disc. The implant can also be adapted to substantially prevent rotation of the vertebrae relative to one another.