Spinal Fixation Implant with Flexible Rods and Crosslink
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Solution Overview
Problem
Current spinal fixation implants may not be ideal for all situations, particularly in promoting fusion and allowing relative movement of vertebrae, as they lack flexibility and optimal anchoring to spinous processes.
Innovation Solution
A spinal implant design featuring two pairs of mounting plates with teeth for secure attachment to spinous processes, interconnected rods with a lower flexural modulus for flexibility, and a crosslink or elastic band to prevent rod separation, allowing for small vertebral movement and promoting fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid mounting plates are used to securely anchor to spinous processes, then anchoring strength is improved, but flexibility and ability to promote fusion deteriorate
Solution Approach 1:
The implant is divided into distinct components with different mechanical properties: rigid mounting plates for anchoring and flexible rods for motion accommodation. This segmentation allows each component to perform its specific function optimally without compromise.
Solution Approach 2:
Different parts of the implant have different local mechanical properties - the mounting plates are made rigid for strong anchoring to spinous processes, while the rods are made flexible to accommodate vertebral motion and promote fusion. Each component's local quality is optimized for its specific function.
2Stability of the object's composition
If rigid structure is used to provide stable fixation, then stability is improved, but ability to allow relative vertebral movement deteriorates
Solution Approach 1:
The implant transitions from a completely rigid structure to a dynamic system where the flexible rods can bend and deform elastically in response to vertebral motion. This allows the implant to maintain stable fixation while accommodating physiological movement and promoting fusion through controlled micromotion.
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 implant provides stable fixation while allowing for limited vertebral movement, enhancing fusion outcomes by securely anchoring to spinous processes and accommodating natural spinal motion.
Implementation Method 1
a plurality of teeth on a first medial face configured to bite into a spinous process
Implementation Method 2
The first and second rods have a flexural modulus that is less than a flexural modulus of the mounting plates. The rod flexibility allows a small amount of relative movement of the vertebrae, which may be helpful in promoting fusion.
Data Source
AI summary
A spinal implant has two pairs of mounting plates or “staples,” two rods, and a crosslink. Each mounting plate mounts to a lateral side of a spinous process. Each rod interconnects a pair of mounting plates. The crosslink is disposed through the interspinous space and interconnects the rods. The crosslink hinders movement of the rods away from each other. The rods have a flexural modulus less than the mounting plates. The rod flexibility allows a small amount of relative movement of the vertebrae, which may be helpful in promoting fusion.