Modular Double-Rod Spinal Stabilization System
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Solution Overview
Problem
Existing bone stabilization devices for vertebrae lack the ability to dynamically adjust elastic properties and provide a compact, stable design for effective dynamic stabilization.
Innovation Solution
A modular double-rod system with polyaxial bone screws and adjustable rods, incorporating spring elements and rod connectors to enhance stiffness and flexibility, allowing for variable elastic properties and improved stability under bending and torsional loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single rigid rod is used to connect bone anchoring elements, then structural strength is provided, but the device lacks dynamic adjustment capability and has high profile height
Solution Approach 1:
The single rod is divided into two separate rods that can independently connect to the bone anchoring elements. This segmentation allows each rod to be optimized for specific functions (one rigid for strength, one elastic for dynamic adjustment) while reducing the overall profile height of the device assembly.
Solution Approach 2:
The device transitions from a purely rigid rod to a hybrid system incorporating both rigid and elastic rods. The elastic rod introduces dynamic adjustment capability through its ability to deform and return, allowing the device to adapt to physiological movements and loading conditions.
2Stability of the object's composition
If a single large-diameter rod is used, then bending and torsional stability is achieved, but the device complexity and profile height increase
Solution Approach 1:
The stabilization function is segmented between two rods of smaller diameter rather than one large-diameter rod. This reduces the profile height and simplifies manufacturing while maintaining stability through the combined action of rigid and elastic components.
Solution Approach 2:
The system uses composite construction with rigid rod (metal) providing bending stability and elastic rod (elastomer or polymer) providing torsional stability and dynamic adjustment. This composite approach achieves the stability of a large rod while using smaller, less complex components.
3Reliability
If fixed connection is used between rod and bone anchoring element, then translational movement is prevented, but dynamic stabilization capability is lost
Solution Approach 1:
The connection system incorporates both fixed and movable joints. The fixed connection ensures reliable attachment to bone anchoring elements, while the elastic rod introduces controlled movement capability. This allows the system to maintain connection reliability while achieving dynamic stabilization through the elastic deformation of the rod.
Solution Approach 2:
The system allows change in the elastic properties of the rod (through material selection and geometric design) to optimize the balance between connection reliability and dynamic stabilization capability. The elastic rod's stiffness can be tuned to provide appropriate resistance to movement while maintaining secure connection.
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 modular design allows for enhanced stability and adjustable dynamic properties, improving the ability to stabilize vertebrae by optimizing rod material and configuration for specific clinical needs.
Implementation Method 1
An elastic element is inserted between the two bone anchoring elements. The elastic element acts on the bone anchoring elements to exert a force in a direction of the longitudinal axis.
Implementation Method 2
On each rod a spring element is provided and the rods are connected by rod connectors
Data Source
AI summary
A stabilization device for bone parts or vertebrae includes two bone anchoring devices for anchoring in the bone parts or vertebrae. At least one of the bone anchoring devices includes an anchoring element with an anchoring section for anchoring in a bone part or a vertebra and a head, and a receiving part for receiving a stabilization rod. The receiving part has a seat for receiving the head so that the head can pivot with respect to the receiving part. The stabilization device includes a first pressure element which is movable in the receiving part so that it can be pressed onto the head to lock the angular position of the head. The stabilization device includes at least two stabilization rod sections, and at least two guiding channels within the receiving part which have a distance from each other for guiding through the at least two stabilization rod sections so that the rod sections do not touch each other.