Dynamic Spinal Stabilization Rod with Flexible Section
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current spinal stabilization methods, such as fusion, result in irreversible loss of range of motion and can accelerate degeneration in neighboring segments, failing to provide adequate pain relief and mimicking natural spinal movement.
Innovation Solution
A functionally dynamic spinal stabilization system comprising flexible and rigid couplers with gripping arms and internal range-of-motion limiting mechanisms, allowing for adjustment and mimicking natural spinal movement, while providing segmental stiffness and controlling motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fusion is used to stabilize unstable motion segment units, then mechanical stability is improved, but range of motion is permanently lost and stress is transferred to neighboring segments causing accelerated degeneration
Solution Approach 1:
The stabilization system employs a dynamic rod-shaped implant element with an integral flexible section that allows controlled motion between vertebrae. The flexible section provides dynamic adaptability by permitting physiological range of motion while maintaining mechanical stability, resolving the contradiction between stability and motion preservation through elastic deformation of the rod material.
Solution Approach 2:
The system changes the mechanical parameters of the stabilization apparatus by using a rod element with specific flexibility characteristics. The flexible section of the rod has controlled stiffness that allows it to deform elastically under physiological loads, enabling motion control without permanent fixation, thus maintaining both stability and range of motion.
2Stability of the object's composition
If fusion is used to stabilize the spine, then mechanical stability is improved, but pain relief is inadequate and natural spinal movement is not mimicked
Solution Approach 1:
The dynamic rod element with flexible section mimics natural spinal movement by allowing physiological flexion, extension, and lateral bending. This dynamic motion capability reduces stress concentration and prevents the pain associated with rigid fusion by distributing loads more naturally across the spinal column.
Solution Approach 2:
The flexible section of the rod is designed with specific elastic properties that allow it to deform under physiological loads, changing its shape to accommodate natural spinal motion. This parameter change enables the implant to function more like natural spinal tissue, reducing pain while maintaining stability.
3Stability of the object's composition
If a rigid coupler is used to prevent motion at a spinal segment, then fusion is promoted, but motion control and physiological response are lost
Solution Approach 1:
The rod-shaped implant element transitions from a completely rigid structure to one with an integral flexible section. This flexible portion provides dynamic response to physiological loads while the rigid portions maintain structural integrity and promote fusion at the bone anchor sites, achieving both fusion promotion and physiological adaptability.
Solution Approach 2:
The rod element is segmented into rigid portions and a flexible portion. The rigid sections provide stable anchoring and fusion promotion, while the flexible section between them allows physiological motion. This segmentation resolves the contradiction by distributing different functional requirements to different parts of the implant.
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 effectively stabilizes vertebral segments, allows for adjustment over time, and minimizes tissue damage during implantation, providing pain relief and maintaining near-normal spinal motion.
Implementation Method 1
The flexible coupler may include an internal range-of-motion limiting mechanism configured to limit motion of the flexible coupler in bending, compression, and tension
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4C
AI summary
A functionally dynamic stabilization unit and system for treatment of spinal instability are provided. Each unit, and collectively, the system, is configured to control flexion, extension and translation of the affected unstable vertebral area, thereby stabilizing the vertebral segments by restoring normal function. This is achieved by providing a unit and system that allow for lateral bending, axial compression, rotation, anterior segmental height adjustment, and posterior segmental height adjustment. The unit and system provide sufficient segmental stiffness, while also limiting, or controlling, the range of motion (i.e., sufficient stiffness in the neutral or active zone, while limiting or preventing motion outside of the active zone) to stabilize the vertebral segments. In use, the system mimics the natural movement of the normal spine. Furthermore, the system includes a rigid, fusion-promoting coupler configured for use in an adjacent level, or as a substitute for the functionally dynamic unit. The modularity of the system allows adjustment over time and easier revision surgery, and is configured for minimally-invasive, delivery or implantation.