Segmented Vertebral Stabilization Cord with Variable Filament Stiffness

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Solution Overview

Problem

Current spinal stabilization systems fail to effectively alleviate pain, provide dynamic stability, and restore range of motion in the spinal column, particularly in cases of diseased, degenerated, or damaged facet joints, ligaments, and intervertebral discs.

Innovation Solution

A vertebral stabilization system comprising first, second, and third vertebral anchors secured to vertebrae, with a cord extending between them, featuring different sets of intermingled filaments for varying stiffness and tension characteristics, allowing for customized tensioning to accommodate specific spinal segment pathologies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a uniform cord is used throughout the spinal stabilization system, then the device complexity is reduced, but the ability to provide customized tensioning for different spinal segment pathologies is limited

Engineering Contradiction:
Improvecustomized tensioning capabilityVSAvoidcord structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cord is divided into multiple distinct segments, each with different filament compositions and mechanical properties. This segmentation allows each portion of the cord to be optimized for specific tensioning requirements at different spinal levels, enabling customized treatment for various pathologies without requiring entirely separate cords for each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different segments of the cord are constructed with locally optimized filament properties (material composition, diameter, stiffness) tailored to the specific mechanical demands of each spinal segment being treated. This local quality variation allows the single cord to provide differentiated tensioning characteristics along its length, addressing diverse pathological conditions at different vertebral levels.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If multiple subsets of filaments with different properties are used in the cord, then the tensioning characteristics can be customized for different spinal segments, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvetensioning customizationVSAvoidcord formation process
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The manufacturing process is segmented into distinct phases where different filament subsets are introduced at different stages. This allows each filament subset to be independently prepared and then integrated into the cord structure in a controlled manner, simplifying the overall manufacturing complexity compared to creating a fully heterogeneous cord in a single process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different filament subsets are prepared and pre-organized before being integrated into the final cord structure. This preliminary action allows each filament type to be optimally configured for its intended function before assembly, reducing the complexity of the final integration process and enabling more precise control over the mechanical properties of each cord segment.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the cord allows for a range of motion, then dynamic stability is provided, but the ability to limit excessive motion may be compromised

Engineering Contradiction:
Improverange of motionVSAvoidmotion control precision
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The cord's mechanical parameters (stiffness, elasticity, damping characteristics) are varied along its length through different filament compositions. This parameter variation allows the cord to provide different levels of motion restriction at different spinal levels - more compliant segments allow physiological range of motion while stiffer segments provide greater motion control, achieving both goals simultaneously through spatially varying properties.

Inventive Principle:
Principle #35Parameter changes

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 dynamic stabilization, limits excessive motion, and allows for a range of motion by interacting under compression, shear, and tensile loading, effectively addressing pain and instability issues in the spinal column.

Implementation Method 1

A first length of the cord includes a first set of intermingled filaments, and a second length of the cord includes a second set of intermingled filaments... the first subset of filaments and a third subset of filaments different from the second subset of filaments

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2501309B1Cord for vertebral stabilization system
Publication Date: 2016.11.02 ZIMMER GMBH
  • EP2501309B1 patent drawingFigure 1
  • EP2501309B1 patent drawingFigure 2
  • EP2501309B1 patent drawingFigure 2A

AI summary

A spinal stabilization system (10) including a cord (30) extendable between first (12a), second (12b) and third (12c) vertebral anchors. A first length (LI) of the cord includes a first set of intermingled filaments (33), and a second length (L2) of the cord includes a second set of intermingled filaments (33). The first set of intermingled filaments includes a first subset of filaments (33a) and a second subset of filaments (33b), and the second set of intermingled filaments includes the first subset of filaments (33a) of the first set of intermingled filaments and a third subset of filaments (33c) different from the second subset of filaments of the first set of intermingled filaments. When secured to the first, second and third vertebral anchors, a first portion of the cord may be tensioned a first amount and a second portion of the cord may be tensioned a second amount different from the first amount.