Spinal Tether Clamping Assembly Self-Locking Mechanism

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Solution Overview

Problem

Existing spinal fixation assemblies often rely on locking teeth or complex mechanisms to secure tethers, which can be cumbersome and may not provide a secure lock without additional steps or components.

Innovation Solution

A spinal fixation assembly featuring a tether devoid of locking teeth, utilizing an inner and outer coupling piece with a first passage that allows the tether to be clamped between the inner and outer surfaces, enabling movement in one direction while locking in place to prevent movement in the opposite direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If locking teeth or complex mechanisms are used to secure tethers, then the tether can be locked in place, but the device complexity increases and the operation becomes cumbersome

Engineering Contradiction:
Improvetether locking securityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the traditional locking teeth from the tether and extracts the locking function to a separate clamping assembly. The clamping assembly includes a clamp that engages with the tether and a locking mechanism that secures the clamp to the rod, separating the tether itself from the complex locking components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system is divided into distinct functional components: the tether (simple engagement element), the clamp (secures tether to rod), and the locking mechanism (prevents clamp removal). This segmentation allows each component to be optimized independently, with the tether remaining simple while the locking function is provided by the clamping assembly.

Inventive Principle:
Principle #1Segmentation

2Reliability

If additional locking features or components are added to secure the tether, then the tether can be locked reliably, but the ease of operation decreases

Engineering Contradiction:
Improvetether locking securityVSAvoidfixation process simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The clamp is pre-configured with engagement features that automatically engage the tether as it is positioned on the rod. The surgeon simply needs to position the clamp and activate the locking mechanism, with the engagement features doing the work of securing the tether automatically.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If a simple tether without locking teeth is used, then the ease of operation improves, but the reliability of tether securing deteriorates

Engineering Contradiction:
Improvetether installation simplicityVSAvoidtether locking security
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The clamp serves as an intermediary component between the simple tether and the locking mechanism. The clamp has engagement features that interface with the tether and locking features that interface with the rod, allowing the tether to remain simple while the clamp provides the necessary securing function.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 assembly provides a secure and self-locking mechanism for the tether, eliminating the need for additional locking features and simplifying the fixation process, while maintaining stability and preventing unwanted loosening.

Implementation Method 1

the tether can be clamped in between the inner surface and the outer surface so as to allow the tether to move through the first passage in a first direction and lock the tether in place so as to at least substantially prevent the tether from moving through the first passage in a second direction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3917420B1Tether clamping assemblies for spinal fixation
Publication Date: 2025.04.02 ORTHO DEV CORP
  • EP3917420B1 patent drawingFigure 1
  • EP3917420B1 patent drawingFigure 2A
  • EP3917420B1 patent drawingFigure 2B

AI summary

Tether clamping assemblies, such as clamping assemblies used to clamp a tether about a spinal feature to assist in spinal fixation, and related methods and systems. In some embodiments, the assembly may comprise a tether configured to engage a bone or other anatomical feature, an inner coupling piece, and an outer coupling piece. A first passage may be at least partially defined by an inner surface of the outer coupling piece and an outer surface of the inner coupling piece. The first passage may be configured such that the tether can be clamped in between the inner surface and the outer surface to allow the tether to move through the first passage in a first direction and lock the tether in place. The inner and outer surfaces preferably differ in surface roughness to facilitate automatic or self-locking of the tether in the assembly.