Spinal Fixation Pivoting Screw Multi-Plane Adjustment

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Solution Overview

Problem

Current spinal fixation systems lack multi-plane adjustment capabilities, limiting their ability to effectively correct spinal injuries and deformities by restricting the pivoting and lateral adjustment of bone screws and spinal rod connectors.

Innovation Solution

A spinal fixation system featuring a pivoting screw assembly with a hinge portion allowing pivotal motion and a nut with locking tabs for securing the screw and connector at desired angular positions, enabling multi-plane adjustment and stabilization of elongated members relative to fixation devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a fixed spinal fixation system is used, then the structural stability is improved, but the adaptability for multi-plane adjustment deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidmulti-plane adjustment capability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent applies the dynamics principle by introducing a pivot assembly that enables the bone screw to rotate and adjust its orientation relative to the spinal rod connector. This dynamic mechanism allows the fixation system to transition from a static, fixed-position design to one that can be adjusted in multiple planes (sagittal, coronal, and transverse planes), thereby achieving multi-plane adaptability while maintaining structural stability through controlled movement and locking capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the spinal fixation system into distinct functional components: a bone screw with pivot assembly, a spinal rod connector, and a locking mechanism. This segmentation allows independent adjustment of the bone screw orientation relative to the connector while maintaining the overall structural integrity of the fixation system, resolving the contradiction between stability and adaptability.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If a multi-axial bone anchor is used, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:
Improveease of positioningVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the pivot assembly, bone screw, and locking mechanism into an integrated unit that attaches to the spinal rod connector. This combination provides multi-axial adjustment capabilities (ease of operation) while consolidating multiple functions into a single device component, thereby managing overall system complexity rather than increasing it proportionally.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bone screw assembly serves multiple functions: it provides structural fixation, enables multi-plane adjustment through pivoting, and allows for locking at desired positions. This multi-functionality achieves ease of operation for positioning while avoiding the need for separate adjustment devices, thus controlling device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If a pivoting screw assembly with locking mechanism is used, then the precision of angular positioning is improved, but the device complexity increases

Engineering Contradiction:
Improveangular positioning precisionVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical adjustment systems with a streamlined pivot assembly that utilizes a simple rotation-and-lock mechanism. This mechanism achieves precise angular positioning through direct mechanical engagement of the bone screw with the connector, avoiding the need for complex gears, cams, or multi-stage adjustment devices, thereby maintaining precision while controlling complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2265201B1Spinal fixation system
Publication Date: 2012.10.03 WARSAW ORTHOPEDIC INC
  • EP2265201B1 patent drawingFigure 1
  • EP2265201B1 patent drawingFigure 2A~2B
  • EP2265201B1 patent drawingFigure 3~3A

AI summary

Embodiments of a spinal implant system include a fixation element, a connector body, and a compression member. The fixation element has a bone engaging portion, a pivoting portion, and a hinge portion. The hinge portion permits pivotal motion of the pivoting portion relative to the bone engaging portion. Additionally, the connector body defines a channel configured for receipt of an elongate member and defines an elongate slot configured for receipt of the pivoting portion of the fixation element. The pivoting portion is positionable in any one of a plurality of positions along the elongate slot. The compression member is adapted to engage the pivoting portion of the fixation element and press against the connector body to lock the pivoting portion at a desired angular position relative to the bone engaging portion and lock the connector body to the fixation element at the desired position along the elongate slot.