Spinal Rod Post-Operative Adjustment Mechanism

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Solution Overview

Problem

Current spinal implants lack the ability to adjust dimensions post-operatively, limiting their adaptability to the natural growth and movement of the spine, which can lead to suboptimal fusion and stability between vertebrae.

Innovation Solution

A spinal implant with a post-operative adjustable dimension feature, utilizing a mechanism such as a rotating sleeve with left- and right-handed threads, connected to pedicle screws, allowing for remote control operation via an electric motor, hydraulic, or pneumatic actuation, to adjust the distance between attachment members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed-dimensional spinal implant is used, then the implant structure is simple and reliable, but it cannot adapt to spinal growth and movement post-operatively

Engineering Contradiction:
Improveadaptability to spinal growthVSAvoidimplant structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spinal implant incorporates a variable dimension rod with a threaded interface and actuating mechanism that allows post-implantation adjustment of the distance between attachment members. The rod can be lengthened or shortened by rotating the actuating mechanism, enabling adaptation to spinal growth and movement while maintaining structural integrity through the threaded connection system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The implant is divided into separable components including first and second attachment members connected by a variable dimension rod. This segmentation allows the rod to be independently adjusted while the attachment members remain anchored to the spine, providing adaptability without compromising the overall structural reliability of the fixation system.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If a post-implantation adjustable mechanism is added, then adaptability to spinal growth is improved, but device complexity increases

Engineering Contradiction:
Improvepost-operative adjustabilityVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The actuating mechanism is designed to be operable by the patient or healthcare provider without requiring surgical intervention. The threaded interface and actuating mechanism can be manually or electrically operated from outside the body, allowing self-adjustment of the rod dimension to accommodate spinal growth while avoiding the complexity of surgical revision procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent describes both manual mechanical actuation through the threaded interface and electrical actuation options. The electrical system replaces complex manual mechanical operations with motorized control, reducing the operational complexity for the user while maintaining precise control over the rod dimension adjustment.

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

3Ease of operation

If an electric motor actuation system is used, then ease of operation is improved, but use of energy increases

Engineering Contradiction:
Improveremote control operationVSAvoidenergy consumption of motor
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent describes hydraulic or pneumatic actuation alternatives to electric motors. These fluid-based systems use pressurized fluid to drive the actuating mechanism, providing easy operation through remote control while consuming less energy than electric motors. The fluid pressure is generated by an external pump or compressed gas system, eliminating the need for continuous electrical power consumption.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Enables precise adjustment of the spinal implant post-surgery, accommodating spinal growth and movement, enhancing fusion stability and adaptability between vertebrae, thereby improving surgical outcomes.

Implementation Method 1

The rotating element has two threads in two different directions, left and right, and two threaded shafts are engaged in these threads

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP2503947B1Spinal rod having a post-operative adjustable dimension
Publication Date: 2016.10.26 SPINE21 LTD
  • EP2503947B1 patent drawingFigure 1
  • EP2503947B1 patent drawingFigure 2
  • EP2503947B1 patent drawingFigure 3~4

AI summary

A spinal implant (200) including first spinal attachment member (201) for attaching to a first spinal portion, second spinal attachment member (202) for attaching to a second spinal portion, and a post- implantation variable dimension rod disposed between the first and second spinal attachment members, which is operable after completing surgery in which said spinal implant was installed into a patient, to cause relative movement between the first and second spinal attachment members.