External Magnetic Adjustment for Implanted Distraction Control

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Solution Overview

Problem

Current treatments for scoliosis, such as braces and fusion surgeries, are ineffective or invasive, and existing distraction osteogenesis methods are cumbersome and painful, posing challenges for patients, especially those with Adolescent Idiopathic Scoliosis and Early Onset Scoliosis.

Innovation Solution

An external adjustment device with permanent magnets and a motor system allows controlled, non-invasive distraction or retraction of implanted distraction devices using handles and buttons, featuring sensors for precise control and user-friendly operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional distraction devices are adjusted through multiple surgeries, then the distraction effect can be achieved, but the patient experiences pain, increased infection risk, and reduced compliance

Engineering Contradiction:

Improvedistraction effectVSAvoidpain and infection risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical adjustment system (surgical exposure and manual adjustment) with a magnetic field-based adjustment system. An external magnet applies magnetic force to rotate the internal magnet, which in turn rotates the screw mechanism to distract the bone, eliminating the need for surgical exposure during adjustment and reducing pain and infection risk.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an internal magnet as an intermediary component that transmits force from the external magnet to the screw mechanism. This internal magnet acts as a mediator that allows remote adjustment of the distraction device without direct mechanical access, enabling painless and infection-free adjustments.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If distraction devices require surgical exposure for adjustment, then precise control is possible, but the procedure becomes invasive and cumbersome

Engineering Contradiction:

Improveadjustment controlVSAvoidadjustment procedure

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the invasive mechanical adjustment procedure with a non-invasive magnetic field-based adjustment system. The external magnet can be positioned and oriented to apply precise magnetic force, enabling accurate control of the distraction device without surgical exposure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables the patient or caregiver to perform adjustments independently without requiring surgical intervention. The external magnet can be applied externally to the skin, allowing the user to control the distraction device themselves, improving ease of operation and reducing reliance on surgical procedures.

Inventive Principle:

Principle #25Self-service

3Reliability

If multiple surgeries are performed for device adjustment, then the distraction effect can be maintained, but the treatment duration and patient burden increase

Engineering Contradiction:

Improvedistraction effect maintenanceVSAvoidtreatment duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces repeated surgical procedures with a non-invasive magnetic adjustment system that can be performed externally and frequently as needed. This eliminates surgical recovery time and allows for continuous maintenance of the distraction effect without the time loss associated with multiple surgeries.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables continuous adjustment of the distraction device through external magnetic application, allowing the distraction effect to be maintained and modified as needed without interruption from surgical procedures. The magnetic field can be applied continuously or periodically to maintain the desired distraction effect.

Inventive Principle:

Principle #20Continuity of useful action

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

Provides a non-invasive, patient-friendly method for adjusting distraction devices, enhancing compliance and reducing the need for multiple surgeries, while minimizing pain and complications.

Implementation Method 1

at least one permanent magnet configured for rotation about an axis in response to magnetic field applied by external magnet

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP4275631B1External adjustment device for distraction device

Publication Date: 2025.10.01 NUVASIVE SPECIALIZED ORTHOPEDICS INC

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AI summary

A controller (700) for magnetically generating rotational motion in a remote device comprises first and second driver magnets (706, 708), each having a first elongate rotational axis, a north pole (902, 908) on a first side of the rotational axis, a south pole (906, 904) on a second side of the rotational axis and a first central magnetic axis (1122, 1120) extending transversely to the rotational axis and through the centers of the north and south poles. A flux reference point (1177) is equidistant from the first drive magnet (706) and the second driver magnet (708). A drive system provides for synchronous rotation of the first and second driver magnets (706, 708) about the first and second rotational axes. At least one of the first and second central magnetic axes (1122, 1120) is oriented at a rotational offset relative to the flux reference point (1177).