Sensor-Integrated External Fixation Strut Length Adjustment

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Solution Overview

Problem

Existing external fixation systems face challenges with manual and cumbersome strut length adjustments, leading to human errors, frame instability, and inaccurate adjustments, particularly due to the complexity of existing programmable tools requiring patient involvement and measurement.

Innovation Solution

An external fixation strut equipped with an integrated sensor that measures its length and communicates directly with a programmable tool via a data port, eliminating the need for external power and simplifying the adjustment process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual adjustment methods are used for external fixation struts, then ease of operation is maintained, but measurement precision and reliability deteriorate due to human errors and frame instability

Engineering Contradiction:
Improvestrut length measurement precisionVSAvoidadjustment operation complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces manual mechanical measurement and adjustment methods with an automated electronic system. A sensor integrated into the strut mechanically measures the strut length and converts it to an electrical signal, which is then processed by a controller to automatically adjust the strut length according to the treatment plan, eliminating manual measurement errors while maintaining operational simplicity through automation.

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

2Extent of automation

If programmable tools with external measurement requirements are used, then automation is improved, but device complexity and ease of operation worsen due to additional user tasks and measurement requirements

Engineering Contradiction:
Improveadjustment process automationVSAvoidtool and measurement system complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent merges the measurement function and adjustment function into a single integrated system. The sensor is built directly into the strut structure, and the controller is integrated with the adjustment mechanism. This combination eliminates the need for separate external measurement tools and manual intervention, achieving full automation while reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The strut system performs self-measurement through the integrated sensor that automatically detects the strut length without external intervention. The controller then automatically executes the adjustment based on the measured data and pre-programmed treatment parameters, enabling the system to serve itself without requiring additional user tasks or external measurement devices.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If integrated sensors and data ports are added to struts, then measurement precision and automation are improved, but manufacturing cost and device complexity increase

Engineering Contradiction:
Improvestrut length measurement precisionVSAvoidstrut manufacturing cost and complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies the sensor and electronic components only at specific locations where measurement data is needed, rather than throughout the entire strut structure. The sensor is positioned at strategic points to detect strut length changes, and the data port is located at the adjustment end, allowing precise measurement while minimizing the amount of expensive electronic materials and manufacturing complexity required.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4389030B1Tool for external fixation strut adjustment, adjustable external fixation strut, and kit comprising said fixator strut and said tool
Publication Date: 2025.07.23 ORTHOFIX SRL
  • EP4389030B1 patent drawingFigure 1~3
  • EP4389030B1 patent drawingFigure 4
  • EP4389030B1 patent drawingFigure 5~6

AI summary

The present disclosure relates to an external fixation strut (200'), comprising: an elongated body (211) comprising at least a first shaft (212) and a second shaft (213) moveable with respect to each other to modify the length of said elongated body (211); at least a sensor (214') integrated in the external fixation strut (200') and adapted to perform at least a measurement which is indicative of the length of the elongated body (211); wherein said sensor (214') communicates with a programmable tool for lengthening/shortening the external fixation strut (200') through a data port which is engageable by said programmable tool.