Bone Resistance Measurement Tool for Osteoporosis Fixation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for assessing the local mechanical resistance within porous bone structures are unreliable and invasive, particularly when trying to determine the quality of fixation elements in areas of varying density or porosity, as they often rely on global data or surface measurements that do not accurately represent the specific insertion site.

Innovation Solution

A device capable of measuring mechanical resistance dynamically by drilling a hole and inserting a tool with blades to measure torsional force and twisting angle, allowing for continuous data recording and comparison to standardized values, which can be stored and processed for accurate prediction of fixation quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If non-invasive methods (microwaves, radiogrammetry, NMR) are used to characterize bone porosity, then patient safety is improved, but measurement precision of local mechanical resistance deteriorates

Engineering Contradiction:
Improvepatient safetyVSAvoidlocal mechanical resistance measurement
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent replaces purely non-invasive physical fields (microwaves, NMR) with a minimally invasive mechanical measurement system that uses a drilled hole and rotational tool to directly measure mechanical resistance, achieving superior local measurement precision while maintaining patient safety through controlled minimal invasion

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

Solution Approach 2:

The patent introduces a drill hole as an intermediary access path that allows the measuring tool to reach hidden internal regions of the bone without requiring extensive surgical exposure, enabling precise local measurement while minimizing overall surgical trauma

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If surface hardness measurement is used to assess bone quality, then measurement simplicity is improved, but measurement precision of local mechanical resistance deteriorates

Engineering Contradiction:
Improvemeasurement simplicityVSAvoidlocal mechanical resistance measurement
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the bone structure into accessible surface regions and hidden internal regions, using the drill hole to access the internal spongiosa layer where fixation elements will actually be placed, allowing separate measurement of surface and internal mechanical properties

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from two-dimensional surface hardness measurement to three-dimensional internal mechanical resistance measurement by drilling through the cortical bone surface into the spongiosa, enabling assessment of the actual insertion site properties

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If static measurement at a specific site is performed, then measurement simplicity is improved, but reliability of fixation quality prediction deteriorates

Engineering Contradiction:
Improvemeasurement simplicityVSAvoidfixation quality prediction
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements dynamic measurement by continuously rotating the tool with blades through the spongiosa and recording mechanical resistance as a function of rotation angle and depth, providing comprehensive characterization of the bone structure rather than a single static value

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent maintains continuous measurement action during tool rotation through the bone, recording mechanical resistance continuously or at multiple discrete angles (e.g., 0°, 90°, 180°, 270°) to capture the anisotropic properties of the spongiosa structure

Inventive Principle:
Principle #20Continuity of useful action

4Device complexity

If measuring instrument tip is not guided during impact measurement, then device complexity is reduced, but measurement precision and reliability deteriorate

Engineering Contradiction:
Improveguidance systemVSAvoidmechanical resistance measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary drilling of a guide hole before insertion of the measuring tool, creating a predetermined path that guides the tool tip to the exact measurement location in the spongiosa, ensuring consistent and repeatable measurements

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pre-drilled hole acts as an intermediary guide structure that directs the measuring tool along a controlled path, eliminating the need for complex real-time guidance systems while ensuring measurement accuracy at the target site

Inventive Principle:
Principle #24Intermediary (Mediator)

5Measurement precision

If high torsional force is applied to measure mechanical resistance, then measurement precision is improved, but bone structure damage increases

Engineering Contradiction:
Improvemechanical resistance measurementVSAvoidbone structure damage
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies partial action by using moderate torsional forces sufficient to rotate the blade through the spongiosa and engage the cortical bone, rather than excessive forces that would cause damage, achieving adequate measurement precision with minimal trauma

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent converts the potentially harmful high torsional force into a beneficial measurement signal by using the resistance encountered during controlled rotation as the measurement parameter, where the force needed to rotate the blade through different bone densities provides direct information about mechanical resistance

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 nondestructive, accurate measurement of local mechanical resistance within porous bone structures, providing reliable data for predicting the quality of fixation elements, especially in osteoporotic bones, with the ability to display results and guide implant placement for improved surgical outcomes.

Implementation Method 1

measuring the torsional force and/or the twisting angle

Methodology Applied
Scientific EffectTorsion: Torque

Implementation Method 2

drilling of a hole through a first part of a porous bone structure

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP1937147B1Method and device for measuring the local mechanical resistance of a porous body
Publication Date: 2014.09.03 AO TECH AG
  • EP1937147B1 patent drawingFigure 1
  • EP1937147B1 patent drawingFigure 2
  • EP1937147B1 patent drawingFigure 3

AI summary

Method and device for determining the local mechanical resistance inside of a porous body having a variable density and/or porosity, e.g. a porous bone the method comprising: selecting a site of said porous body destined to receive a fixation element, in particular a screw or a bone implant; drilling a hole into said porous body; and measuring a mechanical parameter of the porous structure surrounding said drilled hole by inserting a suitable tool (1) into said drill hole. The device comprises : A) a tool (1) with a shank (4) designed such that it is insertable into a hole artificially drilled into said body and that is capable of exerting a torsional force on said porous structure surrounding said drilled hole by inserting said shank (4) of the tool (1 ) into said drill hole; B) a measuring unit (20) determining elastic or destructive properties of said porous body generated by torsion force of said tool in said porous body; C) displaying properties of said porous body determined by said measuring unit (20).