Flowable Bone Graft Material with Wash-Out Resistance

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Solution Overview

Problem

Current bone graft materials face challenges such as inadequate resorbability, poor porosity, and wash-out resistance, which affect their ability to maintain physical integrity in wet environments and promote optimal bone formation.

Innovation Solution

Development of flowable bone graft materials comprising a porous inorganic composition of calcium phosphate, bioactive glass, and biocompatible polymers like carboxymethyl cellulose, which improves handling properties and maintains physical integrity in wet conditions, allowing for convenient delivery and ideal osteoconductive properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the flowability of the bone graft material is increased to improve injectability, then the ease of operation is improved, but the wash-out resistance decreases

Engineering Contradiction:
ImproveinjectabilityVSAvoidwash-out resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the particle size parameter of calcium phosphate from conventional fine particles (<250 μm) to larger particles (250-850 μm), which inherently improves wash-out resistance. To compensate for reduced flowability, the patent introduces carboxymethyl cellulose as a binding agent and uses controlled hydration to achieve optimal flow properties for injection while maintaining wash-out resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining calcium phosphate particles with carboxymethyl cellulose polymer and bioactive glass. This composite structure allows the material to exhibit both flowability (from the polymer matrix) and wash-out resistance (from the interlocked particle-polymer structure), resolving the contradiction between injectability and structural integrity.

Inventive Principle:
Principle #40Composite materials

2Reliability

If larger particle size calcium phosphate is used to improve wash-out resistance, then the reliability is improved, but the flowability decreases

Engineering Contradiction:
Improvewash-out resistanceVSAvoidflowability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces carboxymethyl cellulose as an intermediary substance that mediates between the large calcium phosphate particles. This polymer acts as a binding agent that connects particles together, creating a cohesive structure that maintains flowability despite the use of larger particles, thereby enabling both wash-out resistance and injectability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent controls the hydration level and polymer concentration parameters to optimize the flow characteristics of the composite material. By adjusting these parameters, the material achieves a balance where large particles provide structural integrity while the hydrated polymer matrix ensures adequate flowability for injection.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If thermoplastic polymers are used to create pliable bone graft materials, then the ease of operation is improved, but the resorbability deteriorates

Engineering Contradiction:
ImprovepliabilityVSAvoidresorbability
Core Design Contradiction:
Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent changes the chemical composition parameter from thermoplastic polymers to carboxymethyl cellulose, a natural polymer with inherent biodegradability. This substitution maintains the pliability needed for handling and injection while ensuring the material can be resorbed by the body, thus resolving the contradiction between operability and resorbability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a biodegradable polymer that is designed to be temporary in the body, serving its function during the healing process and then being naturally resorbed. This approach contrasts with permanent thermoplastic materials, allowing the graft to provide structural support when needed and then disappear as natural bone regenerates.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The flowable bone graft materials exhibit enhanced wash-out resistance and osteoconductive properties, enabling effective bone repair and regeneration while maintaining physical integrity in wet environments, suitable for various clinical applications.

Implementation Method 1

one or more biocompatible polymers comprising carboxymethyl cellulose

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

The role of pore size and porosity in promoting revascularization, healing, and remodeling of bone has been recognized as a critical property for bone grafting materials

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3072538B1Bioactive flowable wash-out resistant bone graft material and method for production thereof
Publication Date: 2019.05.22 ORTHOVITA INC
  • EP3072538B1 patent drawingFigure 1~2
  • EP3072538B1 patent drawingFigure 3
  • EP3072538B1 patent drawingFigure 4

AI summary

The present invention relates to a flowable bone graft material including an inorganic composition comprising calcium phosphate having a particle size of about 100 µm to about 1,000 µm, bioactive glass, and one or more biocompatible polymers comprising carboxymethyl cellulose and a fluid.