Bone Filling Cement Stiffness and Heat Reduction
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Solution Overview
Problem
Current acrylic bone cements used in vertebroplasty and kyphoplasty have mechanical properties that are too stiff for spongy bone, leading to increased risk of fractures in adjacent vertebrae and excessive heat generation during polymerization, which can cause tissue necrosis.
Innovation Solution
A composite bone cement with a matrix of poly(methyl methacrylate) and methyl methacrylate monomer, incorporating calibrated hydrophilic flexible solid particles of gelatin or poly(glycerol sebacate) to reduce stiffness and polymerization temperature, achieving a Young's modulus similar to vertebral spongy bone while maintaining biocompatibility and injectability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional acrylic bone cement is used for vertebroplasty, then the cement provides sufficient mechanical strength and stiffness, but the high stiffness causes fractures in adjacent vertebrae
Solution Approach 1:
The patent changes the mechanical parameters of the cement by incorporating hydrophilic flexible particles, reducing the Young's modulus from typical acrylic cement values (>2000 MPa) to a lower range (100-1500 MPa) that matches spongy bone stiffness, thereby eliminating the stiffness mismatch that causes adjacent fractures
Solution Approach 2:
The patent creates a composite material system combining acrylic cement matrix with hydrophilic flexible particles (gelatin or poly(glycerol sebacate)), where the composite structure provides both the necessary mechanical strength and reduced stiffness to match bone properties
2Strength
If conventional acrylic bone cement is used for vertebroplasty, then the cement provides adequate structural support, but excessive heat is generated during polymerization causing tissue necrosis
Solution Approach 1:
The patent changes the thermal parameters of the polymerization process by incorporating hydrophilic flexible particles that act as heat sinks and thermal regulators, reducing the peak polymerization temperature from excessive levels (>80°C) to a safer range (<60°C), thereby preventing thermal necrosis of surrounding tissues
Solution Approach 2:
The hydrophilic flexible particles serve as intermediary heat-absorbing elements within the cement matrix, absorbing excess polymerization heat and dissipating it, thereby mediating between the exothermic polymerization reaction and the surrounding sensitive bone tissue
3Object-affected harmful factors
If the cement stiffness is reduced to match spongy bone, then adjacent fractures are prevented, but the cement may lack sufficient mechanical strength
Solution Approach 1:
The patent uses composite material design where the acrylic cement matrix provides the base mechanical strength and stiffness, while the incorporated hydrophilic flexible particles provide stress distribution and energy absorption, creating a synergistic effect where the composite as a whole achieves both reduced stiffness (matching bone) and maintained sufficient strength
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 cement exhibits a Young's modulus of less than 1,500 MPa, reduced polymerization temperature, and improved biointegration, reducing the risk of adjacent fractures and tissue damage, while maintaining radiopacity and injectability.
Implementation Method 1
A composite bone cement with a matrix of poly(methyl methacrylate) and methyl methacrylate monomer, incorporating calibrated hydrophilic flexible solid particles of gelatin or poly(glycerol sebacate) to reduce stiffness
Implementation Method 2
reduced polymerization temperature
Data Source
AI summary
The present invention relates to an injectable bone cement for filling bones with mechanical properties equivalent to those of vertebral spongy bone comprising 70 to 99 wt. % of an acrylic polymer combined with an inorganic type radiopaque compound and 1 to 30 wt. % of calibrated hydrophilic flexible solid particles, said calibrated hydrophilic flexible solid particles being chosen from gelatin, poly(glycerol sebacate) or a mixture thereof.A bone cement according to the invention is particularly intended for vertebroplasty, kyphoplasty or cementoplasty.