Methacrylated CMC-MC Hydrogel for Disc Height Restoration
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Solution Overview
Problem
Current treatments for intervertebral disc degeneration, such as discectomy and spinal fusion, fail to restore disc biomechanical function and are associated with high recurrence rates and complications, while existing nucleus pulposus replacements do not effectively polymerize in situ or conform to the disc's geometry, leading to extrusion and fatigue issues.
Innovation Solution
An injectable hydrogel composed of methacrylated carboxymethylcellulose (CMC) and methylcellulose (MC) that gels in situ at body temperature, providing a stable polymerization and conforming to the disc's geometry, thereby preventing extrusion and restoring disc height and biomechanics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If acellular biomaterials are used as NP replacements, then disc height is maintained and loads are redistributed, but material extrusion through the annulus occurs and fatigue failure develops
Solution Approach 1:
The patent changes the physical-chemical parameters of the hydrogel by incorporating double bond functional groups that enable covalent crosslinking with the annulus fibrosus. This transforms the material from a non-bonding state to a chemically bonded state, preventing extrusion and fatigue failure while maintaining disc height
Solution Approach 2:
The patent creates a composite material system where the hydrogel contains double bond functional groups that chemically bond with collagen in the annulus fibrosus. This composite structure integrates the NP replacement with the surrounding tissue, eliminating material extrusion and fatigue failure
2Manufacturing precision
If redox crosslinking is used to enable injectable CMC hydrogel, then polymerization is improved, but extravasation of polymer solution occurs and limited polymerization results
Solution Approach 1:
The patent changes the chemical parameters by incorporating double bond functional groups into the CMC hydrogel structure, enabling covalent crosslinking that prevents polymer solution extravasation and ensures complete polymerization within the disc space
Solution Approach 2:
The patent replaces the mechanical confinement approach with chemical bonding mechanisms. The double bond functional groups create covalent bonds with the annulus fibrosus, substituting physical containment with chemical attachment to prevent polymer solution leakage
3Object-affected harmful factors
If discectomy is performed to relieve pain, then immediate pain relief is achieved, but disc biomechanical function is lost and recurrence rate increases
Solution Approach 1:
The patent enables the disc to self-repair by providing a hydrogel formulation that spontaneously crosslinks in situ at physiological temperature. The double bond functional groups allow the material to self-bond with the annulus fibrosus, restoring disc biomechanics without requiring surgical intervention or external fixation
Solution Approach 2:
The patent changes the physical state of the NP replacement material to match native NP properties. The hydrogel formulation replicates the viscoelastic characteristics and hydration levels of healthy nucleus pulposus, restoring disc biomechanical function while providing pain relief
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 hydrogel effectively restores disc height and biomechanical properties, including neutral zone stiffness and range of motion, without herniation or extrusion, and supports cell encapsulation, offering a renewable and cost-effective alternative to synthetic polymers.
Implementation Method 1
wherein the patient has a body temperature of at least 33° C.; and permitting the composition of matter to undergo thermal gelation at the body temperature of the patient, thereby forming a hydrogel between the first bone and the second bone
Data Source
AI summary
An injectable carboxymethylcellulose (CMC) and methylcellulose (MC) hydrogel derived from the plant-based polysaccharide, cellulose, is provided which gels in situ and repairs the intervertebral disc in the spinal column or other cartilaginous tissues. One specific application is for replacement of the nucleus pulposus (NP), the central gelatinous region of the intervertebral disc, following injury or degeneration.