PVA-PEG Hydrogel for Minimally Invasive Disc Replacement
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Solution Overview
Problem
Current treatments for degenerated intervertebral discs, such as discectomy and spinal fusion, fail to restore healthy physiologic function and prevent further deterioration, and there is a lack of minimally invasive techniques for replacing or supplementing the nucleus pulposus to alleviate chronic back pain.
Innovation Solution
A hydrogel composition comprising poly(vinyl alcohol) and polyethylene glycol, with optional poly(vinyl pyrrolidone), is formulated to have a higher polymer content than the precursor solution, providing improved mechanical properties and osmotic pressure, which is implanted into the intervertebral disc to restore function and prevent further wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional surgical treatments such as discectomy and spinal fusion are performed, then back pain relief may be achieved, but the healthy physiologic function of the disc is not restored and further deterioration is not prevented
Solution Approach 1:
The invention changes the physical and chemical parameters of the implantable composition by incorporating PEG to achieve phase separation and form a hydrogel with specific mechanical properties and osmotic pressure that mimics native nucleus pulposus tissue, thereby restoring disc function while relieving pain
Solution Approach 2:
The invention uses a composite material system comprising PVA and PEG polymers that undergo liquid-liquid phase separation to form a hydrogel composite with dual functionality: mechanical support and osmotic pressure generation, enabling both pain relief and physiological function restoration
2Reliability
If the nucleus pulposus is replaced or supplemented with hydrogel composition, then pain relief and disc function restoration are achieved, but the procedure requires minimally invasive technique development
Solution Approach 1:
The invention exploits the phase transition behavior of PVA-PEG-water systems where the composition transitions from a liquid precursor solution to a solid hydrogel through temperature-induced phase separation, enabling minimally invasive injection followed in situ gelation to restore disc function
Solution Approach 2:
The invention uses PEG as an intermediary substance that mediates the phase separation process and generates osmotic pressure within the hydrogel structure, facilitating both the minimally invasive delivery and the subsequent restoration of physiological disc function
3Strength
If hydrogel composition with higher polymer content is formulated, then mechanical properties and osmotic pressure are improved, but the formulation complexity increases compared to precursor solution
Solution Approach 1:
The invention performs preliminary formulation of the PVA-PEG precursor solution with controlled composition ratios before implantation, allowing the phase transition and hydrogel formation to occur in situ, thereby achieving high mechanical properties without complex pre-processing steps
Solution Approach 2:
The invention utilizes the phase transition of the PVA-PEG-water system to automatically concentrate the polymer content and form the hydrogel structure with enhanced mechanical properties, eliminating the need for complex formulation processes while achieving the desired strength and osmotic pressure
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 composition effectively relieves pain, restores disc function, and prevents further deterioration by providing enhanced mechanical properties and osmotic stability, offering a minimally invasive solution for disc supplementation.
Implementation Method 1
Inemura I.: 'Liquid-Liquid Phase Separation and Gelation in the Poly(vinyl alcohol)-Poly(ethylene glycol)-Water System. Dependence on Molecular Weight of Poly(ethylene glycol)', Polymer Journal, Vol. 18, No. 3, pp 269-272 (1986), discloses phase separation in PVA-PEG-water systems in which a lower phase of PVA-rich particles and a PEG-rich upper phase are formed.
Implementation Method 2
The hydrogel composition may preferably have an osmotic pressure of at least 0.1 MPa.
Implementation Method 3
The hydrogel composition may preferably have a viscosity at 45° C of 0.02 kP to 2.0 kP. The hydrogel composition may preferably have a viscosity at 37° C of at least 0.475 kP.
Data Source
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AI summary
A method of forming and the resulting hydrogel composition comprising poly( vinyl alcohol) at a final concentration of about 20% (w/w) to about 65% (w/w) and polyethylene glycol at a final concentration of about 2% (w/w) to about 20% (w/w), wherein the hydrogel composition has a total polymer content, above about 30% (w/w), higher than the total polymer content of a precursor polymer solution formulated prior to the formulation of the hydrogel composition. The hydrogel composition may further comprise poly( vinyl pyrrolidone) at a final concentration of about 0.10% (w/w) to about 0.75% (w/w).