Cross-linked Hydrogels for Disc Repair via Fine-Needle Injection
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Solution Overview
Problem
Current hydrogel technologies for repairing or supplementing the nucleus pulposus of intervertebral discs require high temperatures and large gauge needles, leading to patient discomfort and potential expulsion of the implant, with few minimally invasive techniques available to restore the disc's mechanical properties.
Innovation Solution
Development of hydrogels suitable for safe injection through fine gauge needles (17-gauge or smaller) at a temperature of about 65°C, using a mixture of polyvinyl alcohol, polyvinylpyrrolidone, and polyethylene glycol, which provide a mechanical modulus of 0.1 to 5.0 MPa, allowing for effective tissue implantation without causing substantial tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pre-heated hydrogels are injected through large gauge needles, then the hydrogel can be injected, but severe patient discomfort and potential implant expulsion occur
Solution Approach 1:
The patent changes the physical parameters of the hydrogel by adjusting its viscosity and gelation characteristics. The hydrogel is formulated to remain injectable at lower temperatures without requiring pre-heating, thereby enabling injection through fine gauge needles while avoiding tissue damage and implant expulsion
Solution Approach 2:
The patent uses composite hydrogel formulations combining multiple polymers (polyvinyl alcohol, polyvinylpyrrolidone, and polyethylene glycol) to achieve the desired balance between injectability and mechanical properties. This composite approach allows the hydrogel to be injected through fine needles while maintaining sufficient structural integrity
2Object-affected harmful factors
If hydrogels are injected through fine gauge needles, then patient discomfort and implant expulsion are reduced, but the hydrogel must provide sufficient mechanical properties to support the intervertebral disc
Solution Approach 1:
The patent optimizes the gelation kinetics and mechanical properties of the hydrogel to ensure that upon injection through fine gauge needles, the hydrogel rapidly forms a stable gel structure with sufficient mechanical modulus (0.1 to 5.0 MPa) to support the intervertebral disc
Solution Approach 2:
The composite polymer system enables the hydrogel to achieve both injectability through fine needles and adequate mechanical strength. The combination of polymers provides synergistic effects that enhance both flow characteristics during injection and structural properties after implantation
3Ease of operation
If high temperature is used for hydrogel injection, then injection is possible, but substantial tissue damage occurs
Solution Approach 1:
The patent fundamentally changes the temperature parameter for hydrogel injection, formulating the hydrogel to be injectable at lower temperatures (without requiring pre-heating to high temperatures). This eliminates thermal damage to surrounding tissues while maintaining injection capability through fine gauge needles
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 hydrogels enable safe and effective injection and implantation in the nucleus pulposus, providing the necessary mechanical properties to support the intervertebral disc, reducing pain and preventing further deterioration, while minimizing patient discomfort and implant expulsion.
Implementation Method 1
hydrogels that are flowable when heated above their melting temperature and that provide an elastic solid at physiological temperature
Implementation Method 2
hydrogels that are flowable when heated above their melting temperature
Data Source
AI summary
The present disclosure relates to hydrogels and their use for repairing or supplementing body tissue. The hydrogels are capable of safe injection into patients through fine gauge needles and are suitable for repairing or supplementing the nucleus pulposus of an intervertebral disc. Methods of manufacturing and methods of using the hydrogels of the present disclosure to repair or replace tissues are also disclosed.