Resorbable Nonwoven Implant Pouches for Tissue Ingrowth
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Solution Overview
Problem
Existing pouches for implantable medical devices are complex to manufacture, can trap bacteria leading to post-operative infections, and require additional coating steps for bioactive agents, necessitating multiple manufacturing steps and permanent polymer removal post-implantation.
Innovation Solution
Resorbable nonwoven pouches are produced in a single step without multifilament fibers, incorporating bioactive agents directly into the nonwoven structure, allowing tissue ingrowth and eliminating the need for polymer coatings, with tailored porosity and surface roughness for secure fit and infection prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If knitted or woven multifilament fibers are used to make pouches, then the pouches can be manufactured using traditional textile processes, but they trap bacteria and result in post-operative infections
Solution Approach 1:
The patent employs a nonwoven monofilament structure with controlled porosity that allows tissue ingrowth while preventing bacterial entrapment. The porous architecture enables fluid and cellular penetration without creating the interwoven spaces in knitted or woven fabrics that harbor bacteria, thus resolving the contradiction between manufacturability and infection prevention.
Solution Approach 2:
The invention extracts and eliminates the problematic multifilament construction from the pouch design, replacing it with a monofilament nonwoven structure. This extraction of the harmful multifilament component while retaining the functional benefits of a textile-like material solves the contradiction by removing the bacterial trapping mechanism while preserving ease of manufacture through established nonwoven processes.
2Strength
If pouches are made from permanent polymer materials, then they provide structural support and secure fit, but they require surgical removal when the implantable device needs to be accessed or replaced
Solution Approach 1:
The patent transforms the static, permanent nature of traditional polymer pouches into a dynamic, time-dependent system. The pouch begins with sufficient mechanical strength to secure the device during implantation and healing, then progressively degrades and is replaced by tissue over time. This dynamic transition from synthetic support to biological integration eliminates the need for surgical removal while maintaining structural integrity when needed.
Solution Approach 2:
The invention utilizes changes in material parameters over time - specifically, the degradation of polymer molecular weight and mechanical properties as a function of time in the physiological environment. The pouch maintains adequate strength parameters during the critical healing period, then gradually loses strength as it is resorbed and replaced by tissue, thereby providing structural support when needed while enabling easy access when required.
3Object-affected harmful factors
If pouches are coated with polymer coatings containing bioactive agents, then infection prevention is improved, but the manufacturing process becomes more complex and requires additional coating steps
Solution Approach 1:
The patent merges the bioactive agent incorporation step with the primary pouch manufacturing process. Instead of separately coating the pouch with bioactive agents after fabrication, the antimicrobial agents are integrated into the nonwoven structure during the forming process itself. This consolidation of steps reduces manufacturing complexity while maintaining effective infection prevention through sustained release of bioactive agents.
Solution Approach 2:
The invention performs the bioactive agent incorporation action preliminarily, during the pouch formation process rather than as a subsequent coating step. By pre-incorporating antimicrobial agents into the nonwoven structure during manufacturing, the pouch is prepared with infection-preventing capabilities built-in before implantation, eliminating the need for separate post-fabrication coating operations and reducing overall manufacturing complexity.
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 nonwoven pouches provide a secure fit, reduce infection risk, and degrade naturally, eliminating the need for surgical removal, while eluting bioactive agents to prevent infections and promoting tissue integration.
Implementation Method 1
The pouches remodel over time, and are completely replaced by in-growing tissue as the pouches degrade
Implementation Method 2
Resorbable nonwoven pouches... degrade naturally, eliminating the need for surgical removal
Implementation Method 3
the pouches are preferably porous and permit tissue in-growth
Implementation Method 4
permit tissue in-growth
Implementation Method 5
eluting bioactive agents to prevent infections
Implementation Method 6
incorporating one or more bioactive agents in the nonwoven structure of the pouch as it is formed
Data Source
AI summary
Nonwoven resorbable pouches that at least partially enclose implantable medical devices and improved methods for producing the implantable medical device pouches are described. The nonwoven pouches may comprise one or more drugs. Implantable medical devices that are placed in the pouches prior to implantation are prevented from migrating from the site of implantation by tissue ingrowth into the pouch. Antibiotics may be incorporated into the pouches to prevent post-operative infections. The pouches may be formed in fewer steps than conventional pouches, and without polymer coatings. Nonwoven pouches can be formed in one step by dry spinning instead of using multiple processing steps. In embodiments, the nonwoven pouches are smoother on the inside than the outside to tightly fit the implantable medical devices internally while encouraging external tissue ingrowth. In embodiments, the nonwoven pouches eliminate the use of knitted or woven multifilament fibers that can trap bacteria and result in post-operative infection.