Moldable Polymer Cushion for Bone Implant Contour Matching
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Solution Overview
Problem
Current orthopedic, maxillofacial, and plastic surgery implants often result in a step-off at the bone-implant interface, causing discomfort, friction, and potential ulceration due to their inability to match the contour of the underlying bone, and existing solutions like pre-formed plastic covers fail to provide a secure and effective fit after the implant shape is modified.
Innovation Solution
A bio-compatible, non-absorbable polymer that transitions from a malleable state in vivo to a retained shape, allowing surgeons to custom-fit a cushioning layer between the implant and tissue, reducing friction and irritation, and can be lubricious or impregnated with lubricants for enhanced comfort and ease of removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal implants are used to provide adequate strength, then mechanical strength is improved, but the ability to match bone contour deteriorates causing step-offs
Solution Approach 1:
The implant system is divided into two separate components: a rigid metal implant for structural support and a separate moldable cushion layer for contour matching. This segmentation allows each component to optimize its specific function without compromise.
Solution Approach 2:
The solution uses a composite structure combining metal (for strength) with a moldable polymer material (for contour adaptation). This composite approach allows both mechanical strength and bone contour matching to be achieved simultaneously through material combination.
2Shape
If pre-formed plastic covers are used to reduce step-offs, then bone contour matching is improved, but adaptability after implant modification deteriorates
Solution Approach 1:
The cushion material transitions from a dynamic, moldable state during surgery to a stable, retained shape after implantation. This dynamic property allows the material to be adapted to the specific implant configuration while maintaining its custom fit long-term.
Solution Approach 2:
The material undergoes a parameter change from malleable to shape-retentive, enabling it to be molded to the implant contour during surgery and then maintain that custom shape permanently. This parameter transformation resolves the contradiction between initial adaptability and long-term fit stability.
3Manufacturing precision
If implant shape is modified to fit bone, then bone fragment opposition is improved, but hardware prominence and step-off worsen
Solution Approach 1:
The cushion is applied after implant modification to preliminarily address the step-off issue. By placing the moldable cushion over the modified implant, the prominence problem is resolved without requiring revision of the implant itself or removal of the bone fragment opposition achieved through modification.
4Strength
If metal implants are used, then mechanical strength is improved, but friction with soft tissue worsens causing tendonitis and ulceration
Solution Approach 1:
The moldable cushion acts as an intermediary layer between the metal implant and the surrounding soft tissue. This intermediate layer eliminates direct contact between the friction-causing metal surface and the soft tissue, preventing tendonitis and ulceration while allowing the metal implant to maintain its mechanical strength function.
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 polymer solution effectively minimizes discomfort and the risk of irritation and infection by providing a smooth, custom taper between the implant and bone, reducing friction and allowing for easy removal of the implant when necessary, while maintaining a secure fit and reducing palpable differences with natural tissue.
Implementation Method 1
a bio-compatible, non-absorbable polymer having a first state and a second state. When the polymer is in its first state, the polymer is malleable in vivo so it can be formed into a desired shape
Data Source
AI summary
Custom moldable cushions for covering medical implants fastened to a bone are provided. Such cushions inhibit irritation of the surrounding soft tissue by covering the bone-implant interface and by reducing friction caused by movement of soft tissue adjacent the implant. Such cushions may also be employed to spread and absorb forces reducing patient discomfort and risk of injury and infection associated with such implants.