Porous Tissue Ingrowth Scaffold with Interlocking Layer Pores
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Solution Overview
Problem
Medical implants with porous scaffolds for bone and tissue ingrowth often have reduced strength due to weak layer interfaces and high production costs, particularly in shear planes parallel to individual layers.
Innovation Solution
A three-dimensional scaffold with layers bonded together, each having different pore patterns on top and bottom surfaces, with adjacent surfaces aligning to form continuous porosity, enhancing shear strength and allowing for cost-effective manufacturing by reducing strut thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laminate scaffolds are constructed with thin metal layers to reduce cost, then manufacturing cost is reduced, but strength is reduced due to low contact area between adjacent layers
Solution Approach 1:
The invention transitions from a two-dimensional layer stacking approach to a three-dimensional interlocking pore pattern design. By configuring pore patterns in adjacent layers to interlock vertically, the scaffold achieves enhanced strength through increased contact area and mechanical interlocking, while still using thin layers for cost-effectiveness.
Solution Approach 2:
The invention employs asymmetric pore patterns where the pore configuration in one layer is deliberately different from adjacent layers. This asymmetry creates complementary interlocking features that enhance mechanical strength at layer interfaces, resolving the contradiction between using thin layers and maintaining strength.
2Ease of manufacture
If scaffold strut thickness is reduced to enable cost-effective manufacturing, then production cost is reduced, but shear strength in planes parallel to layers is insufficient
Solution Approach 1:
The invention addresses the shear strength issue by extending the load-bearing mechanism from two-dimensional layer planes into the third dimension through vertical pore interlocking. This allows thin struts to achieve adequate shear strength through three-dimensional mechanical interlocking rather than relying solely on increased thickness.
Solution Approach 2:
The scaffold functions as a composite structure where multiple thin layers with complementary pore patterns work together to create a unified load-bearing system. The composite effect of interlocked layers provides enhanced shear strength that exceeds what would be achievable with a single thick layer.
3Strength
If layer thickness is increased to bolster scaffold strength, then strength is improved, but manufacturing cost increases
Solution Approach 1:
Instead of increasing layer thickness to improve strength, the invention uses three-dimensional pore pattern interlocking to achieve the same strength enhancement. This approach maintains thin layers for cost-effectiveness while gaining strength through vertical mechanical interlocking.
Solution Approach 2:
The scaffold is segmented into multiple thin layers rather than a single thick layer. These segmented layers are designed with complementary pore patterns that interlock to provide cumulative strength, achieving the strength of thicker construction at lower cost through efficient material distribution.
Data Source
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AI summary
A three-dimensional scaffold for a medical implant includes a plurality of layers bonded to each other. Each layer has a top surface and a bottom surface and a plurality of pores extending from the top surface to the bottom surface. Each layer has a first pore pattern of the pores at the top surface and a different, second pore pattern at the bottom surface. Adjacent surfaces of at least three adjacent layers have a substantially identical pore pattern aligning to interconnect the pores of the at least three adjacent layers to form a continuous porosity through the at least three adjacent said layers.