Hyperboloid Bone Scaffold with Porous Lattice for Spinal Fusion
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Solution Overview
Problem
Current bone fusion methods using rigid metal or PEEK fusion cages lack mechanical integrity and biological activity, leading to implant subsidence, stress shielding, and limited load sharing, which can result in bone resorption and failure, and are associated with donor site morbidity and limited supply of biologically active graft materials.
Innovation Solution
A surgically sized bone scaffold with optimized hyperboloid geometry and 3D printed from biocompatible materials, providing enhanced mechanical properties, biologically active capability, and customizable design for load-bearing and osteointegration, allowing for cell and bone graft deposition to facilitate spinal fusion, and is completely bioresorbable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid metal or PEEK fusion cages are used, then mechanical stability is improved, but biological activity is lost and stress shielding occurs
Solution Approach 1:
The patent changes the mechanical parameters of the implant by using a porous lattice structure with controlled density and strut thickness. This allows the implant to have reduced stiffness compared to solid metal cages, enabling stress transfer to the bone while maintaining sufficient mechanical stability. The porous structure transforms the implant from a rigid stress-shielding object to a compliant load-sharing structure.
Solution Approach 2:
The patent employs a porous lattice structure as the core architectural feature of the fusion cage. This porous design reduces the overall density and stiffness of the implant, allowing it to share loads with the surrounding bone tissue rather than shielding it. The porous structure also facilitates bone ingrowth and enhances biological integration while maintaining mechanical integrity.
2Strength
If rigid fusion cages are used, then immediate mechanical stability is achieved, but load sharing between implant and bone is limited
Solution Approach 1:
The patent adjusts the mechanical parameters of the implant through controlled porous lattice design, where strut thickness, pore size, and lattice density are optimized to match the mechanical properties of natural bone. This parameter optimization enables the implant to transition from a rigid load-bearing structure to a compliant load-sharing structure that transfers stresses to the surrounding bone, promoting physiological loading and bone remodeling.
3Reliability
If biologically active graft materials are used, then bone regeneration is improved, but donor site morbidity and limited supply occur
Solution Approach 1:
The porous lattice structure serves as a scaffold that can be filled with bone graft materials (autograft, allograft, or synthetic bone substitute). The porous architecture provides a large surface area and interconnected channels that facilitate cell migration, nutrient transport, and bone ingrowth. This allows the use of smaller amounts of biologically active graft material while achieving effective bone regeneration, thereby reducing the need for large autograft harvests and associated donor site morbidity.
4Strength
If traditional fusion cages are used, then structural integrity is maintained, but material usage is excessive
Solution Approach 1:
The patent divides the solid metal cage structure into a segmented porous lattice architecture. Instead of using a continuous solid structure, the design employs interconnected struts and pores that distribute mechanical loads efficiently throughout the structure. This segmentation reduces material usage while maintaining structural integrity through the trabecular-like architecture that mimics natural bone structure.
Solution Approach 2:
The porous lattice structure reduces material usage by creating a lightweight architecture with controlled porosity. The struts are designed with optimal thickness and distribution to provide sufficient mechanical strength while minimizing material consumption. This porous design eliminates the need for excessive material that would be required in solid cage constructions, reducing both material cost and weight.
Data Source
AI summary
A spinal fusion bone scaffold having a first member including a first base plate and a first plurality of struts each having a first end engaging the first base plate and a second, free end. The first plurality of struts is configured to form at least part of a hyperbolic curve such that said bone scaffold includes an overall optimized hyperboloid shape having an outer diameter and an inner waist diameter. The scaffold may include a second member including a second plurality of struts each having a first end and a second end, each of the second plurality of struts being configured to form at least part of the hyperbolic curve. The scaffold includes connecting means for connecting said second member to said first member, which are aligned so as to complete the hyperbolic curve while generating hyperboloid geometry of the bone scaffold.