Porous Interbody Lattice Structure for Spinal Implant Stability
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Solution Overview
Problem
Existing spinal implants lack optimal designs for reducing migration and ensuring proper placement, particularly in spinal surgical procedures, and do not adequately accommodate patient-specific bone density variations.
Innovation Solution
The development of porous interbody spinal implants with a lattice structure featuring a gradient of pore sizes and beam diameters, superior projections for reducing migration, and radiographic markers for precise placement, allowing for patient-specific stiffness adjustment and improved visibility during surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional solid spinal implant is used, then structural strength is maintained, but bone integration is reduced and migration risk increases
Solution Approach 1:
The implant utilizes a porous lattice structure with interconnected struts and pores that allow bone tissue ingrowth while maintaining structural integrity. The porous architecture provides mechanical strength through the lattice geometry while enabling biological integration through bone ingrowth into the pore spaces, thereby resolving the contradiction between strength and bone integration.
Solution Approach 2:
The implant employs a composite structure combining lattice regions with different pore sizes and beam diameters, creating zones of varying stiffness. This composite lattice design allows different regions to serve different functions: higher stiffness in load-bearing areas and lower stiffness in bone integration areas, simultaneously achieving both structural strength and reliable bone integration.
2Ease of manufacture
If uniform pore sizes are used throughout the implant, then manufacturing is simplified, but patient-specific bone density variations are not accommodated
Solution Approach 1:
The implant features a lattice structure with spatially varying pore sizes and beam diameters. Regions with larger pores and thicker beams provide higher stiffness for areas requiring load-bearing, while regions with smaller pores provide lower stiffness for areas requiring bone integration. This local variation in structural properties allows the implant to accommodate patient-specific bone density variations while maintaining manufacturability through systematic design patterns.
3Measurement precision
If radiographic markers are added to the implant, then placement visibility is improved, but implant complexity increases
Solution Approach 1:
Radiographic markers are integrated directly into the lattice structure of the implant rather than being separate components. The markers are formed as part of the lattice framework, combining the structural function of the lattice with the radiographic visualization function of the markers. This merging approach improves placement visibility while minimizing the increase in overall implant complexity.
4Stability of the object's composition
If a dense solid structure is used, then migration resistance is improved, but bone ingrowth is reduced
Solution Approach 1:
The lattice structure provides migration resistance through its overall geometric configuration and connection to adjacent bone structures, while the porous nature of the lattice simultaneously enables bone ingrowth into the implant. The interconnected struts provide mechanical stability to prevent migration, while the open pore spaces allow bone tissue to penetrate and integrate with the implant structure, resolving the contradiction between migration resistance and bone ingrowth.
Data Source
AI summary
In various aspects, an implant includes a body having a lattice structure, with the lattice structure extending continuously from a superior surface of the body to an inferior surface of the body. The lattice structure may define a gradient of pores, with each pore in the gradient having a plurality of vertices. Additionally, the implant may include a plurality of projections extending superiorly from each of the plurality of vertices of each pore of the gradient of pores at the superior surface of the body, with each projection of the plurality of projections having a directionality. The implant may also include one or more radiographic markers incorporated into the lattice structure, the one or more radiographic markers having a density greater than the density of the lattice structure immediately around the one or more radiographic markers and being comprised of the same material as the lattice structure.