Solid-Porous Spinal Interbody Implants for Bone Ingrowth

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Solution Overview

Problem

Existing spinal implants face challenges in achieving both improved bone ingrowth capacity and suitable load-bearing capacity, often requiring complex and expensive manufacturing processes due to limited porous material usage and lower modulus of elasticity.

Innovation Solution

Spinal interbody implants are designed with a combination of solid and porous materials, utilizing additive manufacturing to create structures with varying porosities and lattice configurations that enhance bone ingrowth while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If porous material is used to promote bone ingrowth, then bone integration is improved, but load-bearing capacity is reduced

Engineering Contradiction:
Improvebone integrationVSAvoidload-bearing capacity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The implant applies local quality by using porous material only at specific locations (upper and lower surfaces) where bone ingrowth is most needed, while maintaining solid material in the central region for load-bearing. This spatial differentiation of material properties resolves the contradiction between bone integration and load-bearing capacity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The implant uses composite materials by combining porous material (for bone ingrowth) with solid material (for structural strength) in a single device. This composite approach allows simultaneous achievement of both bone integration and load-bearing capacity that cannot be achieved with a single material type.

Inventive Principle:
Principle #40Composite materials

2Reliability

If porous material is used throughout the implant, then bone ingrowth is maximized, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvebone ingrowth capacityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The implant applies local quality by using porous material only at specific locations (upper and lower surfaces) where bone ingrowth is most needed, while maintaining solid material in the central region for load-bearing. This spatial differentiation of material properties resolves the contradiction between bone integration and load-bearing capacity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The implant applies partial action by using porous material only to the extent necessary for bone ingrowth (thin layers at surfaces), rather than throughout the entire implant. This partial application reduces manufacturing complexity and material costs while still achieving the bone ingrowth objective.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If material with lower modulus of elasticity is used, then bone ingrowth is promoted, but structural strength is reduced

Engineering Contradiction:
Improvebone ingrowth promotionVSAvoidstructural strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The implant applies local quality by using porous material only at specific locations (upper and lower surfaces) where bone ingrowth is most needed, while maintaining solid material in the central region for load-bearing. This spatial differentiation of material properties resolves the contradiction between bone integration and load-bearing capacity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The implant uses composite materials by combining porous material (for bone ingrowth) with solid material (for structural strength) in a single device. This composite approach allows simultaneous achievement of both bone integration and load-bearing capacity that cannot be achieved with a single material type.

Inventive Principle:
Principle #40Composite materials

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 combination of solid and porous materials in spinal implants improves bone integration and load-bearing capabilities, accelerating recovery times through enhanced bone growth and nutrient distribution.

Implementation Method 1

The outer tubular part is made of a first material with a first porosity and the inner fill part is made of a second material with a second porosity greater than the first porosity

Methodology Applied
Scientific EffectPorosity: Porosity

Data Source

PatentEP4221639B1Spinal interbody implants
Publication Date: 2025.09.17 STRYKER CORP
  • EP4221639B1 patent drawingFigure 1A~1C
  • EP4221639B1 patent drawingFigure 1D~1F
  • EP4221639B1 patent drawingFigure 2A~2B

AI summary

Disclosed herein are embodiments of a spinal implant having structures that incorporate a solid material and a porous material. The solid material provides the implant with an outer shell for structural integrity while the porous material, distributed within an interior of the implant as a lattice structure for example, promotes visibility of the implant in radiological imaging, promotes bony ingrowth and cell attachment and improves wicking.