Bone Cage Offset Protrusions for Fusion Surface Area
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Solution Overview
Problem
Current bone cages for fusion procedures lack optimal designs that balance bone ingrowth promotion with structural rigidity and manufacturing ease, particularly in providing sufficient surface area for bone adhesion and fusion while maintaining desired spacing between bones.
Innovation Solution
The bone cage design features first and second spaced apart frames with interdigitating protrusions of varying angles, lengths, and widths that extend into a bone ingrowth cavity without contacting each other, allowing for enhanced bone adhesion and fusion while maintaining structural integrity, and can be fabricated from materials like PEEK, carbon fiber, and titanium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bone cage includes a solid structure to maintain spacing between bones, then structural rigidity is improved, but the surface area available for bone adhesion and fusion is reduced
Solution Approach 1:
The bone cage structure is segmented into multiple protrusions that extend into the cavity from opposite frames. These protrusions create a segmented architecture that provides both structural support and increased surface area for bone adhesion, resolving the contradiction between rigidity and adhesion surface area.
Solution Approach 2:
The protrusions extend into the third dimension within the cavity, creating a multi-dimensional structure. This dimensional transformation allows the cage to maintain spacing (structural function) while providing additional surface area through the protruding elements that bones can adhere to, effectively addressing both requirements simultaneously.
2Reliability
If the bone cage includes protrusions extending into the cavity to promote bone ingrowth, then bone adhesion is improved, but the structural integrity and spacing maintenance capability may be compromised
Solution Approach 1:
The protrusions on opposite frames are positioned asymmetrically with lateral offsets, creating an interdigitating pattern. This asymmetric arrangement allows bone to adhere to multiple protrusions from different frames simultaneously, enhancing fusion reliability while the distributed structure maintains overall structural integrity through the interlocking geometry.
Solution Approach 2:
The protrusions are pre-positioned to extend into the cavity at specific angles and positions before bone ingrowth occurs. This preliminary structural arrangement guides bone growth pathways and provides immediate adhesion surfaces, ensuring reliable bone-cage integration while maintaining the structural framework needed for spacing maintenance.
3Reliability
If the bone cage uses complex protrusion structures with varying angles and offsets to enhance bone ingrowth, then bone fusion capability is improved, but manufacturing complexity increases
Solution Approach 1:
The protrusions exhibit local quality variations with different angles, lengths, and lateral offsets at specific locations within the cavity. This localized differentiation optimizes bone ingrowth at each position while the overall pattern can be manufactured using standardized processes, balancing fusion capability with manufacturing feasibility.
Solution Approach 2:
The protrusion pattern on one frame can be copied or mirrored on the opposite frame with lateral offsets, creating a systematic interdigitating structure. This copying approach with modular repetition simplifies manufacturing compared to completely unique features, while still achieving the complex geometry needed for enhanced bone fusion capability.
Data Source
AI summary
A bone cage may include first and second spaced apart frames defining a bone ingrowth cavity therebetween, a plurality of first protrusions each having a proximal end coupled to the first frame and a distal end extending into the cavity toward the second frame but not contacting the second frame, and a plurality of second protrusions each having a proximal end coupled to the second frame and a distal end extending into the cavity toward the first frame but not contacting the first frame. Furthermore, the distal ends of the first protrusions may be laterally offset from the distal ends of the second protrusions.