Segmented Bone Anchor with Variable Density Lattice
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Solution Overview
Problem
Current medical implants face challenges in achieving strong and healthy bone attachment and growth due to limitations in material selection, which often compromise on strength, stiffness, fatigue resistance, and radiolucency, and lack effective mechanisms for osteointegration and bone ingrowth.
Innovation Solution
The development of a bone anchor with multiple segments of varying volumetric density and material composition, featuring a lattice structure that promotes bone ingrowth in one segment while preventing it in another, allowing for secure attachment and potential later removal, utilizing a combination of nonresorbable and resorbable materials with a detachable mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single material is used for the entire implant, then manufacturing is simple, but the implant cannot simultaneously provide strong structural support and promote bone ingrowth
Solution Approach 1:
The implant is divided into multiple segments along its longitudinal axis, each segment comprising different materials with different volumetric densities. The first segment includes a first material configured to promote bone ingrowth, while the second segment includes a second material configured to resist bone ingrowth. This segmentation allows each segment to perform its specific function optimally while maintaining overall structural integrity.
Solution Approach 2:
Different regions of the implant are assigned different material properties tailored to their specific functions. The first segment uses a resorbable material with higher porosity to promote bone ingrowth where needed, while the second segment uses a non-resorbable material with lower porosity to provide structural support and resist bone ingrowth where appropriate. This local differentiation of material properties resolves the contradiction between strength and ease of manufacture.
2Adaptability or versatility
If a resorbable material is used, then bone ingrowth is promoted, but the implant loses structural support over time
Solution Approach 1:
The implant is divided into multiple segments along its longitudinal axis, each segment comprising different materials with different volumetric densities. The first segment includes a first material configured to promote bone ingrowth, while the second segment includes a second material configured to resist bone ingrowth. This segmentation allows each segment to perform its specific function optimally while maintaining overall structural integrity.
Solution Approach 2:
The implant uses composite construction with at least a first resorbable material and at least a second non-resorbable material. The resorbable material degrades over time as bone ingrows, while the non-resorbable material maintains structural support throughout the implant's service life. This composite approach allows the implant to adapt to changing mechanical requirements as bone heals and integrates.
3Reliability
If the implant is designed for permanent fixation, then stability is maximized, but future removal or revision surgery becomes more difficult
Solution Approach 1:
The implant incorporates a resorbable component that dynamically changes over time through biological resorption. Initially, the resorbable material provides structural support alongside the non-resorbable material, ensuring stable fixation. As time progresses, the resorbable material gradually degrades and is replaced by natural bone, transforming the implant from a permanently fixed device to one that integrates with and can be removed with the healed bone tissue.
4Adaptability or versatility
If uniform volumetric density is used throughout the implant, then manufacturing is simplified, but bone ingrowth cannot be selectively promoted in specific regions
Solution Approach 1:
Different regions of the implant are assigned different material properties tailored to their specific functions. The first segment uses a resorbable material with higher porosity to promote bone ingrowth where needed, while the second segment uses a non-resorbable material with lower porosity to provide structural support and resist bone ingrowth where appropriate. This local differentiation of material properties resolves the contradiction between strength and ease of manufacture.
Solution Approach 2:
The first material is configured with a volumetric density that promotes bone ingrowth, implying a porous or lattice structure that allows bone cells to infiltrate and grow. The second material has a different volumetric density configured to resist bone ingrowth. This variation in volumetric density and porosity across different segments enables selective bone ingrowth promotion while maintaining overall device functionality.
Data Source
AI summary
The variable or adjustable depth medical implants disclosed herein are cable of depth adjustment prior to implantation. The variable depth implants permit a single implant to provide multiple footprint configurations, allowing a surgeon adjustability in the operating room. The implants can comprise a metallic lattice designed for specific physical properties, such as an elastic modulus. In some examples, the main body of the implant is taller than the adjustable portion of the implant so that the physical properties of the main body of the implant are controlling at the implant site. In some embodiments, the variable implant is constructed in an additive process as a single unit.Disclosed herein is, in some embodiments, a multi-segment bone anchor configured to allow variable bone ingrowth or attachment between each segment. In some versions, a lower segment is configured to allow bone ingrowth and a detachable upper segment is configured to prevent bone ingrowth, making the bulk of the bone anchor removable.