Bone Graft Cage with Nested Mesh Sleeves
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Solution Overview
Problem
Existing methods for treating large bone defects with bone grafts often face challenges in maintaining the graft material in place, as it may fall away from the target site before incorporation into the healing bone, leading to ineffective healing.
Innovation Solution
A mesh-based graft containment device with an outer sleeve matching the bone's outer surface and an inner sleeve matching the medullary canal, along with an interstitial mesh to hold the graft material and prevent migration, custom-built using 3D printing for patient-specific dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mesh container is used to contain bone graft material, then the graft material is prevented from falling away from the target site, but the device complexity increases due to the need for precise mesh sizing and shaping to match the bone profile
Solution Approach 1:
The mesh container is divided into an outer sleeve portion and an inner sleeve portion, with the outer sleeve matching the outer surface profile of the bone and the inner sleeve matching the medullary canal profile. This segmentation allows each portion to be optimized for its specific function while simplifying the overall design and manufacturing process.
Solution Approach 2:
The inner sleeve is positioned within the outer sleeve, creating a nested structure where the inner sleeve contains the bone graft material and the outer sleeve provides additional containment and structural support. This nested configuration enhances graft retention while maintaining a relatively simple device structure.
2Adaptability or versatility
If custom-built 3D printing is used to create patient-specific dimensions, then the adaptability to specific patient needs is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The 3D printing process allows for easy modification of geometric parameters such as sleeve diameter, length, mesh opening size, and overall shape to match patient-specific bone anatomy. By changing digital design parameters rather than physical tooling, the system achieves high adaptability without requiring extreme manufacturing precision for each custom case.
Solution Approach 2:
The basic mesh container design with outer and inner sleeves serves multiple functions: containing graft material, providing structural support, facilitating bone ingrowth through mesh openings, and adapting to different patient anatomies. This multi-functionality reduces the need for highly specialized custom components for each patient.
3Reliability
If the outer sleeve is sized to match the outer surface of the bone, then the graft material is contained effectively, but the ease of manufacture decreases due to the need for precise profiling
Solution Approach 1:
The outer sleeve is designed with localized mesh density and opening patterns that provide enhanced containment at critical areas while maintaining easier manufacturability in other regions. The mesh structure allows for variable local properties without requiring the entire sleeve to be manufactured with maximum precision.
Solution Approach 2:
The mesh structure of the outer sleeve provides dynamic adaptability, allowing the sleeve to conform to slight variations in bone surface geometry without requiring precise pre-matching of every surface contour. The flexible mesh can adjust to the bone profile while maintaining effective graft containment.
Data Source
AI summary
A device is for containing a bone graft material. The device includes a mesh outer sleeve extending longitudinally from a proximal end to a distal end and sized and shaped to correspond to a profile of an outer surface of a target bone. The outer sleeve includes a plurality of openings extending therethrough, longitudinally adjacent ones of the plurality of openings being offset from one another relative to a longitudinal axis of the device. The device also includes a mesh inner sleeve connected to an interior surface of the outer sleeve via at least one strut so that a bone graft collecting space is defined therebetween The inner sleeve is sized and shaped to correspond to a profile of a medullary canal of the target bone. The inner sleeve includes a plurality of openings extending therethrough.