Sequential-Channel Graft Compression for Low-Trauma Bone Tunnels
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Solution Overview
Problem
Traditional ACL and PCL reconstruction surgeries face complications such as increased healing time, tissue trauma, and graft failure due to the significant volume of bone tunnels drilled and the use of traditional graft fixation methods, which can lead to suboptimal healing environments and mechanical inferiority.
Innovation Solution
A graft compression system utilizing an expandable and compressible elongate compression tube made of materials like Nitinol or stainless steel, which can reduce the graft diameter by 50% or more, allowing for smaller bone tunnels and a biologic compressive fit, minimizing micro-motion and eliminating the need for interference screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional graft fixation methods are used with standard graft diameter, then the graft can be easily inserted into the bone tunnel, but micro-motion occurs between graft and bone leading to fibrous scar formation and mechanically inferior healing
Solution Approach 1:
The patent applies parameter changes by reducing the graft diameter to create a tighter fit within the bone tunnel. This dimensional parameter modification eliminates micro-motion between the graft and bone, preventing fibrous scar formation and improving the healing environment while maintaining adequate blood supply to the graft.
Solution Approach 2:
The patent inverts the traditional approach by compressing the graft to a smaller diameter before insertion, rather than using a larger graft that requires fixation devices. This inverted methodology allows the graft to expand in situ to fill the tunnel completely, creating intimate contact with the bone tunnel walls without requiring interference screws or buttons.
2Reliability
If bone tunnels are drilled with diameter equal to graft diameter, then the graft fits the tunnel, but significant tissue trauma and swelling occur
Solution Approach 1:
The patent changes the dimensional parameters by using a compressed graft with reduced diameter that is smaller than the bone tunnel diameter. This allows the tunnel to be drilled with sufficient clearance to avoid excessive tissue trauma while the compressed graft can be inserted and will expand to create a secure fit, eliminating the need for the tunnel to match the full graft diameter.
3Object-affected harmful factors
If graft diameter is reduced by compression, then bone tunnel volume can be reduced minimizing tissue trauma, but the graft must be compressed significantly (50% or more volume reduction)
Solution Approach 1:
The patent applies segmentation by dividing the compression function into separate components: a compression device with adjustable compression elements that can independently apply force to the graft, and a delivery system that separates the compression phase from the insertion phase. This modular approach manages the complexity of achieving 50% or more volume reduction while maintaining control over the compression process.
Solution Approach 2:
The patent applies preliminary action by compressing the graft to the required reduced diameter before insertion into the bone tunnel. This pre-compression prepares the graft in advance, allowing the surgeon to insert a compacted graft that will subsequently expand in situ, thereby minimizing tissue trauma during the surgical procedure itself.
4Reliability
If traditional ACL and PCL reconstruction surgery is performed with standard graft size, then the procedure is straightforward, but healing time is increased and patient recovery is slower
Solution Approach 1:
The patent changes the critical parameter of graft diameter to create a tighter fit within the bone tunnel. This parameter modification eliminates micro-motion and creates a mechanically superior environment for healing, directly reducing healing time and accelerating patient recovery while maintaining straightforward surgical technique.
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 system enables quicker patient recovery, reduces tissue trauma and swelling, and improves healing by creating a well-fixed graft with a biologic compressive fit, enhancing surgical outcomes.
Implementation Method 1
an expandable and compressible elongate compression tube made of materials like Nitinol or stainless steel, which can reduce the graft diameter by 50% or more
Data Source
AI summary
A graft compression system for compressing soft tissue grafts used in connection with reconstructive surgery. The graft compression system includes an upper press body and lower press body, pivotally couple to one another, each having inner sides having a plurality of parallel semi-circular shaped channels formed thereon. The plurality of parallel semi-circular shaped channels have sequentially decreasing channel widths. The upper press body and said lower press body of the graft compression system are configured to pivot about a pivot pin such that the inner sides abut one another, and such that the two sets of semi-circular shaped channels are substantially aligned with one another so as to receive a graft for compression. A screw press barrel is attached to the lower press body, on a side opposite the pivot pin, and is configured to compress the upper press body and lower press body.