Shape Memory Orthopedic Implant with Cannulations for Bone Augmentation
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Solution Overview
Problem
Shape memory surgical implants face challenges in effectively fusing or distracting bone pieces, especially in patients with poorer bone quality due to osteoporosis or trauma, as they lack sufficient structural integrity to arrest the movement of the implant's legs during transition, leading to improper fixation and healing.
Innovation Solution
An orthopedic implant with shape memory material that transitions between natural and insertion shapes, featuring cannulations for delivering bone augmentation materials to enhance structural integrity, ensuring the implant can exert adequate force for fusion or distraction regardless of bone quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shape memory implant is used to affix bone pieces, then the implant can exert force for fusion or distraction, but in patients with poorer bone quality, the bone lacks structural integrity to arrest movement of the implant's legs, resulting in improper fixation
Solution Approach 1:
The patent combines shape memory alloy (superelastic material) with bone augmentation material (cement or graft) to create a composite fixation system. The shape memory implant provides elastic recovery force while the bone augmentation material fills voids and bonds to the bone, creating a composite structure that compensates for poor bone quality and ensures reliable fixation.
Solution Approach 2:
The bone augmentation material acts as an intermediary between the shape memory implant and the bone tissue. It transfers and distributes the forces exerted by the implant's leg movement, preventing stress concentration that would cause failure in poor quality bone, and provides additional structural support during the healing process.
2Force
If the implant transitions from insertion shape to natural shape to exert force, then fusion or distraction is promoted, but in poor bone quality, the legs over-transition to a position incapable of imparting adequate force
Solution Approach 1:
The bone augmentation material serves as a mediator that couples the implant legs to the bone, ensuring that the force generated during shape transition is effectively transmitted to the bone pieces. This prevents force loss due to leg over-transition or slippage in poor quality bone.
Solution Approach 2:
The patent modifies the mechanical parameters of the fixation system by introducing bone augmentation material that changes the stiffness and friction characteristics at the implant-bone interface. This allows the implant to maintain controlled force delivery even when bone quality is poor, preventing over-transition while ensuring adequate force for healing.
3Strength
If bone augmentation material is delivered through cannulations, then structural integrity is enhanced, but the implant structure becomes more complex
Solution Approach 1:
The shape memory implant serves multiple functions: it provides mechanical fixation through its legs, delivers bone augmentation material through integrated cannulations, and exerts corrective force through shape transition. This multi-functionality reduces the need for separate components, offsetting the added complexity with functional integration.
Solution Approach 2:
The cannulations are integrated within the implant structure itself, with channels running through the bridge and legs. The bone augmentation material is delivered through these nested channels directly to the bone, eliminating the need for separate delivery devices and reducing overall system complexity despite the added internal structure.
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 implant effectively fixes bones by delivering bone augmentation materials through cannulations, enhancing structural integrity and allowing the implant to impart sufficient force for proper fusion or distraction, even in bones with poor quality, thereby ensuring stable fixation and healing.
Implementation Method 1
Shape memory materials such as nitinol (nickel-titanium) due to their superelastic or temperature dependent properties currently are employed in the manufacture of surgical implants
Implementation Method 2
surgical implant manufactured from a shape memory material with superelastic or temperature dependent properties
Data Source
AI summary
An apparatus for fixating bone includes an orthopedic implant. The orthopedic implant may be manufactured from a shape memory material such that the orthopedic implant is moveable between a natural shape and an insertion shape. The orthopedic implant defines at least a first cannulation therethrough adapted to deliver a bone augmentation material to the bone. The orthopedic implant implants into the bone in its insertion shape. After implantation of the orthopedic implant, the first cannulation facilitates delivery into the bone of a bone augmentation material that augments the bone. The orthopedic implant once implanted attempts to transition from its insertion shape to its natural shape such that the orthopedic implant fixates the bone.