Shape Memory Anchoring for Reversible Medical Implant Coupling
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Solution Overview
Problem
Current coupling devices for medical implants, such as femoral stems, can cause adverse reactions and complications, lead to longer recovery times, and are difficult to replace during re-surgery without damaging the bone.
Innovation Solution
An anchoring device with shape memory material anchors that extend from a retracted to an extended position by temperature changes, providing a secure and reversible coupling mechanism for medical implants within the medullary cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current coupling techniques (fasteners, pins, adhesive, or friction fit) are used to insert coupling devices into the medullary cavity, then the implant can be secured to the femur, but adverse reactions occur leading to complications and longer recovery times
Solution Approach 1:
The patent replaces traditional mechanical coupling systems (fasteners, pins, adhesive) with a shape memory material-based anchoring system. The anchors are inserted in a compressed state and then expanded using shape memory effect triggered by temperature change or phase transition, eliminating the need for mechanical fasteners or adhesives that cause adverse tissue reactions.
Solution Approach 2:
The patent utilizes parameter changes in the shape memory material, specifically temperature-induced phase transitions between austenite and martensite phases. The material transitions from a compressed martensite state during insertion to an expanded austenite state for anchoring, or vice versa for retrieval, enabling secure coupling without traditional mechanical means.
2Stability of the object's composition
If current coupling devices are used to secure implants in the medullary cavity, then the implant is initially stable, but the implant can become loose within the medullary cavity over time
Solution Approach 1:
The patent employs dynamic anchors made of shape memory material that can actively change their state between compressed and expanded configurations. This dynamic capability allows the anchors to maintain secure engagement with the medullary cavity over time, preventing implant loosening while enabling retrieval when needed, thus improving both long-term stability and duration of action.
3Reliability
If current coupling devices are used to secure implants, then the implant is firmly anchored, but the devices are difficult to replace during re-surgery causing damage to the bone
Solution Approach 1:
The patent utilizes phase transitions of shape memory material to enable reversible anchoring. During surgery, the anchors are inserted in a compressed martensite phase, expanded to austenite phase for secure anchoring, and can be reverted to martensite phase for easy retrieval. This phase transition mechanism provides both secure anchoring and easy retrievability without bone damage.
4Adaptability or versatility
If shape memory material anchors are used that extend from retracted to extended position by temperature changes, then secure and reversible coupling is achieved, but the device complexity increases
Solution Approach 1:
The patent employs shape memory material that automatically responds to temperature changes without requiring external control systems. The material self-actuates between compressed and expanded states based on ambient temperature or controlled thermal input, eliminating complex mechanical actuators or control systems while achieving reversible coupling.
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 anchoring device ensures a secure and rigid coupling of medical implants to bone, allowing for easy removal and reimplantation during re-surgery without bone damage, and maintains stability over time.
Implementation Method 1
The at least one anchor includes a shape memory material. The at least one anchor is movable from a retracted position to an extended position by either increasing the temperature of the anchor above an austenite finishing temperature or decreasing the temperature of the anchor below a martensite finishing temperature.
Implementation Method 2
The at least one anchor is movable from a retracted position to an extended position by either increasing the temperature of the anchor above an austenite finishing temperature or decreasing the temperature of the anchor below a martensite finishing temperature.
Implementation Method 3
The at least one anchor further includes a resilient member that is biased toward the extended position and urgable toward the retracted position.
Data Source
AI summary
Various implementations include an anchoring device including a tubular body and at least one anchor. The at least one anchor extends along an opening between a first axial end and a second axial end of the opening. The at least one anchor includes a shape memory material. The at least one anchor is movable from a retracted position to an extended position by either increasing the temperature of the anchor above an austenite finishing temperature or decreasing the temperature of the anchor below a martensite finishing temperature. The anchor has a smaller radius of curvature in a plane that includes the longitudinal axis in the extended position than in the retracted position. When used as a coupler for medical implants, the device can be easily removed and reimplanted during re-surgery without damaging the bone of a patient by increasing or decreasing the temperature of the shape memory material anchors.