Hinged-Arm Expanding Implant With Controlled Bridging Motion
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Solution Overview
Problem
Existing orthopedic implants face challenges in efficiently expanding within the body to achieve desired deployment configurations, particularly in minimally invasive procedures, with limitations in deployment mechanisms and potential for unwanted motion during expansion.
Innovation Solution
An expanding implant with hinged arms utilizing a threaded bolt actuator, asymmetric actuator linkages, and a bridging element engaged via double pin-in-slot mechanism to ensure controlled and amplified motion, limiting unwanted sliding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a threaded bolt actuator with asymmetric actuator linkages is used, then deployment precision and control are improved, but device complexity increases
Solution Approach 1:
The implant is divided into modular components including the base, hinged arms, bridging element, and actuator system with threaded bolt and linkages. This segmentation allows each component to be optimized independently for precision while maintaining overall system controllability despite increased complexity.
Solution Approach 2:
Asymmetric actuator linkages are employed to achieve precise control over the expansion motion of the hinged arms. The asymmetric configuration allows for controlled amplification of motion in specific directions, improving deployment precision while the complexity is managed through the functional necessity of the asymmetric design.
2Stability of the object's composition
If a rigid bridging element with double pin-in-slot engagement is used, then stability during expansion is improved, but device complexity increases
Solution Approach 1:
The double pin-in-slot engagement mechanism is pre-configured in the rigid bridging element to automatically constrain and guide the expansion motion of the hinged arms. This preliminary arrangement ensures stability during expansion without requiring active control during the deployment process, managing complexity through passive mechanical guidance.
Solution Approach 2:
The rigid bridging element with double pin-in-slot engagement acts as an intermediary component that mediates the expansion motion between the hinged arms and the actuator system. It provides stable guidance and constraint while transferring motion, improving stability during expansion while the complexity is justified by the mediating function.
3Ease of operation
If the implant is designed for minimally invasive insertion in collapsed form, then ease of insertion is improved, but deployment control becomes more difficult
Solution Approach 1:
The implant is designed to collapse into a compact configuration that can be nested within a delivery system for minimally invasive insertion. The hinged arms and bridging element are arranged to fold or compress together, allowing easy insertion through small incisions while the nested structure is later deployed using the threaded bolt actuator system to achieve controlled expansion.
Solution Approach 2:
The implant transitions from a static collapsed state for insertion to a dynamic expanded state for function. The hinged arms and actuator system enable controlled transformation between these states, improving ease of insertion while the dynamic deployment mechanism manages the complexity of controlled expansion after insertion.
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
Enables precise and controlled expansion of orthopedic implants, enhancing deployment efficiency and stability during minimally invasive surgeries, particularly in spinal applications.
Implementation Method 1
the actuator comprises: (a) a threaded bolt extending within the base and mounted so as to be rotatable about a central axis of the threaded bolt
Data Source
AI summary
An implant (500, 600) includes first and second arms (14a, 14b) hinged to a base (12) at spaced-apart locations. An actuator (18, 22a, 22b, 602, 604, 606) is deployed to rotate the arms from an initial position in opposing angular motion towards a final position. A rigid bridging element (28) bridges between the arms so that deployment of the arms towards the final position displaces the bridging element away from the base. Engagement between the bridging element and at least one of the arms is via a double pin-in-slot engagement in which two non-collinear pins (30, 40) are engaged in respective non-parallel slots (32, 42).