Expandable Interbody Implant Locking Mechanism
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Solution Overview
Problem
Current intervertebral implants lack an efficient locking mechanism to maintain expansion and facilitate controlled contraction, which can lead to instability during bone fusion procedures.
Innovation Solution
The development of an expandable spinal implant with a locking system utilizing pinions and a linear rack, biased by a spring, to lock and unlock the extendable support elements, allowing for controlled expansion and contraction, and a stop mechanism to limit maximum expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If expandable implants are used to facilitate insertion with a low profile, then ease of insertion is improved, but stability during bone fusion may be compromised without an effective locking mechanism
Solution Approach 1:
The implant transitions from a dynamic expandable state to a static locked state. The locking mechanism converts the implant from a movable, adjustable structure to a fixed, stable structure once the desired expansion is achieved, thereby maintaining both ease of insertion and stability during bone fusion.
Solution Approach 2:
The patent replaces simple mechanical expansion with a controlled locking system involving pinions, racks, and springs. This mechanical substitution provides precise control over the expansion and locking process, ensuring both ease of insertion and reliable stability during the bone fusion procedure.
2Reliability
If a locking mechanism is added to maintain expansion, then stability is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is designed to be self-actuating through the interaction of springs and pinions. The spring-loaded system automatically engages the locking mechanism when the implant reaches the desired expansion, reducing the need for complex external control systems and minimizing overall device complexity while maintaining stability.
Solution Approach 2:
The rack acts as an intermediary element between the pinion gears and the expansion mechanism. This intermediary component simplifies the overall system by providing a straightforward mechanical connection that translates rotational motion into linear motion, thereby maintaining stability without excessive complexity.
3Adaptability or versatility
If the locking system allows controlled contraction, then adaptability is improved, but reliability may be compromised due to potential instability
Solution Approach 1:
The locking mechanism provides dynamic control over the implant's state, allowing transitions between locked and unlocked configurations. This dynamic capability enables controlled contraction when needed while maintaining stability during the locked state, thereby balancing adaptability with reliability throughout the surgical procedure.
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 locking system ensures stable engagement of vertebral bodies, optimizing bone fusion by maintaining expansion while allowing controlled contraction, thus enhancing the surgical outcome.
Implementation Method 1
The rack may be configured so as to bias the locking system towards the locked configuration
Data Source
AI summary
An expandable interbody implant is expandable from a contracted configuration to an expanded configuration by moving opposing first and second vertebral-engaging surfaces apart from one another. The implant includes a locking system for restraining contraction of the implant. The locking system may have a locked configuration, in which the first and second surfaces are prevented from moving back towards the contracted configuration, and the locking system may have an unlocked configuration, in which the first and second surfaces are permitted to move back towards the contracted configuration. The locking system may be controlled by rotation of one or more pinions. The pinions may, in turn, be controlled by linear movement of a rack. The rack may be configured so as to bias the locking system towards the locked configuration. The implant may also include a stop for constraining the maximum expansion of the implant.