Adjustable Spinal Implant With Hinge And Locking Pawl
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Solution Overview
Problem
Current intervertebral implants face challenges in accommodating varying disc space shapes and heights, leading to issues such as excessive retraction of blood vessels or neural elements during implantation, which can result in vascular damage, suboptimal stability, or implant migration due to inadequate sizing.
Innovation Solution
An adjustable spinal implant with a pivotable design, featuring a locking pawl and key mechanism that allows the implant to be inserted in a collapsed position and expanded to fit anatomical spaces accurately, along with a specialized insertion tool for transitioning the implant between locked and unlocked states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed-size implant is used to bridge the disc space, then the implant can provide immediate stability, but it cannot accommodate variation in disc space shape and height, leading to suboptimal stability or implant migration
Solution Approach 1:
The implant transitions from a fixed rigid structure to a dynamic adjustable structure that can change its dimensions. The upper body and lower body are connected via a hinge joint, allowing the implant to be adjusted between collapsed and expanded positions to match varying disc space heights and shapes, thereby providing optimal stability for each patient's anatomy
Solution Approach 2:
The implant allows modification of its geometric parameters (height, angle) to adapt to different disc spaces. By changing the relative position of the upper and lower bodies through the hinge mechanism, the implant can be customized in-situ to match the specific shape and height of the patient's disc space, ensuring reliable stability
2Length of moving object
If a large implant diameter is used during posterior approach, then adequate implant size can be achieved, but excessive traction on neural elements is required for placement
Solution Approach 1:
The implant is divided into two separate bodies (upper body and lower body) connected by a hinge. This segmentation allows the implant to be inserted in a collapsed or reduced configuration, minimizing the space required for insertion and reducing traction on neural elements, while still achieving the necessary final implant size for stability
Solution Approach 2:
The upper body can be positioned within or adjacent to the lower body in a nested or collapsed configuration during insertion. This nesting allows the implant to pass through the surgical approach with minimal diameter, reducing neural element traction, and then be expanded to the required final size for adequate stability
3Length of moving object
If the implant is inserted in an expanded position, then adequate disc space filling is achieved, but excessive retraction on blood vessels is required during anterior approach
Solution Approach 1:
The implant is designed to be dynamically adjustable after insertion. It can be inserted in a collapsed position to minimize retraction on blood vessels, then expanded in-situ to the required height for adequate disc space filling, thereby eliminating the need for excessive pre-insertion expansion
Solution Approach 2:
The implant is prepared in a collapsed or reduced state before insertion, allowing easy passage through the surgical approach with minimal retraction on blood vessels. The expansion to final size is performed as a preliminary action after insertion, ensuring safe placement before achieving the required disc space filling
4Adaptability or versatility
If the implant allows movement between collapsed and expanded positions, then adaptability to disc space variation is improved, but device complexity increases due to hinge and locking mechanisms
Solution Approach 1:
The locking mechanism is designed to be self-contained and self-operating. The pawl and ratchet teeth engage automatically through the natural movement of the adjustment mechanism, and the spring-loaded pawl provides automatic locking without requiring additional actuators or complex control systems. This self-service approach minimizes overall device complexity while maintaining adjustability
Data Source
AI summary
An adjustable spinal implant includes a lower body, an upper body, a locking pawl, and a locking key. The upper body and the lower body are pivotable relative to one another between a collapsed position and an expanded position. The upper body includes a locking flange that extends towards the lower body. The locking pawl is coupled to the lower body and is moveable between a locked position such that the upper and lower bodies are fixed relative to the one another and an unlocked position such that the upper and lower bodies are moveable relative to one another. The locking key is moveable between a locked state such that the locking pawl is fixed in the locked position and an unlocked state wherein the locking pawl is moveable between the locked position and the unlocked position.