Intervertebral Implant Threaded Spindle Axial Stability
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Solution Overview
Problem
Existing intervertebral implants lack securement against axial displacements during and before operation, leading to potential instability and requiring additional locking mechanisms, which complicates handling and increases operation time.
Innovation Solution
A compact intervertebral implant design featuring a lower and upper implant part secured by a threaded spindle with a self-locking thread mechanism, allowing for stepless distance adjustment between apposition parts, and a clip connection for axial fixation, ensuring stability without additional locking, while maintaining a low construction height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the implant parts are loosely mounted with axial slots and pins, then the construction allows for assembly flexibility, but the implant lacks securement against axial displacements during operation
Solution Approach 1:
The threaded spindle enables dynamic adjustment of the distance between upper and lower implant parts during surgery, allowing the implant to be adapted to different vertebral spacing requirements while maintaining secure axial connection through the threading mechanism
Solution Approach 2:
The threaded spindle is extracted as a separate component that can be inserted into the upper implant part, providing the threading function without requiring complex integrated structures. This separate element enables secure axial connection while maintaining assembly flexibility
2Reliability
If additional locking mechanisms are added to prevent axial displacements, then axial stability is improved, but the device complexity and operation time increase
Solution Approach 1:
The threaded spindle serves multiple functions: it connects the upper and lower implant parts axially, provides securement against axial displacements through the threading engagement, and enables stepless distance adjustment during surgery. This single component replaces what would otherwise require separate locking mechanisms
Solution Approach 2:
The self-locking thread mechanism provides automatic axial stability without requiring additional active locking components. The threading geometry itself provides the securement function, eliminating the need for separate locks or fasteners
3Length of moving object
If a compact design with low construction height is implemented, then the implant fits better in the vertebral space, but the distance adjustment mechanism becomes more constrained
Solution Approach 1:
The threaded spindle is nested within the upper implant part's internal threading, allowing the adjustment mechanism to be contained within the compact implant structure. This nested arrangement enables distance adjustment functionality without significantly increasing the external dimensions or construction height of the implant
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 solution provides enhanced stability and simplified handling, reducing operation time and increasing safety by preventing axial displacements and allowing for precise, stepless adjustment of the implant's position, while being easy to assemble and use.
Implementation Method 1
a threaded spindle, guided in the upper implant part and connected with the lower implant part, having an outside thread that interacts with the inside thread
Implementation Method 2
The threaded spindle is connected with the lower implant part so as to be fixed axially but movable rotationally, by means of a clip connection
Data Source
AI summary
An intervertebral implant comprising a lower implant part, having a central axis and an apposition section, designed to rest against the covering surface of the adjacent lower vertebra and an upper implant part comprising a bore with an internal thread, a central axis and an apposition section, designed to rest against the covering surface of the adjacent upper vertebra. Specifically, the lower and upper implant parts are secured in relation to each other against rotation about the central axis and a threaded screw with an external thread is guided in the upper implant part and connected to the lower implant part, the external thread cooperating with the internal thread. The lower and upper implant parts, and the threaded screw lie coaxially along their common central axis, the threaded screw being connected to the lower implant part so that it is axially fixed but able to rotate.