Intervertebral Implant Insertion Instrument with Mediator Holder
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Solution Overview
Problem
The insertion of intervertebral implants between vertebrae is challenging due to the existing apparatus subjecting the implant to axial force and shearing, making it difficult to position the implant correctly without damaging the spine.
Innovation Solution
An instrument with upper and lower ramps, an adjustable spreader, and an implant holder that allows for controlled distraction of the vertebrae, keeping the implant separate from the ramps during insertion and withdrawal, reducing friction and the required force needed for positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the implant remains in contact with the guide members during advancement, then the implant can be positioned forwardly, but the implant is subjected to axial force and shearing which may damage the spine
Solution Approach 1:
The patent introduces an implant holder as an intermediary component between the guide members and the implant. The holder engages the implant and transfers the pushing force from the guide members to the implant, allowing the implant to be advanced without direct contact with the guide members. This eliminates axial force and shearing on the implant while maintaining positioning capability.
Solution Approach 2:
The system is segmented into distinct functional components: guide members for separation, an implant holder for gripping and advancing the implant, and the implant itself. This segmentation allows each component to perform its specific function without imposing harmful forces on the implant, resolving the contradiction between positioning ease and force reduction.
2Ease of operation
If the spreader is advanced forwardly to separate the vertebrae, then the implant can be positioned between the vertebrae, but the implant is subjected to compressive force
Solution Approach 1:
The implant holder serves as a mediator that decouples the spreader's forward motion from direct contact with the implant. The holder is pushed by the spreader but grips the implant to advance it separately, ensuring the implant does not experience compressive force from the spreader while still achieving proper positioning between the separated vertebrae.
Solution Approach 2:
The vertebrae are separated by the spreader in advance before the implant is advanced into position. This preliminary separation creates the necessary intervertebral space, allowing the implant to be inserted without experiencing compressive force during the separation process itself.
3Productivity
If the implant is advanced forwardly in contact with the guide members, then the implant can be inserted in the intervertebral space, but the required force increases due to friction
Solution Approach 1:
The implant holder acts as a mediator that grips the implant and advances it through the intervertebral space without the implant contacting the guide members. This eliminates friction between the implant and guide members, significantly reducing the force required for insertion while maintaining efficient advancement.
Solution Approach 2:
The direct mechanical contact between the implant and guide members is replaced by a gripping mechanism (implant holder) that transfers force through friction between the holder and implant, rather than between the implant and guide members. This substitution reduces the overall friction and force requirements for 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 positioning of the implant between vertebrae with reduced risk of damage, minimizing contact with the ramps to prevent compressive force and shearing, thus facilitating easier and safer insertion and retention of the implant.
Implementation Method 1
A drive member has a longitudinal axis and a screw thread thereon. The drive member is disposed between the upper and lower ramps and extends through a passage in the bracket assembly.
Implementation Method 2
The upper ramp bears against the adjustable spreader as the spreader forwardly advances along the longitudinal axis causing the upper ramp to separate from the lower ramp.
Data Source
AI summary
An instrument for inserting an implant between vertebrae includes an upper and a lower ramp each having a respective proximal and a distal end. A bracket assembly is coupled to the upper and lower ramps at the proximal ends. The bracket assembly biases the upper and lower ramps closed at the distal end. A drive member has a longitudinal axis and a screw thread thereon. The drive member is disposed between the upper and lower ramps and extends through a passage in the bracket assembly. An adjustable spreader is operably coupled to the drive member and movable between the upper and lower ramps along the longitudinal axis by rotation of the drive member. The adjustable spreader separates the upper ramp from the lower ramp during forwardly movement along the longitudinal axis. An implant holder is coupled to the adjustable spreader.