Intervertebral Spacer With Deployable Projections Against Migration
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Solution Overview
Problem
The stability of the vertebral column is compromised due to factors such as aging, mechanical injury, and disease, leading to impaired disc function and the need for additional support between adjacent vertebrae.
Innovation Solution
A spacer is inserted between vertebrae with moveable tissue engaging projections that deploy after insertion to stabilize the device and prevent migration, using an actuation subassembly with a drive nut, screw, and cam frame to extend the projections for engagement with adjacent tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spacer is inserted between adjacent vertebrae to provide support, then spinal stability is improved, but the spacer may migrate or tip due to lack of stabilization
Solution Approach 1:
The spacer transitions from a static structure to a dynamic one with deployable projections. The projections remain retracted during insertion to maintain a low profile, then extend after insertion to engage the vertebral bodies, providing active stabilization against migration and tipping forces.
Solution Approach 2:
The stabilization function is segmented from the main spacer body. The projections are separate, movable components that can be independently deployed, allowing the spacer to maintain its primary support function while adding stabilization only when needed.
2Stability of the object's composition
If tissue engaging projections are extended to stabilize the spacer, then migration and tipping are prevented, but the device complexity increases
Solution Approach 1:
The actuation mechanism merges multiple functions into a single integrated system. The cam frame, drive screw, and drive nut work together as one assembly that can be actuated by a single driver, simultaneously controlling multiple projections through the cam slots without requiring separate mechanisms for each.
Solution Approach 2:
The cam frame acts as an intermediary mechanism between the drive screw and the projections. It translates the rotational motion of the drive screw into the linear extension motion of the projections through its cam slots, providing a mechanical advantage and simplified control.
3Ease of operation
If projections are kept retracted during insertion, then insertion ease is improved, but stabilization function is not activated
Solution Approach 1:
The projections are prepared in a retracted state before insertion, allowing easy placement of the spacer between the vertebral bodies. After successful insertion, the actuation mechanism is activated to extend the projections, transitioning from the insertion phase to the stabilization phase in a controlled sequence.
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 spacer effectively stabilizes the vertebrae by engaging with surrounding tissue, preventing migration and tipping, facilitating fusion and providing structural support.
Implementation Method 1
the actuation subassembly comprise a drive nut, a drive screw coupled to the drive nut, and a cam frame coupled to the drive screw, wherein the cam frame is disposed between the first endplate and the second endplate to engage the tissue engaging projections
Data Source
AI summary
A spacer for separating bones of a joint, the spacer includes a first endplate configured to engage a first bone of the joint; a second endplate configured to engage a second bone of the joint; tissue engaging projections, wherein the tissue engaging projections are moveable from a retracted position to a deployed position; and an actuation subassembly that extends between the first endplate and the second endplate, wherein the actuation subassembly comprise a drive nut, a drive screw coupled to the drive nut, and a cam frame coupled to the drive screw, wherein the cam frame is disposed between the first endplate and the second endplate to engage the tissue engaging projections.