Spinal Fixation Anchor Cam Mechanism
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Solution Overview
Problem
Current spinal fixation systems, such as pedicle screws, require multiple rotations and are time-consuming to secure into osseous tissue, making the surgical procedure labor-intensive.
Innovation Solution
A fixation assembly comprising an anchor with a cam mechanism that rotates between aligned and misaligned positions to secure to osseous tissue, reducing the rotational effort required for insertion, featuring a shaft with ridges that drive the cam's rotation and a flange to limit insertion depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pedicle screws are used for spinal fixation, then reliable spinal stabilization is achieved, but the procedure becomes time-consuming and labor-intensive due to multiple rotations required for securement
Solution Approach 1:
The fixation assembly employs a dynamic cam mechanism that transitions from an inserted state to a secured state through a single rotational motion. The cam rotates within the anchor, converting rotational motion into linear engagement force that secures the anchor to osseous tissue, eliminating the need for multiple rotations required by traditional pedicle screws
Solution Approach 2:
The invention extracts the cam mechanism from the traditional multi-component pedicle screw system, creating a simplified anchor-cam-shaft assembly. This extraction allows the cam to perform the securing function independently within the anchor, reducing the overall complexity and procedural steps required for fixation
2Reliability
If traditional pedicle screws are used for spinal fixation, then reliable spinal stabilization is achieved, but the procedure becomes labor-intensive due to multiple rotations required for securement
Solution Approach 1:
The cam mechanism provides a dynamic securing action where a single rotation of the shaft drives the cam to engage with the osseous tissue. This dynamic motion converts the operator's rotational input into effective securing force, making the operation simpler and less labor-intensive compared to the multiple rotations required by traditional screws
Solution Approach 2:
The cam mechanism is designed to self-secure the anchor to the bone through its rotational motion. As the shaft rotates, the cam automatically engages with the osseous tissue and locks the anchor in place, eliminating the need for separate securing steps or additional rotational operations
3Productivity
If the anchor is designed with minimal length extension into osseous tissue, then surgical efficiency is improved, but the securing capability may be compromised
Solution Approach 1:
The cam mechanism creates a dynamic engagement that maximizes securing capability within a compact anchor length. The rotational motion of the cam generates progressive engagement force that secures the anchor to the bone efficiently, allowing minimal insertion depth while maintaining reliable fixation
Solution Approach 2:
The cam is pre-positioned within the anchor in a retracted state that allows minimal insertion depth. Upon rotation, the cam automatically engages with the osseous tissue in a controlled manner, ensuring sufficient securing capability is achieved within the limited anchor length without requiring excessive insertion depth
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 fixation assembly significantly reduces the rotational effort needed for securement, allowing for faster and more efficient spinal stabilization with minimal length extension into osseous tissue, compared to traditional pedicle screws.
Implementation Method 1
A cam is disposed within the slot of the anchor. The cam is positioned to rotate about the longitudinal axis of the anchor between a first position and a second position to enable the first and second projections and the cam to secure the anchor to osseous tissue.
Implementation Method 2
The shaft is rotatably disposed within the anchor and positioned to rotate the cam between the first and second positions.
Implementation Method 3
The cam is positioned to rotate about the longitudinal axis of the anchor between a first position and a second position to enable the first and second projections and the cam to secure the anchor to osseous tissue.
Data Source
AI summary
A fixation assembly includes an anchor, a cam, and a shaft. The anchor defines a longitudinal axis and includes a spine that extends along the longitudinal axis. The spine has a first projection and a second projection that extend from the spine in a direction transverse to a longitudinal axis. The anchor defines a slot between the first and second projections. The cam is disposed with the slot and is positioned to rotate about the longitudinal axis between first and second positions to enable the first and second projections and the cam to secure the anchor to osseous tissue. The shaft is rotatably disposed within the anchor and positioned to rotate the cam between the first and second positions. In the first position, the cam is aligned with the first and second projections, and in the second position, the cam is misaligned with the first and second projections.