Snap Fit Rod Fastener System for Spinal Fixation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rod systems for spinal fixation are slow and labor-intensive to assemble, and post-assembly adjustments are difficult due to rigid attachments.
Innovation Solution
A fastener system comprising a fixation shaft, a pressure-responsive clamp, and a connector that frictionally engages a workpiece opening, allowing for quick assembly and adjustment by modifying the opening size through pressure application, with a bias mechanism for secure locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamp with arms and a fastener nut is used to secure a rod to a pedicle screw, then a secure attachment is achieved, but the assembly process becomes slow and labor-intensive
Solution Approach 1:
The clamp is divided into a body portion and a jaw portion that can move relative to each other. The jaw portion can be independently positioned and secured to the rod, allowing for faster assembly while maintaining secure attachment. This segmentation enables the clamp to quickly engage the rod without requiring complex multi-step fastening procedures.
Solution Approach 2:
The clamp incorporates a dynamic mechanism where the jaw portion can move between an open position for easy rod insertion and a closed position for secure attachment. This dynamic capability allows the clamp to adapt during assembly, enabling rapid engagement while ensuring reliable fixation once the rod is secured.
2Reliability
If a fastener is tightly secured to close off the opening between clamp arms, then a rigid and secure attachment is achieved, but post-assembly adjustments become difficult to make
Solution Approach 1:
The clamp is designed with a dynamic jaw portion that can move relative to the body portion even after initial securing. This allows the clamp to be adjusted post-assembly by simply moving the jaw portion to the desired position and re-securing it, providing ease of adjustment while maintaining secure attachment. The dynamic design eliminates the need to completely disassemble and reassemble the clamp for adjustments.
3Strength
If a rigid clamp structure is used to secure the rod, then structural strength is achieved, but the ability to accommodate positioning adjustments is reduced
Solution Approach 1:
The clamp is segmented into a rigid body portion that provides structural strength and a movable jaw portion that provides positioning flexibility. The rigid body maintains overall structural integrity while the movable jaw allows for easy positioning adjustments. This segmentation enables the clamp to simultaneously achieve both structural strength and adaptability for different rod positions.
Solution Approach 2:
The clamp incorporates a dynamic jaw portion that can be moved to different positions along the rod while maintaining secure attachment. This dynamic capability provides positioning flexibility without compromising the structural strength of the overall clamp assembly. The rigid body portion ensures strength while the movable jaw portion enables adaptability for various positioning requirements.
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
Facilitates faster and more efficient assembly of rods and pedicle screws, enabling easier adjustments and reducing the time required for orthopedic fixation, while providing a secure and adjustable attachment.
Implementation Method 1
The fixation shaft is configured to frictionally engage the workpiece opening
Implementation Method 2
The pressure-responsive portion is configured to modify the opening in response to pressure
Implementation Method 3
The connector is configured to connect the clamp to the fixation shaft and exert pressure on the pressure-responsive portion of the clamp so as to modify the opening
Implementation Method 4
A bias mechanism, such as a spring washer, may be configured for placement between the threaded nut and the body of the clamp
Data Source
AI summary
Implementations of the present disclosure provide a snap fit rod and fastener system including one or more fasteners for securing one or more rods to secure a spine or other anatomical structure. The fasteners include a fixation shaft, a clamp and a connector. The fixation shaft (for example a pedicle screw) is configured to frictionally engage a bone (vertebra) or other workpiece. The clamp has a pressure responsive portion that defines an opening configured to receive a rod. The connector is configured to connect the clamp to the fixation shaft and exert pressure on the clamp to modify the opening and secure the rod. A bias mechanism, such as a washer spring may be included to urge against the pressure responsive portion and which can be overcome by pressure on the rod for the “snap fit” effect. For additional adjustability, the clamp may be pivotally mounted on the fixation shaft.