Pedicle Screw Reduction Linkage for High-Grade Spondylolisthesis
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Solution Overview
Problem
Existing pedicle screw instruments face challenges in achieving a universal fit with standard pedicle screws and providing an improved range of motion to correct high-grade spondylolisthesis effectively.
Innovation Solution
A pedicle screw distractor and reduction instrument featuring a main body with pivot axes, distraction and reduction mechanisms, and anchors that allow for universal coupling with poly-axial screws, enabling controlled distraction and reduction of pedicle screws to correct spinal misalignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing pedicle screw instruments are used, then the basic distraction function is provided, but the range of motion is insufficient to correct high-grade spondylolisthesis effectively
Solution Approach 1:
The instrument incorporates multiple pivot axes (first pivot axis, second pivot axis, third pivot axis) that enable dynamic multi-planar motion. The secondary link pivotably mounted at the first pivot axis and the distal anchor pivotably coupled at the second pivot axis allow the device to adapt its orientation and achieve greater range of motion for correcting high-grade spondylolisthesis
2Adaptability or versatility
If existing pedicle screw instruments are used, then basic distraction is achieved, but universal coupling with standard poly-axial screws is not provided
Solution Approach 1:
The anchors are designed with universal coupling features that interface with standard poly-axial screw heads. The anchor structure includes a body that receives the screw head and a foot that engages with the rod, allowing the same anchor design to work with various standard pedicle screw systems without requiring custom instrumentation
3Manufacturing precision
If distraction force is applied to correct spondylolisthesis, then spinal misalignment is reduced, but tissue stress increases during the correction process
Solution Approach 1:
The multi-pivot linkage system provides dynamic motion that distributes distraction forces through multiple degrees of freedom. This allows gradual, controlled correction of spinal misalignment while minimizing sudden load spikes that could damage neural or soft tissues
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 instrument provides a versatile and effective solution for correcting high-grade spondylolisthesis by allowing for a wide range of motion and precise alignment of pedicle screws, minimizing tissue stress during the correction process.
Implementation Method 1
a distraction actuator coupled to the drive link and structured to move the main body relative the secondary link about the first pivot axis
Implementation Method 2
a reduction actuator engaged with the distal anchor tab and the race of the reduction foot to move the distal anchor foot relative to the main body about the second pivot axis
Implementation Method 3
a proximal bar pivotably coupled to the secondary link about the third pivot axis
Data Source
AI summary
A pedicle screw distractor and reduction instrument that includes a main body including a distraction tab and a reduction foot; a secondary link pivotably mounted to the main body; a drive link coupled between the secondary link and the distraction aperture; a distraction actuator coupled to the drive link and structured to move the main body relative the secondary link; a proximal anchor pivotably coupled to the secondary link and including a proximal anchor foot configured to engage a proximal pedicle screw; a distal anchor pivotably coupled to the main body and including a distal anchor foot configured to engage a distal pedicle screw; and a reduction actuator engaged between the reduction foot and the distal anchor to move the distal anchor foot relative to the main body.