Polyaxial Screw-Rod Construct for Occipital-Cervical Stabilization
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Solution Overview
Problem
Current spinal fixation devices face challenges in capturing spine rods at extreme angles and providing stable occipital-cervical fixation, particularly due to limited anchor points and potential for intracranial injuries during occipital screw placement, which complicates surgeries and reduces fusion rates.
Innovation Solution
The method involves using polyaxial screws and condyle screws placed in the occipital condyles to achieve stable occipital-cervical fixation, allowing for greater flexibility in screw angulation and reducing the need for multiple attachment points, thereby improving fusion rates and minimizing complications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If occipital screws are placed for fixation, then stable occipital-cervical fixation is achieved, but risk of intracranial injuries increases
Solution Approach 1:
The patent removes the occipital screws from the fixation system entirely, replacing them with a rod-to-rod connection mechanism. This extraction eliminates the harmful factor of intracranial injury risk associated with occipital screw placement while maintaining fixation stability through the alternative connection method between rods and cervical vertebrae.
Solution Approach 2:
The rod-to-rod connection mechanism serves multiple functions: it provides stable fixation, allows for angular adjustment to accommodate spinal curvature, and eliminates the need for occipital screw placement. This multi-functional approach resolves the contradiction by achieving fixation stability without the associated surgical risks.
2Adaptability or versatility
If coupling elements are rotated to extreme angles for rod capture, then flexibility in accommodating spinal curvature is improved, but device reliability decreases
Solution Approach 1:
The coupling element incorporates a dynamic mechanism that allows controlled rotation and angular adjustment during rod insertion. This dynamic capability enables the system to adapt to various spinal curvatures while maintaining structural integrity and reliability through controlled movement rather than extreme static angles.
Solution Approach 2:
The coupling element's angular parameters can be adjusted within a controlled range to accommodate spinal curvature variations. By changing these parameters dynamically during surgery rather than requiring extreme fixed angles, the system maintains both adaptability and device reliability.
3Reliability
If multiple attachment points are used for occipital fixation, then fixation stability is improved, but surgical complexity and time increase
Solution Approach 1:
The patent eliminates the need for multiple occipital attachment points by removing occipital screws from the system. The fixation stability previously achieved through multiple attachment points is now accomplished through the rod-to-rod connection mechanism combined with cervical vertebrae anchoring, thereby reducing surgical complexity and time.
4Adaptability or versatility
If spine rods are bent in multiple planes to pass through coupling elements, then adaptability to spinal curvature is improved, but rod strength decreases
Solution Approach 1:
Instead of bending the rod in multiple planes which weakens it, the coupling element provides dynamic angular adjustment capability. This allows the rod to be inserted at various angles without physical bending, thereby maintaining rod structural integrity while still accommodating spinal curvature.
Solution Approach 2:
The patent replaces the mechanical bending of rods with a mechanical adjustment system in the coupling element. This substitution allows curvature accommodation through controlled rotation and angle adjustment rather than permanent deformation of the rod, preserving its strength.
Data Source
AI summary
Occipital-cervical stabilization using occipital condyle fixation with a polyaxial screw-rod construct.