Vertebral Fixing System Ligature Locking Mechanism
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Solution Overview
Problem
Existing vertebral fixing systems face challenges in establishing secure fixation points when screws cannot be inserted into curved spine vertebrae and the use of hooks is too dangerous, leading to potential jamming issues with flexible ligatures during traction.
Innovation Solution
A vertebral fixing system featuring a connecting part with passageways for two ligature strands, adjustable locking means that can be screw-fastened to create friction and prevent translation, ensuring controlled tension and effective clamping between the ligature and vertebrae or rib processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hooks are used to establish fixing points on vertebrae, then fixation can be achieved without inserting into the vertebral body, but the risk of damaging the spinal cord increases significantly
Solution Approach 1:
The patent introduces a connecting part as an intermediary device that attaches to the rod and engages with the rib or transverse process through a ligature, rather than directly engaging with the vertebra. This intermediary connecting part allows the fixation system to achieve stable attachment without hooks that could endanger the spinal cord, thus resolving the contradiction between ease of fixation and safety.
2Adaptability or versatility
If flexible ligatures are used to connect the connecting part to ribs or transverse processes, then adaptability to curved spines is improved, but the ligatures may jam during traction operations
Solution Approach 1:
The patent employs adjustable locking means that can change the physical state of the ligature from flexible to constrained. The locking means include friction elements and clamping structures that can adjust the tension and position of the ligature, preventing jamming while maintaining adaptability to curved spine configurations. This parameter change approach resolves the contradiction between flexibility and reliability.
3Strength
If screws are inserted into the pedicles of vertebrae, then secure fixation points are established, but this is not possible when pedicles are small or damaged
Solution Approach 1:
The patent segments the fixation system into separate functional components: a connecting part that attaches to the rod, a flexible ligature that connects to the rib or transverse process, and adjustable locking means. This segmentation allows the system to achieve secure fixation through alternative anatomical landmarks (ribs or transverse processes) rather than relying solely on the pedicles, thus resolving the contradiction between fixation strength and adaptability to damaged or small pedicles.
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
This system provides reliable and controlled locking of the ligature, preventing jamming and ensuring proper fixation by distributing tension effectively across the vertebrae or rib processes, even in curved spine conditions, while minimizing risk to the spinal cord.
Implementation Method 1
adjustable locking means which are capable of taking a first position relative to the connecting part in which the two ligature strands are free in said strand-passing passageway(s), a second position relative to the connecting part in which the two ligature strands are prevented from moving in translation relative to the connecting part
Data Source
AI summary
A vertebral fixing system suitable for being mounted on a vertebra of the spine for connecting it to a rod. The system includes: a connecting part suitable for being connected to the rod, a flexible ligature of elongate shape having two free ends suitable for connecting together the connecting part and at least a portion of a vertebra and/or a rib, and an adjustable locking member mounted on the connecting part. The connecting part defines at least one passageway for passing the ligature in such a manner that two distinct strands of the ligature can be engaged in the passageway so that the two strands of the ligature define a first ligature portion forming a loop extending from one side of the connecting part, and second and third ligature portions extending from the other side of the connecting part.