Flexible Fusion Rod Insertion for Long Percutaneous Rod Placement
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Solution Overview
Problem
Existing fusion rod insertion methods in percutaneous fusion surgery face limitations, particularly in the 'inside' approach, where long rods are difficult to insert due to rigid connections and limited space within pedicle screw towers, restricting rod length and complicating the procedure.
Innovation Solution
The use of flexible elements, such as wires or strips, connected to the fusion rod and guided through arcuate members, allowing the rod to be pulled into the towers, along with a rod inserter that controls rod orientation, facilitating easier and longer rod placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a rigid connection insertion tool is used to push the fusion rod into the tower, then the rod can be inserted with controlled orientation, but the rod length is limited due to space constraints inside the tower and rotation mechanism limitations
Solution Approach 1:
The patent replaces the rigid connection insertion tool with a flexible element (wire or strip) that can be pulled through the tower to draw the fusion rod inside. This flexible element can navigate the tower's internal space and rotation mechanism more effectively, enabling insertion of longer rods without being constrained by the tower's internal dimensions.
Solution Approach 2:
Instead of pushing the rod into the tower from the outside using a rigid tool, the invention inverts the approach by pulling the rod inside the tower using a flexible element that is drawn through the tower's internal space. This reversal of the insertion direction allows for greater rod length capability.
2Object-affected harmful factors
If the 'inside' approach is used to insert the fusion rod through the tower, then soft tissue management is improved and stress on soft tissues is reduced, but it becomes particularly difficult to insert long fusion rods
Solution Approach 1:
The flexible element (wire or strip) used to pull the fusion rod through the tower can bend and navigate the tower's internal geometry, allowing long rods to be inserted via the 'inside' approach without excessive soft tissue stress. The flexibility enables the element to follow the tower's path while accommodating longer rod lengths.
3Ease of operation
If the 'outside' approach is used to insert the fusion rod through small incisions, then ease of access and instrumentation simplicity are improved, but soft tissue management is compromised and stress on soft tissues increases
Solution Approach 1:
The flexible element acts as an intermediary that transmits the pulling force from the insertion tool through the tower to the fusion rod. This intermediary mechanism enables the 'inside' approach to be as simple as the 'outside' approach while maintaining superior soft tissue management, as the flexible element can be manipulated from outside to pull the rod through internal pathways.
Data Source
AI summary
A fusion rod includes mounting structures located at different places thereon, and a first flexible element attached to one of the mounting structures and a second flexible element attached to another of the mounting structures.