Fenestrated Bone Screw for Directional Cement Placement
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Solution Overview
Problem
Current spinal implant systems lack effective directional control for cement placement during surgical procedures, leading to potential complications such as extravasation and inadequate fixation in areas of bone degeneration.
Innovation Solution
A fenestrated bone screw with strategically positioned openings and a directional indicator allows for controlled, uni-directional cement deployment, enhancing fixation and avoiding areas of diminished bone quality by facilitating targeted cement placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional bone fasteners are used for cement placement, then the procedure is simple, but directional control is lost leading to cement extravasation and inadequate fixation
Solution Approach 1:
The bone fastener shaft is segmented with multiple openings distributed at different locations and orientations. These openings divide the cement delivery function into multiple directional outlets, allowing controlled placement of cement in specific regions while preventing uncontrolled extravasation through the closed tip design.
Solution Approach 2:
Different regions of the bone fastener have different properties: the shaft contains openings for controlled cement delivery in specific directions, while the tip is closed to prevent extravasation. This local differentiation of structure and function enables precise directional control of cement placement while maintaining safety.
2Reliability
If cement is placed without directional control, then the procedure is fast, but fixation is inadequate in areas of bone degeneration
Solution Approach 1:
The bone fastener is pre-configured with strategically positioned openings before insertion. This preliminary arrangement of cement delivery pathways allows the surgeon to achieve reliable fixation in areas of bone degeneration without time-consuming intraoperative adjustments, maintaining surgical efficiency while improving fixation reliability.
3Ease of operation
If the shaft is open-ended for cement delivery, then cement placement is easy, but cement extravasation occurs causing complications
Solution Approach 1:
The shaft is segmented with multiple discrete openings instead of being fully open-ended. This segmentation allows cement to be delivered through controlled pathways while the closed tip prevents uncontrolled extravasation, balancing ease of delivery with safety.
Solution Approach 2:
The potential harm of an open-ended shaft causing extravasation is converted into a benefit by strategically placing openings in controlled positions. The same openness that could cause harm is transformed into controlled delivery pathways that prevent extravasation while maintaining ease of cement injection.
Data Source
Figure 1
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Figure 3~3a
AI summary
A bone fastener includes a shaft. The shaft includes a wall that defines a longitudinal cavity and a plurality of openings in communication therewith. The openings are disposed in axial alignment along the shaft and the wall is closed exclusive of the openings. In some embodiments, systems, spinal constructs, surgical instruments and methods are disclosed.