Cannulated Screw With Solid Stem For Bone Cement Delivery
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Solution Overview
Problem
Existing devices for stabilizing bone fractures and osteoporotic tissue face challenges in delivering high viscosity fluids like bone cement effectively due to fluid flow issues, leading to inadequate stabilization and resistance to deformation and shear forces.
Innovation Solution
A cannulated screw with a stem and engagement means that transforms into a solid screw, ensuring stable engagement and preventing fluid reflux, allowing for effective delivery of medicinal substances and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a cannulated screw with holes is used for injecting bone cement, then medicinal substances can be delivered to the bone tissue, but the high viscosity fluids cannot reach the furthest holes effectively due to fluid flow limitations
Solution Approach 1:
The screw is divided into multiple holes along its length, allowing bone cement to be delivered to different locations. The segmentation enables targeted delivery at multiple points rather than requiring a single long passage.
Solution Approach 2:
Instead of relying on linear flow through a single channel, the invention uses multiple holes distributed along the screw length, transforming the delivery problem from a one-dimensional flow issue to a multi-point distribution system.
2Quantity of substance
If a cannulated screw is used to allow fluid injection, then medicinal substances can be introduced, but the device has insufficient stability to deformation and resistance to shear forces
Solution Approach 1:
A solid stem is nested inside the cannulated screw body, filling the hollow interior. This nested structure provides internal support to the cannulated screw, significantly enhancing its resistance to deformation and shear forces while preserving the external hollow structure needed for cement injection.
Solution Approach 2:
The device combines the cannulated screw structure (hollow for injection) with an internal solid stem (for strength), creating a composite structure that exhibits both injection capability and mechanical strength.
3Strength
If a stem is inserted into the screw for structural support, then resistance to deformation improves, but fluid reflux into the cannulated screw cannot be prevented
Solution Approach 1:
A check valve is introduced as an intermediary component between the external environment and the internal channel. This valve allows outward flow of injected materials while preventing inward reflux of biological fluids, mediating the flow directionality.
Solution Approach 2:
The check valve provides dynamic flow control, allowing the system to adapt to pressure changes during injection and preventing reflux when pressure gradients reverse, transforming a static structure into a dynamically responsive system.
4Strength
If traditional osteosynthesis means are used for elderly patients with osteoporotic tissue, then bone stabilization is attempted, but the low bone stability does not guarantee satisfactory results
Solution Approach 1:
Bone cement with osteoconductive properties is injected through the screw holes into the osteoporotic bone tissue, creating a porous interface that promotes bone ingrowth and enhances the reliability of stabilization in low-density bone.
Solution Approach 2:
The invention merges mechanical fixation (screw) with biological fixation (bone cement with osteoconductive properties), combining immediate mechanical stability with long-term biological integration for enhanced reliability in osteoporotic bone.
Data Source
AI summary
The present invention relates to a device for the selective biological synthesis of a bone tissue arranged to allow the stabilization of a fracture or an osteoporotic bone tissue and for the introduction of medicinal substances for bone diseases.