Cannulated Bone Screw With Angular Blind Channels
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Solution Overview
Problem
Current bone screw technologies face challenges in delivering substances to specific areas within bones, especially the intervertebral disc, due to distal substance discharge during minimally invasive surgery, and require complex handling for plug insertion, and lack efficient minimally invasive removal methods.
Innovation Solution
A cannulated bone screw with a coaxial through bore and angularly disposed blind channels connected to the exterior via fenestrations, allowing oriented substance delivery and featuring flexible directing means for easy extraction, enabling precise delivery to vertebral end plates and intervertebral discs without puncturing the disc annulus and facilitating minimally invasive surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a through bore with distal opening is used to allow guiding wire insertion for minimally invasive surgery, then minimally invasive surgery is enabled, but substance discharge is mainly distal and cannot be oriented to specific bone areas
Solution Approach 1:
The through bore is segmented into multiple blind channels that are angularly disposed around the through bore. Each blind channel can receive a separate catheter or needle, allowing independent orientation of substance delivery to different bone areas while maintaining the single distal opening for minimally invasive insertion.
2Manufacturing precision
If a plug member is inserted into the internal longitudinal passage to close the passage at the distal end after removal of the guiding wire, then radial ejection of substance is enabled, but the system requires complex handling for plug insertion
Solution Approach 1:
The blind channels are designed to be open at the proximal end, allowing dynamic access for catheter or needle insertion after the guiding wire is removed. This eliminates the need for a plug member and complex insertion procedures, while still enabling oriented substance delivery through the angularly disposed channels.
3Adaptability or versatility
If disc puncture and perforation of the disc annulus is performed to deliver substances to the intervertebral disc, then intravenous treatments can access the disc, but degenerative disc disease often occurs
Solution Approach 1:
The blind channels are angularly disposed to direct substances locally to specific target areas within the vertebral body, such as the superior or inferior end plate. This allows precise localized delivery to the intervertebral disc through the vertebral body without requiring direct puncture of the disc annulus, thereby avoiding the harmful effects of disc perforation.
4Adaptability or versatility
If the bone screw is implanted for substance delivery, then treatment of bone and intervertebral disc is enabled, but minimally invasive extraction requires easy location of the screw head
Solution Approach 1:
A radiopaque marker is provided on the screw head or associated components. This marker appears on radiographic images, enabling easy location of the screw head for minimally invasive extraction while maintaining the treatment capability of the implanted bone screw.
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
Enables precise and oriented delivery of substances to the intervertebral disc and vertebral body, reducing the risk of degenerative disc disease, and allows for local radiotherapy and easy retrieval of the bone screw through minimally invasive surgery.
Implementation Method 1
Avascular tissue nutrients are delivered by diffusion from the capillaries at the disc-vertebral body interface. Consequently, intravenous treatments have difficulties to access intervertebral disc.
Data Source
AI summary
The present invention relates to a bone screw comprising a screw body comprising a proximal end, a distal end, a longitudinal axis and a thread along all or a portion of said screw body; a screw head; a through bore extending coaxially through said screw head and through said screw body from the proximal end up to the distal end; at least three blind channels angularly-disposed around the bore; each of said channels being configured to receive a perforated catheter or a needle; a plurality of radially-disposed fenestrations; wherein each of said channels is connected to an exterior of said screw body through at least one fenestration; and flexible directing means secured to the screw head. The present invention also relates to a system comprising such bone screw, to a method of delivering a substance to an intervertebral disc using the system according to the invention and to a method of treating vertebral tumor using the system according to the invention.