Self-Drilling Bone Screw Geometry for Precise Low-Torque Insertion
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Solution Overview
Problem
Existing bone screws face challenges in achieving quick and accurate placement, requiring additional equipment and increasing operational difficulty and risk during spinal procedures.
Innovation Solution
A bone screw design featuring an elongate shank with cutting edges having a positive rake angle and trailing surfaces angled to minimize drag, allowing efficient advancement into bone with reduced torque and force requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional bone screws are used, then the screw can be implanted into bone, but additional equipment is required and operational difficulty increases
Solution Approach 1:
The patent combines the drilling function and screw fixation function into a single integrated bone screw device. The screw includes a drill tip with cutting edges at its distal end, eliminating the need for separate drilling equipment and simplifying the overall system while maintaining both drilling and fixation capabilities.
Solution Approach 2:
The drill tip with cutting edges is pre-formed as an integral part of the bone screw before implantation. This preliminary preparation of the drilling function allows the screw to create its own insertion path without requiring pre-drilling or separate drilling equipment during the surgical procedure.
2Manufacturing precision
If conventional bone screws are used, then the screw can be implanted into bone, but operational time increases and precision decreases
Solution Approach 1:
The bone screw is segmented into distinct functional zones: a drill tip with cutting edges for precise bone penetration, a transition zone, and a threaded shaft for fixation. This segmentation allows each zone to perform its specific function optimally, improving both placement precision and speed by eliminating the need for separate drilling and screwing operations.
Solution Approach 2:
The cutting edges at the drill tip are designed with specific geometric features including a positive rake angle and trailing surfaces angled to minimize drag. These dynamic geometric features optimize the cutting action during rotation, enabling faster and more precise bone penetration while reducing the torque required for insertion.
3Force
If cutting edges with positive rake angle are used, then torque requirements are reduced, but manufacturing complexity increases
Solution Approach 1:
The cutting edges are designed with optimized geometric parameters including a positive rake angle and specifically angled trailing surfaces. These parameter changes reduce the torque required for bone penetration by improving the cutting efficiency, while the geometric features are designed to be manufacturable using standard machining processes.
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
Facilitates easy and precise insertion of bone screws into bone, reducing operational time and complexity while ensuring correct placement.
Implementation Method 1
cutting edges having a positive rake angle and trailing surfaces angled to minimize drag, allowing efficient advancement into bone with reduced torque and force requirements
Data Source
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AI summary
Various bone screws configured to be implanted into bone and methods of use are provided. In an exemplary embodiment, a bone screw is provided with an elongate shank and a head with a drive feature configured to couple with a driver tool for being advanced into bone and a threaded shank. The screw can have a distal end or tip that has one or more cutting edges thereon configured to cut bone as the bone screw is inserted into bone.