Orthopaedic Drill Bit Geometry for Bone Swarf Reintroduction
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Solution Overview
Problem
In orthopaedic drilling, conventional drill bits fail to effectively collect and reintroduce bone swarf for autograft formation due to the ejection of shavings mixed with fluids, making it impractical for minimal access procedures, particularly in osteoporotic bone where reinforcement is crucial.
Innovation Solution
A drill bit design with helically extending flutes oriented in a counter-clockwise direction to the drilling direction, featuring a tapered tip with primary and secondary cutting edges, and a pyramidal arrangement of tip faces, which allows for the collection and reintroduction of bone swarf by reversing the wiping effect during retraction, facilitating improved bone re-growth and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional drill bits with clockwise flutes are used, then drilling operation is performed effectively, but bone swarf is ejected and cannot be collected for autograft
Solution Approach 1:
The flutes are configured to extend helically in a counter-clockwise direction opposite to the clockwise rotation direction of the drill bit. This inversion causes the flutes to wipe bone swarf toward the apex during rotation, and during retraction the flutes deposit the swarf back into the drill hole, enabling collection for autograft without requiring complex collection systems.
2Productivity
If bone swarf is ejected from drill hole, then drilling efficiency is improved, but autograft formation is compromised
Solution Approach 1:
The drill bit design enables recovery of bone swarf that would otherwise be discarded. The counter-clockwise flutes collect swarf during the drilling stroke and deposit it back into the drill hole during retraction, allowing the bone material to be reused as autograft while maintaining efficient drilling performance.
3Reliability
If synthetic bone fillers are used to augment fixation, then device stability is improved, but patient's own material is replaced
Solution Approach 1:
The drill bit enables the patient's own bone material to be recovered and reused as autograft, eliminating the need for synthetic fillers or donor graft material. The system serves itself by collecting and returning the bone swarf to promote bone re-growth and provide biological reinforcement for fixation devices.
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
The drill bit enhances bone re-growth and stability by effectively collecting and reintroducing bone swarf, reducing the need for synthetic fillers and promoting autograft formation, especially in osteoporotic bone, while minimizing drill bit aggression and improving control during surgery.
Implementation Method 1
a plurality of flutes, each flute extending helically along the body into the tip; each of the flutes helically extending in an opposite direction to the drilling direction
Implementation Method 2
A primary cutting edge is defined by the junction between the leading edge of each of the tip faces and the adjacent trailing side wall of the adjacent flute. It is these primary cutting edges that cut material being drilled
Implementation Method 3
The cutting end part of the drill bit, generally known as the tip or point, is formed by grinding the end region of the rod to provide a generally conical end part with end or tip faces extending from each land towards either a chiselled edge
Data Source
AI summary
A drill bit (100) having a longitudinal axis (101) and to be rotated about the axis (101) in a drilling direction (102) to perform a drilling operation. The drill bit (100) comprises a body (120) having a longitudinal length with a proximal end (121) and a distal end (122). The body (120) has a diameter. A tapered tip (110) extends from the proximal end (121) and terminates in an apex (111) at an end of the drill bit (100). The drill bit (100) also comprises a plurality of flutes (140) with each flute (140) extending helically along the body (120) into the tip (110). The drill bit (100) also comprises a land (150) between each of the flutes (140) and extends to the tip (110). The drill bit (100) also comprises a plurality of tip faces (190) on the tip (110) and extends from a corresponding land (150) to the apex (111), where each of the tip faces (190) has a tip face leading edge (173) and a tip face trailing edge (174). Each of tip face leading edges (173) forms an intersection with an adjacent one of the flutes (140) to provide a plurality of primary cutting edges (175). In a tip cross-sectional plane extending perpendicular to the axis (101) through each of the primary cutting edges (175), each of the primary cutting edges (175) lies on a circle extending about the axis (101) and each of the tip face trailing edges (174) lies entirely within the circle. Each of the flutes (140) helically extends in an opposite direction to the drilling direction (102).