Bone Screw Drill Instrument with Sliding Sleeve and Countersink Bit
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Solution Overview
Problem
Current surgical instruments for drilling holes for bone screws lack efficient mechanisms for adjusting drill depth and preventing misalignment, which can lead to inaccuracies and increased surgical time due to the need for multiple tools and potential misuse of incorrectly sized tools.
Innovation Solution
A surgical instrument featuring a shaft with a primary drill fluted portion and a countersink drill bit, where a sleeve with a complementary inner surface is longitudinally slidable and locked at a selected position using a locking mechanism, allowing for precise adjustment and torque transmission, enabling the same tool to drill, guide, and countersink without swapping components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate tools are used for drilling, guiding, and countersinking, then each function can be performed by a specialized tool, but the number of tools increases and surgical time increases
Solution Approach 1:
The patent combines drilling, guiding, and countersinking functions into a single integrated instrument. The shaft includes a drill bit at one end and a countersink drill bit at the other end, while the sleeve provides guiding functionality. This merging eliminates the need for multiple separate tools and reduces surgical time by allowing all operations to be performed with one instrument.
Solution Approach 2:
The instrument is designed as a universal tool that performs multiple functions: the shaft with its drill bit creates the hole, the sleeve guides the instrument, and the countersink drill bit countersinks the hole. This multi-functionality allows a single tool to replace several specialized tools, improving surgical efficiency.
2Productivity
If a single instrument performs multiple functions, then surgical time is reduced, but the mechanism complexity increases
Solution Approach 1:
The instrument is segmented into distinct functional components: a shaft with a drill bit, a separate sleeve with guiding features, and a countersink drill bit. This segmentation allows each component to perform its specific function while maintaining overall simplicity. The modular design makes the complex multi-functional instrument easier to manufacture and understand.
Solution Approach 2:
The sleeve is designed to surround the shaft, with the countersink drill bit positioned at the distal end of the sleeve. This nested arrangement allows multiple functions to be compactly integrated without significantly increasing the overall instrument size or complexity. The sleeve nests around the shaft, and the countersink bit nests within the sleeve structure.
3Ease of operation
If the sleeve is freely slidable on the shaft, then depth adjustment is easy, but torque transmission becomes unreliable
Solution Approach 1:
The connection between the sleeve and shaft is made dynamic rather than fixed. The sleeve can slide freely along the shaft for easy depth adjustment during the approach phase, but once the drill bit engages the bone, friction and mechanical interference prevent further sliding, ensuring reliable torque transmission during drilling. This dynamic behavior automatically adapts to the operational phase.
Solution Approach 2:
Friction acts as an intermediary mechanism between the sleeve and shaft. During the approach phase, the sleeve slides freely with minimal friction. During the drilling phase, friction increases to prevent slippage and ensure reliable torque transmission. This intermediary friction force mediates between the need for easy adjustment and reliable power transmission.
4Ease of operation
If the drill depth is not precisely controlled, then the instrument is easier to operate, but drilling accuracy decreases
Solution Approach 1:
The patent replaces complex mechanical depth control mechanisms (such as threaded adjustments or cam-based systems) with a simpler friction-based sliding connection. The sleeve slides freely on the shaft without requiring mechanical locking mechanisms, making the instrument easier to operate while still providing sufficient depth control through the natural friction and mechanical interference that occur during drilling.
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
This solution allows for precise and efficient drilling and countersinking with a single instrument, reducing surgical time and minimizing the risk of tool misalignment, while providing a robust torque transmission mechanism and easy depth adjustment, enhancing surgical precision and efficiency.
Implementation Method 1
The sleeve's inner surface contacts the outer surface of the shaft's middle portion at least at the non-curved part such that the shaft can transmit torque to the sleeve
Data Source
AI summary
An instrument for drilling a hole for a bone screw comprises a shaft having a primary drill fluted portion, a shank, and a middle portion there between. Part of an outer surface of the shaft's middle portion is non-curved. A sleeve surrounds the shaft. The sleeve has an inner surface that is complementary to the outer surface of the shaft's middle portion such that the sleeve slides with respect to the shaft. The sleeve's inner surface contacts the outer surface of the shaft's middle portion at the non-curved part such that the shaft can transmit torque to the sleeve. A countersink drill bit is provided at an end of the sleeve proximate the shaft's primary drill fluted portion. A locking mechanism selectively holds the sleeve in a fixed position with respect to the shaft, locating the countersink drill bit at a selected position with respect to the shaft's drilling end.