Variable Head Driver Expandable Mechanism for Secure Implant Engagement
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Solution Overview
Problem
Existing surgical drivers for placing threaded implants in bone tissue face challenges such as complex assemblies, wear and tear leading to malfunction, and difficulty in maintaining a secure fit between the screw head and the driver, which can result in the screw detaching during procedures.
Innovation Solution
A surgical driver with a simplified assembly comprising an outer cannulated shaft and an inner cannulated shaft with a tapered tip, allowing for a secure engagement of the driving member with the implant through an expandable mechanism, reducing the risk of deformation and improving ease of use and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple moving parts and self-retaining features are added to the driver to hold the screw firmly, then the screw attachment security is improved, but the device complexity increases and malfunction rates increase
Solution Approach 1:
The driver employs nested cannulated shafts where an inner cannulated shaft fits within an outer cannulated shaft. The inner shaft contains a tapered tip that expands the driving member, while the outer shaft provides structural support. This nested configuration achieves secure screw attachment through the expandable mechanism rather than multiple separate retaining features, thereby reducing overall device complexity while maintaining reliability.
Solution Approach 2:
The driver utilizes a dynamic expandable driving member that transitions from a compressed state during insertion to an expanded state during actuation. The tapered tip on the inner shaft forces the driving member to expand, creating a secure grip on the implant. This dynamic mechanism replaces static multiple retaining features, simplifying the device while ensuring firm screw attachment throughout the procedure.
2Reliability
If complex articulating features with multiple moving parts are used to lock the screw, then the screw holding capability is improved, but the ease of operation deteriorates and repair difficulty increases
Solution Approach 1:
The driver is segmented into distinct functional components: an outer cannulated shaft for structural support and guidance, an inner cannulated shaft for actuation, and an expandable driving member for screw engagement. This segmentation allows each component to perform its specific function efficiently. The inner shaft can be independently actuated to expand the driving member, providing simple operation while maintaining secure screw holding capability.
Solution Approach 2:
The design extracts the locking function from complex articulating mechanisms and implements it through the expandable driving member. By removing the need for separate locking features and multiple moving parts, the driver achieves secure screw holding through the expansion mechanism alone, thereby simplifying operation and reducing the number of components that require coordination during use.
3Productivity
If the driver is used repeatedly, then productivity is improved, but wear and tear causes malfunction and the driver must be discarded
Solution Approach 1:
The driver design incorporates an expandable driving member that distributes contact forces across a larger surface area during screw engagement. This expansion mechanism reduces point-load stresses on the driving surfaces, providing beforehand cushioning against wear. By reducing stress concentration, the driver maintains reliable performance over repeated uses, extending its service life and reducing the frequency of replacement.
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 driver provides a secure and reliable attachment of the implant to the driver, reducing the risk of detachment during surgery, while also simplifying the assembly and maintenance, thus extending the lifespan of the instrument and reducing costs.
Implementation Method 1
The distal tip of the inner shaft is tapered and is utilized for affecting the outer diameter of the tip of the outer shaft... The inner shaft... cooperates with the outer shaft to affect the driving member
Data Source
AI summary
An apparatus for use in placing an implant into a patient is disclosed. The apparatus features an outer assembly having an outer shaft with an expandable driving member at its distal end and an inner cannulated shaft that fits within and cooperates with the outer shaft to affect the driving member. The inner shaft includes an actuation knob attached to the proximal end of the inner shaft. A locking or driving thread is included on the outer surface of the inner shaft, proximal to the adjustment knob. The outer shaft includes a housing with the threaded interior such that when the inner shaft is mounted within the outer shaft, the driving thread operates with the threaded interior of the housing to allow for the inner shaft to be advanced along the inside of the outer shaft as the knob is turned. The tip of the inner shaft interacts with the interior of the driving member to expand the driving member.