Ultrasonic Handpiece for Bone Screw Augmentation
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Solution Overview
Problem
Existing methods for augmenting bone screws in osteoporotic bones using fixation cement lack reliability and even distribution due to variable manual pressure application.
Innovation Solution
An ultrasonic handpiece with a preloaded sonotrode and adjuster wheel system is used to consistently apply vibrations and compression to a polymeric rod, ensuring reliable and controlled fluidization of the cement within the bone screw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual compression force is applied to jet fixation cement into the bone screw, then the cement can be introduced into the bone, but the pressure varies from application to application and during application causing unreliable and uneven distribution
Solution Approach 1:
The patent replaces the manual mechanical compression system with an ultrasonic vibration system. The ultrasonic handpiece generates high-frequency vibrations that fluidize the fixation cement and propel it into the bone screw through acoustic radiation pressure and cavitation effects, eliminating the need for manual compression and ensuring consistent, reliable cement distribution.
Solution Approach 2:
The patent changes the physical state and delivery parameters of the fixation cement by using ultrasonic vibration to temporarily fluidize the cement (changing its viscosity parameter) and then propel it into the bone screw. This parameter change allows for controlled, reliable material distribution without manual pressure variation.
2Manufacturing precision
If manual pressure is applied to the fixation cement, then the cement can be jetted into the bone screw, but the pressure is not even during application resulting in uneven cement distribution
Solution Approach 1:
The patent replaces the complex manual pressure control mechanism with a standardized ultrasonic vibration system. The ultrasonic handpiece provides consistent, controlled vibrations that evenly fluidize and distribute the fixation cement throughout the bone screw, achieving uniform material distribution without complex pressure control.
Solution Approach 2:
The patent uses ultrasonic vibration to create high-frequency oscillations that uniformly fluidize the fixation cement and propel it into the bone screw. This vibrational mechanism ensures even distribution of the cement material throughout the implant site, eliminating the unevenness caused by manual pressure application.
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 approach ensures a reproducible and even augmentation of the bone screw by providing a defined compression force and controlled material distribution, enhancing the stability of the bone screw within the bone.
Implementation Method 1
the ultrasonic converter activated so that the polymeric rod liquefies
Implementation Method 2
the polymeric rod liquefies
Data Source
AI summary
An ultrasonic handpiece is used for augmenting a bone screw. The handpieces comprise a housing, an ultrasonic converter shiftingly accommodated in the housing, and a sonotrode connected to one end of the ultrasonic converter. The sonotrode protrudes from the housing into the bone screw. An adjuster wheel is adjustably connected to the housing. A spring is provided the ends of which are supported by the ultrasonic converter and the adjuster wheel, respectively. The ultrasonic converter is preloaded in the direction away from the adjuster wheel by setting the adjuster wheel, thereby the sonotrode is urged with a selected force into the bone screw and the augmentation material is pressed out of the bone screw and into the bone.