Ultrasonic Cement Removal Tool with Helical Dimples
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Solution Overview
Problem
Existing ultrasonically-vibrated surgical tools for removing surgical cement from orthopaedic implants during revision arthroplasty can cause local bone damage and struggle with cement hardening, making the removal process inefficient and risky, especially for elderly patients with brittle bones.
Innovation Solution
The development of ultrasonically-vibratable surgical tools with a shaft featuring helically extending recesses and mixed torsional/longitudinal mode vibrations to efficiently soften and remove surgical cement, reducing the risk of bone damage and facilitating easier cement extraction by converting a portion of longitudinal-mode vibrations to torsional-mode vibrations, which helps in efficient cement removal and reduces re-hardening issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonically-vibrated tools are used to remove surgical cement, then cement removal efficiency is improved, but bone damage risk increases
Solution Approach 1:
The patent applies ultrasonic vibrations to the surgical tool to rapidly soften and remove PMMA cement from bone cavities. The high-frequency vibrations generate localized energy that breaks down the cement material, dramatically improving removal efficiency compared to conventional chiseling methods while reducing the mechanical contact force that could damage bone.
Solution Approach 2:
The patent changes the physical state of the cement from hardened to softened through ultrasonic vibration energy input. This parameter change (from solid to softened state) allows the cement to be easily removed without requiring high mechanical forces that could damage the surrounding bone structure.
2Loss of time
If ultrasonically-vibrated tools are used for cement removal, then procedure time is reduced, but anesthesia risk increases
Solution Approach 1:
The ultrasonic vibration mechanism enables rapid cement softening and removal, reducing the surgical procedure time from hours to minutes. This time reduction directly decreases the duration of general anesthesia required, thereby reducing anesthesia-related risks for the patient.
3Ease of operation
If longitudinal-mode ultrasonic vibrations are used, then tool operation is simplified, but cement removal effectiveness is reduced
Solution Approach 1:
The patent employs longitudinal-mode ultrasonic vibrations that are easiest to generate and operate. The tool head delivers these vibrations to the cement, effectively softening it for removal while maintaining simple tool operation and activation procedures.
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 tools enable rapid and convenient extraction of residual surgical cement from hollow bones, reducing the risk of bone damage and anesthesia complications, while the mixed-mode vibrations enhance the efficiency of cement removal and ease of tool cleaning.
Implementation Method 1
application of ultrasonically-vibrated tools led to rapid softening and even flow of the PMMA cement
Implementation Method 2
The operative head is adapted to soften surgical cement when vibrated ultrasonically
Data Source
AI summary
An ultrasonically-vibratable surgical tool for cement removal in revision arthroplasty, comprises an elongate solid shaft. This can be mounted at its proximal end to a source of ultrasonic vibrations, so that the shaft acts as a waveguide for propagation of the ultrasonic vibrations. The shaft has at its distal end an operative head to act on the cement. An intermediate portion of the elongate shaft is provided with at least one row of dimples extending helically along and around that portion of the elongate shaft. Each dimple is separate from each adjacent dimple. The dimples may have a shallow part-spherical profile.