Ultrasonic Transducer Tissue Selectivity via Force Sensing
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Solution Overview
Problem
Conventional ultrasonic surgical aspirators lack proper tissue selectivity, especially at low amplitudes, and fail to control reserve power effectively, which is a limitation in neurosurgery and other procedures requiring precise tissue removal.
Innovation Solution
The use of an integral piezoelectric ceramic force sensing element in an ultrasonic surgical transducer allows for enhanced tissue selectivity by separating surgical tip stroke and power control, enabling precise amplitude modulation and pulse width modulation to manage power and cavitation, thereby improving tissue selectivity and control at low amplitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ultrasonic surgical aspirators are used, then tissue removal function is provided, but tissue selectivity is insufficient especially at low amplitudes
Solution Approach 1:
The patent segments the control functions by separating stroke control (via sense ceramic feedback) from power control (via amplitude modification parameters), allowing independent optimization of tissue selectivity and amplitude range. This segmentation enables precise control at low amplitudes while maintaining full power capability when needed.
Solution Approach 2:
The system dynamically adjusts the amplitude of the drive signal based on selected tissue selectivity levels and stored amplitude modification parameters. The controller modifies the reference drive signal in real-time, creating dynamic waveforms that adapt to different surgical requirements, thereby improving tissue selectivity across the full amplitude range.
2Manufacturing precision
If amplitude is reduced to improve tissue selectivity, then control over critical structures is enhanced, but reserve power control becomes ineffective
Solution Approach 1:
The patent changes the parameter of drive signal amplitude dynamically based on tissue selectivity level and stored modification parameters. By modifying the amplitude parameter in conjunction with sense ceramic feedback, the system maintains effective reserve power control while achieving improved tissue selectivity across all amplitude settings, not just at reduced amplitudes.
3Manufacturing precision
If piezoelectric transducer with sense ceramic is used, then tissue selectivity is enhanced, but device complexity increases
Solution Approach 1:
The patent merges the sensing function (sense ceramic) directly into the piezoelectric transducer structure, eliminating the need for separate sensing mechanisms. This integration achieves enhanced tissue selectivity through direct feedback while minimizing the increase in device complexity by combining multiple functions within a single integrated transducer assembly.
4Manufacturing precision
If amplitude modulation is applied to control tissue selectivity, then precision of tissue removal is improved, but control system complexity increases
Solution Approach 1:
The patent implements feedback control using the sense ceramic to monitor tip position and adjust the drive signal amplitude accordingly. The controller uses stored amplitude modification parameters and real-time feedback to automatically modulate amplitude, improving precision of tissue removal while managing control system complexity through automated closed-loop control rather than manual adjustment mechanisms.
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 provides improved tissue selectivity and control over a broader range of amplitudes, including low settings, reducing the risk of tissue damage and enhancing the precision of tissue removal in neurosurgery and other surgical procedures.
Implementation Method 1
a transducer disposed in the handpiece and having a sense ceramic that provides a voltage proportional to stress or charge proportional to deflection of the surgical tip
Implementation Method 2
an ultrasonic transducer supported within a handpiece, an ultrasonically vibrating horn or tip operably connected to the ultrasonic transducer
Implementation Method 3
A magnetostrictive transducer coupled with the connecting body functions as a first stage of the booster horn
Data Source
AI summary
Some implementations provide a high-powered compact ultrasonic transducer having an integral piezoelectric ceramic force sensing element utilized to enable enhanced tissue selectivity with a piezoelectric based transducer. Some implementations additionally or alternatively relate to methods and apparatus for driving ultrasonic surgical devices, such as methods and apparatus that modulate an amplitude of a drive signal, provided to an ultrasonic surgical device, in accordance with a selected tissue selectivity level. For example, the amplitude of the drive signal for a given tissue selectivity level can be varied with time in accordance with amplitude modification parameters that are particularized to the given tissue selectivity level. Some of those implementations additionally implement a corresponding duty cycle, for the drive signal, that corresponds to the selected tissue selectivity level.