Method for detecting blade breakage using rate and/or impedance information
First Claim
1. A method for distinguishing between bad hand pieces and blade failures in an ultrasonic surgical system, comprising the steps of:
- applying a drive signal to an ultrasonic hand piece/blade at a predetermined drive frequency;
monitoring and storing a rate of change of a resonance frequency and a rate of change of a resonance impedance of the hand piece/blade as the drive frequency is changed in memory of the generator;
performing a diagnostic self test in an ultrasonic generator located in the ultrasonic surgical system;
monitoring the ultrasonic generator in the ultrasonic surgical system to determine whether lock is present;
if lock is not present, retrieving the rate of change of the resonance frequency and the rate of change of the resonance impedance from memory of the generator;
comparing the rate of change of the resonance frequency and the rate of change of the resonance impedance to obtain a fastest rate of change which is stored in the memory of the generator; and
if the rates of change are higher than normal rates of change due to temperature changes associated with longer blades, displaying a message on a liquid crystal display of the generator.
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Accused Products
Abstract
Failures associate with bad hand pieces and blade failures in an ultrasonic surgical system are distinguished by monitoring the rate of change of the resonance frequency and the rate of change of the resonance impedance of the hand piece/blade as the drive frequency is changed. As the system reaches resonance, the control system locks onto the resonance frequency. When a loss of lock occurs with no recovery, the rate of change of the frequency and rate of change of the impedance are compared to obtain the fastest rate of change which is stored in non-volatile memory of the ultrasonic generator. If the rates of change are higher than normal rates of change due to temperature changes with the longest blades, a “Bad Blade” message is displayed on an LCD.
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Citations
9 Claims
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1. A method for distinguishing between bad hand pieces and blade failures in an ultrasonic surgical system, comprising the steps of:
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applying a drive signal to an ultrasonic hand piece/blade at a predetermined drive frequency;
monitoring and storing a rate of change of a resonance frequency and a rate of change of a resonance impedance of the hand piece/blade as the drive frequency is changed in memory of the generator;
performing a diagnostic self test in an ultrasonic generator located in the ultrasonic surgical system;
monitoring the ultrasonic generator in the ultrasonic surgical system to determine whether lock is present;
if lock is not present, retrieving the rate of change of the resonance frequency and the rate of change of the resonance impedance from memory of the generator;
comparing the rate of change of the resonance frequency and the rate of change of the resonance impedance to obtain a fastest rate of change which is stored in the memory of the generator; and
if the rates of change are higher than normal rates of change due to temperature changes associated with longer blades, displaying a message on a liquid crystal display of the generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
displaying a “
Bad Blade”
message on the liquid crystal display, if the rates of change are higher than the normal rates of change due to the temperature changes associated with the longer blades; and
displaying a “
Bad Hand Piece”
message on the liquid crystal display, if the fastest rates of change are lower than the normally expected rates of change due to the temperature changes associated with the blades having the longest physical length and the generator passed the diagnostic self test.
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9. The method of claim 8, wherein the normally expected rates of change are constant values which are stored in the memory of the generator.
Specification