High frequency electrosurgical apparatus for thermal coagulation of biologic tissues
First Claim
1. High frequency electro surgical apparatus for thermal coagulation of biologic tissues comprising a high frequency electric generator having a fundamental frequency (f1) of operation and having an output circuit equipped with a coagulation electrode for contact with biological tissues of a patient and with switching means for manual or automatic activation of said generator to produce an output of high frequency current and for automatic switching off of a coagulation operation in dependence upon changes in electric conductivity of said tissues of said patient, and further comprising, in accordance with the invention:
- electrical monitoring means (25) having an input coupled to said output circuit of said high frequency generator for monitoring amplitude fluctuations of the output of said high frequency electric generator during each coagulation operation by monitoring at least one of the current and voltage of said output, said monitoring means including means (50, 51,
52) for deriving from the output high frequency current (IHF) of said generator, a voltage proportional to the amplitude fluctuations (A(t)2) of said high frequency current (IHF), first detection means (53, 55, 58, 60,
62) coupled for being responsive to the output of said voltage deriving means for producing, at an output of said first detection means, a first DC voltage (Ua) proportional to said amplitude fluctuations (A(t)) of said high frequency current (IHF) and second detection means (54, 56, 61,
63) coupled for response to rising portions of fluctuations of said high frequency current and constituted as a peak value detector, for producing, at an output of said second detection means, a second DC voltage (Ub) which rises proportionally to the rising portion of fluctuations of said high frequency current;
voltage comparison means (67) coupled for response to said respective outputs of said first and second detection means for comparing said first DC voltage (Ua) and a predetermined adjustable fraction (kUb) of said second DC voltage and producing a comparison result signal at an output of said comparison means;
a bistable switching control circuit (70) coupled to said output of said comparison means and connected for being set by the comparison result signal of said voltage comparison means (67) when said first DC voltage (Ua) becomes smaller than said predetermined fraction (kUb) of said second DC voltage and thereby to produce an output control signal (Q);
means coupled for response to said bistable circuit (70) and connected to said high frequency generator for shutting off the output of said high frequency generator in response to said output control signal (Q) of said bistable circuit (70), andmeans (23) for reactivating, and usable for initially activating, the output of said high frequency generator in response to operation of a manual switch (21), to operation of an automatic switch (22) or to both said manual switch and said automatic switch.
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Accused Products
Abstract
A high frequency surgical apparatus for the thermal coagulation of biologic tissues is described, in which for monitoring the fluctuations in amplitude of the high frequency current during each coagulation process a current monitor (25) is provided, which by means of a current-to-voltage coverter generates an electrical voltage proportional to the amplitude fluctuations of the high frequency current, from which voltage, by means of a first detector, a first direct voltage proportional to the amplitude fluctuations is formed and, by means of a second detector acting as a peak value detector, a second direct voltage is formed that rises in proportion to the amplitude of the high frequency current. The first direct voltage (Ua) and the second direct voltage (kUb), which is divided downward by an adjustable factor by means of a voltage divider, are supplied to a voltage comparator, the output signal of which sets a bistable circuit as soon as the first direct voltage (Ua) becomes lower than the downwardly divided second direct voltage (kUb). The output signal of the bistable circuit switches the high frequency current off until the high frequency current is switched back on again by actuation of a manual switch and/or by means of an automatic switch. Instead of or in addition to this current monitor (25), and electric arc monitor (26) for monitoring the generation of anharmonic frequencies of the base frequency of the frequency generator can be connected to the output of the surgical apparatus, the arc monitor including a filter which passes at least one of the anharmonic frequencies, generated by the electric arc, of the base frequency of the high frequency generator. The output signal of the filter is supplied to a voltage comparator, the output signal of which resets a bistable circuit such that its output signal switches off the high frequency current.
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Citations
10 Claims
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1. High frequency electro surgical apparatus for thermal coagulation of biologic tissues comprising a high frequency electric generator having a fundamental frequency (f1) of operation and having an output circuit equipped with a coagulation electrode for contact with biological tissues of a patient and with switching means for manual or automatic activation of said generator to produce an output of high frequency current and for automatic switching off of a coagulation operation in dependence upon changes in electric conductivity of said tissues of said patient, and further comprising, in accordance with the invention:
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electrical monitoring means (25) having an input coupled to said output circuit of said high frequency generator for monitoring amplitude fluctuations of the output of said high frequency electric generator during each coagulation operation by monitoring at least one of the current and voltage of said output, said monitoring means including means (50, 51,
52) for deriving from the output high frequency current (IHF) of said generator, a voltage proportional to the amplitude fluctuations (A(t)2) of said high frequency current (IHF), first detection means (53, 55, 58, 60,
62) coupled for being responsive to the output of said voltage deriving means for producing, at an output of said first detection means, a first DC voltage (Ua) proportional to said amplitude fluctuations (A(t)) of said high frequency current (IHF) and second detection means (54, 56, 61,
63) coupled for response to rising portions of fluctuations of said high frequency current and constituted as a peak value detector, for producing, at an output of said second detection means, a second DC voltage (Ub) which rises proportionally to the rising portion of fluctuations of said high frequency current;voltage comparison means (67) coupled for response to said respective outputs of said first and second detection means for comparing said first DC voltage (Ua) and a predetermined adjustable fraction (kUb) of said second DC voltage and producing a comparison result signal at an output of said comparison means; a bistable switching control circuit (70) coupled to said output of said comparison means and connected for being set by the comparison result signal of said voltage comparison means (67) when said first DC voltage (Ua) becomes smaller than said predetermined fraction (kUb) of said second DC voltage and thereby to produce an output control signal (Q); means coupled for response to said bistable circuit (70) and connected to said high frequency generator for shutting off the output of said high frequency generator in response to said output control signal (Q) of said bistable circuit (70), and means (23) for reactivating, and usable for initially activating, the output of said high frequency generator in response to operation of a manual switch (21), to operation of an automatic switch (22) or to both said manual switch and said automatic switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification