Fast pulse thermal cautery probe and method
First Claim
1. An apparatus for heating tissue without causing deep tissue damage, comprising:
- an electrically powered thermal probe having a heating element and an active heat-transfer portion which is in direct thermal contact with said heating element so that heat is transferred to said heat-transfer portion principally by conduction, said heat-transfer portion having a unit heat capacity of less than 1 joule/°
C. to allow said probe to cool from a temperature sufficiently high to coagulate within a sufficiently short period to prevent excessive heat penetration; and
power-generating means connected to the heating element of said probe applying an electric current pulse to said heating element during a heating cycle having sufficient energy to allow said probe to coagulate tissue during said heating cycle.
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Accused Products
Abstract
A miniaturized, endoscopically deliverable thermal cautery probe for cauterizing internal vessels. The probe is applied to tissues cold, and a large number of electric heating pulses of equal energy are then applied to an internal heating element in the probe. The probe has an internal heating element in direct thermal contact with an active heat-transfer portion that has a low heat capacity to insure quick heating and subsequent cooling, thereby adequately coagulating tissue while minimizing heat penetration and resulting tissue damage. The electrical power applied to the probe is continuously measured and is terminated when the energy delivered reaches a preset value. The number of such pulses applied to the probe (and hence the total energy delivered) may be preset while the duration of the period during which the pulses were applied is displayed. Alternatively, the duration of the period during which such pulses are applied to the probe may be preset while the number of pulses applied (and hence the total energy delivered) is displayed. The heating element for the probe is a controlled breakdown diode which has a breakdown voltage that is a function of its temperature so that the temperature can be controlled. The heating element has a resistance of greater than 0.5 ohm to provide adequate power dissipation with relatively low currents. A washing fluid, preferably flowing along the outside of the probe toward its tip, cleans blood from the tissue to be coagulated to make the source of blood more readily visible.
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Citations
30 Claims
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1. An apparatus for heating tissue without causing deep tissue damage, comprising:
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an electrically powered thermal probe having a heating element and an active heat-transfer portion which is in direct thermal contact with said heating element so that heat is transferred to said heat-transfer portion principally by conduction, said heat-transfer portion having a unit heat capacity of less than 1 joule/°
C. to allow said probe to cool from a temperature sufficiently high to coagulate within a sufficiently short period to prevent excessive heat penetration; andpower-generating means connected to the heating element of said probe applying an electric current pulse to said heating element during a heating cycle having sufficient energy to allow said probe to coagulate tissue during said heating cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. An apparatus for heating tissue without causing deep tissue damage, comprising:
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an electrically powered thermal probe having an internal heating element, said probe including an active heat-transfer portion in direct thermal contact with said heating element so that heat is transferred to said heat-transfer portion principally by conduction, said heat-transfer portion having a unit heat capacity which is sufficiently low so that the period during which the temperature of said probe rises from 40 percent of range between an initial temperature and a peak temperature, and subsequently falls to 40 percent of said range, can be less than 5 seconds; and power-generating means connected to the heating element of said probe applying an electric current to said heating element during a heating cycle having a duration of less than 3 seconds and sufficient energy to allow said probe to coagulate tissue during said heating cycle. - View Dependent Claims (25, 26)
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27. A method of heating tissue without causing deep tissue damage, comprising:
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placing a thermal cautery probe in contact with said tissue, said probe having a thermal mass which is sufficiently low that tissue in contact with said probe reduces its temperature from a peak value to 50 percent of said peak value in less than one second after power is removed from said probe; applying electric power to said probe for a heating period of less than 5 seconds, said power being of sufficient magnitude in relation to the thermal mass of said probe to cauterize said tissue during said heating period; and removing said probe from said tissue at any time after said heating period since the low thermal mass of said probe allows said probe to quickly cool after said heating period to prevent deep pentration of said tissue regardless of the duration that said probe is applied to said tissue. - View Dependent Claims (28, 29, 30)
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Specification