Electrosurgical Generator With Adaptive Power Control
First Claim
1. An electrosurgical generator for applying output power to tissue, the electrosurgical generator comprising:
- a tissue impedance measurement circuit configured to measure tissue impedance; and
a controller coupled to the tissue impedance measurement circuit, the controller adapted to cycle output power from the electrosurgical generator to cause a cycling of the tissue impedance by applying the output power to tissue and then adjusting the output power to at least one of a lower output value and termination of output power, the controller further adapted to re-apply the output power to tissue if measured tissue impedance does not indicate tissue desiccation and to terminate output power when the measured tissue impedance indicates tissue desiccation.
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Accused Products
Abstract
An electrosurgical generator has an output power control system that causes the impedance of tissue to rise and fall in a cyclic pattern until the tissue is desiccated. The advantage of the power control system is that thermal spread and charring are reduced. In addition, the power control system offers improved performance for electrosurgical vessel sealing and tissue welding. The output power is applied cyclically by a control system with tissue impedance feedback. The impedance of the tissue follows the cyclic pattern of the output power several times, depending on the state of the tissue, until the tissue becomes fully desiccated. High power is applied to cause the tissue to reach a high impedance, and then the power is reduced to allow the impedance to fall. Thermal energy is allowed to dissipate during the low power cycle. The control system is adaptive to tissue in the sense that output power is modulated in response to the impedance of the tissue.
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Citations
18 Claims
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1. An electrosurgical generator for applying output power to tissue, the electrosurgical generator comprising:
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a tissue impedance measurement circuit configured to measure tissue impedance; and a controller coupled to the tissue impedance measurement circuit, the controller adapted to cycle output power from the electrosurgical generator to cause a cycling of the tissue impedance by applying the output power to tissue and then adjusting the output power to at least one of a lower output value and termination of output power, the controller further adapted to re-apply the output power to tissue if measured tissue impedance does not indicate tissue desiccation and to terminate output power when the measured tissue impedance indicates tissue desiccation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 18)
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11. An electrosurgical generator for treating tissue by applying energy, the electrosurgical generator comprising:
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a desiccation detector configured to determine completeness of tissue desiccation; and a controller coupled to the desiccation detector, the controller adapted to cycle output power to cause a cycling of tissue impedance in response to the degree of tissue desiccation, the controller further adapted to re-apply the output power to tissue if the desiccation detector does not indicate tissue desiccation. - View Dependent Claims (12, 13, 14, 15)
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16. A method for applying electrosurgical energy to tissue to treat tissue, the method comprising:
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a) cycling output power from an electrosurgical generator to cause a cycling of tissue impedance by applying output power to tissue and then adjusting output power to at least one of a lower output value and termination of output power; b) re-applying output power to tissue if tissue impedance does not indicate tissue desiccation; c) allowing the tissue impedance to fall to a predetermined minimum value and then raising the output power to cause an increase in tissue impedance; and d) repeating steps b and c until tissue impedance at least reaches a predetermined value that corresponds to tissue desiccation. - View Dependent Claims (17)
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Specification