Method and apparatus for plasma-mediated thermo-electrical ablation
First Claim
1. A method for cutting a material submerged in a conductive liquid medium, said method comprising:
- a) providing a cutting electrode having an elongate cutting portion;
b) providing a return electrode;
c) immersing said cutting electrode and said return electrode in said conductive liquid medium;
d) applying a voltage between said cutting electrode and said return electrode such that said conductive liquid medium is heated to produce a vapor cavity around said elongate cutting portion and to ionize a gas inside said vapor cavity to produce a plasma;
e) modulating said voltage in pulses having a modulation format selected to minimize the size of said vapor cavity, a rate of formation of said vapor cavity, and a heat diffusion into said material; and
f) cutting said material with an edge of said elongate cutting portion.
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Accused Products
Abstract
An apparatus and method for cutting a material including conducting and non-conducting materials such as biological tissue, cellulose or plastic while the material is submerged in a conductive liquid medium. The apparatus has a cutting electrode with an elongate cutting portion having an aspect ratio (length to width) of 1 or more and a return electrode. The two electrodes are immersed in the conductive medium and a voltage is applied between them to heat the medium, thus producing a vapor cavity around the elongate cutting portion and ionizing a gas inside the vapor cavity to produce a plasma. The voltage applied between the electrodes is modulated in pulses having a modulation format selected to minimize the size of the vapor cavity, its rate of formation and heat diffusion into the material while the latter is cut with an edge of the elongate cutting portion. The modulation format includes pulses ranging in duration from 10 μs to 10 ms, as well as minipulses and micropulses, as necessary. The apparatus and method of invention allow the user to perform efficient thermal ablation and electrosurgical procedures in particular at power levels as low as 10 mW with minimal thermal and cavitation damage.
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Citations
34 Claims
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1. A method for cutting a material submerged in a conductive liquid medium, said method comprising:
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a) providing a cutting electrode having an elongate cutting portion;
b) providing a return electrode;
c) immersing said cutting electrode and said return electrode in said conductive liquid medium;
d) applying a voltage between said cutting electrode and said return electrode such that said conductive liquid medium is heated to produce a vapor cavity around said elongate cutting portion and to ionize a gas inside said vapor cavity to produce a plasma;
e) modulating said voltage in pulses having a modulation format selected to minimize the size of said vapor cavity, a rate of formation of said vapor cavity, and a heat diffusion into said material; and
f) cutting said material with an edge of said elongate cutting portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An apparatus for cutting a material submerged in a conductive liquid medium, said apparatus comprising:
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a) a cutting electrode having an elongate cutting portion;
b) a return electrode;
c) a voltage source for applying a voltage between said cutting electrode and said return electrode such that when said cutting electrode and said return electrode are immersed in said conductive liquid medium said conductive liquid medium is heated to produce a vapor cavity around said elongate cutting portion and to ionize a gas inside said vapor cavity to produce a plasma; and
d) a pulse control for modulating said voltage in pulses of a modulation format selected to minimize the size of said vapor cavity, a rate of formation of said vapor cavity, and heat diffusion into said material. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification