Self-limiting electrosurgical return electrode
First Claim
1. An electrosurgical electrode configured to be disposed beneath a patient during electrosurgery to provide a return path for an electrosurgical current used in electrosurgery, the electrosurgical electrode comprising:
- a sheet of material having an effective bulk resistivity equal to or greater than about 8,000Ω
.cm;
an upper surface having sufficient area to limit a current density to safe thresholds while obviating the need for direct contact between the patient and the electrode, wherein the effective impedance of the electrode is inversely proportional to the effective contact area between the patient and the electrode and the electrosurgical electrode being self-limiting so that the electrosurgical current is limited to safe thresholds so as to prevent an undesirable patient burn at a contact area between the patient and the electrode in the event of an accidental reduction in the contact area below a threshold level.
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Accused Products
Abstract
A self-limiting electrosurgical return electrode for use with electrosurgery. Through selection of impedance characteristics for the materials of the principal body of the electrode, and through tailoring of electrode geometries, the electrode is self-regulating and self-limiting as to current density and temperature rise to prevent patient trauma. The return electrode includes a sheet of material having an effective bulk impedance equal to or greater than about 4,000Ω.cm and one or more connectors for making electrical connection to the sheet. The effective bulk impedance of the sheet may arise from resistive components, capacitive components, inductive components, or combinations thereof. Configuration of the return electrode allows the electrode to self-limit the electrode'"'"'s current densities, thereby preventing burning of a patient during surgery. Through employment of washable surface areas, the electrode is made readily cleanable, disinfectable, sterilizable, and reusable. An optional sleeve is provided for cooperative use with the electrode.
97 Citations
20 Claims
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1. An electrosurgical electrode configured to be disposed beneath a patient during electrosurgery to provide a return path for an electrosurgical current used in electrosurgery, the electrosurgical electrode comprising:
-
a sheet of material having an effective bulk resistivity equal to or greater than about 8,000Ω
.cm;
an upper surface having sufficient area to limit a current density to safe thresholds while obviating the need for direct contact between the patient and the electrode, wherein the effective impedance of the electrode is inversely proportional to the effective contact area between the patient and the electrode and the electrosurgical electrode being self-limiting so that the electrosurgical current is limited to safe thresholds so as to prevent an undesirable patient burn at a contact area between the patient and the electrode in the event of an accidental reduction in the contact area below a threshold level. - View Dependent Claims (2, 3, 4, 5)
where t=thickness (cm) κ
=dielectric constant of insulating materialβ
=total impedance divided by the AAMI standard (75 ohms)ω
=angular frequency of electrosurgical generator (radians/sec)ρ
=bulk resistivity (Ω
.cm)A=electrode area (cm2) ε
o=electrical permittivity constant (F/cm).
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6. An electrosurgical electrode configured to be disposed beneath a patient during electrosurgery to provide a return path for an electrosurgical current used in electrosurgery, the electrosurgical electrode comprising:
-
a sheet of material having an effective bulk resistivity equal to or greater than about 8,000Ω
.cm;
an upper surface having a greater surface area than that of the projected area of the buttocks or torso of a patient allowing the patient to move during the course of a procedure while a sufficient portion of the patient will remain in contact with the electrode such that the effective impedance of the electrode allows sufficient current to permit electrosurgery while self-limiting a current density to safe thresholds so as to prevent an undesirable patient burn at a contact area between the patient and the electrode in the event of an accidental reduction in the contact area below a threshold level, the surface area obviating the need for direct contact between the patient and the electrode, wherein the effective impedance of the electrode is inversely proportional to the effective contact area between the patient and the electrode. - View Dependent Claims (7, 8, 9, 10)
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11. An electrosurgical electrode configured to be disposed beneath a patient during electrosurgery to provide a return path for an electrosurgical current used in electrosurgery, the electrosurgical electrode comprising:
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a sheet of material having an effective bulk resistivity equal to or greater than about 8,000Ω
.cm;
an upper surface having sufficient area to self-limit a current density to no more than 100 mA/cm2 so as to prevent an undesirable patient burn at a contact area between the patient and the electrode in the event of an accidental reduction in the contact area below a threshold level while obviating the need for direct contact between the patient and the electrode, wherein the effective impedance of the electrode is inversely proportional to the effective contact area between the patient and the electrode. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification