Surgery – Instruments – Electrical application
Patent
1998-07-27
2000-03-21
Cohen, Lee
Surgery
Instruments
Electrical application
606 42, 606 45, 606 49, 607151, A61B 1739
Patent
active
060397349
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to an electrosurgical instrument having a monopolar electrode unit, and in particular to an instrument which is operable at high frequencies, typically in excess of 5 MHz.
A known electrosurgical system comprises a handpiece, a monopolar electrode unit having a single treatment electrode projecting from the handpiece, a generator unit, and a cable coupling the generator unit to the handpiece. Such systems are commonly used for various types of electrosurgery. Normally, a conductive pad is applied to the body of the patient and connected to a return terminal of the generator unit to provide a return path for electrosurgical currents. Disadvantages of this arrangement include the localisation of electrosurgical currents in tissue in the region of the return pad and, particularly at higher frequencies, the unpredictability of reactive components created by the cable between the generator and the handpiece, leading to unpredictable voltage levels at the electrode.
SUMMARY OF THE INVENTION
According to this invention, there is provided an electrosurgical instrument comprising a handpiece, a monopolar electrode unit having a single treatment electrode projecting from the handpiece, and a radio-frequency generator within the handpiece, wherein the generator has a single direct radio-frequency output patient connection for providing an active output connection between generator and patient and taking the form of a connection to the treatment electrode, and wherein the generator has no other direct radio-frequency output connection, the return path between generator and patient being provided for by indirect patient connection means including an electrically conductive shield around the generator and forming part of the handpiece, the shield forming a capacitive coupling element between the generator and the surroundings.
This allows the generator to be isolated from external elements other than the electrode. In particular, the generator has no other radio frequency output connection to, for example, an earthed element or to a return pad. By providing the generator within the handpiece, unpredictable impedance changes due to the effects of supplying radio-frequency currents through a cable are avoided. Radio-frequency return currents pass between the patient and the generator by stray capacitive coupling via a conductive shield located around the generator.
Preferably, the operating frequency of the generator is 5 MHz or greater. The higher the frequency, the greater the attainable current level due to the reduced reactance of the return path at raised frequencies. The generator may be powered from a battery within the handpiece. This minimises radiated interface.
The presence of an electrically conductive shield around the generator minimises the variation in stray capacitance caused by the user gripping the handpiece in different ways. The shield is preferably isolated from the generator and may form a tubular handpiece body, e.g. in the form of a metallic casing, or the handpiece body may be formed of an electrically insulative material which is metallised to provide the conductive shield. Where the metallisation layer is on the outside of the handpiece body, or the handpiece body is itself metallic, the outer metallic surface is preferably covered by an electrically insulating outer layer. Provision of the shield reduces stray capacitance variations because the capacitance between the relevant generator conductors and the shield is constant, and the shield provides a conductive body of constant area capacitively coupled to the patient.
The invention also includes a method of applying electrosurgical energy to a living body, the method comprising placing the electrode of an instrument as described above in contact with the body and activating the generator, the stray capacitance between the generator and the body providing a radio-frequency current return path.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example with r
REFERENCES:
patent: 1787709 (1931-01-01), Wappler
patent: 1814791 (1931-07-01), Ende
patent: 2894512 (1959-07-01), Tapper
patent: 3054405 (1962-09-01), Tapper
patent: 3197612 (1965-07-01), Reich
patent: 3234356 (1966-02-01), Babb
patent: 3478744 (1969-11-01), Leiter
patent: 3658067 (1972-04-01), Bross
patent: 3875945 (1975-04-01), Friedman
patent: 4271837 (1981-06-01), Schuler
patent: 4281373 (1981-07-01), Mabille
patent: 4463759 (1984-08-01), Garito et al.
patent: 4580562 (1986-04-01), Goof et al.
patent: 4657016 (1987-04-01), Garito et al.
patent: 4706667 (1987-11-01), Roos
patent: 4818954 (1989-04-01), Flachenecker et al.
patent: 4878493 (1989-11-01), Pasternak et al.
patent: 4909255 (1990-03-01), Farin
patent: 5007908 (1991-04-01), Rydell
patent: 5047026 (1991-09-01), Rydell
patent: 5047027 (1991-09-01), Rydell
patent: 5085659 (1992-02-01), Rydell
patent: 5133721 (1992-07-01), Angulo
patent: 5171255 (1992-12-01), Rydell
patent: 5196007 (1993-03-01), Ellman et al.
patent: 5217458 (1993-06-01), Parins
patent: 5254117 (1993-10-01), Rigby et al.
patent: 5306238 (1994-04-01), Fleenor
patent: 5330469 (1994-07-01), Fleenor
patent: 5342356 (1994-08-01), Ellman et al.
patent: 5395368 (1995-03-01), Ellman et al.
Valleylab Publication: Advances in Bipolar Electrosurgery for Laparoscopic Surgery, pp. 1-4.
Mentor O & O, Inc. Publication: Introducing the Mentor Wet Field Cordless Coagulator, Instruction Manual, 7 pgs.
Odontosurge 2, 2 pg product description.
Patil et al., "Electroconvergent Cautery", Neurosurgery, vol. 35, No. 4, Oct. 1994, pp. 785-788.
Total Radiosurgery, Electrosurgery, and Bipolar with the Office Practice in Mind, 1 pg product description.
Servotome.TM. Classic System 50 Watts, Electrosurgery, Satelec, 2 pg product description.
Cohen Lee
Gyrus Medical Limited
LandOfFree
Electrosurgical hand-held battery-operated instrument does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrosurgical hand-held battery-operated instrument, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrosurgical hand-held battery-operated instrument will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-726626