Surgery – Instruments – Electrical application
Reexamination Certificate
2001-07-19
2003-02-04
Gibson, Roy D. (Department: 3739)
Surgery
Instruments
Electrical application
C606S051000, C606S050000
Reexamination Certificate
active
06514252
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to the structure and use of bipolar forceps and other instruments for coagulating, cutting, and necrosing tissue.
Electrosurgery refers broadly to a class of medical procedures which rely on the application of high frequency electrical energy, usually radiofrequency energy, to patient tissue to achieve a number of possible effects, such as cutting, coagulation, hyperthermia, necrosis, and the like. Of particular interest to the present invention, bipolar electrosurgical devices rely on contacting electrodes of different polarity in close proximity to each other against or into tissue. For example, bipolar forceps
100
(
FIGS. 1 and 2
) have been used for cutting and coagulating tissue, where the opposed jaws
102
and
104
of the forceps are connected to different poles of an electrosurgical power supply. The high frequency electrical current thus flows from one jaw to the other through the tissue present therebetween. Use of such bipolar forceps is effective for a number of purposes and advantageous in that its effect is generally limited to the tissue held between the jaws. Heating, however, is not totally limited to such intermediate tissue, and in some instances heating of adjacent tissues can be problematic. Such heating occurs because the current flows not only between the jaws but also laterally outward, as shown by flux lines F in FIG.
1
B.
Various improvements to bipolar forceps have been proposed. For example, the placement of pins or other tissue-penetrating elements onto the tissue-engaging surface(s) of either or both jaws has been suggested for a variety of purposes. Regardless of the intended purpose, the placement of tissue-penetrating elements on the jaw(s) can marginally focus the current density and somewhat lessen heating of adjacent tissues. Such prior designs employing tissue-penetrating elements, however, still cause unwanted heating of adjacent tissues in at least certain circumstances.
A second problem with conventional bipolar forceps is limited power delivery. With conventional forceps, jaws having a length of about 20 mm and a width of about 5 mm can usually deliver only 25 W of power without causing charring of the tissue. Charring greatly increases electrical resistance through the tissue and can result in premature termination of the treatment. With such a low power level, the time to fully coagulate the tissue can be excessive.
It would therefore be desirable to provide still further improved bipolar forceps and other electrosurgical device designs. In particular, it would be desirable to provide bipolar forceps which provide a very high degree of focused heating, i.e., provide heating of tissue between the jaws with minimized heating of tissue adjacent to the jaws. It would be further desirable to provide bipolar forceps which can deliver higher current flows and densities to the tissue being treated without charring the tissue and terminating the current flow. Such device designs should be relatively simple and easy to fabricate. The devices and methods should be compatible with conventional electrosurgical power supplies and usable in a wide variety of procedures, including cutting, coagulation, and necrosis, where the localized and specific heating of patient tissues is desired. At least some of these objectives will be met by the invention described hereinafter.
2. Description of the Background Art
Radio frequency power apparatus and methods for delivering radio frequency energy to tissue via bipolar surgical instruments are described in co-pending application Ser. No. 09/808,096 filed Mar. 13, 2001, assigned to the assignee of the present application. Bipolar forceps having penetrating elements on opposed jaws thereof are described in U.S. Pat. Nos. 5,527,313 and 5,217,460; Soviet Union Patent Publication SU 197711; and French Patent No. 598,149. Bipolar electrosurgical instruments having laterally spaced-apart electrodes on opposed jaws are described in U.S. Pat. Nos. 5,833,690; 5,702,390; 5,688,270; and 5,403,312. A blood vessel coagulation device having electrode arrays on opposed jaws of forceps is described in U.S. Pat. No. 5,151,102. Other bipolar electrosurgical devices are described in U.S. Pat. Nos. 5,797,941; 5,665,085; 5,662,680; 5,582,611; 5,445,638; 5,441,499; 5,383,876; 5,403,312; 5,098,431; and 4,043,342. A radiofrequency tumor heating device comprising parallel electrode arrays of opposite polarity is described in U.S. Pat. No. 4,016,886.
The full disclosures of each of the above references are incorporated herein by reference.
SUMMARY OF THE INVENTION
The present invention provides improved bipolar surgical instruments, such as forceps, graspers, or the like, which comprise a pair of opposed jaws at the distal end of a shaft. The present devices may be usable in a wide variety of procedures, including open surgical and laparoscopic surgical procedures, and are designed for one-handed operation by a user. The present invention is directed at a unique electrode configuration on either or both of the jaws which will provide improved current focussing characteristics and lessened heating of adjacent tissues. In particular, electrode members on either or both of the jaws will be laterally spaced apart from each other when the jaws are closed so that current will flow from one electrode to the other with minimum current flow outside of the region defined between the electrodes. Optionally, a pair of electrodes can be provided on each jaw with a positive and negative electrode on one jaw and a positive and negative electrode on the other jaw, with the two positive electrodes and the two negative electrodes being aligned with each other when the jaws are closed to define the desired focussed current flow.
At least one of the electrode members will include tissue-penetrating elements. Usually a first line of electrically coupled tissue-penetrating elements will be provided on a first electrode member, and a second line of electrically coupled tissue-penetrating elements will be provided on a second electrode member. Third and fourth lines of electrically coupled tissue-penetrating elements will preferably be provided when third and fourth electrode members are provided on the instrument. The first and second lines (and optionally third and fourth lines) of tissue-penetrating elements will be electrically isolated from each other to permit energization in a bipolar manner, i.e., each line of electrically coupled tissue-penetrating elements may be separately connected to the opposite pole of a conventional electrosurgical power supply. An exemplary radio frequency electrosurgical generator for use with the present invention is described in co-pending application Ser. No. 09/808,096, assigned to the assignee herein. The shaft includes or comprises an actuating mechanism for moving the jaws between opened and closed configurations, where the lines of tissue-penetrating elements lie parallel to and spaced-apart from each other when the jaws are closed. In this way, the jaws can be closed on a target tissue structure, such as a fallopian tube, artery, vein, other hollow organs, and the like, in order to penetrate the lines of elements into the tissue. By then applying high frequency electrical energy to the lines in a bipolar manner, current flux will be focused to within that portion of the tissue which lies between the adjacent lines, with minimum heating of tissue outside of the parallel lines. Usually, but not necessarily, the lines will both be straight. Alternatively, the lines could be nonlinear, e.g., curved, serpentine, zig-zag, or the like, so long as the patterns are similar and the lateral spacing between adjacent points on the lines remains substantially constant. Preferably, the spacing between the adjacent lines of tissue-penetrating elements will be in the range from 0.5 mm to 10 mm, more preferably from 2 mm to 5 mm.
Preferably, at least some of
Bachman Alan
Hancock Andrew H.
Nezhat Camran
Gibson Roy D.
Perfect Surgical Techniques, Inc.
Townsend and Townsend / and Crew LLP
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