Surgery – Instruments – Electrical application
Reexamination Certificate
2000-06-30
2002-05-14
Gibson, Roy (Department: 3739)
Surgery
Instruments
Electrical application
C606S050000, C606S045000
Reexamination Certificate
active
06387094
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a medical instrument for dissecting tissue in the human or animal body, having an elongated shaft and having at the distal end of the shaft two jaw parts that are movable relative to one another and that coact cuttingly and/or graspingly, at least one of the jaw parts being configured as an electrode which can be impinged upon by high-frequency current.
“Dissecting” for the purposes of the present invention is understood to mean the cutting of tissue and/or grasping or gripping of tissue in order to cut of f tissue in the body and remove it or set it aside.
An instrument of this kind is preferably used in minimally invasive surgery in which, in contrast to conventional open surgery, the instrument is guided from outside through a small incision into the surgical area, the surgical procedure being performed under endoscopic monitoring.
In such an instrument, often not only is the purely mechanical effect of the jaw parts used to cut off or cut through tissue, but the jaw parts or at least one of the jaw parts can additionally be impinged upon by monopolar high-frequency current so as on the one hand to enhance the cutting effect by way of the thermal effect of the high-frequency current in the tissue, and on the other hand to bring about coagulation of the tissue at the cutting point generating heat , so as to reduce or even eliminate the bleeding that occurs when the tissue is cut through.
While at first only the dissection of smaller portions of tissue could be performed successfully in minimally invasive surgery, the development of minimally invasive surgery is now moving toward removing even larger portions of tissue, for example the large intestine or organs. When removing larger portions of tissue, it is also necessary to cut through larger tissue bridges, which moreover may contain larger vessels. The more severe bleeding that possibly occurs in this context cannot be managed, however, with the monopolar-mode instrument, so that it is additionally necessary, when cutting through larger tissue bridges, to use bipolar-mode coagulation instruments.
This means, however, that while dissecting (i.e. in order to cut through such larger tissue bridges), the surgeon must make an instrument change several times if he or she does not was to rely only on the lesser coagulating effect of the monopolar-mode instrument. The operation thus proceeds in such a way that the surgeon removes tissue principally with the monopolar-mode instrument and, when he or she arrives at a tissue bridge containing a larger vessel, must remove the monopolar-mode cutting instrument from the patient's body and bring to the operating location a bipolar-mode coagulation instrument. This instrument change is, however, cumbersome, extends the length of the procedure quite considerably in some cases, and increases the risk of complications.
There is known, from the catalog of the German company styled Karl Storz GmbH & Co., Tuttlingen entitled “Karl Storz-Endoskope,” Gynecology volume 2/96, page BI/COA 5/7, a bipolar coagulation instrument that has at the distal end two pairs of jaw parts spaced apart from one another, each pair of which is configured as an electrode that can be impinged upon by high-frequency current. The two jaw part pairs are spaced apart from one another and can therefore be operated as a bipolar electrode arrangement. Arranged between the jaw part pairs is a cutting tool in the form of a scalpel that is selectably movable back and forth. With this instrument, a vessel can be clamped between the two jaw part pairs and coagulated, and then cut through by advancing the cutting tool. This instrument is, however, less suitable for being used principally as a dissecting instrument for cutting through tissue. Instead, the principal function of this instrument is bipolar coagulation.
Instruments similar to this are described in WO 95/15124 and U.S. Pat. No. 5,445,638.
In the case of the known instruments cited above, the cutting effect by way of the displaceable scalpel arranged between the coagulation electrodes is purely mechanical, i.e. with no assistance from high-frequency current. In addition, these cutting devices are predominantly suitable only for cutting through vessels, but not for making longer cuts and also not for grasping.
For the purpose cited initially of dissecting tissue in the human or animal body, in which larger portions of tissue are removed and large tissue bridges need to be cut through for the purpose, an instrument of the kind cited initially is therefore functionally correct, since with such an instrument the cutting through of tissue is to the fore.
It is therefore the object of the invention to develop an instrument of the kind cited initially in such a way that with this instrument even larger portions of tissue, and thus larger tissue bridges containing larger vessels, can be cut through with no risk of excessive bleeding.
SUMMARY OF THE INVENTION
According to the present invention this object is achieved by a medical instrument comprising:
an elongated shaft having a distal end;
two jaw parts at said distal end of said shaft, said two jaw parts being movable relative to one another and configured to coact for dissecting said tissue, at least one of said two jaw parts being configured as an electrode which can be impinged upon by high-frequency current,
wherein a further electrode which can be impinged upon by a high-frequency current is provided which can be optionally displaced from a retracted proximal position into a distal position adjacent to said two jaw parts in which position said further electrode forms in coaction with said at least one jaw part configured as an electrode one pole of an electrode arrangement for bipolar coagulation of said tissue.
What is therefore made available according to the present invention is an instrument with which it is possible, while using a monopolar-mode instrument in standard fashion, to dissect tissue by cutting and/or grasping, and if necessary to coagulate very small vessels in conventionally monopolar fashion.
If, however, the surgeon encounters a tissue bridge which appears to contain larger vessels, this tissue bridge can be gripped between the jaw parts and the further electrode by advancing the further electrode into the distal position adjacent to the jaw parts. The at least one jaw part configured as an electrode and the further electrode can then be impinged upon by high-frequency current so that the tissue lying therebetween can be coagulated in bipolar fashion. In other words, the jaw parts form the one electrode pole and the further electrode the second electrode pole. Then, preferably after the further electrode has been slid back into its proximal position, dissection can continue with the jaw parts, either purely mechanically or under the action of monopolar current. The invention thus makes available an instrument operable in monopolar fashion for dissecting tissue, in combination with a selectably or optionally connectable bipolar coagulation device, thus achieving the considerable advantage that an instrument change is not necessary for dissection and for bipolar coagulation, and larger portions of tissue can also be dissected quickly and safely while preventing bleeding.
The underlying object of the invention is thus completely achieved.
In a preferred embodiment, the jaw parts are curved out of a longitudinal axis of the shaft, and the further electrode is arranged on a concave side of the jaw parts.
The advantage of this feature is that when the further electrode is advanced into its distal position, the tissue to be coagulated in bipolar fashion can be securely grasped and held between the jaw parts and the further electrode. The curved configuration of the jaw parts acts in this context as a catch hook and backstop preventing the tissue from escaping laterally as the further electrode is advanced.
In a further preferred embodiment, the further electrode is of planar configuration and has approximately the same width dimension as the
Gibson Roy
Karl Storz GmbH & Co. KG
St. Onge Steward Johnston & Reens LLC
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