Surgery – Instruments – Electrical application
Reexamination Certificate
2001-05-25
2003-02-18
Peffley, Michael (Department: 3739)
Surgery
Instruments
Electrical application
C606S048000
Reexamination Certificate
active
06520960
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a bipolar medical instrument for cutting tissue comprising a first working element and at least one second working element, which are arranged adjacent to one another at a distal end of the instrument. The first working element and the second working element are configured as an electrode connectable to high frequency power and a counter electrode.
Such an instrument is disclosed in the German catalogue of the company Karl Storz GmbH & Co. KG, Tuttlingen, “STORZ Karl Storz-Endoskope”, Vol. “Laparoskopie”, 3
rd
Edition 1/1999, page BI-COA 10/2. Such a bipolar medical instrument is used for example in laparoscopic surgery for treating tissue in the human or animal body.
Incisions are made in the tissue being treated and cause bleeding, which must be stopped.
In the known instrument, bipolar high frequency power is used only for stopping bleeding, i.e. for coagulation. The placement of incisions in the tissue takes place mechanically, namely with a scalpel-like knife.
The known instrument mentioned before comprises a first working element in the form of a jaw and a second working element also in the form of a jaw, where the jaws are arranged side by side at a spacing from one another, in other words like a pair of forceps. The jaw forming the first working element is formed as an electrode which can be supplied with high frequency power and the jaw forming the second working element is formed as a counter electrode. The first jaw can be connected with a corresponding electric line to one pole of a high frequency voltage source and the second jaw can be connected through a corresponding electric line to the other pole of the high frequency voltage source. The first jaw and the second jaw are insulated from one another due to their spacing.
A comparable instrument is disclosed in WO 97/17033. When switching on the high frequency source, a current flux develops in the tissue between the first jaw and the second jaw, so that the coagulation effect is limited to the region between the two sets of jaws. To coagulate a vessel, the vessel is grasped to extend transversely to the jaw.
The cutting function of this known instrument for cutting tissue, in particular for cutting through vessels present in the tissue, is realized with a scalpel -like knife arranged between the first jaw and the second jaw. The knife can be projected forwardly in axial direction by actuating a separate handle at the proximal end of the instrument, for example to cut through a vessel which is grasped to extend transversely to the sets of jaws. The cutting effect of the knife is purely mechanical. By providing the knife between the first and second jaws, the insertion of an additional cutting tool, for example a cutter or a scalpel, into the operation area is avoided as well as the associated exchange of instruments in comparison to other conventional bipolar instruments having only the coagulation function.
Even so, the configuration of this known instrument with the scalpel-like knife for cutting tissue is of disadvantage when the dimensions of the instrument are to be reduced, i.e. when the instrument is to be constructed as small as possible. The known instrument has a diameter of about 10 mm, while a diameter of such instruments of about 5 mm is desirable for some applications.
Reducing the diameter of the known instrument from 10 mm to 5 mm is however not possible for the following reasons. The scalpel-like knife must be placed between the first jaw and the second jaw, so that the first jaw and the second jaw of the known instrument already have a diameter of only 3 mm and are spaced from one another by about 3 mm. A reduction of the total diameter of the arrangement of the first jaw, the second jaw and the scalpel-like knife to 5 mm would require the reduction of the diameter of the first jaw and the second jaw to less than 1 mm. The stability of the jaws, which make up the working elements, is however no longer ensured with such dimensions. A reliable treatment of the tissue with the instrument requires a sufficient stability of the first and second working elements.
A further instrument is disclosed in the mentioned German catalogue on page BI-COA 5/12, which is a grasping and coagulation instrument without a cutting function. Its working element comprises an upper and a lower jaw part. The two jaw parts are configured as a grasping tool and also as an electrode and counter electrode, so that current can flow for coagulation between the jaw parts through the tissue grasped there between.
The present invention however is not limited to improving an instrument that is limited to grasping and coagulation functions. Therefore, the term “working element” will be understood generally in the present invention, as long as the working elements constitute an electrode and a counter electrode independent of their shape or other functions.
Generally, the object of the present invention is to provide a bipolar instrument for cutting tissue of the above- mentioned type, by which the cutting function is realized in a manner, which is not mechanical.
SUMMARY OF THE INVENTION
The object is achieved by a bipolar medical instrument for cutting tissue, comprising:
a shaft having a distal end and a proximal end;
a first working element disposed at said distal end of said shaft, said first working element being configured as an electrode connectable to high frequency current;
at least one second working element disposed at said distal end of said shaft and adjacent to said first working element, said at least one second working element forming a counter electrode with respect to said first working element,
wherein at least one of said first working element and said second working element comprises at least one projection, which is directed toward the other of said first and second working elements, and a free end of said at least one projection is configured such that a concentration of the current density occurs at said free end.
The advantageous effect of concentrating the current density in the present instrument is that an incision can be made in the tissue or a vessel in the tissue can be cut off using electrical energy. Compared to the known instrument, the function of cutting is therefore not realized with a mechanical cutting instrument, such as a scalpel-like knife, but with an “electric blade”. The placement of an incision with the present instrument is guided by hand such that the “electric cutter” formed between the at least one projection and the other working element is moved through the tissue or through the vessel. The cutting process itself takes place substantially without contact.
Although the invention is not limited to improving the mentioned conventional instrument, also the use of the present invention with this known instrument has the particular advantage that the jaw forming the first working element and the jaw forming the second working element can be formed with larger diameter and therefore are more stable due to the lack of a mechanical cutting instrument between the two sets of jaws in the known instrument. This is the case, even when the total diameter of the instrument should be reduced, for example to 5 mm. In this case, the further advantage results with the present configuration of the invention, that no further handle need be provided on the instrument for cutting the tissue, as is the case in the known instrument, where the scalpel-like knife is moved back and forth. In contrast, the cutting procedure in the present instrument takes place with the working elements themselves, so that the constructive complexity of the present instrument is advantageously reduced.
In a preferred embodiment, both the first working element and the second working element comprise at least one projection.
The feature advantageously leads to increased concentration of the current density between the first and second working elements, where the electric cutting effect can be further improved.
Preferably, the at least one projection of the first working elem
Blocher Martin
Remorgida Valentino
Karl Storz GmbH & Co. KG
Peffley Michael
St. Onge Steward Johnston & Reens LLC
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