DE102013002163A1 - Surgical instrument for endoscopic- or arthroscopic purposes based on the electrotomy, has active electrode and neutral electrode, where both electrodes are arranged on handle, and active electrode is formed with its effective area - Google Patents

Abstract

The surgical instrument has an active electrode (3) and a neutral electrode (1), where the both electrodes are arranged on a handle. The active electrode is formed with its effective area in an annular manner. The active electrode has a circular front surface which has a circular depression (5) in its central region. The peripheral edge of the depression defines the effective area. An electrical insulator (2,4) is arranged in the bottom of the depression.

Description

The invention relates to a surgical instrument for the electrotomy according to the preamble of claim 1.

The electrosurgical instrument according to the invention, for example for endoscopic or arthroscopic purposes, is based on electrotomy. Electrotomy is the cutting or coagulation of biological tissue. In this case, by means of small-area electrodes, a high current density is generated at the transition point of the current to the tissue. The required electrical power must be sufficient to heat the tissue in a very short time to over 100 ° C. The extremely rapid heating leads to the vaporization of the cell fluid and cell rupture. The electrosurgical instrument according to the invention can equally be used for coagulating biological tissue, but here at lower temperatures.

The instrument according to the invention for the electrotomy is specifically intended for endoscopic or arthroscopic electrosurgery, namely for the treatment of tissue in body cavities or joints and is normally used in the presence of an expanding medium, which serves to inflate the body site to be treated, or a saline fluid. The stretching of the body cavity provides the space to gain access to the surgical site to improve visibility and allow the device to be handled.

In principle, it is known that in high-frequency (HF) surgery, alternating current is used in the designated frequency (300 kHz to 4 MHz) for tissue separation or tissue coagulation. A distinction is made between two application techniques, namely the monopolar method and the bipolar method. For each of these two methods different electrodes are used, which are activated via different controls. The invention is based both on the monopolar and the bipolar process.

The bipolar method differs from the monopolar method in that the neutral electrode is miniaturized and brought near the active electrode. Thus, both poles, namely the active electrode and the neutral electrode, are located in one instrument. As a result, in contrast to the monopolar method, the current does not flow through the entire body, but only between the adjacent poles of this bipolar electrode. The current paths are short and thus defined. As a result, as in the monopolar method, cutting or coagulation of the tissue is possible.

Known endoscopic or arthroscopic instruments for the electrotomy initially have a handle. At this handle, a rod-shaped electrode holder may be arranged. This electrode holder carries at the front end the active electrode and - in the bipolar process - behind it additionally the neutral electrode. Between these two electrodes, an electrical insulator is provided.

The aim of the active electrode is to generate a high electrical current density at the crossing point of the current to the tissue. The available electrical power must be sufficient to heat the tissue in a very short time to over 100 ° C. In the previously known electrical instruments for electrotomy can be achieved only with great technical effort that the electrotically effective area of the active electrode is low, and indeed as a prerequisite for the high electrical current density.

Based on this, the present invention seeks to provide a surgical instrument for the electrotomy of the type described, which allows a small-area active electrode for the electrotomic effective range in a technically simple manner.

The technical solution is characterized by the features in the characterizing part of claim 1.

This creates a surgical instrument for electrosurgery, which is characterized by a small-area active electrode, which defines the electrotomic effective range. Specifically, the active electrode is ring-shaped with its electrotomic effective range. This is understood to mean that the front side or end-side working region of the active electrode defines a ring, which is to be understood in the most general sense. This means that the cross-sectional contour of this ring can be arbitrary and in particular adapted to the surgical requirements. The advantage of this ring-shaped active electrode in the electrotomic effective range is that the annular surface occupies only a very small area compared to the entire end face of the active electrode. This means that a high current density is thereby generated at the crossing point of the current from this ring to the tissue. As a result, the tissue is heated within the shortest possible time to the necessary temperature with the predetermined electrical power in order to vaporize the cell fluid and to achieve a cell rupture.

The preferred embodiment according to claim 2 proposes that the end face of the active electrode has a recess in the central region. This means that the peripheral area of the active electrode around this depression defines the annular electrotomic effective area of the active electrode. The advantage in this embodiment of the active electrode is that this recess can be very easily introduced into the active electrode, so that the active electrode according to the invention can be produced without problems. Because it is only necessary that the above-mentioned depression is introduced into the end face of the active electrode, in order then to automatically define the ring-shaped electrotomic effective region around this depression.

According to the embodiment in claim 3, the recess may be formed in multiple stages. This means that, seen from the outer ring radially inwardly more recess steps can be provided. Thus, for example, initially a relatively flat step may be provided, to which a deeper depression follows in the radial inner region of the active electrode.

According to the embodiment in claim 4, an insulator is arranged in the bottom of the recess. This insulator may consist of a wide variety of insulating materials, for example of a ceramic, of plastic or of a metal oxide. Other insulator materials are conceivable. The insulator has the effect that the tissue can not come into contact with the bottom of the depression. Rather, the tissue encounters the insulator without generating current flow between the active electrode and the tissue.

Alternatively, according to the development in claim 5, the recess can also go back into a discharge channel. This discharge channel can be used to pump out the remnants of the treated tissue as well as vapor and air bubbles arising during the electrotomy.

The development according to claim 6 proposes that the neutral electrode is sleeve-shaped and that in this sleeve of the neutral electrode, the active electrode is inserted with a rear shaft. The two electrodes are electrically isolated from each other.

It proposes the development according to claim 7, that the sleeve-shaped neutral electrode has a tubular peripheral insulation. This creates a simple way to realize an electrical insulation.

Finally, a preferred development according to claim 8 proposes that the active electrode is arranged exchangeably, in particular in the neutral electrode. This means that the instrument can be equipped with different active electrodes for reuse.

An embodiment of a surgical instrument according to the invention for the electrotomy will be described below with reference to the drawings. In these shows:

1 a perspective view of the surgical instrument;

2 a longitudinal sectional view through the surgical instrument in 1 ,

The electrosurgical instrument for endoscopic or arthroscopic purposes firstly has a tubular neutral electrode on a - not shown - electrode holder of a handle 1 on. This neutral electrode 1 is peripherally equipped with electrical insulation.

In the front opening of the tubular neutral electrode 1 is with its rear, rod-shaped end an active electrode 3 inserted. Surrounded is the active electrode 3 from an electrical insulation 4 , which are in the area of the neutral electrode 1 the two electrodes 1 . 3 electrically isolated from each other. This electrical insulation 4 extends all the way to the angled head of the active electrode 3 , Only the front of the active electrode 3 is released.

The aforementioned face of the active electrode 3 has a recess 5 on. This depression 5 is designed in several stages, wherein the outer peripheral edge defines an annular electrotomic effective range. The ring has an outer diameter of 1.0 to 6.0 mm and an inner diameter of 0.5 to 5.0 mm. So closes at this outer ring radially inwardly initially a relatively shallow depression 5 at. This opens in the middle area then in a deeper depression 5 , The bottom of this (deeper) depression 5 is through an insulator 6 educated. This may consist of a ceramic, plastic, a metal oxide, etc.

The surgeon works with this instrument with the above-described annular end region of the active electrode 3 , Because the area between this annular active electrode 3 and the tissue to be treated is low, a high current density results at the junction of the current to the tissue. As a result, the tissue is heated to the desired temperature within a very short time.

LIST OF REFERENCE NUMBERS

1

neutral electrode

2

electrical insulator

3

active electrode

4

electrical insulator

5

deepening

6

insulator

Claims (8)

Surgical instrument for electrotomy, with an active electrode ( 3 ) and with a neutral electrode ( 1 ), the two electrodes ( 1 . 3 ) are arranged on a handle, characterized in that the active electrode ( 3 ) is annular with its electrotomic effective range. Instrument according to the preceding claim, characterized in that the active electrode ( 3 ) has a round end face and that the round end face in its central region has a round depression ( 5 ), wherein the peripheral edge of this recess ( 5 ) defines the electrotomic effective range. Instrument according to claim 2, characterized in that the recess ( 5 ) is formed in several stages. Instrument according to claim 2 or 3, characterized in that in the bottom of the recess ( 5 ) an electrical insulator ( 6 ) is arranged. Instrument according to claim 2 or 3, characterized in that the recess ( 5 ) back into one in the active electrode ( 3 ) trained discharge channel passes. Instrument according to one of the preceding claims, characterized in that the neutral electrode ( 1 ) is sleeve-shaped and that the active electrode ( 3 ) with its rear, rod-shaped end with intermediate arrangement of a sleeve-shaped insulation ( 4 ) in the sleeve-shaped neutral electrode ( 1 ) is inserted. Instrument according to claim 6, characterized in that the sleeve-shaped neutral electrode ( 1 ) at least partially by a sleeve-shaped electrical insulation ( 2 ) is surrounded. Instrument according to one of the preceding claims, characterized in that the active electrode ( 3 ) is arranged interchangeable.

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