DE102015215755A1 - Electrosurgical instrument and method of operation - Google Patents

Abstract

The invention relates to an electrosurgical instrument for insertion into a body lumen or interstitially into body tissue in an insertion direction for the treatment of human or animal tissue and a method for operating such an electrosurgical instrument. The electrosurgical instrument (1, 100) comprises an instrument shaft (50, 150), at least one energy delivery element (10, 100), and at least one reservoir (20) with at least one outlet opening (21, 121), wherein in the reservoir a conductive medium (30) and an expansible medium (40) are arranged and designed such that upon expansion of the expansible medium, the conductive medium exits through the at least one outlet opening from the reservoir.

Description

The invention relates to an electrosurgical instrument for insertion into a body lumen and / or interstitially in body tissue in an insertion direction for the treatment of human or animal tissue and a method for operating such an electrosurgical instrument.

Electrosurgical instruments are known in the art and may also be referred to as applicators or probes and are most often inserted along a direction of insertion into a body lumen and / or interstitially into body tissue. The direction of insertion is understood to be a direction along which an electrosurgical instrument is introduced into a body lumen or into a body tissue. Due to anatomical conditions and since an electrosurgical instrument can be flexibly designed, the insertion direction is not necessarily an ideal straight line. The insertion direction, in which an electrosurgical instrument is essentially advanced, is therefore considered as the insertion direction. The insertion direction therefore also corresponds essentially to a longitudinal axis of the electrosurgical instrument.

Electrosurgical instruments are used to deliver high frequency electrical current to surrounding tissue and are also referred to as coagulation or ablation instruments. Monopolar electrosurgical instruments require only one electrode. In use, this one electrode interacts with a large return or neutral electrode, which also communicates with a patient's body. For a bipolar application, electrosurgical instruments are provided with at least two electrodes, preferably a distal and a proximal electrode. Such bipolar coagulation or ablation instruments can be acted upon by a high-frequency (HF) voltage of different potential (bipolar), whereby the tissue surrounding the electrodes is heated to such an extent that autologous protein is denatured.

Other electrosurgical instruments have one or more antennas in place of one or more electrodes over which electromagnetic radiation, e.g. Microwave radiation to which body tissue can be indicated.

Electrodes and antennas are summarized here under the term energy delivery element.

A problem with the use of electrosurgical instruments, however, is that with increasing warming the tissue dries out and thus its impedance increases. This can lead to unwanted tissue damage and a decrease in the quality of treatment. To address this problem, it has hitherto been proposed, for example, to cool the electrosurgical instrument, in particular the electrodes, and / or to control the energy input in such a way that dehydration should be avoided as far as possible or as long as possible. Another known solution is to deliver a conductive medium from the electrosurgical instrument. However, this solution is also disadvantageous because the provision and delivery of the conductive medium, especially in an adequate amount and at the appropriate time, is difficult and inappropriate delivery of conductive medium, especially if it heats up strongly, can also lead to unwanted tissue damage.

It is therefore an object of the present invention to provide an electrosurgical instrument and method for operating such an instrument, which are improved over the prior art and / or reduce or eliminate one or more of the mentioned disadvantages. In particular, it is an object of the present invention to provide an electrosurgical instrument and method for operating the same which enhances and / or facilitates delivery of a conductive medium from an electrosurgical instrument.

This object is achieved by an electrosurgical instrument for insertion into a body lumen in an insertion direction for the treatment of human or animal tissue, comprising an instrument shaft, at least one energy delivery element and at least one reservoir having at least one outlet opening, wherein in the reservoir, a conductive medium and an expandable Medium are arranged and designed such that upon expansion of the expansible medium, the conductive medium exits through the at least one outlet opening from the reservoir.

The electrosurgical instrument comprises an instrument shaft, which is preferably elongated and, for example, has a substantially cylindrical outer periphery with a longitudinal axis. Furthermore, the electrosurgical instrument has at least one energy-emitting element, for example an electrode. Preferably, a bipolar electrosurgical instrument has two energy delivery elements, for example two electrodes, which are electrically isolated from each other.

For dispensing a conductive medium, the electrosurgical instrument has a reservoir with at least one outlet opening. Preferably, the reservoir may have two, three or more outlet openings. If properties and / or advantages of an outlet opening are described below, these are preferably also valid for two, three or more outlet openings. Preferably, a plurality of outlet openings are arranged uniformly distributed over the circumference of the instrument shaft.

In this reservoir, the conductive medium to be discharged through the outlet opening are arranged and also an expansible medium. By an expandable medium is meant a medium having substantially at least two states, an unexpanded state and an expanded state. In a delivery state and an initial operating state, the expansible medium is preferably in the unexpanded state. As expansion, for example, a transition into a gaseous phase into consideration and / or swelling.

The change from the non-expanded to the expanded state preferably occurs by the occurrence of an expansion condition. This can be, for example, reaching a predetermined temperature. Upon the occurrence of the expansion condition, the expandable medium changes to the expanded state by expansion, thereby causing the leakage of the conductive medium from the outlet port of the reservoir. For this purpose, preferably the quantities and properties of the conductive medium and of the expansion medium arranged in the reservoir and the receiving volume of the reservoir are coordinated so that the expansion of the expansible medium results in the conductive medium being displaced from the reservoir and the reservoir being displaced by the reservoir must leave at least one exit opening. The expansion condition is preferably selected to occur prior to a critical state of desiccation of the tissue, such that the conductive medium may exit the exit orifice and exert a moisturizing and / or cooling effect prior to dehydration of the tissue and a corresponding increase in impedance.

Preferably, the conductive and expansible media are disposed in the reservoir such that the conductive media is disposed between the expandable media and the exit port, such that upon expansion of the expandable media, substantially all of the conductive media passes through the exit port from the reservoir is expelled before expansible medium exits the reservoir.

The advantage of such an electrosurgical instrument is that no external control of the delivery of conductive medium must be made, but at the onset of the expansion condition automatically conductive medium is discharged, but at the same time also in the absence of the expansion condition, no conductive medium is discharged.

Particularly preferred is the design of the electrosurgical instrument as a disposable instrument, in particular as a sterile disposable instrument.

In a further preferred embodiment it is provided that the reservoir has a first part reservoir for receiving the conductive medium and a second part reservoir for receiving the expansible medium.

In this embodiment, the reservoir is divided into two sub-reservoirs, each of which receives one of the two media. The partial reservoirs can be separated from each other by a preferably flexible membrane. In one possible embodiment, the first and the second partial reservoir are connected to one another via a passage opening via which preferably the expansible medium exits from the second partial reservoir into the first partial reservoir when it expands and in this way the conductive medium from the first partial reservoir through the outlet opening casts.

The first and the second partial reservoir are preferably arranged such that the at least one outlet opening is arranged on the first partial reservoir.

It is further preferred that the expandable medium expands when a predetermined temperature is exceeded, preferably at a temperature of about 40 ° C.-120 ° C., more preferably of 60 ° C.-100 ° C., and even more preferably of 80 ° C. 90 ° C.

The expansion condition of the expandable medium is preferably a predetermined temperature which is preferably tuned to the field of application so as to prevent critical desiccation of the tissue by expelling conductive medium in advance from the exit port of the reservoir in advance by expansion of the expandable medium. Alternatively or additionally, the expansion can be triggered by means of a guided through the expansible medium flow of current.

In a further preferred embodiment, it is provided that the outlet opening and / or the passage opening is or are formed by a porous material. As a porous material comes eg polytetrafluoroethylene (PTFE), Ceramics, eg zirconium oxide (ZrO), or capillary tubes, for example of platinum (Pt), in question.

The outlet opening and / or the passage opening may be formed of different materials. For example, it may be preferred that the outlet opening is formed of a material which allows the passage of conductive medium, but substantially blocks the passage of expansible medium. Furthermore, it may be preferred that the passage opening is formed of a material which allows the passage of expanded expansible medium, but substantially blocks the passage of unexpanded expandable medium and / or conductive medium.

Further, it may be preferred that the outlet opening and / or the passage opening are formed as one-way valves, in which the medium, the opening in one direction only, namely from the reservoir through the outlet opening of the electrosurgical instrument out and / or from the second part reservoir through the passage opening into the first sub-reservoir, but not in the other direction.

Furthermore, it may be preferred that the outlet opening and / or the passage opening has or have a ceramic wick. The training as a ceramic wick has the particular advantage that this can be done a quantity control of the exiting conductive medium. Furthermore, preferably via the formation of the outlet and / or passage openings made of a porous material and / or another material which limits the flow rate of the medium through the respective opening, a control of the discharge amount per time can be achieved in an advantageous manner. In this case, a ceramic wick is understood in particular to mean a continuously porous body made of ceramic, in which a liquid medium is conveyed primarily by capillary action. For this it is preferred if the body has a large ratio of its pore surface to its pore volume.

In a preferred embodiment it is provided that the reservoir is arranged at a distal end of the instrument shaft. It is further preferred that the reservoir is arranged proximal to the at least one energy delivery element.

In a further preferred embodiment of a bipolar electrosurgical instrument, it is provided that the electrosurgical instrument has at least two energy delivery elements and the reservoir is arranged between the two energy delivery elements, for example between two electrodes.

In a further preferred embodiment it can be provided that the electrosurgical instrument has two reservoirs, wherein preferably a reservoir is arranged proximal to the at least one energy delivery element and a reservoir distal to the at least one energy delivery element.

The provision of multiple reservoirs and / or the placement of the reservoir in the vicinity of a power delivery element and / or in the vicinity of the distal end of the instrument shaft has the advantage that the conductive medium emerges in a region which is prone to particular heat generation and therefore particularly there good effect.

The conductive medium is preferably a saline medium, especially a saline gel, or has a saline gel.

The expandable medium is preferably water or an alcohol or preferably comprises water and / or an alcohol. For example, methanol, ethanol, propanol and / or butanol come into question. The expandable medium may further be a mixture of different alcohols and / or other liquids, eg water. The expandable medium may further contain dissolved gases, eg CO ₂ .

According to a further aspect of the invention, the object mentioned at the outset is achieved by an electrosurgical system comprising a high-frequency generator and a previously described electrosurgical instrument.

According to a further aspect of the invention, the object mentioned at the outset is achieved by a method for operating an electrosurgical instrument, comprising: providing a previously described electrosurgical instrument; Expelling the conductive medium through the exit port from the reservoir by expanding the expansible medium.

The system and method and their respective further developments preferably have features or method steps which make them particularly suitable for use with an electrosurgical instrument according to the invention and its further developments.

For the advantages, embodiments and details of execution of the electrosurgical system and its training and the method and its training reference is made to the preceding description of the corresponding features of the electrosurgical instrument.

Preferred embodiments of the invention will be described by way of example with reference to the accompanying figures. Show it:

1 a schematic representation of a distal end portion of an exemplary embodiment of an electrosurgical instrument according to the present invention; and

2 a schematic exemplary representation of a distal end portion of another exemplary embodiment of an electrosurgical instrument according to the invention.

In 1 and 2 are each schematically and exemplarily the distal end portions of electrosurgical instruments 1 . 100 for insertion into a body lumen in an insertion direction for the treatment of human or animal tissue. The electrosurgical instruments 1 . 100 each have an elongated instrument shaft 50 . 150 and an energy delivery element in the form of an annular electrode 10 . 110 ,

In the 1 illustrated variant of an electrosurgical instrument 1 points at the distal end of the instrument shaft 50 a reservoir 20 on with two radial outlet openings 21 , In the reservoir 20 is a conductive medium 30 and an expandable medium 40 arranged.

In 1 is the expandable medium 40 shown in unexpanded state. When the expansion event occurs, in particular a predetermined temperature is reached, the expandable medium expands 40 and thus drives the conductive medium 30 , here a saline gel, from the outlet openings 21 out.

Preferably, the outlet openings 21 designed so that only the passage of conductive medium 30 is enabled and the passage of expandable (or expanded) medium 40 is essentially locked.

In the in 2 illustrated exemplary embodiment of an electrosurgical instrument 100 are two partial reservoirs 122 and 123 provided, which by a flexible membrane 125 are separated from each other. In the first part reservoir 122 is the conductive medium 130 arranged, which over the here axially arranged outlet opening 121 can escape. The second part reservoir 123 contains the expandable medium 140 , which is shown here in the unexpanded state. Upon expansion of the expandable medium 140 this presses the membrane 125 in the direction of the medium 130 or passes through the optionally provided passage opening 124 from the second part reservoir 123 in the first part reservoir 122 above. This becomes the conductive medium 130 from the first part reservoir 122 gradually displaced and thus occurs 130 from the outlet 121 out.

By appropriate design of the outlet openings 21 . 121 by means of appropriate materials and / or by the provision of a ceramic wick, the flow rate of conductive medium can be controlled per time, so that too large and / or too fast delivery of conductive medium can be prevented. In particular, when an expansion temperature adjusted to the temperatures occurring during normal operation is selected and in good time before dehydration of the surrounding tissue by expansion of the expansible medium, the outlet of conductive medium is introduced, can advantageously, in particular easily and efficiently, without a special Control must be provided during operation of the electrosurgical instrument, a wetting of the tissue with conductive medium.

Claims (15)

Electrosurgical instrument ( 1 . 100 ) for introduction into a body lumen and / or interstitially in body tissue in an insertion direction for the treatment of human or animal tissue, an instrument shaft ( 50 . 150 ), at least one energy delivery element ( 10 . 110 ), and at least one reservoir ( 20 ) with at least one outlet opening ( 21 . 121 ), wherein in the reservoir a conductive medium ( 30 ) and an expandable medium ( 40 ) are arranged and designed such that upon expansion of the expansible medium, the conductive medium exits through the at least one outlet opening from the reservoir. Electrosurgical instrument ( 1 . 100 ) according to claim 1, characterized in that the reservoir is a first partial reservoir ( 122 ) for receiving the conductive medium ( 30 ) and a second partial reservoir ( 123 ) for receiving the expansible medium ( 40 ). Electrosurgical instrument ( 1 . 100 ) according to claim 2, characterized in that the first part reservoir ( 122 ) and the second sub-reservoir ( 123 ) by a preferably flexible membrane ( 125 ) are separated from each other. Electrosurgical instrument ( 1 . 100 ) according to claim 2 or 3, characterized in that the first and the second partial reservoir ( 122 . 123 ) via a passage opening ( 124 ) are interconnected. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the expansible medium ( 40 ) expands when a predetermined temperature is exceeded, preferably at a temperature of about 40 ° C-120 ° C, more preferably of 60 ° C-100 ° C and even more preferably of 80 ° C-90 ° C. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the outlet opening ( 21 . 121 ) and / or the passage opening ( 124 ) is formed by a porous material. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the outlet opening ( 21 . 121 ) and / or the passage opening ( 124 ) has or have a ceramic wick. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the reservoir ( 20 ) is disposed at a distal end of the instrument shaft. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the reservoir proximal to the at least one energy delivery element ( 10 . 110 ) is arranged. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the electrosurgical instrument ( 1 . 100 ) has at least two energy delivery elements and the reservoir is arranged between the two energy delivery elements. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the electrosurgical instrument ( 1 . 100 ) has two reservoirs, wherein preferably a reservoir proximal to the at least one energy delivery element and a reservoir distal to the at least one energy delivery element is arranged. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the conductive medium ( 30 ) is a saline gel or has a saline gel. Electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims, characterized in that the expansible medium ( 40 ) Is water or an alcohol or has water and / or an alcohol. An electrosurgical system comprising - a high frequency generator, and - an electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims. Method for operating an electrosurgical instrument ( 1 . 100 ) for insertion into a body lumen and / or interstitially in body tissue in an insertion direction for the treatment of human or animal tissue, comprising: - providing an electrosurgical instrument ( 1 . 100 ) according to at least one of the preceding claims 1-13; - expelling the conductive medium ( 30 ) through the outlet opening ( 21 . 121 ) from the reservoir ( 20 ) by expansion of the expansible medium ( 40 ).

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