GB2492325A

GB2492325A - Electrosurgical electrode

Info

Publication number: GB2492325A
Application number: GB1110646.5A
Authority: GB
Inventors: Kelvin John Varney
Original assignee: Gyrus Medical Ltd
Current assignee: Gyrus Medical Ltd
Priority date: 2011-06-23
Filing date: 2011-06-23
Publication date: 2013-01-02
Anticipated expiration: 2031-06-23
Also published as: GB201110646D0; EP2723264B1; WO2012175912A1; US9414886B2; EP2723264A1; GB2492325B; CN103717165A; CN103717165B; US20140214021A1

Abstract

An electrode (26) for use in an electrosurgical probe, the electrode having two arms (29, 30) defining a longitudinal direction. The electrode (26) also comprises a loop (31) depending from the two arms and defining a cutting area within the loop, and a vaporization member (32) attached to one side of the loop. The vaporization member (32) is such that it does not occlude the cutting area and yet presents a substantial profile when the electrode is moved in the longitudinal direction. The arrangement is such that when the electrode (26) is moved in a first longitudinal direction, the loop (31) is capable of resecting a sample of tissue. When the electrode (26) is moved in the opposite longitudinal direction, the vaporization member (32) is capable of vaporizing tissue adjacent thereto to form a groove therein.

Description

I

ELECTROSURGICAL ELECTRODE

This invention relates to an electrosurgical electrode and in particular to an electrode for use in a system for endoscopic urological surgery using a resectoscope.

Such systems are well known in the art, examples being given in US Patents 5,007,907 and 6,322,494. Such systems include an electrosurgical instrument deployable by means of a resectoscope, and an electrosurgical generator powering the instrument. A generator suitable for powering a urological instrument is described in US Patent 7,211,081. Instruments used in electrosurgical urology surgery are either bipolar, in which case two electrodes are present at the distal end of the instrument, or monopolar.

in which case one electrode is present on the instrument and a second electrode is provided in the form of a patient return plate.

Different types of electrodes have been used previously depending on their intended function. Loop electrodes (see US 4,917,082 as an example) are generally good for tissue resection, while roller electrodes (see US 5,549,605 as an example) or slider dectrodes (see US 5,766,168 as an example) are used for vaporisation andlor coagulation of tissue. The present invention attempts to provide a different electrode capable of efficient tissue resection and vaporisation/coagulation.

According'y there is provided an electrode for use in an electrosurgical probe.

the electrode comprising two arms defining a longitudinal direction, a loop extending laterally from the two arms and defining a cutting area within the loop, and a vaporisation member attached to one side of the loop, the vaporisation member being such that it does not occlude the cutting area and yet presents a substantial profile when the electrode is moved axially in the longitudinal direction, the arrangement being such that when the electrode is moved in a first longitudinal direction, the loop is capable of resecting a sample of tissue, the resected tissue being received within the cutting area, and when the electrode is moved in the opposite longitudinal direction, the vaporisation member is capable of vaporising tissue adjacent thereto to form a groove therein.

The present invention provides an electrode optirnised for both tissue resection and vaporisation. The loop provides effective tissue resection, while the vaporisation member provides effective tissue vaporisation, or alternatively tissue coagulation if a coagulating signal is supplied to the electrode. Previous attempts to combine tissue resection and vaporisation include US patent 5,064,424. This patent provides a partly spherical electrode, with a cutting ioop upstanding from a central flat face of the electrode. The present invention differs from this arrangement in that the vaponsation member is attached to a side facc of the loop, such that the loop is provided at the front or rear face of the electrode. This allows for effective tissue resection when the electrode is moved in a first longitudinal direction, and for effective tissue vaporisation when the electrode is moved in an opposite longitudinal direction. Unlike US patent 5.064,424, in which the instrument would need to be rotated 180 degrees in order to change the action of the instrument, the electrode of the present invention merely needs a change of longitudinal direction in order to completely change the tissue effect.

The vaporisation member conveniently includes an upper surface and a lower surface, and the upper surface of the vaporisation member terminates adjacent the ioop.

This ensures that the vaporisation member does not interfere with the cutting action of the ioop. The term "loop" is meant to include any shape starting and finishing at the two arms, and extending below the arms. The loop does not need to be necessanly U-shaped, but can be a parabola, V-shaped, or any other convenient shape, including three sides of a square or rectangle. Preferably, the loop includes a lowest point which is furthest from the two arms, and the lower surface of the vaporisation member extends upwardly from the lowest point of the loop so as to terminate at a height between the arms and the lowest point of the loop. This upwardly tending structure serves two purposes, the first being to increase the profile of the vaporisation member presented to the tissue, so as to make possible the removal of a groove of tissue when the electrode is moved longitudinally with respect thereto. The second purpose of the upward profile is to guide upwardly "chips" of tissue being cut with the loop, when the electrode is moved in the opposite longitudinal direction. The upward profile urges the tissue up and away from the loop, providing the user with good visibility and preventing removed tissue from becoming tangled with the remainder of the electrosurgical instrument.

According to a preferred embodiment, the vaporisation member includes a curved portion of a shape formed by sweeping an arc with a curve equivalent to at least a section of the loop member. This provides a smooth transition from the loop to the vaporisation member, allowing tissue to pass either side of the ioop when it is cutting through tissue. Preferably, the curved portion of the vaporisation member is of a shape formed by sweeping an arc of at least 45 degrees, conveniently at least 90 degrees, and conceivably at least 120 degrees. Conveniently (but not necessarily), the curved portion of the vaponsation member forms part of the surface of a sphere.

The curved portion conceivably constitutes the entirety of the vaporisation member, or it may alternatively constitute only a portion of the vaporisation member.

Where the curved portion constitutes only a portion of the vaporisation member, the vaporisation member also conveniently includes a linear, upwardly sloping section.

The curved portion is conveniently located between the loop and the upwardly sloping section, such that the linear section provides both the "depth" for the electrode to vaporise a groove of tissue, and also the "mn-off' for chips of tissue cut by the loop.

Preferably, the cross-sectional thickness of the vaporisation member is substantially constant.

The loop extends laterally from the two aims, but not necessarily at an angle of degrees. According to a convenient embodiment, the loop extends laterally at an angle of between 60 and 120 degrees with respect to the two arms. In one arrangement, the loop extends laterally at an angle of less than 90 degrees from the two arms, such that it has an acute angle with respect to the arms. Alternatively, the loop extends laterally at an angle of greater than 90 degrees from the two arms, such that it creates an obtuse angle with the arms. However, the loop may conceivably extend laterally at an angle of substantially 90 degrees from the two arms.

In one arrangement, the vaporisation member is attached to the loop on the same side as the two aims. This is to say, with the arms extending longitudinally from a proximal end to a distal end, and with the electrode attached at the distal end of the arms, the vaporisation member lies on the proximal side of the loop. This means that the loop will cut tissue when the elecnode is moved in a distal direction, and the vaporisation member will form a groove in the tissue when the electrode is moved in a proximal (or retrograde) direction.

Alternatively, the vaporisation member is attached to the loop portion on the opposite side from the two arms. This is to say that the vaporisation member lies on the distal side of the loop, such that the loop will cut tissue when the electrode is moved in a proximal direction, and the vaporisation member will form a groove in the tissue when the electrode is moved in a distal direction. These two alternatives are provided to take into account the preferences of individual surgeons, some of whom prefer to vaporise and some who prefer to cut tissue in a proximal direction.

The electrode preferably forms part of a bipolar electrode assembly in which the electrosurgical probe is provided with a return electrode insulated from the arms and the loop. Bipolar electrosurgical instruments have the advantage that electric current flows directly between the two electrodes, which are both located on the instrument shaft. Alternatively, the electrode forms part of a monopolar electrosurgery system in which the system is provided with a return patient plate electrode separate from the arms and the ioop.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an electrosurgical system for use with an electrode in accordance with the present invention, Figure 2 is an exploded view of a resectoscopic instrument used as part of the electrosurgical system of Figure 1, Figure 3 is a perspective view of an electrode in accordance with the present invention, Figure 4 is a schematic sectional view of the electrode of Figure 3 being used in a first mode of operation, Figure 5 is a schematic sectional view of the electrode of Figure 3 being used in a second mode of operation, Figure 6 is a perspective view of an electrode in accordance with an alternative embodiment of the present invention, Figure 7 is a schematic sectional view of the electrode of Figure 6 being used in a first mode of operation, Figure 8 is a schematic sectional view of the electrode of Figure 6 being used in a second mode of operation, Figure 9 is a perspective view of an electrode in accordance with a further embodiment of the present invention, Figure 10 is a perspective view of the electrode of Figure 9, shown assembled into a bipolar electrosurgical assembly, Figure II is a perspective view of an electrode in accordance with a further embodiment of the present invention, Figure 12 is a schematic sectional view of the electrode of Figure 11 being used in a first mode of operation, Figure] 3 is a schematic sectional view of the electrode of Figure 1] being used in a second mode of operation, Figure 14 is a schematic sectional view of a further embodiment of electrode of the present invention being used in a first mode of operation, and Figure 15 is a schematic sectional view of the electrode of Figure 14 being used in a second mode of operation.

Referring to Figure 1. a generator I has an output socket 2 providing a radio frequency RF) output for an instrument 3 via a connection cord 4. Activation of the generator may be performed from the instrument 3 via a connection in cord 4 or by means of a footswitch unit 5, as shown, connected to the rear of the generator by a footswitch connection cord 6. In the illustrated embodiment footswitch unit S has two footswitch pedals 7 and 8 for selecting a coagulation mode and a cutting/vaporisation mode of the generator respectively. The generator front panel has push buttons 9 and for respectively setting coagulation and cutting/vaporisation power levels, which are indicated in a display 11. Push buttons 12 are provided as a means for selection between alternative coagulation and cutting/vaporisation waveforms.

As shown in Figure 2, the instrument 3 is deployed through a resectoscope 13 including an inner sheath 14, an outer sheath 15, and a rod lens telescope/light source assembly 16. The instrument 3 is part of a working element, indicated generally by the reference W and including a bipolar electrode assembly 17.

The sheaths 14 and 15 provide for the supply and aspiration of an operating site with a fluid medium via a connector 18. The outer sheath 15 locks over the inner sheath 14, forming a watertight seal. Typically, the inner sheath 14 has a diameter of 24Fr, and the outer sheath 15 has a diameter of 27 Fr. The telescope assembly 1 provides the means of illuminating and viewing the operative site via a light source (not shown) connected thereto by a connector 19. The viewing angle of the telescope is generally at 300 to its axis.

The working element W may be either passive or active, that is to say the cutting stroke of the electrode may be as the result of a spring bias or against the force of a spring bias. The telescope asseniNy 16 includes a telescope support tube 20 having a telescope connector 21 at its proximal end, and a sealing block 22 located part way along the support tube 20, the inner sheath 14 being connected to the sealing block.

Both of these interfaces are watertight.An electrode support tube 23 is attached to the underside of the telescope support tube 20 on the distal side of the sealing block 22 for the majority of its length. Two spring-loaded links 24 and an insulation block 25, located between the sealing block 22 and the telescope connector 21, make up the mechanism. The active mechanism is arranged so that the spring-loaded links 24 assist the forward stroke, while, in the passive version the links aid the backward stroke. In general, the range of travel is about 25 mm.

The bipolar electrode assemNy 17 includes an active electrode 26, to be descnbed in more detail subsequently, and a return electrode 27 located on the shaft of the electrode assembly. The electrodes 26 & 27 are connected to the generator 1 via cord 4 connected via socket 28. The electrode support tube 23 is also formed of electrically conductive matenal, and may constitute a further return electrode, also connected to the generator 1 via cord 4.

Referring to Figure 3, the active electrode 26 is suspended from two arms 29 & 30, and comprises a ioop 31 and a vaporisation member 32. The loop 31 acts as a downward continuation of the two arms 29 & 30, and depends therefrom at an angle of degrees. The vaporisation member 32 is in the form of a spherical quadrant, with an upper surface 33 and lower surface 34. Both the upper and lower surfaces are smooth, and the shape of the vaporisation member 32 is that which would be formed by sweeping a lower portion 35 of the loop through an arc of approximately 90 degrees.

The vaporisation member 32 is joined to the side of the loop on its proximal side (i.e. lying underneath the arms 29 & 30), with the upper surface 33 meeting the loop adjacent its upper periphery 36, and the lower surface 34 meeting the loop adjacent its lower periphery 37. Both the loop 31 and vaporisation member 32 are formed of an electncally conductive material such as tungsten or stainless steel. Other materials, such as platinum, iridium etc. are known in the art as being available for use in high temperature electrodes.

Figures 4 & 5 show the electrode 26 of Figure 3 in the removal of tissue, the tissue being shown generally at 38. Figure 4 shows the electrode being moved in a forward (distal) direction, such that the first part of the electrode to contact the tissue is the loop 31. An electrosurgical cutting signal supplied to the dectrode from the generator 1 causes the loop 31 to cut through the tissue, with a chip of tissue being foimed as shown generally at 39. The chip 39 is guided upwardly by the smooth upper surface 33 of the vaporisation member 32. so as to be directed away from the remaining tissue 38.

Figure 5 shows the electrode of Figure 3 being moved in a rearward (proximal) direction, such that the first part of the electrode to contact the tissue 38 is the vaporisation member 32. The smooth lower surface 34 of the vaporisation member presents a relatively wide and deep profile to the tissue 38, such that the movement of the electrode 26 causes the formation of a groove or channel of vaporised tissue. The relatively deep profile of the vaporisation member means that the electrode is capable of the bulk vaporisation of tissue, unlike the slider or roller electrodes of the prior art, which tend to be used merely to remove a surface layer of tissue in a "painting" manoeuvre.

The electrode 26 can also be used to perform the surface coagulation of tissue, in which case the electrode is supplied with a coagulation signal from the generator I, and the electrode is moved over the surface of the tissue 38 with the thwer surface 34 of the vaporisation member 32 in contact therewith. Instead of vaporising the tissue, the coagulating signa' causes the coagulation of the tissue surface, the relativdy smooth and wide nature of the vaporisation member ensuring that coagulation can be performed quickly and effectively. The curved nature of the member 32 means that a groove is produced with a generally rounded profile. as opposed to prior art roller electrodes which tend to form a groove with a rectangular profile. Such rectangular grooves can prove awkward for coagulation purposes, with bleeding occurring in hard to reach corners of the groove. The present device produces a curved groove, and the member 32 can coagulate tissue throughout.

Figure 6 shows an alternative embodiment of electrode 26, in which the ioop 31 depends from the arms 29 & 30 at an obtuse angle, approximately 100 degrees as shown iii Figure 6. Figures 7 & 8 show the electrode of Figure 6 being used on tissue in the forward and rearward directions respectively. The operation of the electrode is substantially as described with reference to Figures 4 & 5, with a forward movement causing the oop 31 to create chips of tissue, and the rearward movement causing the vaporisation member 32 to create a groove in the tissue 38. An advantage in the obtuse angle of the ioop 31 is that it provides an arrangement in which the electrode 26 has its lowest point 43 as part of the curved vaporisation member, making spot coagulation using the electrode easier. The generally upward angle of the loop 31 also helps to ensure that the ioop does not become embedded in tissue when moving forward.

Figure 9 shows a further embodiment of electrode 26, in which the loop 31 depends from the arms 29 & 30 at an acute angle, approximately 80 degrees as shown in Figure 9, Figure 10 shows the electrode 26 of Figure 9 together with a return electrode 27, separated from the electrode 26 by means of electrically insulating spacers 40.

Figure ii shows a further embodiment in which the vaponsation member 32 has not only a partly spherical profile as in Figures 3 to 9, but also a linear section 41.

The vaporisation member of Figure 11 has a curved portion 42 (corresponding to the partly spherical shape of the embodiments of Figures 3 to 9), the curved portion 42 lying adjacent the loop 3t. However, the curved portion 42 gradually changes into the linear section 41, which continues until the top edge of the vaporisation member 32.

This profile is shown more cleady in Figure 12, which shows the electrode 26 being used in a forward motion to cause the loop 31 to cut a chip 39 in the tissue 38. Figure 13 shows the electrode being used in a rearward motion to cause the vaporisation member 36 to form a groove in the tissue 38. The linear section 41 creates a straight line area of contact with the tissue 38, allowing more accurate tissue sculpting to take place. The loop 31 depends from the arms 29 & 30 at an obtuse angle (approximately degrees), and the vaporisation member 32 is attached to the proximal side of the loop 31.

Finally, Figures 14 & 15 show a similar electrode to that of Figures 12 & 13, but with the vaporisation member 32 being attached to the distal side of the loop. This means that the electrode 26 vaponses tissue when the electrode is moved in a forward (or distal) direction, and cuts a chip 39 of tissue when moved in a rearward (or proximal) direction.

The chips 39 of tissue can be collected by the surgeon to form samples for subsequent biopsy. The electrode of the present invention provides a cutting loop for the resection of tissue, and a large area vaporisation electrode for the vaporisation of tissue, the two being provided in a single electrode. Unlike some other arrangements that provide separate electrodes for resection and vaporisation, which must consequently be connected and disconnected in order to provide each function, the present invention provides both functions from a single electrode. However, the surgeon is always confident of which tissue effect is being selected, as the direction of movement of the electrode determines whether a tissue resection or tissue vaporisation effect is achieved.

The electrode 26 is described above as being used with the loop 31 and vaporisation member 32 being disposed below the two anus 29 & 30. However, it is equally practical for the electrode to be used in a different orientation, and references hereth to "upper" or "lower" should not be construed as implying that only one mode of operation is envisaged. The electrode can in practice be inverted, such that the loop 31 and vaponsation member 32 extend above the two arms, or similarly re-oriented such that the loop 31 and vaporisation member 32 extend sideways therefrom. Whichever method of orientation is used, the movement of the electrode in one longitudinal direction allows the loop to resect tissue, while movement in the opposite longitudinal direction allows the vaporisation member to vaporise and/or coagulate tissue.

Claims

<claim-text>Claims I. An electrode for use in an dectrosurgical probe. the electrode comprising two arms defining a longitudinal direction, a ioop extending laterally from the two arms and defining a cutting area within the loop, and a vaporisation member attached to one side of the loop, the vaporisation member being such that it does not occlude the cutting area and yet presents a substantial profile when the electrode is moved axially in the longitudina' direction, the arrangement being such that when the electrode is moved in a first longitudinal direction, the loop is capable of resecting a sample of tissue, the resected tissue being received within the cutting area, and when the electrode is moved in the opposite longitudinal direction, the vaporisation member is capable of vaporising tissue adjacent thereto to form a groove therein.</claim-text> <claim-text>2. An electrode according to claim 1, wherein the vaponsation member includes an upper surface and a lower surface.</claim-text> <claim-text>3. An electrode according to daim 2, wherein the upper surface of the vaporisation member terminates adjacent the loop.</claim-text> <claim-text>4. An electrode according to claim 2 or claim 3. wherein the loop includes a lowest point which is furthest from the two arms, and the lower surface of the vaporisation member extends upwardly from the lowest point of the loop so as to terminate at a height between the arms and the lowest point of the ioop.</claim-text> <claim-text>5. An electrode according to any of claims I to 4, wherein the vaporisation member includes a curved portion of a shape formed by sweeping an arc with a curve equivalent to at least a section of the loop member.</claim-text> <claim-text>6. An dectrode according to claim 5, wherein the curved portion of the vaporisation member is of a shape formed by sweeping an arc of at least 45 degrees.</claim-text> <claim-text>7. An electrode according to claim 6, wherein the curved portion of the vaporisation member is of a shape formed by sweeping an arc of at least 90 degrees.</claim-text> <claim-text>8. An electrode according to claim 7. wherein the curved portion of the vaporisation member is of a shape formed by sweeping an arc of at least 120 degrees.</claim-text> <claim-text>9. An electrode according to any of claims 5 to 8, wherein the curved portion of the vaporisation member forms part of the surface of a sphere.</claim-text> <claim-text>10. An electrode according to any of claims.5 to 9, wherein the curved portion constitutes the entirety of the vaporisation member.</claim-text> <claim-text>11. An electrode according to any of claims 5 to 9, wherein the curved portion constitutes only a portion of the vaporisation member.</claim-text> <claim-text>12. An electrode according to claim II, wherein the vaporisation member also includes a linear, upwardly sloping section.</claim-text> <claim-text>13. An electrode according to claim 12, wherein the curved portion is located between the loop and the upwardly sloping section.</claim-text> <claim-text>14. An electrode according to any preceding claim, wherein the cross-sectional thickness of the vaporisation member is substantially constant.</claim-text> <claim-text>15. An electrode according to any preceding claim, wherein the loop extends laterally at an angle of between 60 and 120 degrees with respect to the two arms.</claim-text> <claim-text>16. An electrode according to claim 15, wherein the loop extends laterally at an angle of less than 90 degrees from the two arms.</claim-text> <claim-text>17. An electrode according to claim 15, wherein the loop extends laterally at an angle of greater than 90 degrees from the two arms.</claim-text> <claim-text>18. An electrode according to daim 15, wherein the ioop extends laterally at an angle of substantially 90 degrees from the two arms.</claim-text> <claim-text>19. An electrode according to any preceding claim, wherein the vaporisation member is attached to the loop on the same side as the two aims.</claim-text> <claim-text>20. An dectrode according to any of claims I to 18, wherein the vaporisation member is attached to the loop portion on the opposite side from the two arms.</claim-text> <claim-text>21. An electrode according to any preceding daim. forming part of a bipolar electrode assembly in which the electrosurgical probe is provided with a return electrode insulated from the arms and the loop.</claim-text> <claim-text>22. An electrode according to any of claims 1 to 20, forming part of a monopolar electrosurgery system in which the system is provided with a return patient plate electrode separate from the arms and the ioop.Amendments to the claims have been filed as follows Claims 1. An electrode for use in an electrosurgical probe, the electrode comprising two arms defining a longitudinal direction, a ioop extending laterally from the two arms and defining a cutting area within the loop, and an electrically conductive vaporisation member attached to and electrically connected to one side of the loop such that when the oop is supplied with RE energy the vaporisation member is also energised, the vaporisation member being such that it does not occlude the cutting area and yet presents a substantial profile when the electrode is moved axially in the longitudinal direction, the arrangement being such that when the electrode is energised and moved in a first longitudinal direction, the loop is capable of resecting a sample of tissue, the resected tissue being received within the cutting area, and when the electrode is energised and moved in the opposite longitudinal direction, the vaporisation member is capable of vaponsing tissue adjacent thereto to form a groove therein. (02. An electrode according to daim 1, wherein the vaporisation member includes an upper surface and a lower surface.3. An electrode according to claim 2, wherein the upper surface of the vaporisation member terminates adjacent the ioop.4. An electrode according to claim 2 or claim 3. wherein the loop includes a lowest point which is furthest from the two arms, and the lower surface of the vaporisation member extends upwardly from the lowest point of the loop so as to terminate at a height between the aims and the lowest point of the loop.5. An electrode according to any of claims 1 to 4. wherein the vaporisation member includes a curved portion of a shape formed by sweeping an arc with a curve equivalent to at least a section of the loop member.6. An electrode according to claim 5, wherein the curved portion of the vaporisation member is of a shape formed by sweeping an arc of at least 45 degrees.7. An electrode according to claim 6, wherein the curved portion of the vaporisation member is of a shape formed by sweeping an arc of at least 90 degrees.8. An electrode according to claim 7. wherein the curved portion of the vaporisation member is of a shape formed by sweeping an arc of at least 120 degrees.9. An electrode according to any of claims 5 to 8, wherein the curved portion of the vaporisation member forms part of the surface of a sphere.10. An electrode according to any of claims.5 to 9, wherein the curved portion constitutes the entirety of the vaporisation member.11. An electrode according to any of claims 5 to 9, wherein the curved portion constitutes only a portion of the vaporisation member.12. An electrode according to claim II, wherein the vaporisation member also includes a linear, upwardly sloping section.13. An electrode according to claim 12, wherein the curved portion is located between the loop and the upwardly sloping section.14. An electrode according to any preceding claim, wherein the cross-sectional thickness of the vaporisation member is substantially constant.15. An electrode according to any preceding claim, wherein the loop extends laterally at an angle of between 60 and 120 degrees with respect to the two arms.16. An electrode according to claim 15, wherein the loop extends laterally at an angle of less than 90 degrees from the two arms.17. An electrode according to claim 15, wherein the loop extends laterally at an angle of greater than 90 degrees from the two arms.18. An electrode according to daim 15, wherein the ioop extends laterally at an angle of substantially 90 degrees from the two arms.19. An electrode according to any preceding claim, wherein the vaporisation member is attached to the loop on the same side as the two aims.20. An dectrode according to any of claims I to 18, wherein the vaporisation member is attached to the loop portion on the opposite side from the two arms.21. An electrode according to any preceding daim. forming part of a bipolar electrode assembly in which the electrosurgical probe is provided with a return electrode insulated from the arms and the loop.22. An electrode according to any of claims 1 to 20, forming part of a monopolar electrosurgery system in which the system is provided with a return patient plate electrode separate from the arms and the ioop.</claim-text>