GB2559373A

GB2559373A - Electrosurgical system

Info

Publication number: GB2559373A
Application number: GB1701774.0A
Authority: GB
Inventors: Atwell Tony
Original assignee: Gyrus Medical Ltd
Current assignee: Gyrus Medical Ltd
Priority date: 2017-02-03
Filing date: 2017-02-03
Publication date: 2018-08-08
Anticipated expiration: 2037-02-03
Also published as: GB2559373B; GB201701774D0

Abstract

A bipolar electrosurgical instrument comprising jaws 13, 14 provided with a cutting electrode (16, Fig 1) and at least two coagulating/sealing electrodes and a closure detecting means preferably in the form of pressure sensors, strain gauges 75A-D, or distance gauges (76, Fig 12A) - for detecting whether the jaws 13, 14 are in their open or closed position. The device also comprises first and second switches (40, 43; Fig 6) to supply different RF waveforms to the electrodes. Actuation of the first switch effects the supply of a first, preferably coagulating, waveform whereas the waveform supplied by the second switch is dependent upon the position of the jaws 13, 14. If the detecting means 75, 76 indicate that the jaws 13, 14 have not been moved from their closed position since the first switch was activated then the waveform supplied by the second switch is a second, preferably cutting waveform. Whereas if when the second switch is activated, the detecting means indicate that the jaws 13, 14 have been moved between their closed and open positions since the first switch was activated then the waveform supplied is a third, preferably blended cutting and coagulating, waveform.

Description

(54) Title of the Invention: Electrosurgical system

Abstract Title: Electrosurgical instrument having jaw closure detecting means (57) A bipolar electrosurgical instrument comprising jaws 13, 14 provided with a cutting electrode (16, Fig 1) and at least two coagulating/sealing electrodes and a closure detecting means - preferably in the form of pressure sensors, strain gauges 75A-D, or distance gauges (76, Fig 12A) - for detecting whether the jaws 13, 14 are in their open or closed position. The device also comprises first and second switches (40, 43; Fig 6) to supply different RF waveforms to the electrodes. Actuation of the first switch effects the supply of a first, preferably coagulating, waveform whereas the waveform supplied by the second switch is dependent upon the position of the jaws 13, 14. If the detecting means 75, 76 indicate that the jaws 13, 14 have not been moved from their closed position since the first switch was activated then the waveform supplied by the second switch is a second, preferably cutting waveform. Whereas if when the second switch is activated, the detecting means indicate that the jaws 13, 14 have been moved between their closed and open positions since the first switch was activated then the waveform supplied is a third, preferably blended cutting and coagulating, waveform.

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ELECTROSURGICAL SYSTEM

This invention relates to an electrosurgical system for the sealing and cutting of tissue. Such systems are commonly used for the treatment of tissue in surgical intervention, most commonly in “keyhole” or minimally invasive surgery, but also in “open” surgery.

It is known to provide an electrosurgical instrument in which the sealing and cutting of tissue is effected by means of a pair of jaw elements. US Patents 6,174,308 & 8,394,094 are two examples of this kind of instrument. These two patents describe the provision of an electrically conductive cutting electrode present on one of the jaws, in order to effect the cutting of tissue grasped therebetween. The present invention attempts to provide an improvement to an arrangement such as this.

Accordingly, an electrosurgical system is provided including, an electrosurgical generator, including a controller and a supply of RF energy, an electrosurgical instrument connected to the generator, the instrument comprising,

i) a handle including an actuating mechanism movable between a first position and a second position, ii) a pair of opposing first and second jaw members, movement of the actuating mechanism from its first position to its second position causing at least one of the jaw members to pivot relative to the other about a pivot mechanism from a first open position in which the jaw members are disposed in a spaced relation relative to one another, to a second closed position in which the jaw members cooperate to grasp tissue therebetween, iii) a first sealing electrode located on one of the jaw members, iv) a second sealing electrode located on one of the jaw members,

v) a cutting electrode located on one of the jaw members and insulated from the first and second sealing electrodes by one or more insulating members, vi) closure detecting means for detecting whether the jaw members are in their first open position or in their second closed position, and switch means comprising first and second switches, the controller being adapted to receive signals from the switch means and to cause the generator to supply a first RF waveform when the first switch is activated, characterised in that the controller is also adapted to receive signals from the closure detecting means, and to cause the generator to supply a second RF waveform when the second switch is activated and the signals from the closure detecting means indicate that the jaw members have not been moved between their first and second positions since the first switch was previously activated, and to cause the generator to supply a third RF waveform when the second switch is activated and the signals from the closure detecting means indicate that the jaw members have been moved between their first and second conditions since the first switch was previously activated.

The controller is adapted to cause the generator to supply a first RF waveform when the first switch is activated, and typically this first RF waveform is a coagulating RF waveform. The controller is also adapted to cause the generator to supply a second RF waveform when the second switch is activated and the signals from the closure detecting means indicate that the jaw members have not been moved between their first and second conditions since the first switch was previously activated. This second RF waveform is typically a cutting RF waveform. Thus, the generator is capable of detecting that the instrument has grasped tissue, applied a coagulating waveform to the tissue, and is still grasping the tissue having not released it. In these circumstances, the cutting RF waveform to be applied to the tissue can be a “pure” cutting waveform.

Furthermore, the controller is adapted to cause the generator to supply a third

RF waveform when the second switch is activated and the signals from the closure detecting means indicate that the jaw members have been moved between their first and second conditions since the first switch was previously activated. This third RF waveform is typically a blend of a cutting RF waveform and a coagulating RF waveform. Thus, the generator is also capable of detecting situations in which the instrument has not previously grasped and coagulated tissue, or where it has grasped and released the tissue and may therefore be grasping different tissue from that previously grasped. In these circumstances, the waveform to be applied to the tissue needs to be a blend of coagulating and cutting waveforms, to ensure that the tissue is properly coagulated as well as cut. This “blend” of cutting and coagulating RF waveforms is conceivably a continuously alternating sequence of cutting and coagulating RF waveforms, or may conveniently be a single pulse of coagulating RF waveform followed by one or more pulses of cutting RF waveform. Either way, the waveform ensures that tissue is coagulated prior to cutting.

The closure detecting means conveniently comprises one or more sensors adapted to detect whether the jaw members have been moved to their second closed position, such as pressure sensors adapted to detect whether the jaw members have been closed with a predetermined minimum closure force therebetween. In this way, the sensors are able to detect whether the jaw members have been closed sufficiently tightly, and whether or not they have been released since the coagulating RF waveform has been applied.

According to one convenient arrangement, the first sealing electrode is located on the first jaw member and the second sealing electrode is located on the second jaw member. Alternatively, the first and second sealing electrodes are both located on either the first or the second jaw member, with insulation members therebetween. The cutting electrode preferably comprises a stationary elongate element, such as a rail or wire electrode. The switch means typically comprises a footswitch assembly located separate from the generator and the electrosurgical instrument, but additionally or alternatively comprises a handswitch assembly located on the electrosurgical instrument.

Typically the first switch is a “blue” coagulation switch or pedal, while the second switch is a “yellow” cut switch or pedal, as is customary in electrosurgical generators and instruments. Whichever arrangement is employed, the system is capable of applying different RF waveforms depending on whether the instrument is detected as grasping tissue and activating the yellow pedal, or grasping the tissue and applying the blue and yellow pedals in sequence without having released the tissue in between.

The invention further resides in a method of treating tissue comprising the steps of

i) grasping tissue with an electrosurgical instrument comprising a pair of opposing first and second jaw members, movable between a first open position and a second closed position, ii) detecting whether the jaw members are in their first open position or in their second closed position, iii) supplying a first RF waveform in response to the activation of a first switch, and iv) supplying a second RF waveform or a third RF waveform in response to the activation of a second switch, the supply of the second or third RF waveform depending on whether the jaw members have been moved to their open position since the activation of the first switch.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic sectional view of an endoscopic electrosurgical instrument forming part of a system in accordance with the invention;

Figure 2 is a perspective view of the jaw assembly of the instrument of Figure i;

Figure 3 is a cross-sectional view of the body of the instrument of Figure 1;

Figure 4 is an end view of the jaw assembly of Figure 2;

Figure 5 is a side view of the jaw assembly of Figure 2;

Figure 6 is a circuit diagram of a switching circuit used in conjunction with the electrosurgical instrument of Figure 1;

Figure 7 is a schematic side view of an alternative embodiment of electrosurgical instrument for use in open procedures and forming part of a system in accordance with the invention;

Figure 8 is an enlarged view of a portion of one of the jaws of the instrument of Figure 7;

Figure 9 is a sectional end view of one of the jaws of the instrument of Figure 7;

Figure 10 is a sectional end view of the other jaw of the instrument of Figure 7;

Figure 11 is a schematic drawing showing the possible location of strain gauges on the instrument of Figure 1;

Figure 12 is a schematic cross-sectional view of an endoscopic electrosurgical instrument forming part of a system in accordance with the invention;

Figure 12A is an enlarged cross-sectional view of a part of Figure 12;

Figure 13 is a schematic cross-sectional view of an alternative embodiment of endoscopic electrosurgical instrument forming part of a system in accordance with the invention; and

Figures 13 A and 13B are enlarged cross-sectional views of parts of Figure 13. Referring to Figure 1, a bipolar forceps device includes an elongated tubular shaft 1 with a proximal end 2, a distal end 3, and a lumen 4 which extends for the entire length of the tubular member. At the proximal end 2 of the tubular member 1 is a scissors-type handle assembly 5 with a first handle 6 and a second handle 7. The second handle 7 is pivotable with respect to the first handle 6, about a pivot pin 8. In a known design of actuation mechanism, the second handle 7 has a pin 9 affixed to the top thereof, such that movement of that handle causes a corresponding movement to a sphere 10 supported in a U-shaped cradle 11.

Fitted into the distal end 3 of the tubular member 1 is a forceps jaw assembly

12, more particularly shown in Figure 2. The jaw assembly 12 comprises a first jaw member 13 and a second jaw member 14, pivotally joined to each other by an insulated rivet 15. The jaw member 13 is provided with a relatively-long, but narrow cutting electrode 16 isolated therefrom by a ceramic insulator 17. As shown in Figure 3, three rigid electrically-conductive rods 18, 19 and 20, each covered with a layer of electrical insulation, extend through the lumen 4 of the tubular member 1. The rods 18, 19 are pivotally connected to the respective jaw members 13, 14 by rigid links 21, whilst the rod 20 is connected by means of a wire 24 (as best shown in Figure 5) to the cutting electrode 16. The proximal ends of the rods 18, 19 and 20 extend from the tubular member 1 through the sphere 10 and terminate in a connector 22, by which means the device can be attached to an electrosurgical generator 26.

As shown in Figure 2, the cutting electrode 16 is in the form of an elongate rail, extending along the length of the jaw member 13. The rail 16 is mounted on top of the ceramic insulator 17 such that it is insulated from the conductive jaw member 13. The rail 16 is typically 50 to 100 microns in width, and protrudes from the ceramic insulator 17 by a distance of approximately 50 microns. When the jaw assembly 12 is in its closed position, the rail 16 is received in a corresponding longitudinal recess 23 in the jaw member 14, best shown in Figure 4. A compressible strip 27 of insulting material is provided in the recess 23.

The device can be used to coagulate tissue, using the jaw assembly 12 in its closed position. The jaw assembly 12 is closed, capturing tissue between the jaw member 13 and the jaw member 14. The cutting rail 16 is received in the recess 23 and, without the supply of an electrosurgical cutting signal thereto, does not have a cutting effect on the tissue therebetween. A coagulating signal from the electrosurgical generator 26 is supplied between the jaw members 13 and 14, via the rods 18 and 19. This causes the coagulation of the tissue held between the jaws 13 and 14.

Alternatively, the device can be used to cut tissue grasped between the jaw members 13 & 14. A cutting signal from the electrosurgical generator 26 is supplied between the cutting electrode 16 (via the rod 20) and one or both of the jaw members 13 & 14 (via the rods 18 & 19).

The device can also be used in a blended cutting and coagulation mode, as described in our US Patent No. 6,966,907. An example of an electrical circuit to provide such an arrangement is shown in Figure 6. The circuit is shown generally at 30 and may be provided as a part of the output stage of the generator 26, as a part of the forceps instrument, or as a separate unit located between the generator and the instrument. Whichever arrangement is employed, input connections 31 and 32 are connected to the output of the generator 26, and output connections 33 and 34 are connected to the rods 18 and 19, and hence to the jaw members 13 and 14. An output connection 35 is connected to the rod 20, and hence to the cutting electrode 16.

Between the input connections 31 and 32 there is a bridge circuit comprising a first transformer 36 and a second transformer 37. The first transformer 36 comprises a primary winding 38 and a secondary winding 39. A switch element 40 is provided in parallel with the primary winding 38. The second transformer 37 comprises a primary winding 41 and a secondary winding 42. A switch element 43 is provided in parallel with the primary winding 41. The switch elements 40 and 43 are operated by a control unit 44.

The second transformer 37 is a step-down transformer in which the secondary winding 42 is itself the primary to a further centre-tapped secondary winding 45 connected across the output connections 33 and 34. An isolation capacitor 46 is provided between the bridge circuit and the output connection 35, and isolation capacitors 47 and 48 are provided between the bridge circuit and the output connections

33 and 34.

The operation of the circuit is as follows. For a predetermined period, the control unit 44 operates the switch 43 to close and provide a short circuit across the primary winding 41 of the second transformer 37. In this arrangement, with the secondary transformer 37 effectively short-circuited, the output of the generator 26 is directed between the output connection 35 and both of the output connections 33 and 34. This has the effect of energising the cutting rail 16 with a cutting voltage, as compared to the jaw members 13 and 14, which effectively act as return electrodes for the electrosurgical cutting operation.

After a predetermined period, the control unit 44 operates to open the switch 43 and then close the switch 40 to provide a short circuit across the primary winding 38 of the first transformer 36. There is a short predetermined delay between the opening of the switch 43 and the closing of the switch 40 to ensure that both switches are never closed at the same time (as this would provide a short circuit across the output connections of the generator 26). With the switch 40 closed, the first transformer 36 is effectively short-circuited, and the output of the generator 26 is directed entirely to the second transformer 37. The second transformer 37 is a step-down transformer, and provides a lower voltage signal between the output connections 33 and 34. This has the effect of energising the first and second jaw members 13 and 14 with a coagulating voltage.

After a predetermined time, the control unit 44 opens the switch 40 and then closes the switch 43, reverting to the arrangement initially described in which a cutting voltage is delivered to the cutting rail 16. By constantly alternating between the two conditions herein described, the circuit provides a rapidly alternating cut and coagulation signal to a forceps device connected thereto. In this way, the forceps device is able to cut tissue, while simultaneously coagulating the tissue in order to curtail bleeding.

Although the forceps device of Figures 1 to 5 is shown as an endoscopic instrument, the invention can also be employed in connection with open instruments, as will be described with reference to Figures 7 to 10. The instrument shown generally at 50, comprises two longitudinal members 51 and 52, mounted for pivotal movement by means of a pivot pin 53. The proximal end of the member 51 is in the form of handle portion 54, and the proximal end of the member 52 is in the form of a handle portion 55. A ratchet mechanism 56 is provided on each handle portion 54, 55 for locking the handle portions when they are moved together into their closed position.

Distal of the pivot pin 53, the longitudinal member 51 forms a jaw member 57, while the longitudinal member 52 forms a jaw member 58. Movement of the handle portions 54 and 55 causes the jaw members 57 and 58 to open and close.

With reference to Figures 8 and 9, the jaw member 57 comprises an integral 5 base portion 59 on which is mounted a shim member 60, secured by means of clips 74. The shim member 60 comprises an insulating strip 61 covered by a metallic surface electrode 62. A cutting electrode assembly 63 is mounted in a recess 64 running longitudinally along the jaw member 57. The cutting electrode assembly 63 comprises a raised insulator block 65, typically of a ceramic material, and a cutting electrode 66 mounted in a further longitudinal recess in the insulator block. The cutting electrode 66 is typically 100 microns in width, and protrudes from the insulator block 65 by a distance of approx 425 microns.

The opposite jaw member 58 (shown in Figure 10) also comprises a base portion 67 and a shim member 68. The shim member 68 also comprises an insulting strip 69 covered by a metallic surface electrode 70. The shim member 68 includes a central recess 71 in which the cutting electrode assembly 63 of the jaw member 57 can be received when the jaw members 57 and 58 are in their closed position. At the base of the recess 71 is a strip 72 of resilient material such as an elastomer, such that the cutting electrode 66 bears against that strip when the jaw members 57 and 58 are closed one against the other. A stop member 73, mounted on one of the jaws, regulates the separation of the jaws when they are in their closed position.

The operation of the instrument 50 will now be described. The jaw members 57 and 58 are moved to their closed position, gripping tissue to be cut therebetween. Then a first coagulating RF signal is supplied between the surface electrodes 62 and 70, causing the coagulation of the tissue held between the jaw members 57 and 58. A second cutting RF signal is then supplied to the cutting electrode 66, causing the cutting of the tissue held by the jaw members 57 and 58.

Whether the instrument is an endoscopic instrument as shown in Figures 1 to 5, or an open instrument as shown in Figures 7 to 10, the instrument contains closure detecting means capable of detecting whether the jaw members are open or closed. Figure 11 shows an instrument in which strain gauges 75 are located on the instrument. Strain gauge 75A is located on the jaw 14, while strain gauge 75B on the outside of the tubular shaft 1. Strain gauge 75C is located on the push rod 18, while strain gauge 75D is located on the handle 6. Clearly, it is not necessary to have strain gauges at all of these locations, and only a single strain gauge may be provided, but the above illustrates several possible locations for the gauges.

Figures 12 and 12A show in more detail an alternative location for the strain gauge 75. The strain gauge is affixed to the push rod 18 at the proximal end thereof, and there is also provided a linear distance gauge 76 to determine the extent of the longitudinal movement of the push rod. Signals from the strain gauge 75 and the linear distance gauge 76 are transmitted via leads 77 to the generator 26.

The operation of the instrument shown in Figures 1 to 5 will now be described in combination with the strain gauges 75. When the jaw assembly 12 is closed, capturing tissue between the jaw member 13 and the jaw member 14, the stain gauges provide a signal to the generator indicating that the jaws are closed. A switch means in the form of a footswitch (not shown) is provided, and the “blue” coagulate pedal is depressed by the user, causing a coagulating signal to be supplied from the electrosurgical generator 26 between the jaw members 13 and 14, via the rods 18 and 19. This causes the coagulation of the tissue held between the jaws 13 and 14.

If the “yellow” cut pedal is subsequently depressed on the footswitch, the generator 26 will determine from the strain gauges 75 whether the jaw assembly 12 has been released since the blue pedal was activated, or whether the tissue has continued to be firmly grasped between the jaw members 13 & 14. If the stain gauges indicate that the jaw assembly has not been released, a pure cutting signal is supplied from the electrosurgical generator 26 in response to the activation of the yellow pedal.

Conversely, when the “yellow” cut pedal is subsequently depressed on the footswitch, if the strain gauges 75 indicate that the jaw assembly has been released and re-applied such that tissue has not been continuously grasped between the jaw members since the blue pedal was activated, the generator 26 supplies a blended cutting and coagulation waveform as described with reference to Figure 6 above. In this circumstance, the generator cannot be certain whether the tissue between the jaw members 13 & 14 is coagulated, as it cannot be sure that the tissue now grasped between the jaws is the same tissue as was grasped when the blue pedal was actuated. Thus, in this situation, the generator supplies a blended waveform containing both coagulating and cutting components, such that a pure cutting waveform is never supplied to tissue which is insufficiently coagulated.

A similar arrangement applies to the instrument 50, with the strain gauges 75 determining whether tissue has been continuously grasped between the jaws 57 & 58 between the activation of the blue and yellow pedals, or whether the jaws have been opened and re-applied. If the tissue has been continuously grasped a pure cutting waveform can be supplied to the cutting electrode 66, but if the jaws have been opened and re-applied, a blended waveform containing both coagulating and cutting components is supplied.

This invention has been described herein in considerable detail in order to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention.

Claims

1. An electrosurgical system including

5 an electrosurgical generator, including a controller and a supply of RF energy, an electrosurgical instrument connected to the generator, the instrument comprising,

i) a handle including an actuating mechanism movable between a first

10 position and a second position, ii) a pair of opposing first and second jaw members, movement of the actuating mechanism from its first position to its second position causing at least one of the jaw members to pivot relative to the other about a pivot mechanism from a first open position in which the jaw members are disposed in a spaced relation relative to

15 one another, to a second closed position in which the jaw members cooperate to grasp tissue therebetween, iii) a first sealing electrode located on one of the jaw members, iv) a second sealing electrode located on one of the jaw members,

v) a cutting electrode located on one of the jaw members and insulated 20 from the first and second sealing electrodes by one or more insulating members, vi) closure detecting means for detecting whether the jaw members are in their first open position or in their second closed position, and switch means comprising first and second switches, the controller being adapted to receive signals from the switch means and to 25 cause the generator to supply a first RF waveform when the first switch is activated, characterised in that the controller is also adapted to receive signals from the closure detecting means, and to cause the generator to supply a second RF waveform when the second switch is activated and the signals from the closure detecting means indicate that the jaw members have not been moved between their first

30 and second conditions since the first switch was previously activated, and to cause the generator to supply a third RF waveform when the second switch is activated and the signals from the closure detecting means indicate that the jaw members have been moved between their first and second conditions since the first switch was previously activated.

2. An electrosurgical system according to claim 1, wherein the first RF

5 waveform is a coagulating RF waveform.

3. An electrosurgical system according to claim 1 or claim 2, wherein the second RF waveform is a cutting RF waveform.

10

4. An electrosurgical system according to claim 3, wherein the third RF waveform is a blend of a cutting RF waveform and a coagulating RF waveform.

5 An electrosurgical system according to any preceding claim, wherein the closure detecting means comprises one or more sensors adapted to detect whether the

15 jaw members have been moved to their second closed position.

6. An electrosurgical system according to claim 5, wherein the one or more sensors comprise pressure sensors adapted to detect whether the jaw members have been closed with a predetermined minimum closure force therebetween.

7. An electrosurgical system according to any preceding claim, wherein the first sealing electrode is located on the first jaw member and the second sealing electrode is located on the second jaw member.

25

8. An electrosurgical system according to any of claims 1 to 6, wherein the first and second sealing electrodes are both located on either the first or the second jaw member.

9. An electrosurgical system according to any preceding claim, wherein the

30 cutting electrode comprises a stationary elongate element.

10.

An electrosurgical system according to any preceding claim, wherein the switch means comprises a footswitch assembly located separate from the generator and the electrosurgical instrument.

11. An electrosurgical system according to any of claims 1 to 10, wherein the 5 switch means comprises a handswitch assembly located on the electrosurgical instrument.

12. A method of treating tissue comprising the steps of

i) grasping tissue with an electrosurgical instrument comprising a pair of 10 opposing first and second jaw members, movable between a first open position and a second closed position, ii) detecting whether the jaw members are in their first open position or in their second closed position, iii) supplying a first RF waveform in response to the activation of a first

15 switch, and iv) supplying a second RF waveform or a third RF waveform in response to the activation of a second switch, the supply of the second or third RF waveform depending on whether the jaw members have been moved to their open position since the activation of the first switch.

Intellectual

Property

Office

Application No: GB1701774.0 Examiner: Mr Geraint Davies