GB2594973A

GB2594973A - An operative shaft for an electrosurgical device

Info

Publication number: GB2594973A
Application number: GB2007089.2A
Authority: GB
Inventors: Clarke Ben; Hoddinott Rhydian; Philip Blake Nathan; Rupalia Sunny; Charles Benn Christopher
Original assignee: Gyrus Medical Ltd
Current assignee: Gyrus Medical Ltd
Priority date: 2020-05-13
Filing date: 2020-05-13
Publication date: 2021-11-17
Anticipated expiration: 2040-05-13
Also published as: GB202007089D0; GB2594973B

Abstract

A hollow elongate operative shaft 3b for a radio frequency (RF) electrosurgical instrument has electrically conductive active and return paths embedded within the structure of the shaft itself. The shaft is configured to be attached to a handle (3a, Fig 3) at a proximal end of the shaft and to an end effector (3c, Fig 3) at a distal end of the shaft. The wall of the shaft is comprised of insulating material 30/38, and both an electrically conductive active path 32 for carrying electrical current from the handle to the end effector and an electrically conductive return path 34 for carrying electrical current from the end effector to the handle are embedded therein such that they are electrically isolated from each other by the wall material. Each path extends lengthwise along the length of the cylinder and circumferentially along an arc of the cylinder wall. A width of the arc of the inactive path is at least the size of the active path width arc but may also be larger. In one embodiment the electrically conductive paths are electrode plates. The shaft may form part of an instrument and system comprising the shaft, an end effector and handle.

Description

An Ooerative Shaft for an Electrosuraical Device

Technical Field

Embodiments of the present invention described herein relate to an electrosurgical device, and in particular to an operative shaft for an electrosurgical device.

Background to the Invention and Prior Art

Electrosurgical instruments provide advantages over traditional surgical instruments in that they can be used for coagulation and tissue sealing purposes. One such prior art arrangement is known from US 5,904,681, which describes a surgical instrument including a mechanical cutting portion, such as a rotary blade or burr, and a radio frequency (RF) cutting and/or cauterizing portion comprising an electrosurgical instrument which operates in bipolar mode. A rotary burr works best to remove hard tissues, such as bone, while the bipolar electrosurgical instrument can be used to cut or ablate soft tissues and/or cauterize tissue, including blood vessels. Alternatively, the mechanical cutting portion may include a rotary blade, which may be used for removing soft tissues, with the electrodes of the electrosurgical system being used for cauterisation or coagulation.

The requirement for the distal end and proximal end of an RF instrument to be electrically connected is highly influential to the design of such instruments. Previously, RF instruments have used separate components to form the circuit, usually in one of two configurations as follows: 1) Having an active wire welded to the active tip and using a single metal shaft as the return path (see Figure 1); or 2) Having an inner metal shaft used as the active path, welded to the active tip and using the outer metal shaft as the return path (see Figure 2).

The addition of a mechanical shaver to the RF instrument limits the feasibility of the methods described above. Firstly, a mechanical shaver consists of a rotating inner blade which must not be obstructed during operation, requiring that there are no components between the inner blade and outer shaft. Secondly, a clear path is required along the inner blade for adequate suction through the device. The only feasible location for either an active shaft or an active wire is therefore on the outside of the shaft assembly. With tight diametric limits due to the specified cannula size, there is minimal space available for external components.

Summary of the Invention

Embodiments of the present invention provide an improved surgical instrument having an end effector mounted on the end of an elongate shaft extending from a handle. The elongate shaft provides electrical connections to the end effector comprising an active path and a return path. The active path and the return path are incorporated into the structure of the shaft itself, eliminating the need for a separate active wire and return electrode plate. That is, the shaft itself is formed with an active electrode plate and a return electrode plate embedded into the structure of the shaft, running along the length of the shaft from a proximal end where the shaft attaches to a handpiece to a distal end to which an end effector is attached. The active electrode plate extends circumferentially (or more generally perimetrically) within the wall of the shaft to a first extent, and the return electrode plate also extends circumferentially (or more generally perimetrically) within the wall of the shaft, to at least the same or an even greater extent than the active electrode. Effectively, therefore, both the active and return electrodes take the form of longitudinally extending shaped metal plates that are embedded within the insulating material of the shaft.

The structure of the shaft is formed from insulating material such that the active path and the return path are electrically isolated from each other. The insulating material may be a ceramic material, for example, alumina, zirconia toughened alumina (ZTA), yttria stabilized zirconia (YTZP) or the like. The active path is arranged to be connected to an active electrode in the end effector. The end effector may be capable of different operations, including mechanical cutting of tissue, and electrosurgical cutting, ablation, sealing and/or coagulation of tissue. The active path connects the active electrode to a RF electrosurgical generator. In use the RF electrosurgical generator supplies an RF ablation, or coagulation or tissue sealing signal to the electrode under control of the operator, as appropriate.

In view of the above, from one aspect the present invention provides an operative shaft for an electrosurgical instrument configured to be attached to a handle at a proximal end of the shaft to an end effector at a distal end of the shaft, the shaft comprising: a hollow elongate cylinder having a wall comprised of insulating material, the cylinder having a length which extends from the proximal end of the shaft to the distal end of the shaft; an electrically conductive active path arranged to carry RF electrical current from the handle to the end effector, the active path extending lengthwise along the length of the cylinder and extending perimetrically along a first width of the cylinder wall; and an electrically conductive return path arranged to carry RF electrical current from the end effector to the handle, the return path extending lengthwise along the length of the cylinder and extending perimetrically along a second width of the cylinder wall, the second width being at least the size of the first width, wherein the active path and the return path are embedded within the wall of the hollow elongate cylinder such that the active path and the return path are electrically isolated from one another by the insulating material.

Such an arrangement improves upon the known operative shaft arrangements of the prior art by incorporating the active and return paths into the shaft's structure. This allows the addition of a mechanical shaver to the RF instrument, as a rotating inner 1.0 blade of the mechanical shaver would not be obstructed during operation by the active and return path components which would ordinarily be located between the inner blade and the outer shaft. Having the active and return paths located in the shaft's structure also allows for adequate suction through the device, as the active and return paths are not obstructing the path along the inner blade. The arrangement also does not require components external to the shaft, allowing the instrument to conform to tight diametric limits due to specified cannula sizes.

Further advantages of the arrangement include that because the shaft contains the active and return conducting paths, there is just one unified structure requiring sealing to the instrument's handle. This simplifies the sealing process as the structure has a simple cylindrical profile. In addition, electrical connections between the conducting paths and the instrument's handle can be simplified and made with fewer parts. Moreover, assembly time of the instrument can be significantly reduced due to fewer parts and processes, and furthermore additional conductive paths can be similarly incorporated into the shaft to provide additional functions at the distal end of the device.

In one embodiment, the second width is larger than the first width. The second width may be greater than 50% larger than the first width, preferably greater than 75% larger than the first width, and more preferably greater than 100% larger than the first width.

In one embodiment the shaft is cylindrical in shape such that the first width and the second widths are respectively first and second arcs.

In one embodiment, the first arc is a minor arc. The first arc may subtend an angle of less than 150 degrees, preferably less than 120 degrees, and more preferably less than 90 degrees.

In one embodiment, the second arc is a major arc. The second arc may subtend an angle greater than 200 degrees, preferably greater than 240 degrees, and more preferably greater than 270 degrees.

In one embodiment, each of the active path and the return path are surrounded by the insulating material. This is advantageous as if the insulating material completely encapsulates the conducing paths, a heat-shrink component is not necessarily required to insulate the conducting paths.

In one embodiment, the active path and the return path are comprised of conducting strips, for example formed of metal.

In one embodiment, the active path and the return path are comprised of conducting wires.

Another aspect of the present disclosure provides an electrosurgical instrument, comprising: a handle; one or more user-operable buttons on the handle that control the instrument to operate, an end effector comprising a mechanical shaver component and an active electrode; and an operative shaft as described above, the active path being connected to the active electrode and the operative shaft further comprising drive componentry operably connected to the end effector to drive the mechanical shaver to operate in use.

A yet further aspect provides an electrosurgical system, comprising: an RE electrosurgical generator; a suction source; and an electrosurgical instrument as described in the above aspect, the arrangement being such that in use the RE electrosurgical generator supplies an RE coagulation or ablation signal via the active path to the active electrode, to permit tissue coagulation or ablation of the same tissue that is being cut by the rotary shaver arrangement.

Another aspect of the invention provides an electrosurgical instrument, comprising: a hand piece; an electrosurgical end effector; and a shaft having the electrosurgical end effector at a distal end thereof, and being fixed at a proximal end thereof to the handpiece; wherein the shaft has an active electrode plate and a return electrode plate embedded within the wall thereof, the respective plates running along the length of the shaft from the proximal end where the shaft attaches to the handpiece to the distal end to which the end effector is attached, the active electrode plate extending perimetrically within the a first part of the wall of the shaft to a first extent, and the return electrode plate also extending perimetrically within a second, different, part of the wall of the shaft, to at least the same or an even greater extent than the active electrode, the active and return electrode plates being insulated from each other by the material of the wall of the shaft between the first and second parts.

In one embodiment the shaft is cylindrical in shape, and the first and second plates extend circumferentially around the respective first and second parts of the circumference of the shaft.

Brief Description of the Drawings

Embodiments of the invention will now be further described by way of example only and with reference to the accompanying drawings, wherein like reference numerals refer to like parts, and wherein: Figure 1 is a section view of the distal assembly of a prior art electrosurgical instrument where the active wire is welded to the active tip and a single metal shaft is utilised as the return path.

Figure 2 is a section view of the distal assembly of a prior art electrosurgical instrument where the inner metal shaft utilised as the active path, welded to the active tip. The outer metal shaft is utilised as the return path.

Figure 3 is a schematic diagram of an electrosurgical system including an electrosurgical instrument; Figure 4 is a cross sectional view of the multi-function shaft; Figure 5 is a cross sectional view of the multi-function shaft comprising a heatshrink layer; Figure 6 is a perspective cutaway view of the multi-function shaft; Figure 7 is a perspective view of the seal between the shaft and the handle of the electrosurgical instrument; Figure 8 is a perspective cutaway view of the printed circuit board (PCB) connections. Description of the Embodiments Referring to the drawings, Figure 3 shows an electrosurgical apparatus including an electrosurgical generator 1 having an output socket 2 providing a radio frequency (RF) output, via a connection cord 4, for an electrosurgical instrument 3. The instrument 3 may have irrigation and suction tubes (not shown) which are connected to an irrigation fluid and suction source (not shown). Activation of the generator 1 may be performed from the instrument 3 via a handswitch (not shown) on the instrument 3, or by means of a footswitch unit 5 connected separately to the rear of the generator 1 by a footswitch connection cord 6. In the illustrated embodiment, the footswitch unit 5 has two footswitches 5a and 5b for selecting a coagulation mode or a cutting or vaporisation (ablation) mode of the generator 1 respectively. The generator front panel has push buttons 7a and 7b for respectively setting ablation (cutting) or coagulation power levels, which are indicated in a display 8. Push 1.0 buttons 9 are provided as an alternative means for selection between the ablation (cutting) and coagulation modes.

The instrument 3 includes a proximal handle portion 3a, a hollow shaft 3b extending in a distal direction away from the proximal handle portion, and a distal end effector assembly 3c at the distal end of the shaft. A power connection cord 4 connects the instrument to the RF generator 1. The instrument may further be provided with activation buttons (not shown), to allow the surgeon operator to activate either the mechanical cutting function of the end effector, or the electrosurgical functions of the end effector, which typically comprise coagulation or ablation. The instrument may also be connected to a suction source (not shown), to provide for suction of debris from the surgery site, for example along a suction lumen provided in the center of the shaft 3b.

Figures 4-6 show the shaft 3b in more detail. The shaft 3b is primarily comprised of a hollow cylinder 30 made from an insulating material. The hollow center of the cylinder can be used to provide a suction path for a suction lumen, when in use.

Embedded within the wall of the cylinder 30 are at least two electrically conductive plates 32 and 34 forming conducting paths -an active path 32 and a return path 34. The conducting paths 32, 34 are electrically isolated from one another by at least two portions of the insulating material 38, 40. The conducting paths electrically connect the handle 3a of the instrument, which contains electrical connections, to the end effector 3c of the instrument. The active path 32 carries RF electrical current from the handle 3a to the end effector 3c. The return path 34 carries RF electrical current from the end effector 3c to the handle 3a. The insulating material 30 may be a plastic material, for example, a thermoplastic polymer such as a polyether ether ketone (PEEK) or the like.

Figure 4 shows a cross-section of the shaft 3b. The active path 32 is formed from a first electrically conducting plate that extends circumferentially along a first arc of the cylinder wall 30. The return path 34 is formed from a second electrically conducting plate that extends circumferentially along a second arc of the cylinder wall 30. The second arc is at least the size of the first arc. The second arc may be larger than the first arc. The second arc may be greater than 50%, 75%, or 100% larger than the first arc. As illustrated in Figure 4, the first arc may be a minor arc. The first arc may subtend an angle of less than 1500, 120°, or 90°. The second arc may be a major arc. The second arc may subtend an angle of greater than 200°, 240°, or 2700. The first and second arcs may be arcs of the same circle. Alternatively, the first and second arcs may be arcs of different circles. The conductive paths 32, 34 may comprise conducting strips of metal or conducting wires. The cylinder 30 defines an internal suction lumen 36 which connects to the suction source 10 at the proximal end of the instrument. In Figure 4, the conducting paths 32, 34 are completely insulated by the insulating material 30. However, in Figure 5, the conducting paths 32, 34 are not completely insulated by the insulating material 30. In this embodiment, the shaft is encapsulated by a heatshrink component 42 which insulates the conducting paths 32, 34.

Figure 6 is a perspective cutaway view of the shaft 3b showing how the active path 32 and the return path 34 are embedded within the insulating structure forming the hollow cylinder 30. Figure 6 shows how the conducting paths 32, 34 extend lengthwise along the length of the cylinder from the proximal end of the shaft to the distal end of the shaft. Figure 6 also shows how the active path 32 and the return path 34 are electrically isolated from one another by a portion of the insulating material 38 (portion 40 not shown).

Figure 7 illustrates one advantage of the invention in that with the shaft 3b containing the active and return conducting paths, there is just one unified structure requiring sealing to the instrument's handle 3a. This simplifies and improves the sealing process as the structure 3b has a simple cylindrical profile.

Figure 8 illustrates a further advantage of the invention in that electrical connections between the conducting paths 32, 34 and printed circuit board (PCB) 44 located in the instrument's handle portion 3a can be simplified and made with fewer parts. The active path 32 is connected to the active female 46 of the PCB 44, and the return path 34 is connected to the return female 48 of the PCB 44. These connections may be in the form of conducting wires or strips. Additional conducting paths can be similarly incorporated into the shaft and connected to the PCB to provide additional functions at the distal end of the device. Due to the simplification of the structure in the shaft itself, in the sealing of the shaft to the handle portion, and in the simplified connections at the PCB, assembly time of the instrument can be significantly reduced due to fewer parts and processes.

One possible way of manufacturing an instrument in accordance with the invention described herein is to 3D print an insulating material around the electrical components (conducting paths 32, 34), leaving a gap to allow for shrinkage when the binding agent is removed and the insulating material is fired to fuse the io arrangement of the insulating materials and the electrical components together.

When in use, electrical current is supplied along the shaft to end effectors at the distal end via the active path 32, and return current is routed back to the generator via the return path 34. Because both the active and return current paths are embedded within the material of the shaft then they are both guaranteed to be electrically isolated from each other and from the user, as well as providing a convenient arrangement which means that it appears as if the shaft is "wire-free" in that no stray wires extend along either outside or the internal lumen of the shaft, providing a safer and more reliable arrangement.

Various modifications may be made to the above described embodiment to provide further embodiments. For example, whilst in the above described embodiment the shaft 3b is described and shown as cylindrical with a circular cross-section, in other embodiments the shaft may be of different shape cross-sections as required, for example, may be of square, rectangular, or oval cross-sections. In each case, however, the active and return current paths 32 and 24 are formed from electrically conducting plates embedded within the wall of the shaft and each extending circumferentially (or perimetrically) around at least part of the perimeter of the shaft, as described above.

Various modifications whether by way of addition, deletion, or substitution of features may be made to above described embodiment to provide further embodiments, any and all of which are intended to be encompassed by the appended claims.

Claims

Claims 1. An operative shaft for an electrosurgical instrument configured to be attached to a handle at a proximal end of the shaft and to an end effector at a distal end of the shaft, the shaft comprising: a hollow elongate shaft body having a wall formed from electrically insulating material, the shaft body having a length which extends from the proximal end of the shaft to the distal end of the shaft; an electrically conductive active path arranged to carry RF electrical current from the handle to the end effector, the active path extending lengthwise along the length of the shaft body and extending perimetrically along a first width of the shaft body wall; and an electrically conductive return path arranged to carry RF electrical current from the end effector to the handle, the return path extending lengthwise along the length of the shaft body and extending perimetrically along a second width of the shaft body wall, the second width being at least the size of the first width; wherein the active path and the return path are embedded within the wall of the hollow elongate shaft body such that the active path and the return path are electrically isolated from one another by the insulating material.zo 2. The operative shaft of claim 1, wherein the shaft body is cylindrical in shape such that the first and the second widths are respectively first and second arcs.3. The operative shaft of claims 1 or 2, wherein the second width is larger than the first width.4. The operative shaft of claim 2, wherein the second width is greater than 50% larger than the first width, preferably greater than 75% larger than the first width, and more preferably greater than 100% larger than the first width.5. The operative shaft of any of claims 1 to 4, wherein the first width is a minor arc.6. The operative shaft of claim 5, wherein the first arc subtends an angle of less than 150 degrees, preferably less than 120 degrees, and more preferably less than degrees.7. The operative shaft of any of claims 1 to 6, wherein the second width is a major arc.8. The operative shaft of claim 7, wherein the major arc subtends an angle greater than 200 degrees, preferably greater than 240 degrees, and more preferably greater than 270 degrees.9. The operative shaft of any of claims 1 to 8, wherein each of the active path and the return path are surrounded by the insulating material.10. The operative shaft of any of claims 1 to 9, wherein the active path and the return path are comprised of conducting strips.11. The operative shaft of any of claims 1 to 9, wherein the active path and the return path are comprised of conducting wires.12. An electrosurgical instrument, comprising: a handle; one or more user-operable buttons on the handle that control the instrument to operate; an end effector comprising: a mechanical shaver component; and an active electrode; and an operative shaft according to any of the preceding claims, the active path being connected to the active electrode and the operative shaft further comprising drive componentry operably connected to the end effector to drive the mechanical shaver to operate in use.13. An electrosurgical system, comprising: an RF electrosurgical generator; a suction source; and an electrosurgical instrument according to claim 11, the arrangement being such that in use the RE electrosurgical generator supplies an RE coagulation or ablation signal via the active path to the active electrode, to permit tissue coagulation or ablation of the same tissue that is being cut by the rotary shaver arrangement.14. An electrosurgical instrument, comprising: a hand piece; an electrosurgical end effector; and a shaft having the electrosurgical end effector at a distal end thereof, and being fixed at a proximal end thereof to the handpiece; wherein the shaft has an active electrode plate and a return electrode plate embedded within the wall thereof, the respective plates running along the length of the shaft from the proximal end where the shaft attaches to the handpiece to the distal end to which the end effector is attached, the active electrode plate extending perimetrically within the a first part of the wall of the shaft to a first extent, and the return electrode plate also extending perimetrically within a second, different, part of the wall of the shaft, to at least the same or an even greater extent than the active electrode, the active and return electrode plates being insulated from each other by the material of the wall of the shaft between the first and second parts.15. An electrosurgical instrument according to claim 14, wherein the shaft is cylindrical in shape, and the first and second plates extend circumferentially around the respective first and second parts of the circumference of the shaft.