Patent Application
20230181235
The present invention relates to electrosurgical instruments. More specifically, the present invention relates to an electrode assembly for an electrosurgical instrument and a method of manufacture.
Surgical instruments, including radio frequency (RF) electrosurgical instruments, have become widely used in surgical procedures where access to the surgical site is restricted to a narrow passage, for example, in minimally invasive “keyhole” surgeries.
RF electrosurgical instruments may include an active electrode which forms a distal RF tip of the instrument, and a return electrode. The distal RF tip provides tissue ablation and/or coagulation effects at a surgical site when a RF power signal is delivered to the electrodes. Typical RF electrosurgical instruments also often use a saline suction pathway at the distal tip during either ablating or coagulating tissue.
Known wet-field RF hand instruments, for applications such as arthroscopy, have an RF tip that is both mechanically and electrically connected to the rest of the instrument assembly via various means. Typically, this is through a mechanical interlock that doubles as an electrical connection, or via a mechanical interlock/adhesive with a secondary connection to an active RF wire, to transmit RF energy.
Some RF instruments also implement a mechanical shaver, with the main mechanical shaving componentry located on the opposite side of the distal tip. An RF shaver distal tip 30 is illustrated by
One previous solution, as described in GB publication number 2590929, provides a tip retention mechanism arranged to fit into a low depth profile within the ceramic insulator. This solution provides an insulator with a single inter-locking angled plane and two-part electrode. Such an arrangement is reliant upon achieving optimum tolerances between the mating insulator, electrode and retainer components, however in practice, once manufacturing tolerances and clearances for assembly are applied, the amount of remaining interlock can be minimal. Furthermore, the amount of ceramic insulator in some cases may not be mechanically robust enough to withstand the expected clinical loads. Similarly, the area of the RF active tip for delivering a tissue effect is relatively large and has an exposed ceramic insulator portion in the centre that may negatively impact on the performance of the ablation and coagulation functions.
There is thus a need to further improve the retention of the active electrode within such RF electrosurgical instruments.
In known RF electrosurgical instruments that implement an active electrode tip and a mechanical shaver, the space available for providing secure retention of the active electrode tip is significantly reduced. The present disclosure therefore seeks to address this problem by providing an active electrode and retainer arrangement that are inserted to a cavity of an insulator and then welded together to secure the active electrode in the insulator for use in tissue treatment. The active electrode and retainer are configured to interlock with at least one internal retention surface of the cavity. Once assembled in the cavity, both the active electrode and the retainer may have a portion that extends out of the cavity, such that it protrudes from the insulator. This allows opposing biasing forces to be exerted on the active electrode and the retainer respectively so as to push the two components against a retention surface within the cavity. Consequently, when the active electrode and the retainer are welded together, any clearance with the retention surfaces inside the cavity, for example, caused by variations between parts during the manufacturing process, is removed or at least minimised. As such, the amount of interlock with the retention surfaces of the cavity can be maximised, thus providing a more robust retention of the active electrode. Furthermore, as the interlocking parts of the insulator are provided beneath the main body of the electrode, the overall active tip area is reduced, which thereby improves the performance of the ablation and coagulation functions.
A first aspect of the present invention provides a method of manufacturing an electrode assembly for use in an end effector of an electrosurgical instrument, comprising providing an outer casing comprising an insulating material, wherein the outer casing comprises a cavity, the cavity comprising a base surface, and a first projection extending from the base surface, the first projection comprising a first retention surface and a second retention surface, wherein at least one of the first and second retention surfaces extends away from the base surface at a non-transverse angle relative to a longitudinal axis of the outer casing, inserting a retainer into the cavity via a first opening in a first wall of the outer casing, wherein the retainer comprises a first retention feature configured to engage the first retention surface, inserting an electrode into the cavity via the first opening, wherein the electrode comprises a second retention feature configured to engage the second retention surface, and joining the electrode and the retainer to form the electrode assembly, such that the electrode assembly is mechanically retained within the outer casing.
In some arrangements, the method further comprises applying a first biasing force on the retainer such that first retention feature is biased against the first retention surface, and a second biasing force on the electrode such that the second retention feature is biased against the second retention surface.
By biasing the electrode and the retainer such that they are biased against the respective retention surfaces so as to remove any clearance before the two components are joined together. In doing so, any part-to-part variations introduced during the manufacturing process are mitigated, thereby maximising the amount of interlock with the retention surfaces.
The biasing forces may be applied by any suitable means. For example, the first and second biasing forces may be applied by placing a magnet in the vicinity of the electrode and the retainer. More specifically, the magnet may be placed within a central location of the electrode assembly such as a suction hole so as to pull the electrode and retainer inwards against the respective retention surfaces.
In other arrangements, the retainer may further comprise a protrusion configured to extend out of the first opening such that the protrusion extends beyond the first wall. The first biasing force may then be applied to the protrusion. Similarly, at least one portion of the electrode may be configured to extend out of the first opening such that the at least one portion extends beyond the first wall. In such cases, the second biasing force may be applied to the at least one portion. As such, both the electrode and the retainer may comprise features that extend beyond the profile of the outer casing to allow biasing forces to be applied. For example, the two biasing forces may be applied to the electrode and the retainer using a mechanical jig, or some other suitable apparatus.
In some arrangements, the first retention surface may extend away from the base surface at an angle transverse to the longitudinal axis, and the second retention surface may extend away from the base surface in a direction towards the distal end of the outer casing at a non-transverse angle relative to a longitudinal axis. That is to say, the first retention surface may be a vertical surface, whilst the second retention surface may be an angled surface.
In other arrangements, the first retention surface may extend away from the base surface in a direction towards the proximal end of the outer casing at a non-transverse angle relative to a longitudinal axis, and the second retention surface may extend away from the base surface in a direction towards the distal end of the outer casing at a non-transverse angle relative to a longitudinal axis. That is to say, both of the retention surfaces may be angled surfaces, with one extending towards the distal end of the outer casing and the other extending in the opposite direction. By providing two angled retention surfaces, the strength of the mechanical retention of the electrode and the retainer is further increased.
In other arrangements, the first retention surface may extend away from the base surface in a first lateral direction at a non-transverse angle relative to a longitudinal axis, and the second retention surface may extend away from the base surface in a second lateral direction at a non-transverse angle relative to a longitudinal axis. That is to say, the retention surfaces may be angled surfaces that extend towards opposing sides of the outer casing. One advantage of this arrangement is that the interlocking mechanism is moved out of the proximal end of the cavity, which typically comprises an entry port for receiving an electrical conductor for connecting the electrode assembly to an electrical supply. Consequently, the proximal inner wall can be made vertical, which vastly reduces the likelihood of excess material building up around the entry port during moulding, with the conductor also then providing a third retention point once it has been assembled and connected to the electrode assembly. As such, a robust mechanical retention that is easy to manufacture is provided.
Preferably, the electrode comprises a tissue treatment surface, the tissue treatment surface being configured to cover the first projection. By providing an arrangement where the interlocking mechanism (i.e. the first projection and the retention features) are provided below the treatment surface, the overall active electrode area is reduced, and the overall performance of the ablation and coagulation functions is improved.
The first projection may comprise a first suction aperture, and the tissue treatment surface may comprise a second suction aperture, the electrode being inserted to the cavity such that the second suction aperture aligns with first suction aperture.
The first projection may be connected to an internal wall of the cavity via an interconnecting wall. That is to say, the first projection may be connected to the outer perimeter of the outer casing to further increase the mechanical strength of the first projection.
The retainer may comprise an electrically conductive material.
The insulating material may comprise a ceramic material.
Joining the electrode and the retainer may comprise welding the electrode and the retainer.
The method may further comprise providing a conductor, the conductor being received within the cavity via a second opening in an internal wall, wherein the conductor is in electrical communication with the electrode assembly.
A second aspect of the present invention provides an electrode assembly for use in an end effector of an electrosurgical instrument, the electrode assembly comprising an electrode, a retainer, and an outer casing comprising an insulating material, wherein the outer casing comprises a cavity configured to receive the electrode and the retainer, the cavity comprising a base surface, and a first projection extending from the base surface, the first projection comprising a first retention surface and a second retention surface, wherein at least one of the first and second retention surfaces extends away from the base surface at a non-transverse angle relative to a longitudinal axis of the outer casing, characterised in that the electrode and the retainer are provided in the outer casing by inserting a retainer into the cavity via a first opening in a first wall of the outer casing, wherein the retainer comprises a first retention feature configured to engage the first retention surface, inserting the electrode into the cavity via the first opening, wherein the electrode comprises a second retention feature configured to engage the second retention surface, and joining the electrode and the retainer to form the electrode assembly, such that the electrode assembly are mechanically retained within the outer casing.
In some arrangements, a first biasing force may be applied to the retainer such that first retention feature is biased against the first retention surface, and a second biasing force may be applied to the electrode such that the second retention feature is based against the second retention surface.
A third aspect of the present invention provides an electrode assembly for use in an end effector of an electrosurgical instrument, the electrode assembly comprising an outer casing comprising an insulating material, wherein the outer casing comprises a cavity, the cavity comprising a base surface, and a first projection extending from the base surface, the first projection comprising a first retention surface and a second retention surface, wherein the first and second retention surfaces extend away from the base surface at a non-transverse angle relative to a longitudinal axis of the outer casing, and an electrode arrangement received in the cavity, the electrode arrangement comprising a retainer and an electrode in electrical communication with the retainer, wherein the retainer comprises a first retention feature configured to engage the first retention surface, and the electrode comprises a second retention feature configured to engage the second retention surface, such that electrode arrangement is mechanically retained within the outer casing.
In some arrangements, the first retention surface may extend away from the base surface in a direction towards the proximal end of the outer casing at a non-transverse angle relative to a longitudinal axis, and the second retention surface may extend away from the base surface in a direction towards the distal end of the outer casing at a non-transverse angle relative to a longitudinal axis.
In other arrangements, the first retention surface may extend away from the base surface in a first lateral direction at a non-transverse angle relative to a longitudinal axis, and the second retention surface may extend away from the base surface in a second lateral direction at a non-transverse angle relative to a longitudinal axis.
The retainer and the electrode may be welded together within the cavity.
Another aspect of the present invention provides an electrosurgical instrument, comprising a hand-piece, one or more user-operable buttons on the handpiece that control the instrument to operate, and an operative shaft, having RF electrical connections, and drive componentry for an end effector, the electrosurgical instrument further comprising an end effector having an electrode assembly in accordance with the aspects described above, the electrode being connected to the RF electrical connections.
The end effector may also comprise a rotary shaver arrangement being operably connected to the drive componentry to drive the rotary shaver to operate in use.
A further aspect of the present invention provides an electrosurgical system, comprising an RF electrosurgical generator, a suction source, and an electrosurgical instrument as described above, the arrangement being such that in use the RF electrosurgical generator supplies an RF coagulation or ablation signal via the RF electrical connections to the active electrode.
Yet a further aspect of the present invention may provide a method for processing an instrument for surgery, the method comprising obtaining an electrosurgical instrument and/or end effector described herein, sterilizing the electrosurgical instrument and/or end effector, and storing the electrosurgical instrument and/or end effector in a sterile container.
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:
In known RF electrosurgical instruments that implement an active electrode tip and a mechanical shaver, the space available for providing secure retention of the active electrode tip is significantly reduced. The present disclosure therefore seeks to address this problem by providing an active electrode and retainer arrangement that are inserted to a cavity on one side of an insulator such that they interlock with a feature of the insulator inside the cavity, biased together so as to maximise the degree of interlock and then welded together to secure the active electrode in the insulator for use in tissue treatment.
The active electrode and retainer are configured to interlock with at least one internal surface of the cavity. In this respect, the cavity of the insulator is provided with an interlocking projection defined by a first retention surface and a second retention surface extending from a base surface of the cavity. At least one of the retention surfaces extends from the base surface at a non-transverse angle to the longitudinal axis of the insulator, to thereby provide an undercut with which a part of the active electrode and/or retainer can interlock. Once assembled in the cavity, both the active electrode and the retainer have a portion that extends out of the cavity, that is to say, at least a portion of the active electrode and the retainer protrudes from the insulator. This allows opposing biasing forces to be exerted on the active electrode and the retainer respectively so as to push the two components against the respective retention surface within the cavity. That is to say, the active electrode is biased against one retention surface, and the retainer is biased against the other retention surface. The active electrode and retainer are then welded together, to retain the active electrode within the insulator.
By applying these biasing forces during welding, any clearance between the active electrode, the retainer, and the respective retention surfaces, for example, caused by variations between parts during the manufacturing process, is removed or at least minimised. As such, the amount of interlock with the retention surfaces can be maximised, thus providing a more robust retention of the active electrode. Furthermore, as the interlocking parts of the insulator are provided beneath the active electrode, the overall active tip area is reduced, which thereby improves the performance of the ablation and coagulation functions.
The electrosurgical instrument 3 is a dual sided (or an opposite sided) RF shaver device. In this respect, the main RF componentry and the main mechanical shaving/cutting componentry of the instrument 3 can be provided on opposite sides of a distal end portion of the instrument 3. In such cases, any of the switching means described above may be provided for selecting between the RF ablation or coagulation mode, and the mechanical shaving mode. The structure of the distal end of the instrument 3 is described in more detail below.
To receive and retain the active tip 102, the insulating casing 104 comprises a cavity 114, the cavity 114 having a base surface 115 with an interlocking projection 116 protruding therefrom, as shown by
To assemble the RF tip 100, the retainer 106 is inserted to the cavity 114. The retainer 106 is configured to fit around the projection 116 such that it sits against the internal walls of the cavity 114. In this respect, the retainer 106 comprises a distal portion 107 that is configured such that it lies against the distal internal wall 117 of the cavity 114, leaving a space 105 between the distal portion 107 and the interlocking projection 116. Furthermore, the walls of the distal portion 107 are also angled such that they run parallel with the distal internal wall 117 and the first retention surface 118, the outer wall of the distal portion 107 abutting the distal internal wall 117. The retainer 106 is then configured to fill the remainder of the cavity 114, with a proximal portion 109 being configured to fit within the space between the proximal internal wall 119 and the second retention surface 120. The proximal portion 109 also comprises a protruding feature 111 that extends out of the cavity 114 such that it protrudes above the top surface 103 of the insulator 104.
As shown in
Once the retainer 106 is in place, the electrode 102 can be inserted such that it sits over the top of the retainer 106 and the interlocking projection 116, thereby protruding above the top surface 103 of the insulator 104. As shown in
The active electrode 102 comprises a retention feature 128 that extends down from the lower surface (i.e. the opposite side to the tissue treatment surface 126), which is configured to fit within the space 105 between the distal portion 107 of the retainer 106 and the interlocking projection 116. That is to say, the retention feature 128 is also angled relative to the longitudinal axis X such that the external walls are parallel with the first retention surface 118 and the distal portion 107 of the retention 106. The proximal end of the active electrode 102 is also configured to mate with the protruding feature 111 of the retainer 106.
Once assembled, a first biasing force in the proximal direction (denoted by arrow A in
In other arrangements, the biasing forces may be applied using one or more strong magnets so as to bias the active electrode 102 and retainer 2016 without physically touching them, thereby making it easier to weld or join the components at the same time. For example, a strong magnet (not shown) placed in the centre of the suction apertures 122, 124 would pull both components inwards prior to welding.
The addition of biasing forces during production helps to mitigate any clearances in the interlock mechanism caused by part-to-part variation that may occur during manufacture. As the interlock clearances are removed before the active electrode 102 and retainer 106 are welded together, the resulting interlock with the first and second retention surfaces 118, 120 is as robust as possible for each individual assembly, regardless of the variance in component tolerance. Furthermore, the overall active electrode area is reduced, with no portion of the insulator 104 being exposed within the tissue treatment surface 126, thereby improving the performance of the ablation and coagulation functions.
However, the step of applying external biasing forces may be omitted if the active electrode 102 and the retainer 106 have tight manufacturing tolerances and a relatively tight fit within the cavity 114 of the insulator 104. In this respect, if the part-to-part variation is very low, the same mechanical intent may be achieved without the need to bias the components during the welding process.
Whilst the above example shows the first retention surface 118 being an angled surface and the second retention surface 120 being a vertical surface, it will of course be appreciated that this arrangement may be reversed. That is to say, the first retention surface 118 and the retention feature 128 of the electrode 102 may be vertical, whilst the second retention surface 120 and the proximal portion 109 of the retainer 206 may be angled.
In this second example, the second retention surface 220 of the interlocking projection 216 also extends at an acute angle relative to the longitudinal axis of the RF tip, the second retention surface 220 extending in the proximal direction. Likewise, the proximal internal face 219 of the proximal cavity 225 also extends in the proximal direction at an obtuse angle relative to the longitudinal axis, such that the second retention surface 220 and the proximal internal face 219 are parallel with each other. As with the previous examples, the insulator 204 also comprises a suction aperture 222 and a channel 221 for receiving an electrical conductor (not shown) to connect the RF tip to an electrical supply. However, the entry point of the channel 221 must be on provided on an angled plane to correspond to the angled internal wall 219.
In this example, the retainer 206 is configured to be received by the proximal cavity 225 and comprises a proximal interlocking portion 209 that is configured to fit within the space provided between the second retention surface 220 and the proximal internal wall 219. In this respect, the proximal portion 209 is angled such that the walls of the proximal portion 209 sit flush against the second retention surface 220 and the proximal internal wall 219. As with the previous example, the retainer 206 comprises a protruding feature 211 that extends out of the cavity 214 such that it protrudes above the top surface 203 of the insulator 204.
The active electrode 202 is configured in substantially the same way as the active electrode 102 described with reference to the first example, the active electrode 202 comprising a tissue treatment surface 226 that sits above the top surface 203 of the insulator 204, a suction aperture 224, and a retention feature 228 that is configured to be received in the space provided between the first retention surface 218 and the distal internal face 217. In this respect, the external walls of the retention feature 228 are also angled such that they abut both the distal internal face 217 and the first retention surface 218. As before, the active electrode 202 is also configured to mate with the protruding feature 211 of the retainer 206.
Once assembled, a first biasing force may be exerted on the active electrode 202 in the proximal direction (denoted by arrow A in
As in the first example, the overall active electrode area is reduced, with no portion of the insulator 204 being exposed within the tissue treatment surface 226, thereby improving the performance of the ablation and coagulation functions. In the second example, however, the retainer 206 has been shortened so it no longer reaches under the retention feature 228 of the electrode 202. This allows additional space within the cavity 214 to include a second angled interlock between the retainer 206 and the second retention face 220 of the insulator 204, further strengthening the mechanical retention of the welded active electrode 202 and retainer 206 within the insulator 204.
The retainer 306 and the active electrode 302 have a similar configuration to that shown in
As such, this arrangement provides the same benefits described with reference to the first and second examples, with the additional advantage of that the design of the interlocking projection 316 is not linked to the entry to the channel 321 in the proximal internal wall of the cavity 314. Therefore, a double interlock is achieved to aid tip retention robustness, whilst improving the ease with which the insulator 304 is manufactured, since the conductor 310 enters the cavity 314 on a vertical face, which vastly reduces the likelihood of excess material building up around the entry port during moulding. Furthermore, this provides three distributed anchor points (400, 500 and 600) to secure the active electrode 302 within the insulator 304, further improving the strength of the mechanical retention.
Various further modifications to the above described embodiments, whether by way of addition, deletion or substitution, will be apparent to the skilled person to provide additional embodiments, any and all of which are intended to be encompassed by the appended claims.
The electrosurgical instrument and/or end effector disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the electrosurgical instrument and/or end effector can be reconditioned for reuse after at least one use. Reconditioning can include a combination of the steps of disassembly of the electrosurgical instrument, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the electrosurgical instrument can be disassembled, and any number of particular pieces or parts of the device (such as the end effector) can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the electrosurgical instrument can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those of ordinary skill in the art will appreciate that the reconditioning of an electrosurgical instrument can utilize a variety of different techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned electrosurgical instrument, are all within the scope of the present application.
Preferably, the invention described herein will be processed before surgery. First a new or used instrument is obtained and, if necessary, cleaned. The instrument can then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK® bag. The container and instrument are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or higher energy electrons. The radiation kills bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container keeps the instrument sterile until it is opened in the medical facility. The electrosurgical instrument may also be sterilized using any other technique known in the art, including but limited to beta or gamma radiation, ethylene oxide, or steam.
| Number | Date | Country | |
|---|---|---|---|
| 63289909 | Dec 2021 | US |
