Resilient barrier for inclusion within a robotic surgical instrument

Abstract

There is provided a resilient barrier for a robotic surgical instrument and a method of manufacturing the resilient barrier. The robotic surgical instrument comprises a shaft, an end effector and a plurality of elongate elements extending through the shaft and configured to operate the end effector. The robotic surgical instrument also comprises the resilient barrier, which is located inside the shaft extending over a cross-sectional area of the shaft. The resilient barrier is fabricated from a deformable material and comprises a plurality of holes and a recess. Each of the elongate elements passes through a respective hole in the resilient barrier.

Description

[0001] RESILIENT BARRIER FOR INCLUSION WITHIN A ROBOTIC SURGICAL INSTRUMENT

[0002] BACKGROUND

[0003] This disclosure relates to resilient barriers for inclusion within robotic surgical instruments, e.g. for use in robotic laparoscopic surgery.

[0004] Figure 1 illustrates multiple robots 101, 102, 103 operating in a common workspace. In this example, the robots are surgical robots being used to perform an operation on a person 104. Each robot comprises a base connected to a surgical instrument via a flexible arm. The surgical instrument penetrates the body of the patient 104 at a port so as to access the surgical site. At its distal end, the instrument comprises an end effector for engaging in a surgical procedure.

[0005] A variety of end effectors are known, each adapted to perform a particular surgical function. Figure 2 illustrates a surgical instrument 200 having a pair of serrated jaws 204 as the end effector. The surgical instrument comprises an interface 201 by means of which the surgical instrument connects to the robot arm. A shaft 202 extends between the interface 201 and an articulation 203. Articulation 203 terminates in the end effector 204. The articulation 203 permits the end effector 204 to move relative to the shaft 202. It is desirable for at least two degrees of freedom to be provided to the motion of the end effector 204 by means of the articulation.

[0006] The international patent application published with the publication number WO 2020 / 109812 describes the internal structure of a robotic surgical instrument.

[0007] SUMMARY

[0008] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0009] There is provided a robotic surgical instrument comprising: a shaft; an end effector; a plurality of elongate elements extending through the shaft and configured to operate the end effector; and a resilient barrier inside the shaft extending over a cross-sectional area of the shaft, wherein the resilient barrier is fabricated from a deformable material and comprises a plurality of holes and a recess, wherein each of the elongate elements passes through a respective hole in the resilient barrier.

[0010] The recess may be located more centrally than the holes with respect to the cross-sectional area of the shaft.

[0011] The shaft may be a hollow cylinder and the resilient barrier may be cylindrical. The area of the end faces of the cylindrical resilient barrier may match, and may be aligned with, the cross-sectional area of the shaft which is defined by the interior wall of the shaft.

[0012] The recess may be in the centre of one of the end faces of the cylindrical resilient barrier.

[0013] The depth of the recess in the resilient barrier may be less than the thickness of the resilient barrier but at least a threshold depth.

[0014] The recess may be larger than each of the holes.

[0015] The resilient barrier may be configured to inhibit passage of fluid through the shaft from one side of the resilient barrier to the other.

[0016] An outer edge of the resilient barrier may be in sealed contact with the interior wall of the shaft around the outer edge of the cross-sectional area. The resilient barrier may be located at the distal end of the shaft.

[0017] The resilient barrier may be fabricated from silicone.

[0018] The diameter of each of the holes may be less than or equal to the diameter of the respective elongate element that passes through that hole in the resilient barrier.

[0019] The elongate elements may be arranged to pass through the cross-sectional area of the shaft at respective natural positions in the plane perpendicular to the longitudinal axis of the shaft. The resilient barrier may be fabricated such that, for one or more of the elongate elements, the respective hole in the resilient barrier through which the elongate element passes is in a position in the fabricated resilient barrier that corresponds, when the resilient barrier is arranged to extend over the cross-sectional area of the shaft, to a position within the shaft that is offset from the natural position of the elongate element by a non-zero amount in the plane perpendicular to the longitudinal axis of the shaft, such that: (i) the minimum distance between any pair of holes in the fabricated resilient barrier is greater than or equal to a threshold distance, and (ii) the minimum distance between any hole in the fabricated resilient barrier and the outer edge of the fabricated resilient barrier is greater than or equal to the threshold distance.

[0020] The plurality of elongate elements may comprise: (i) one or more driving elements configured to control movement of the end effector relative to the shaft, and / or (ii) one or more electrosurgical elements configured to provide electrical power to the end effector when the instrument is an electrosurgical instrument.

[0021] The end effector may comprise a pair of bipolar jaws. The robotic surgical instrument may further comprise an articulation connecting the end effector to a distal end of the shaft. The articulation may comprise joints permitting the end effector to adopt a range of orientations relative to a longitudinal axis of the shaft. The plurality of elongate elements may comprise pairs of driving elements configured to drive the joints and a pair of electrosurgical elements configured to provide electrical power to the bipolar jaws, the driving elements and the electrosurgical elements extending through the shaft.

[0022] The robotic surgical instrument may further comprise an instrument interface connected to a proximal end of the shaft. The instrument interface may have an open structure through which fluid can move.

[0023] The resilient barrier may be press-fitted into the shaft of the robotic surgical instrument.

[0024] There is provided a resilient barrier configured to be inserted into, and extend over a cross- sectional area of, a shaft of a robotic surgical instrument, wherein the resilient barrier is fabricated from a deformable material, and wherein the resilient barrier comprises: a plurality of holes; and a recess, wherein each of the holes is arranged to allow a respective elongate element of the robotic surgical instrument extending through the shaft to pass through the hole for operating an end effector of the robotic surgical instrument.

[0025] The resilient barrier may be manufactured as a discrete component to be inserted into the shaft of the robotic surgical instrument.

[0026] The resilient barrier may comprise a plurality of recesses.

[0027] There is provided a method of manufacturing a resilient barrier configured to be inserted into, and extend over a cross-sectional area of, a shaft of a robotic surgical instrument, wherein the method comprises: putting a material into a mould of the shape of the resilient barrier; and setting the material in the mould to thereby form the resilient barrier, wherein the set material is a deformable, solid material, wherein the resilient barrier comprises: a plurality of holes; and a recess, wherein each of the holes is arranged to allow a respective elongate element of the robotic surgical instrument extending through the shaft to pass through the hole for operating an end effector of the robotic surgical instrument.

[0028] There is provided a robotic surgical instrument comprising: a shaft; an end effector; a plurality of elongate elements extending through the shaft and configured to operate the end effector, wherein the elongate elements are arranged to pass through a cross-sectional area of the shaft at respective natural positions in the plane perpendicular to the longitudinal axis of the shaft; and a resilient barrier inside the shaft extending over the cross-sectional area of the shaft, wherein the resilient barrier is fabricated from a deformable material and comprises a plurality of holes, wherein each of the elongate elements passes through a respective hole in the resilient barrier, wherein the resilient barrier is fabricated such that, for one or more of the elongate elements, the respective hole in the resilient barrier through which the elongate element passes is in a position in the fabricated resilient barrier that corresponds, when the resilient barrier is arranged to extend over the cross-sectional area of the shaft, to a position within the shaft that is offset from the natural position of the elongate element by a non-zero amount in the plane perpendicular to the longitudinal axis of the shaft, such that: (i) the minimum distance between any pair of holes in the fabricated resilient barrier is greater than or equal to a threshold distance, and (ii) the minimum distance between any hole in the fabricated resilient barrier and the outer edge of the fabricated resilient barrier is greater than or equal to the threshold distance.

[0029] There is provided a resilient barrier configured to be inserted into, and extend over a cross- sectional area of, a shaft of a robotic surgical instrument, wherein the resilient barrier is fabricated from a deformable material, and wherein the resilient barrier comprises: a plurality of holes, wherein each of the holes is arranged to allow a respective elongate element of the robotic surgical instrument extending through the shaft to pass through the hole for operating an end effector of the robotic surgical instrument, and wherein for one or more of the holes, a position of the hole in the resilient barrier is offset by a non-zero amount from a position corresponding to a natural position for its respective elongate element, such that: (i) the minimum distance between any pair of holes in the resilient barrier is greater than or equal to a threshold distance, and (ii) the minimum distance between any hole in the resilient barrier and the outer edge of the resilient barrier is greater than or equal to the threshold distance.

[0030] There is provided a method of manufacturing a resilient barrier configured to be inserted into, and extend over a cross-sectional area of, a shaft of a robotic surgical instrument, wherein the method comprises: putting a material into a mould of the shape of the resilient barrier; and setting the material in the mould to thereby form the resilient barrier, wherein the set material is a deformable, solid material, wherein the resilient barrier comprises a plurality of holes, wherein each of the holes is arranged to allow a respective elongate element of the robotic surgical instrument extending through the shaft to pass through the hole for operating an end effector of the robotic surgical instrument, and wherein for one or more of the holes, a position of the hole in the resilient barrier is offset by a non-zero amount from a position corresponding to a natural position for its respective elongate element, such that: (i) the minimum distance between any pair of holes in the resilient barrier is greater than or equal to a threshold distance, and (ii) the minimum distance between any hole in the resilient barrier and the outer edge of the resilient barrier is greater than or equal to the threshold distance.

[0031] For the one or more of the holes, the position corresponding to the natural position for its respective elongate element may be the position on the resilient barrier that matches, when the resilient barrier is arranged to extend over the cross-sectional area of the shaft, a natural position at which the respective elongate element passes through the cross-sectional area of the shaft.

[0032] The above features may be combined as appropriate, as would be apparent to a skilled person, and may be combined with any of the aspects of the examples described herein. BRIEF DESCRIPTION OF THE FIGURES

[0033] Examples will now be described in detail with reference to the accompanying drawings in which:

[0034] Figure 1 illustrates a person being operated on by a robotic system comprising three surgical robots;

[0035] Figure 2 illustrates a known surgical instrument;

[0036] Figure 3 illustrates a surgical robot having a robotic surgical instrument attached to its distal end;

[0037] Figure 4 illustrates a robotic surgical instrument;

[0038] Figure 5 illustrates a distal end of a robotic surgical instrument;

[0039] Figure 6A illustrates a view of a cross-sectional area of a shaft of a robotic surgical instrument, showing the natural positions of elongate elements which extend through the shaft;

[0040] Figure 6B illustrates a plan view of a resilient barrier that is to be inserted into, and extend over the cross-sectional area of, the shaft;

[0041] Figure 6C illustrates a side view of a section of the resilient barrier;

[0042] Figure 7 illustrates the distal end of an electrosurgical instrument;

[0043] Figure 8 is a flow chart for a method of manufacturing a resilient barrier;

[0044] Figure 9A illustrates a plan view of a mould of the shape of the resilient barrier;

[0045] Figure 9B illustrates a side view of the mould with another component arranged to press molten material into the mould; and

[0046] Figure 10 illustrates a plan view of a resilient barrier which comprises two recesses.

[0047] The accompanying drawings illustrate various examples. The skilled person will appreciate that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the drawings represent one example of the boundaries. It may be that in some examples, one element may be designed as multiple elements or that multiple elements may be designed as one element. Common reference numerals are used throughout the figures, where appropriate, to indicate similar features. DETAILED DESCRIPTION

[0048] The following description is presented by way of example to enable a person skilled in the art to make and use the invention. The present invention is not limited to the embodiments described herein and various modifications to the disclosed embodiments will be apparent to those skilled in the art.

[0049] The shaft of a robotic surgical instrument is hollow, thereby allowing elongate elements to extend through the shaft for operating the end effector of the robotic surgical instrument. The elongate elements may be referred to as elongate control elements and may be configured to control an operation of the end effector. Since the shaft is hollow, fluid (e.g. liquid or gas) may pass into the interior of the shaft. For example, for abdominal laparoscopic surgery, the abdominal cavity is typically inflated with insufflation gas (such as CO2) so as to enable the surgeon better visibility of and access to the surgical site, but the insufflation gas may escape from the surgical site through the interior of the shaft of the robotic surgical instrument. As another example, bodily fluids (e.g. blood) from the patient may pass from the surgical site into the shaft of the robotic surgical instrument. It would be desirable to reduce or prevent the leakage of fluid, such as insufflation gas and / or bodily fluids, from the surgical site into the shaft of the robotic surgical instrument. For example, if bodily fluids pass into the shaft of a surgical instrument during an operation then the surgical instrument cannot be used in another operation (e.g. involving a different patient) until the interior of the shaft has been thoroughly cleaned and sterilised, which can be a time-consuming and costly process. The sterilisation processes are often standardised, and standard sterilisation tools (e.g. an autoclave) may not be sufficient to reduce the level of contamination of the instrument below a maximum threshold of allowable contamination. Therefore, instruments may be designed such that existing sterilisation methods effectively remove contaminants below the threshold.

[0050] For example, a resilient barrier (or "bung", "stopper" or "seal") can be inserted into the shaft, such that it extends over a cross-sectional area of the shaft, thereby inhibiting the passage of fluid through the interior of the shaft. When the resilient barrier has been inserted into the shaft, the outer edge of the resilient barrier is in sealed contact with the interior wall of the shaft. The resilient barrier is made from a deformable material, such as silicone, and comprises a plurality of holes, where each of the holes is arranged to allow a respective elongate element to pass through the hole. The resilient barrier can be manufactured as a separate component and then assembled into the robotic surgical instrument by inserting it into the shaft, and then feeding the elongate elements through the respective holes in the resilient barrier. The resilient barrier can be fabricated by compression moulding, i.e. by pressing a material into a mould of the shape of the resilient barrier and allowing the material to set to form the resilient barrier. When the material has set it is a deformable solid at room temperature.

[0051] It is a general aim in the design of a robotic surgical instrument to keep the cross-sectional area of the shaft small, so that the instrument can enter a patient's body through a small incision. Furthermore, the positions of the elongate elements in the shaft are precisely designed for optimal function of the instrument, e.g. by aligned them with pulleys by which they control the movement of joints. As such, the elongate elements have specific positions (referred to herein as "natural positions") in a plane perpendicular to the longitudinal axis of the shaft, and it is generally not desirable for the positions of the elongate elements to deviate significantly from these natural positions. In the description herein, the "natural positions" are the positions that the elongate elements would have if the resilient barrier were not present in the shaft of the robotic surgical instrument. In examples described herein, the elongate elements extend through the shaft in a direction that is parallel to the longitudinal axis of the shaft.

[0052] The process for manufacturing the resilient barriers may not be perfectly precise, such that the positions of the holes might not always exactly align with the natural positions of the respective elongate elements which are to pass through the holes. As such, it is useful for the resilient barrier to be deformable such that the shape of the resilient barrier in the plane perpendicular to the longitudinal axis of the shaft can be altered slightly, e.g. by the elongate elements pushing laterally on their respective holes to thereby alter the positions of the holes of the resilient barrier in the plane perpendicular to the longitudinal axis of the shaft. One way to make the resilient barrier more deformable would be to make it thinner. However, if the resilient barrier is too thin then it is more likely that deforming the resilient barrier will break the sealed contact between the outer edge of the resilient barrier and the interior wall of the shaft, thereby reducing the effectiveness of the resilient barrier in terms of inhibiting the passage of fluid through the shaft. Furthermore, if the resilient barrier is too thin then the likelihood of it tearing rather than deforming where it touches the elongate elements is increased. Any tears in the resilient barrier will significantly reduce the effectiveness of the resilient barrier in terms of inhibiting the passage of fluid through the shaft. As such, in examples described herein, rather than making the resilient barrier thinner, the resilient barrier is formed with a recess, to thereby make the resilient barrier more deformable (e.g. such that the positions of the holes can be altered slightly by the elongate elements so that the (altered) positions of the holes match the natural positions of the elongate elements) without compromising the effectiveness of the sealed contact between the outer edge of the resilient barrier and the interior wall of the shaft. In other words, the presence of the recess allows the resilient barrier to be more easily deformed, e.g. to accommodate small shifts in the positions of the holes. For example, the recess may be in the centre of a face of the resilient barrier that is perpendicular to the longitudinal axis of the shaft. Furthermore, using a resilient barrier which comprises a recess means that the resilient barrier is formed from less material, thereby making the resilient barrier lighter and making it cheaper to manufacture. It is beneficial for robotic surgical instruments to be light so that less force is required to move them, thereby reducing the power consumption of the surgical robot.

[0053] Furthermore, some constraints may be imposed upon the design of the resilient barrier to ensure that the resilient barrier can be reliably manufactured, e.g. using a compression moulding technique as described herein. In particular, for the material to reliably flow correctly into the shape of the mould, there may be a minimum distance (which may be referred to herein as a "threshold distance") between any pair of holes in the resilient barrier and between any hole and the outer edge of the resilient barrier. As such, in examples described herein the resilient barrier may be fabricated such that for one or more of the elongate elements, the respective hole in the resilient barrier through which the elongate element passes is in a position in the fabricated resilient barrier that corresponds, when the resilient barrier is arranged to extend over the cross-sectional area of the shaft, to a position within the shaft that is (intentionally) offset from the natural position of the elongate element by a non-zero amount in the plane perpendicular to the longitudinal axis of the shaft. The offsets of the holes relative to the corresponding natural positions are such that the design of the resilient barrier complies with the manufacturing constraints, e.g. so that (i) the minimum distance between any pair of holes in the resilient barrier (when it is fabricated) is greater than or equal to the threshold distance, and (ii) the minimum distance between any hole in the resilient barrier and the outer edge of the resilient barrier (when it is fabricated) is greater than or equal to the threshold distance. Ensuring that the design of the resilient barrier complies with the manufacturing constraints mentioned above means that the resilient barrier can be reliably manufactured. The "non-zero amount" by which the position of a hole may be offset is small, e.g. less than the diameter of the hole. Since the resilient material is deformable in the plane perpendicular to the longitudinal axis of the shaft, the elongate elements can deform the resilient material to alter the positions of the holes to match the natural positions of the elongate elements within the shaft. This alteration of the positions of the holes is facilitated by the inclusion of the recess in the resilient barrier.

[0054] Figure 3 illustrates a surgical robot having an arm 300 which extends from a base 301. The arm comprises a number of rigid limbs 302. The limbs are coupled by revolute joints 303. The most proximal limb 302a is coupled to the base by joint 303a. It and the other limbs are coupled in series by further ones of the joints 303. Wrist 304 couples one limb (302b) to the most distal limb (302c) of the arm. The most distal limb 302c has an arm interface 305 for interfacing a surgical instrument 306. Each joint 303 of the arm has one or more motors 307 which can be operated to cause rotational motion at the respective joint, and one or more position and / or torque sensors 308 which provide information regarding the current configuration and / or load at that joint. For clarity, only some of the motors and sensors are shown in figure 3. The arm may be generally as described in the applicant's patent application published with the publication number WO 2015 / 132549.

[0055] The arm terminates in an arm interface 305 for interfacing with an instrument interface 313 of the instrument 306. The instrument 306 maytake the form described with respect to figure 2. The instrument may have a diameter less than 8mm. For example, the instrument may have a diameter less than 6mm. For example, the instrument diameter may be between 5mm and 6mm. The instrument diameter may be the diameter of the shaft. The instrument diameter may be the diameter of the profile of the articulation. It might be the case that the diameter of the profile of the articulation matches or is narrower than the diameter of the shaft. The arm interface 305 comprises a drive assembly for driving articulation of the instrument. Movable interface elements of the drive assembly interface mechanically engage corresponding movable interface elements of the instrument interface in order to transfer drive from the robot arm to the instrument. During a typical operation, one instrument may be exchanged for another several times. Thus, the instrument is attachable and detachable from the robot arm during the operation.

[0056] Controllers for the motors and torque sensors are distributed with the robot arm. The controllers are connected via a communication bus to control unit 309. A control unit 309 comprises a processor 310 and a memory 311. Memory 311 stores in a non-transient way software that is executable by the processor to control the operation of the motors 307 to cause the arm 300 to operate in the manner described herein. In particular, the software can control the processor 310 to cause the motors (for example via distributed controllers) to drive in dependence on inputs from the sensors 308 and from a surgeon command interface 312. The control unit 309 is coupled to the motors 307 for driving them in accordance with outputs generated by execution of the software. The control unit 309 is coupled to the sensors 308 for receiving sensed input from the sensors, and to the command interface 312 for receiving input from it. The respective couplings may, for example, each be electrical or optical cables, or may be provided by a wireless connection. The command interface 312 comprises one or more input devices whereby a user can request motion of the end effector in a desired way. The input devices could, for example, be manually operable mechanical input devices such as control handles or joysticks, or contactless input devices such as optical gesture sensors. The software stored in memory 311 is configured to respond to those inputs and cause the joints of the arm and instrument to move accordingly, in compliance with a pre-determined control strategy.

[0057] Figure 4 illustrates a robotic surgical instrument 400. The middle portion of the shaft is omitted for ease of illustration. The end effector 404 is connected to the shaft 402 by articulation 403. Figure 5 illustrates the distal portion of the robotic surgical instrument 400 in more detail. The articulation 403 comprises joints which permit the end effector 404 to move relative to the shaft 402. A first joint 501 permits the end effector 404 to rotate about a first axis 503. The first axis 503 is transverse (e.g. perpendicular) to the longitudinal axis of the shaft 505. A second joint 502 permits the end effector 404 to rotate about a second axis 504. The second axis 504 is transverse (e.g. perpendicular) to the first axis 503. Thus, articulation of the first and second joints enables the end effector to take a range of attitudes (i.e. orientations) relative to the shaft.

[0058] The articulation 403 comprises a first body part 506 and a second body part 507. The first body part connects the shaft 402 to the second body part 507. The first body part 506 is fast with the shaft 402. The first body part is connected to the second body part by the first joint 501. The second body part 507 connects the first body part 506 to the end effector 404. The second body part 507 is connected to the first body part by the first joint 501, and is connected to the end effector 404 by the second joint 502. Thus, the first joint 501 permits the second body part 507 to rotate relative to the shaft 402 about the first axis 503; and the second joint 502 permits the end effector 404 to rotate relative to the second body part 507 about the second axis 504.

[0059] The joints of the articulation are driven by driving elements. The driving elements are elongate elements which extend from the joints in the articulation through the shaft to the instrument interface. The driving elements are secured to the interface elements of the instrument interface. Thus, the robot arm transfers drive to the end effector as follows: movement of a drive assembly interface element moves an instrument interface element which moves a driving element which moves a joint of the articulation which moves the end effector. In examples described herein, each driving element can be flexed laterally to its main extent at least in those regions where it engages the internal components of the articulation and instrument interface. In other words, each driving element can be flexed transverse to its longitudinal axis in the specified regions. This flexibility enables the driving elements to wrap around the internal structure of the instrument, such as the joints and pulleys. The driving elements may be wholly flexible transverse to their longitudinal axes. The driving elements are not flexible along their main extents. The driving elements resist compression and tension forces applied along their length. In other words, the driving elements resist compression and tension forces acting in the direction of their longitudinal axes. The driving elements have a high modulus. The driving elements remain taut in operation. They are not permitted to become slack. Thus, the driving elements are able to transfer drive from the instrument interface to the joints. The driving elements may be cables.

[0060] In the example shown in Figure 5, the first joint 501 is driven by a first pair of driving elements A1,A2, and the second joint 502 is driven by a second pair of driving elements B1,B2. In this example, each joint is driven by its own pair of driving elements. In other words, each joint is driven by a dedicated pair of driving elements. The joints may be independently driven. A pair of driving elements may be constructed as a single piece. This single piece may be secured to the joint at one point, thereby ensuring that when the pair of driving elements is driven, the drive is transferred to motion of the joint about its axis. Alternatively, a pair of driving elements may be constructed as two pieces. In this case, each separate piece is secured to the joint.

[0061] Each pair of driving elements is connected to an instrument interface element 405a, 405b of the instrument interface 401 at the proximal end of the shaft. Figures 4 and 5 illustrate two pairs of driving elements: A1,A2 and B1,B2. In these examples, there may be another pair of driving elements C1,C2 which is not shown in Figures 4 and 5, but which extend through the shaft and can be used to control the opening and closing of the jaws of the end effector 404. In other examples, there may be more or fewer driving elements extending through the shaft than in the examples shown in the figures.

[0062] The instrument interface 401 may have a structure which is open to the passage of fluids. In such a structure, gas / liquid in the shaft 402 may be able to pass through and out of the instrument interface 401 uninhibited. As described above, for some types of surgery (e.g. for laparoscopic surgery), a cavity around the surgical site is typically inflated with insufflation gas (e.g. to a pressure that is greater than atmospheric pressure) so as to enable the surgeon better visibility of and access to the surgical site. However, when using an instrument of the type described with reference to Figures 4 and 5, the insufflation gas may escape from the surgical site through the interior of the shaft of the surgical instrument and out through the open structure of the instrument interface of the surgical instrument. It is generally beneficial to reduce the amount of insufflation gas that escapes from the surgical site in this manner. Furthermore, as described above, if bodily fluids, such as blood, pass into the interior of the shaft then the interior of the shaft will need to be cleaned and sterilised before the surgical instrument can be reused in another operation (e.g. on another patient). As such, it is beneficial to reduce the amount of bodily fluids that can pass from the surgical site into the interior of the shaft.

[0063] The robotic surgical instrument 400 of Figures 4 and 5 comprises a resilient barrier 406 inside the shaft 402 which extends across a cross-sectional area of the shaft. The cross-sectional area may be transverse to the longitudinal axis 505 of the shaft. For example, the cross- sectional area may be in a plane comprising an axis 508 perpendicular to the longitudinal axis 505 of the shaft. Alternatively, the cross-sectional area may be in a plane at an angle (i.e. not parallel) to both axis 508 and longitudinal axis 505 of the shaft. The outer edge of the resilient barrier 406 is in sealed contact with the interior wall of the shaft at all points around the outer edge of the cross-sectional area. The resilient barrier 406 is fabricated from a material which inhibits the passage of fluid through it. Thus, the resilient barrier 406 acts as a stopper (or a seal or a bung), inhibiting the passage of fluid (such as the insufflation gas) through the shaft from the side of the resilient barrier facing the articulation to the opposing side of the resilient barrier facing the interior of the shaft. The resilient barrier 406 is internal to the shaft 402. The resilient barrier 406 may be located anywhere along the shaft. Preferably, the resilient barrier 406 is located in the distal end of the shaft proximal to the end effector 404. The closer the resilient barrier 406 to the distal end of the shaft, the less fluid (e.g. insufflation gas or bodily fluids) that can leak from the surgical site into the instrument before being inhibited by the resilient barrier. Furthermore, placing the resilient barrier close to the distal end of the shaft improves the effectiveness of the sterilisation process, e.g. in the case of autoclave by the flow of steam through the shaft between the distal end of the shaft and the resilient barrier. If the resilient barrier were placed at the proximal end of the shaft, it would be more difficult to remove contaminants from the shaft as they would be spread over a larger volume with more spaces and cavities for the contaminants to be deposited within.

[0064] Figure 6A illustrates an end-on view of the cross-sectional area of the shaft 402, showing the natural positions of a plurality of elongate elements which extend through the shaft. In this example, there are eight elongate elements extending through the shaft: three pairs of driving elements (A1,A2, B1,B2 and C1,C2) and one pair of electrosurgical elements ( El, E2) . This may be an example in which the robotic surgical instrument is a bipolar electrosurgical instrument, e.g. bipolar forceps, where each of the two electrosurgical elements is connected to a respective one of the jaws of the instrument, such that the two jaws act as two active electrodes. In this example, the three pairs of driving elements control the movement of the end effector, e.g. to control rotation of the end effector about the two axes 503 and 504 and to control the opening and closing of the jaws of the end effector. More generally, the elongate elements may be elongate control elements which are used for controlling the operation of the end effector. For example, the elongate control elements may comprise: (i) one or more driving elements configured to control movement of the end effector relative to the shaft, and / or (ii) one or more electrosurgical elements configured to provide electrical power to the end effector, when the instrument is an electrosurgical instrument, for use in controlling when the end effector is electrified. The elongate control elements may be cables.

[0065] As described above, the "natural positions" of the elongate elements are the positions that the elongate elements have within the shaft in the plane perpendicular to the longitudinal axis of the shaft. The elongate elements may extend through the shaft in a direction parallel to the longitudinal axis of the shaft, such that the natural positions of the elongate elements within the plane perpendicular to the longitudinal axis of the shaft are constant along the length of the shaft. These natural positions of the elongate elements may be designed and specified very precisely and carefully for optimal configuration of the instrument, e.g. to ensure that the profile of the instrument (e.g. which may be dependent upon the diameter of the shaft) is small, and so that the driving elements can efficiently transfer drive to the joints in the articulation.

[0066] Figure 6B illustrates a plan view of the resilient barrier 406. The diameter of the resilient barrier 406 matches (i.e. is equal to or is slightly largerthan) the internal diameter of the shaft 402, so that the resilient barrier can be inserted into, and extend over the cross-sectional area of, the shaft, whilst having a sealed contact between the outer edge of the resilient barrier and the internal wall of the shaft. In some examples, the resilient barrier may be tapered (or "wedged") so that it can be more easily inserted into the shaft and pressed into place. In some examples, the resilient barrier may be fixed to the inner wall of the shaft, e.g. by glueing or heat bonding. The resilient barrier 406 comprises a plurality of holes 602 and a recess 604. Each of the elongate elements passes through a respective hole in the resilient barrier. Therefore, in this example, the number of holes in the resilient barrier matches the number of elongate elements passing through the shaft. All of the holes in the resilient barrier are filled, e.g. with a single one of the elongate elements. In other words, the resilient barrier does not include any holes that are not filled (e.g. by a respective elongate element passing through it), such that when the resilient barrier is assembled into the shaft with the elongate elements passing through their respective holes, the resilient barrier provides an effective seal inhibiting the passage of fluid through the shaft.

[0067] In the example of Figures 6A and 6B, the driving element Al passes through hole 602AI, the driving element Bl passes through hole 602BI, the driving element Cl passes through hole 602ci, the electrosurgical element El passes through hole 602EI, the driving element A2 passes through hole 602AZ, the driving element B2 passes through hole 602BZ, the driving element C2 passes through hole 602c2, and the electrosurgical element E2 passes through hole 602E2. In examples described herein, the diameter of each of the holes 602 is less than or equal to the diameter of the respective elongate element that passes through that hole in the resilient barrier. This ensures that the resilient barrier 406 provides an effective seal around each of the elongate elements that pass through it. For example, the diameter of an elongate element may be deand the diameter (dh) of the respective hole through which that elongate element passes may be in the range (de— 0.1mm) < dh< de. For example, demay be in a range from 0.3mm to 0.6mm. The diameters of different elongate elements may be the same or different to each other. Likewise, the diameters of different holes may be the same or different to each other. As a specific example, each of the elongate elements may have a diameter of 0.45mm, and each of the holes may have a diameter of 0.4mm. Since the resilient material is made from a deformable material (e.g. silicone), the resilient barrier can deform slightly around each of the holes where necessary to allow the elongate elements to pass through their respective holes (even if the diameter of the holes is smaller than the diameter of the respective elongate elements). There may be a small amount of frictional contact between the elongate elements and the resilient barrier. It is beneficial to keep the frictional force acting on a driving element as a result of its contact with the resilient barrier low, e.g. less than a threshold frictional value. This threshold frictional value may be a value < 1.5N. For example, the threshold frictional value may be 1.5N. The threshold frictional value may be a value < 0.5N. For example, the threshold frictional value may be 0.5N. The threshold frictional value may be a value <0.1N. For example, the threshold frictional value may be 0.1N. This may be achieved, for example, by lubricating the contact area of the resilient barrier 406 and / or driving element.

[0068] In other examples it would be possible for the holes to have larger diameters than the respective elongate elements, which may be useful in terms of reducing friction between the driving elements and the resilient barrier. In these other examples, although the resilient barrier would inhibit the passage of fluid in the shaft to some extent, the resilient barrier would not provide such an effective seal inhibiting the passage of fluid in the shaft when compared with the examples described above in which the diameter of each of the holes is less than or equal to the diameter of the respective elongate element that passes through that hole. For example, in these other examples, in which the holes have larger diameters than the respective elongate elements, approximately 200ml of insufflation gas may pass through the shaft per minute; whereas in the examples described above in which the diameters of the holes is less than or equal to the diameters of the respective elongate elements, approximately 1ml of insufflation gas may pass through the shaft per minute.

[0069] Figure 6C illustrates a side view of a section of the resilient barrier 406 in the plane represented by the dashed line 606 in Figure 6B. The holes 602 may be referred to as "through holes" because they pass all the way through the resilient barrier 406. The recess 604 may be referred to as a "blind hole" because it does not pass all the way through the resilient barrier 406. The recess may also be referred to using different terminology, e.g. a "cavity", a "concavity", a "gap", an "indent", a "notch", or a "groove" to give some examples.

[0070] The recess 604 is in a face of the resilient barrier 406 that is perpendicular to the longitudinal axis 505 of the shaft 402 (when the resilient barrier is arranged within the shaft). The depth of the recess 604 (denoted ‘d’ in Figure 6C) in the resilient barrier is less than the thickness of the resilient barrier (denoted ' in Figure 6C). However, the depth of the recess, d, is at least a threshold depth. In other words, the depth of the recess is at least a minimum depth, such that the presence of the recess 604 in the resilient barrier 402 increases the ability of the material of the resilient barrier to deform to thereby move the positions of the holes in the resilient barrier in the plane perpendicular to the longitudinal axis of the shaft. Having the recess in the resilient barrier improves the ability of the resilient barrier to alter its shape, without reducing the thickness of the resilient barrier, T, at the outer edge of the resilient barrier. Reducing the thickness of the resilient barrier at the outer edge of the resilient barrier may reduce the effectiveness of the sealed contact between the outer edge of the resilient barrier and the internal wall of the shaft. As an example, the thickness of the resilient barrier, T, may be in a range 1mm < T < 8mm. To give a specific example, T may be 2mm. To give an example, the threshold depth mentioned above in relation to the depth of the recess may T 1 be - such that the depth, d, of the recess in the resilient barrier is in a range - T < d < T . As T another example, the threshold depth mentioned may be - such that the depth, d, of the recess in the resilient barrier is in a range -T < d < T . To give a specific example, d may be 3

[0071] - T. As another specific example, T may be 2mm and d may be 1.5mm. In other examples (not shown in the figures) there may be a recess on both the top and bottom sides (i.e. on opposing sides) of the resilient barrier, such that a thin section of the resilient barrier is in the middle of the resilient barrier rather than at one of the sides, where the thin section is formed with two blind holes on opposing sides of the resilient barrier.

[0072] The recess 604 is located more centrally than the holes 602 with respect to the face of the resilient barrier that is to extend over the cross-sectional area of the shaft. In the examples shown in the figures, the shaft 402 is a hollow cylinder and the resilient barrier 406 is cylindrical. The area of the end faces of the cylindrical resilient barrier (e.g. as shown in Figure 6B) matches, and is aligned with, the cross-sectional area of the shaft which is defined by the interior wall of the shaft 402 (e.g. as shown in Figure 6A). In the example shown in Figures 6B and 6C the resilient barrier is a disc (which may be referred to as a "puck"). For example, the length (i.e. thickness) of the cylindrical shape of the resilient barrier is less than the diameter of the end faces of the cylindrical shape of the resilient barrier. For example, the thickness of the resilient barrier may be 4mm and the diameter of the end faces of the resilient barrier (which matches the internal diameter of the shaft 402) may be 6mm. The recess 604 is in the centre of the end face of the cylindrical resilient barrier which is shown in Figure 6B. The recess does not extend all the way through the resilient barrier, such that it is not present in the opposing end face of the cylindrical resilient barrier (i.e. the face opposite the face shown in Figure 6B). Positioning the recess so that it is centrally located in one of the end faces of the resilient barrier makes the resilient barrier more able to deform slightly at the positions of the holes in the plane parallel to the end faces of the resilient barrier. Furthermore, in the example shown in Figures 6B and 6C the recess 604 is rotationally symmetric about the longitudinal axis of the resilient barrier (i.e. about an axis into the page in Figure 6B and vertical in Figure 6C), e.g. the recess is cylindrical, which means that the recess facilitates the deformation of the resilient barrier in all directions equally (i.e. isotropically) in the plane parallel to the end faces of the resilient barrier. When the resilient barrier 406 is assembled into the shaft 402 of the robotic surgical instrument, the plane parallel to the end faces of the resilient barrier 406 is perpendicular to the longitudinal axis 505 of the shaft.

[0073] The recess 604 is larger than each of the holes 602. As described above, the recess is on one face of the resilient barrier, and the recess may, for example, have an area that is in a range from 3% to 33% of the area of the face of the resilient barrier. For example, the recess may have an area that is 10% of the area of the face of the resilient barrier. For example, when the recess is cylindrical, the diameter of the recess 604 may be in a range from 1mm to 3.5mm. To give a specific example, the diameter of the recess 604 may be 2mm, and the diameter of each of the holes may be 0.45mm. The diameter of the face of the resilient barrier in which the recess is located may for example be 6mm. The larger the recess 604, the more it will allow the resilient barrier to deform, and the lighter the resilient barrier will be. In examples described above, the resilient barrier 406 has one recess, but in other examples, the resilient barrier could have multiple recesses. For example, Figure 10 illustrates a plan view of a resilient barrier 1006 which comprises two recesses 10041 and 1004?. The resilient barrier 1006 also comprises holes 1002AI, 1002BI, 1002CI, 1002EI, 1002AZ, 1002BZ, 1002C2 and 1002E2, which substantially correspond to the holes 602AI, 602BI, 602CI, 602EI, 602A2, 602B2, 602C2 and 602E2 of resilient barrier 406 shown in Figure 6B. In general, the recess(es) do not need to be located centrally on a face of the resilient barrier. For example, neither of the recesses 1004 of the resilient barrier 1006 are at the centre of the face of the resilient barrier 1006 that is shown in Figure 10. As described above, a surgical instrument may have a pair of jaws as the end effector. However, the surgical instrument may have any type of end effector. For example, the instrument may be an electrosurgical instrument having electrosurgical end effectors. For example, figure 7 illustrates an electrocautery instrument having an electrocautery end effector for cauterising tissue at the surgical site. The electrocautery end effector 701 illustrated is a monopolar hook. It will be understood that this is for illustrative purposes only. The electrocautery end effector may take any suitable form and shape. For example, the electrocautery end effector may be a bipolar device having two electrocautery end effector elements.

[0074] Referring to figure 3, for the case that the instrument is an electrocautery instrument, the command interface 312 also comprises one or more inputs whereby the user can request activation and / or deactivation of the electrocautery instrument. The software stored in memory 311 may be configured to respond to these inputs by causing power to the electrocautery instrument to be activated and / or deactivated in compliance with a predetermined control strategy. The control strategy may include safety features which only cause power to be applied to the electrocautery instrument if certain conditions are met. Thus, in summary, a surgeon at the command interface 312 can control the electrocautery instrument to move (with drive being transferred to the end effector via elongate driving elements through the shaft) and can also control power to the electrocautery instrument to be activated / deactivated (with electrical power being provided to the end effector via elongate electrosurgical elements through the shaft) in such a way as to perform a desired surgical procedure.

[0075] The articulation 403 and driving elements Al, A2, Bl, B2 of the electrocautery instrument of figure 7 are as described with respect to figures 4 and 5. The shaft 402 of figure 7 houses two fewer driving elements than in examples described above because the instrument is not a grasping instrument. Furthermore, the shaft 402 of figure 7 houses an additional element El compared to the shaft of figures 4 and 5. The additional element is an elongate element which extends from the proximal end of the shaft, through the shaft and the interior of the articulation to the end effector. The additional element can be flexed laterally to its main extent at least in those regions where it engages the internal components of the instrument. In other words, the additional element can be flexed transverse to its longitudinal axis in those regions. This flexibility enables the additional element to wrap around the internal structure of the instrument, such as the joints and pulleys. The additional element may be wholly flexible transverse to its longitudinal axes. The additional element is not flexible along its main extent. Thus, the additional element may resist compression and tension forces applied along its length. In other words, the additional element may resist compression and tension forces acting in the direction of its longitudinal axis. The additional element may have a high modulus. The additional element may remain taut in operation. The additional element may be a cable.

[0076] In the example of figure 7, the additional element is an electrosurgical element which provides power to the end effector. Specifically, the additional element is an electrocautery element which provides power to the electrocautery end effector. The electrocautery element passes through the interior of the instrument shaft and the interior of the articulation to its connection point 702 with the electrocautery end effector. The electrocautery element may be a power cable. In this case, the electrocautery element is electrically connected to the electrocautery end effector at connection point 702.

[0077] The electrocautery element is long enough to fully accommodate movement of the joints of the articulation. This length could interfere with movement of the articulation as a result of the electrocautery element becoming slack and catching on other components internal to the articulation. In order to address this, the electrocautery element El may be constrained to wrap around the second axis 504 at least one full revolution in a straight configuration of the electrocautery instrument in which the electrocautery end effector is aligned with the shaft. As the electrocautery end effector 701 is articulated about the second joint 502 in a first rotational direction, the electrocautery element El winds about the second axis 504. The electrocautery element El thereby accommodates the rotation without becoming slack. As the electrocautery end effector 401 is articulated about the second joint 502 in a second rotational direction which opposes the first rotational direction, the electrocautery element El unwinds about the second axis 504. The electrocautery element El thereby accommodates the rotation without becoming so taut as to restrict the rotation of the electrocautery end effector in the second rotational direction. Alternatively, or additionally, the electrocautery element may be constrained by the resilient barrier 406. As described above the electrocautery element El has a diameter that is equal to or slightly larger than the diameter of the hole 602EI in the resilient barrier 406 that it passes through, and the resilient barrier may deform slightly around the element El to accommodate this. The resilient barrier is in resilient contact with the element El so as to provide a resilient force opposing movement of the element El. The resilient barrier provides a spring like force to the element El, acting to return the element El to its original position when the element El is pulled either towards the proximal end of the shaft or towards the end effector. The resilient contact between the resilient barrier 706 and the element El thus helps to stop slack of the additional element El bunching up in the articulation. It is noted that the driving elements are more taut than the electrosurgical element(s).

[0078] The electrosurgical element El may be secured to a driving element in the shaft 402. For example, the electrosurgical element El may be bonded to a driving element for a portion of the shaft. This prevents the electrosurgical element El from catching on and interfering with the driving elements in the shaft. The electrosurgical element El may be crimped to a driving element. The electrosurgical element El is not secured to a driving element in any region in which the electrosurgical element is constrained to interact with structure of the instrument, for example pulleys, joints, or the resilient barrier. If the electrosurgical element El is secured to a driving element in a portion of the shaft, then the resilient barrier is located between that portion of the shaft and the articulation (although this does not necessarily need to be the case). Figure 7 illustrates an example in which electrosurgical element El is secured to driving element B2 in portion 703 of shaft 402. Sheath 704 encompasses electrosurgical element El and driving element B2, thereby securing them to each other. The sheath 704 may be a heat sleeve. Resilient barrier 706 is located in the shaft between portion 703 and articulation 403. In the example shown in Figure 6A, the electrosurgical element El may be secured to driving element Al, and the electrosurgical element E2 may be secured to driving element A2.

[0079] The driving elements may be composed of different portions. For example, the portions of each driving element which engage the instrument interface and the articulation may be flexible. Between these flexible portions, the driving element may be a spoke. These spokes are denoted Als, A2s, Bls, B2s in figure 7. The spokes are wholly enclosed in the shaft 402. The spokes are stiffer than the flexible portions of the driving elements. The spokes may be rigid. As shown in figure 7, the electrosurgical element El may be bonded to the spoke B2s of one of the driving elements B2. The electrosurgical element El may be bonded to the spoke for most of the length of the shaft. In figure 7, the driving elements are flexible (for example cables) at the location in which they pass through holes in the resilient barrier. Alternatively, the driving elements may be spokes at the location in which they pass through holes in the resilient barrier. One or more of the driving elements may be spokes whilst one or more other of the driving elements may be flexible at the location in which they pass through holes in the resilient barrier.

[0080] In the instrument described with respect to figure 7, the resilient barrier has the dual effects of (i) reducing the leakage rate of fluid (e.g. insufflation gas and bodily fluids) from the surgical site, and (ii) tensioning the electrosurgical element to avoid slack getting caught in the articulation.

[0081] In all the instruments described, the resilient barrier does not substantially constrain the motion of the driving elements. This is because movement of the end effector is very finely tuned by the instrument interface elements driving the driving elements. If the resilient barrier were to constrain the driving elements in the same way as it constrains the additional element, an unknown and inconsistent frictional force would be applied to the driving elements which would affect the relationship between the movement of the instrument interface elements and the movement of the distal driving elements at the joints they are driving in an unpredictable way.

[0082] In the examples shown in the figures the elongate elements are elongate control elements for controlling an operation of the end effector. In particular, in the examples shown in the figures the elongate elements are driving elements and electrosurgical elements. More generally, the elongate elements could be any elements extending through the shaft for operating the end effector. Other examples of such elements are electrical leads, fibre optic conduits, tubes for administering or removing material, and conduits for other energy forms (such as vibration). In the case that there are further elongate elements in the shaft, each additional elongate element is treated the same as the elongate elements described herein. In other words, each additional elongate element passes through a respective hole in the resilient barrier as described herein.

[0083] Figure 7 illustrates a monopolar hook end effector which is powered by a single electrosurgical element El. However, there may be one or more further electrosurgical elements in the shaft. For example, for the case that the electrocautery end effector is a bipolar device having two electrocautery end effector elements, those two end effector elements may be powered by separate electrosurgical elements. Standard instruments do not have more cables going through their shafts to their end effectors than in a bipolar device having two electrocautery end effector elements. The resilient barriers described herein are particularly advantageous for instruments which have a large number of cables to be routed through a small-diameter shaft, for ensuring a low rate of fluid leakage from the surgical site through the shaft.

[0084] Figure 8 is a flow chart for a method of manufacturing the resilient barrier406. In an example described herein, the resilient barrier 406 is manufactured by compression moulding using a mould of the shape of the resilient barrier 406. The resilient barrier 406 is a discrete component, i.e. it may be manufactured separately to the instrument. The manufactured resilient barrier 406 can then be press-fitted into the shaft of an instrument, with the cables threaded through the respective holes in the resilient barrier. Figure 9A illustrates a plan view of the mould 900 of the shape of the resilient barrier. Figure 9B illustrates a side view of a section of the mould 900 in the plane represented by the dashed line 906 in Figure 9A. Figure 9B also shows another component 906 (which may be referred to as a "press" or a "heated press") arranged to press material 908 (e.g. in molten form) into the mould 900.

[0085] In step S802 a material is put (e.g. pressed) into the mould 900. The material may be a rubber, such as silicone. The compression moulding process may involve using pre-formed 'blanks' of the material in the basic disc-shape of the resilient barrier 406 (but without the holes 602 or the recess 604). The blanks may provide a surplus of material to be placed in the mould 900, which ensures that the mould can be totally filled. The blank is placed in the mould 900 and the press 906 applies pressure to the material in the mould 900. The press 906 may be a hydraulic press, which may be heated to apply both heat and pressure to the blank. The heat of the press 906 causes the material to become molten, and the pressure applied by the press ensures that the material (in its molten form) fully takes the shape defined by the mould 900.

[0086] In step S804 the material is set in the mould 900 to thereby form the resilient barrier 406. The set material is a deformable, solid material (at room temperature and at atmospheric pressure). The material of the resilient barrier is impermeable to fluids such as insufflation gases and water-based liquids, such as those found in the body. For example, the material of the resilient barrier may be silicone. Alternatively, material of the resilient barrier may be one of neoprene, natural rubber, nitrile rubber, butyl rubber, synthetic rubber, PVC and a thermoplastic elastomer. Step S804 may involve completing a cure cycle for a given time period. When the cure cycle is completed, the press 906 is moved away and the set material (i.e. the resilient barrier) is removed from the mould 900. The fabricated resilient barrier 406 can then be assembled into the shaft 402 of the robotic surgical instrument as described above.

[0087] In the example shown in Figures 9A and 9B, the mould 900 is cylindrical with the same diameter at the resilient barrier 406, and has a plurality of rods 902 corresponding to the plurality of holes 602 in the resilient barrier 406, and a bump 904 corresponding to the recess 604 in the resilient barrier 406. In particular, the shape and position of the rods 902AI, 902BI, 902CI, 902EI, 902A2, 902BZ, 902C2 and 902E2 match the shape and position of the respective holes 602AI, 602BI, 602CI, 602EI, 602A2, 602B2, 602C2 and 602E2, and the shape and position of the bump 904 matches the shape and position of the recess 604. The bump 904 may be referred to with other terms, such as a "protrusion" or a "knob". Figure 9B shows the material 908 after it has been pressed and cured in the mould 900 by the press 906. As shown in Figure 9B the material 908 (when it has been pressed and set) has a thickness, T, which is the thickness of the resilient barrier 406.

[0088] As mentioned above, the resilient barrier 406 is fabricated such that, for one or more of the elongate elements (Al, Bl, Cl, El, A2, B2, C2, E2) , the respective hole (602AI, 602BI, 602CI, 602EI, 602A2, 602B2, 602C2, 602E2) in the resilient barrier 406 through which the elongate element passes is in a position in the fabricated resilient barrier 406 that corresponds, when the resilient barrier 406 is arranged to extend over the cross-sectional area of the shaft 402, to a position within the shaft 402 that is offset from the natural position of the elongate element by a non-zero amount in the plane perpendicular to the longitudinal axis 505 of the shaft 402. The rods 902 in the mould 900 are at positions that match the positions of the holes 602 of the resilient barrier 406. As such, the position of one or more of the rods 902 is offset from the natural position of the corresponding elongate element by the non-zero amount. The offset(s) are used to comply with one or more manufacturing constraints. In particular, the offset(s) are used to ensure that the minimum distance between any pair of holes 602 in the resilient barrier 402 (i.e. the minimum distance between any pair of rods 902 in the mould 900) is greater than or equal to a threshold distance. Furthermore, the offset(s) are used to ensure that the minimum distance between any hole 602 in the resilient barrier 406 and the outer edge of the resilient barrier (i.e. the minimum distance between any rod 902 in the mould 900 and the outer edge of the mould 900) is greater than or equal to the threshold distance. The threshold distance is the minimum distance between holes (or between a hole and the edge of the resilient barrier) that can be reliably manufactured. Complying with these manufacturing constraints ensures that the material of the resilient barrier can flow sufficiently to completely fill the shape of the mould 900 in step S802, and also ensures that the resulting resilient barrier 406 does not include portions that are thinner than the threshold minimum thickness, thereby ensuring that the resilient barrier 406 does not have portions which might be too weak or prone to breaking. The magnitude of the nonzero amount(s) of the offset(s) may be less than a maximum offset. The magnitude of the non-zero amount(s) of the offset(s) may be less than the diameter of one of the holes 602. The magnitude of the non-zero amount(s) of the offset(s) may be less than 0.25mm.

[0089] The natural positions of the elongate elements may be such that the distance in the plane perpendicular to the longitudinal axis 505 of the shaft 402 between the natural positions of a pair of the elongate elements and is less than the threshold distance. Similarly, the natural positions of the elongate elements may be such that the distance in the plane perpendicular to the longitudinal axis 505 of the shaft 402 between the natural position of an elongate element and the inner wall of the shaft 402 is less than the threshold distance. By comparing Figures 6A and 6B it can be seen that the positions of the holes 602BI, 602CI, 602BZ and 602cz match (i.e. are not offset from) the natural positions of the corresponding elongate elements Bl, Cl, B2 and C2. However, it can be seen by comparing Figures 6A and 6B that the positions of the holes 602AI, 602EI, 602AZ and 6O2EZ do not exactly match (i.e. are offset from) the natural positions of the corresponding elongate elements Al, El, A2 and E2. This is because: (i) the distance between the natural positions of the elongate elements Al and El is less than the threshold distance, (ii) the distance between the natural positions of the elongate elements A2 and E2 is less than the threshold distance, (iii) the distance between the natural position of the elongate element Al and the inner wall of the shaft 402 is less than the threshold distance, and (iv) the distance between the natural position of the elongate element A2 and the inner wall of the shaft 402 is less than the threshold distance. As such, the positions of the holes 602AI, 602EI, 602A2 and 602E2 are offset from the natural positions of their corresponding elongate elements such that: (i) the distance between the holes 602AI and 602EI is at least the threshold distance, (ii) the distance between the holes 602A2 and 602E2 is at least the threshold distance, (iii) the distance between the hole 602AI and the outer edge of the resilient barrier 406 is at least the threshold distance, and (iv) the distance between the hole 602A2 and the outer edge of the resilient barrier 406 is at least the threshold distance.

[0090] In general, if elongate elements have natural positions that are closer to each other or closer to the internal wall of the shaft than the minimum distance then the holes of the resilient barrier are offset from these natural positions so that the distance between holes and between each hole and the edge of the resilient barrier is not less than the minimum distance. For each of the holes, the position corresponding to the natural position for its respective elongate element is the position on the resilient barrier that matches, when the resilient barrier is arranged to extend over the cross-sectional area of the shaft, a natural position at which the respective elongate element passes through the cross-sectional area of the shaft. As mentioned above, the driving elements are taut in the shaft, whilst the electrosurgical elements are not so taut, i.e. the electrosurgical elements are relatively slack in the shaft. In other words, the tension in the driving elements is higher than the tension in the electrosurgical elements. The tension in a driving element is enough such that if the corresponding hole 602 in the resilient barrier 406 is slightly offset from the natural position of the driving element then the driving element is able to push against the hole (e.g. in a direction perpendicular to the longitudinal axis 505 of the shaft 402), causing the resilient barrier to deform slightly such that the position of the hole 602 is moved to align with the natural position of the driving element. The deformation of resilient barrier is in the plane perpendicular to the longitudinal axis of the shaft. In contrast, since the tension in the electrosurgical elements is less than in the driving elements, when the position of a hole 602 is offset from the natural position of an electrosurgical element then the electrosurgical element may alter its position away from its natural position within the shaft in order to pass through the hole 602 in the resilient barrier. The alteration of the position of an elongate element (e.g. an electrosurgical element) may be instead of, or as well as, a slight alteration in the position of the hole caused by the elongate element pushing against the hole causing the resilient barrier to deform slightly.

[0091] The resilient barrier is described herein with reference to examples in which it is to be used with a robotic surgical instrument, e.g. for surgical purposes. However, it is to be understood that an instrument including the resilient barrier described herein could be used for purposes other than surgery. For example, the instrument could be used for non-medical uses, e.g. in a cosmetic procedure or in an industrial field for techniques such as non-destructive testing and hole exploration. For example, the instrument could be used in a procedure performed inside a manufactured article such as a car engine.

[0092] The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

Claims

AMENDED CLAIMS received by the International Bureau on 27 March 2025 (27.03.2025)1. A robotic surgical instrument comprising: a shaft; an end effector; a plurality of elongate elements extending through the shaft and configured to operate the end effector; and a resilient barrier inside the shaft extending over a cross-sectional area of the shaft, wherein the resilient barrier is fabricated from a deformable material and comprises a plurality of holes and a recess, wherein the recess does not pass all the way through the resilient barrier and wherein the recess is included in the resilient barrier without reducing the thickness of the resilient barrier at the outer edge of the resilient barrier, and wherein each of the elongate elements passes through a respective hole in the resilient barrier.

2. The robotic surgical instrument of claim 1, wherein the recess is located more centrally than the holes with respect to the cross-sectional area of the shaft.

3. The robotic surgical instrument of claim 1 or 2, wherein the shaft is a hollow cylinder and the resilient barrier is cylindrical, wherein the area of the end faces of the cylindrical resilient barrier matches, and is aligned with, the cross-sectional area of the shaft which is defined by the interior wall of the shaft.

4. The robotic surgical instrument of claim 3, wherein the recess is in the centre of one of the end faces of the cylindrical resilient barrier.

5. The robotic surgical instrument of any preceding claim, wherein the depth of the recess in the resilient barrier is less than the thickness of the resilient barrier but at least a threshold depth.

6. The robotic surgical instrument of any preceding claim, wherein the recess is larger than each of the holes.

7. The robotic surgical instrument of any preceding claim, wherein the resilient barrier is configured to inhibit passage of fluid through the shaft from one side of the resilient barrier to the other.

8. The robotic surgical instrument of any preceding claim, wherein an outer edge of the resilient barrier is in sealed contact with the interior wall of the shaft around the outer edge of the cross-sectional area.

9. The robotic surgical instrument of any preceding claim, wherein the resilient barrier is located at the distal end of the shaft.

10. The robotic surgical instrument of any preceding claim, wherein the resilient barrier is fabricated from silicone.

11. The robotic surgical instrument of any preceding claim, wherein the diameter of each of the holes is less than or equal to the diameter of the respective elongate element that passes through that hole in the resilient barrier.

12. The robotic surgical instrument of any preceding claim, wherein the elongate elements are arranged to pass through the cross-sectional area of the shaft at respective natural positions in the plane perpendicular to the longitudinal axis of the shaft, and wherein the resilient barrier is fabricated such that, for one or more of the elongate elements, the respective hole in the resilient barrier through which the elongate element passes is in a position in the fabricated resilient barrier that corresponds, when the resilient barrier is arranged to extend over the cross-sectional area of the shaft, to a position within the shaft that is offset from the natural position of the elongate element by a non-zero amount in the plane perpendicular to the longitudinal axis of the shaft, such that: (i) the minimum distance between any pair of holes in the fabricated resilient barrier is greater than or equal to a threshold distance, and (ii) the minimum distance between any hole in thefabricated resilient barrier and the outer edge of the fabricated resilient barrier is greater than or equal to the threshold distance.

13. The robotic surgical instrument of any preceding claim, wherein the plurality of elongate elements comprises: (i) one or more driving elements configured to control movement of the end effector relative to the shaft, and / or (ii) one or more electrosurgical elements configured to provide electrical power to the end effector when the instrument is an electrosurgical instrument.

14. The robotic surgical instrument of any preceding claim, wherein the end effector comprises a pair of bipolar jaws, and wherein the robotic surgical instrument further comprises an articulation connecting the end effector to a distal end of the shaft, the articulation comprising joints permitting the end effector to adopt a range of orientations relative to a longitudinal axis of the shaft; wherein the plurality of elongate elements comprises pairs of driving elements configured to drive the joints and a pair of electrosurgical elements configured to provide electrical power to the bipolar jaws, the driving elements and the electrosurgical elements extending through the shaft.

15. The robotic surgical instrument of any preceding claim, further comprising an instrument interface connected to a proximal end of the shaft, the instrument interface having an open structure through which fluid can move.

16. The robotic surgical instrument of any preceding claim wherein the resilient barrier is press-fitted into the shaft of the robotic surgical instrument.

17. A resilient barrier configured to be inserted into, and extend over a cross-sectional area of, a shaft of a robotic surgical instrument, wherein the resilient barrier is fabricated from a deformable material, and wherein the resilient barrier comprises: a plurality of holes; and a recess that does not pass all the way through the resilient barrier,wherein each of the holes is arranged to allow a respective elongate element of the robotic surgical instrument extending through the shaft to passthrough the hole for operating an end effector of the robotic surgical instrument, and wherein the recess is included in the resilient barrier without reducing the thickness of the resilient barrier at the outer edge of the resilient barrier.

18. The resilient barrier of claim 17, wherein the resilient barrier is manufactured as a discrete component to be inserted into the shaft of the robotic surgical instrument.

19. The resilient barrier of claim 17 or 18, wherein the resilient barrier comprises a plurality of recesses.

20. A method of manufacturing a resilient barrier configured to be inserted into, and extend over a cross-sectional area of, a shaft of a robotic surgical instrument, wherein the method comprises: putting a material into a mould of the shape of the resilient barrier; and setting the material in the mould to thereby form the resilient barrier, wherein the set material is a deformable, solid material, wherein the resilient barrier comprises: a plurality of holes; and a recess that does not pass all the way through the resilient barrier, wherein each of the holes is arranged to allow a respective elongate element of the robotic surgical instrument extending through the shaft to pass through the hole for operating an end effector of the robotic surgical instrument, and wherein the recess is included in the resilient barrierwithout reducingthe thickness of the resilient barrier at the outer edge of the resilient barrier.

21. A robotic surgical instrument comprising: a shaft; an end effector; a plurality of elongate elements extending through the shaft and configured to operate the end effector, wherein the elongate elements are arranged to pass through across-sectional area of the shaft at respective natural positions in the plane perpendicular to the longitudinal axis of the shaft; and a resilient barrier inside the shaft extending over the cross-sectional area of the shaft, wherein the resilient barrier is fabricated from a deformable material and comprises a plurality of holes, wherein each of the elongate elements passes through a respective hole in the resilient barrier, wherein the resilient barrier is fabricated such that, for one or more of the elongate elements, the respective hole in the resilient barrier through which the elongate element passes is in a position in the fabricated resilient barrier that corresponds, when the resilient barrier is arranged to extend over the cross-sectional area of the shaft, to a position within the shaft that is offset from the natural position of the elongate element by a non-zero amount in the plane perpendicular to the longitudinal axis of the shaft, such that: (i) the minimum distance between any pair of holes in the fabricated resilient barrier is greater than or equal to a threshold distance, and (ii) the minimum distance between any hole in the fabricated resilient barrier and the outer edge of the fabricated resilient barrier is greater than or equal to the threshold distance.

22. The robotic surgical instrument of claim 21, wherein the natural positions of the elongate elements are such that: (i) the distance in the plane perpendicularto the longitudinal axis of the shaft between the natural positions of a pair of the elongate elements is less than the threshold distance, and / or (ii) the distance in the plane perpendicular to the longitudinal axis of the shaft between the natural position of an elongate element and the inner wall of the shaft is less than the threshold distance.

23. The robotic surgical instrument of claims 21 or 22, wherein the threshold distance complies with manufacturing constraints.

24. A resilient barrier configured to be inserted into, and extend over a cross-sectional area of, a shaft of a robotic surgical instrument, wherein the resilient barrier is fabricated from a deformable material, and wherein the resilient barrier comprises:a plurality of holes, wherein each of the holes is arranged to allow a respective elongate element of the robotic surgical instrument extending through the shaft to pass through the hole for operating an end effector of the robotic surgical instrument, and wherein for one or more of the holes, a position of the hole in the resilient barrier is offset by a non-zero amount from a position corresponding to a natural position for its respective elongate element, such that: (i) the minimum distance between any pair of holes in the resilient barrier is greater than or equal to a threshold distance, and (ii) the minimum distance between any hole in the resilient barrier and the outer edge of the resilient barrier is greater than or equal to the threshold distance.

25. A method of manufacturing a resilient barrier configured to be inserted into, and extend over a cross-sectional area of, a shaft of a robotic surgical instrument, wherein the method comprises: putting a material into a mould of the shape of the resilient barrier; and setting the material in the mould to thereby form the resilient barrier, wherein the set material is a deformable, solid material, wherein the resilient barrier comprises a plurality of holes, wherein each of the holes is arranged to allow a respective elongate element of the robotic surgical instrument extending through the shaft to pass through the hole for operating an end effector of the robotic surgical instrument, and wherein for one or more of the holes, a position of the hole in the resilient barrier is offset by a non-zero amount from a position corresponding to a natural position for its respective elongate element, such that: (i) the minimum distance between any pair of holes in the resilient barrier is greater than or equal to a threshold distance, and (ii) the minimum distance between any hole in the resilient barrier and the outer edge of the resilient barrier is greater than or equal to the threshold distance.

26. The resilient barrier of claim 24 or the method of claim 25 wherein forthe one or more of the holes, the position corresponding to the natural position for its respective elongate element is the position on the resilient barrier that matches, when the resilient barrier is arranged to extend over the cross-sectional area of the shaft, a natural position at which the respective elongate element passes through the cross-sectional area of the shaft.

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