Patent Description:
Various robotic systems have recently been developed to assist in MIS procedures. Robotic systems can allow for more instinctive hand movements by maintaining natural eye-hand axis. Robotic systems can also allow for more degrees of freedom in movement by including an articulable "wrist" joint that creates a more natural hand-like articulation. In such systems, an end effector positioned at the distal end of the instrument can be articulated (moved) using a cable driven motion system having one or more drive cables that extend through the wrist joint. A user (e.g., a surgeon) is able to remotely operate the end effector by grasping and manipulating in space one or more controllers that communicate with a tool driver coupled to the surgical instrument. User inputs are processed by a computer system incorporated into the robotic surgical system, and the tool driver responds by actuating the cable driven motion system. Moving the drive cables articulates the end effector to desired angular positions and configurations.

One type of end effector is a combination vessel sealer and tissue grasper that has opposing jaws capable of closing down and "grasping" onto tissue. Once tissue is properly grasped, a knife can be advanced distally within a knife slot to transect the grasped tissue, and electrical energy may be applied (prior to, during, or after transection) to the end effector to seal and cauterize the transected tissue.

It is desirable to improve vessel sealers and their operation to make minimally invasive surgeries more effective and efficient.

<CIT> relates to end-effector assemblies for use in surgical instruments and methods of manufacturing a pair of jaw members of an end-effector assembly.

The present invention is defined in independent claim <NUM>.

The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, without departing from the scope of this disclosure.

The present disclosure is related to robotic surgical systems and, more particularly, to improved designs for tissue grasper end effectors.

One example end effector includes a first jaw having a first electrode and a first insulator secured thereto, and a second jaw having a second electrode and a second insulator secured thereto, the first and second jaws being pivotable between open and closed positions. A knife slot may be cooperatively defined in the first and second jaws and define a diamond-shape cross-section when the first and second jaws are in the closed position. A knife may be extendable into the knife slot and longitudinally movable within the knife slot.

A surgical tool disclosed herein includes a wrist including a proximal clevis and a distal clevis rotatably mountable to the proximal clevis at a first pivot axis, and an end effector rotatably coupled to the distal clevis at a second pivot axis, the end effector including opposing first and second jaws rotatably coupled to each other at a jaw pivot axis. The jaw pivot axis may be parallel to the second pivot axis and orthogonal to the first pivot axis, and a longitudinal axis of the end effector may be perpendicular to and intersects the jaw pivot axis.

Another example end effector includes opposing first and second jaws rotatably coupled to each other at a jaw pivot axis, a knife slot defined in one or both of the first and second jaws, and a knife coupled to a distal end of a drive rod and longitudinally extendable into the knife slot. A knife housing may be pivotably coupled between the first and second jaws at the jaw pivot axis and define a cavity sized to receive the knife. The drive rod may be actuatable to move the knife between a stowed position, where the knife is received within the cavity, and an extended position, where the knife is extended out of the cavity and into the knife slot.

<FIG> is a block diagram of an example robotic surgical system <NUM> that may incorporate some or all of the principles of the present disclosure. As illustrated, the system <NUM> can include at least one set of user input controllers 102a and at least one control computer <NUM>. The control computer <NUM> may be mechanically and/or electrically coupled to a robotic manipulator and, more particularly, to one or more robotic arms <NUM> (alternately referred to as "tool drivers"). In some embodiments, the robotic manipulator may be included in or otherwise mounted to an arm cart capable of making the system portable. Each robotic arm <NUM> may include and otherwise provide a location for mounting one or more surgical instruments or tools <NUM> for performing various surgical tasks on a patient <NUM>. Operation of the robotic arms <NUM> and associated tools <NUM> may be directed by a clinician 112a (e.g., a surgeon) from the user input controller 102a.

In some embodiments, a second set of user input controllers 102b (shown in dashed line) may be operated by a second clinician 112b to direct operation of the robotic arms <NUM> and tools <NUM> via the control computer <NUM> and in conjunction with the first clinician 112a. In such embodiments, for example, each clinician 112a,b may control different robotic arms <NUM> or, in some cases, complete control of the robotic arms <NUM> may be passed between the clinicians 112a,b as needed. In some embodiments, additional robotic manipulators having additional robotic arms may be utilized during surgery on the patient <NUM>, and these additional robotic arms may be controlled by one or more of the user input controllers 102a,b.

The control computer <NUM> and the user input controllers 102a,b may be in communication with one another via a communications link <NUM>, which may be any type of wired or wireless telecommunications means configured to carry a variety of communication signals (e.g., electrical, optical, infrared, etc.) according to any communications protocol. In some applications, for example, there is a tower with ancillary equipment and processing cores designed to drive the robotic arms <NUM>.

The user input controllers 102a,b generally include one or more physical controllers that can be grasped by the clinicians 112a,b and manipulated in space while the surgeon views the procedure via a stereo display. The physical controllers generally comprise manual input devices movable in multiple degrees of freedom, and which often include an actuatable handle for actuating the surgical tool(s) <NUM>, for example, for opening and closing opposing jaws, applying an electrical potential (current) to an electrode, or the like. The control computer <NUM> can also include an optional feedback meter viewable by the clinicians 112a,b via a display to provide a visual indication of various surgical instrument metrics, such as the amount of force being applied to the surgical instrument (i.e., a cutting instrument or dynamic clamping member).

<FIG> is an isometric side view of an example surgical tool <NUM> that may incorporate some or all of the principles of the present disclosure. The surgical tool <NUM> may be the same as or similar to the surgical tool(s) <NUM> of <FIG> and, therefore, may be used in conjunction with a robotic surgical system, such as the robotic surgical system <NUM> of <FIG>. Accordingly, the surgical tool <NUM> may be designed to be releasably coupled to a tool driver included in the robotic surgical system <NUM>. In other embodiments, however, aspects of the surgical tool <NUM> may be adapted for use in a manual or hand-operated manner, without departing from the scope of the disclosure.

As illustrated, the surgical tool <NUM> includes an elongated shaft <NUM>, an end effector <NUM>, a wrist <NUM> (alternately referred to as a "wrist joint" or an "articulable wrist joint") that couples the end effector <NUM> to the distal end of the shaft <NUM>, and a drive housing <NUM> coupled to the proximal end of the shaft <NUM>. In applications where the surgical tool is used in conjunction with a robotic surgical system (e.g., the robotic surgical system <NUM> of <FIG>), the drive housing <NUM> can include coupling features that releasably couple the surgical tool <NUM> to the robotic surgical system.

The terms "proximal" and "distal" are defined herein relative to a robotic surgical system having an interface configured to mechanically and electrically couple the surgical tool <NUM> (e.g., the housing <NUM>) to a robotic manipulator. The term "proximal" refers to the position of an element closer to the robotic manipulator and the term "distal" refers to the position of an element closer to the end effector <NUM> and thus further away from the robotic manipulator. Alternatively, in manual or hand-operated applications, the terms "proximal" and "distal" are defined herein relative to a user, such as a surgeon or clinician. The term "proximal" refers to the position of an element closer to the user and the term "distal" refers to the position of an element closer to the end effector <NUM> and thus further away from the user. Moreover, the use of directional terms such as above, below, upper, lower, upward, downward, left, right, and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward or upper direction being toward the top of the corresponding figure and the downward or lower direction being toward the bottom of the corresponding figure.

During use of the surgical tool <NUM>, the end effector <NUM> is configured to move (pivot) relative to the shaft <NUM> at the wrist <NUM> to position the end effector <NUM> at desired orientations and locations relative to a surgical site. To accomplish this, the housing <NUM> includes (contains) various drive inputs and mechanisms (e.g., gears, actuators, etc.) designed to control operation of various features associated with the end effector <NUM> (e.g., clamping, firing, cutting, rotation, articulation, etc.). In at least some embodiments, the shaft <NUM>, and hence the end effector <NUM> coupled thereto, is configured to rotate about a longitudinal axis A<NUM> of the shaft <NUM>. In such embodiments, at least one of the drive inputs included in the housing <NUM> is configured to control rotational movement of the shaft <NUM> about the longitudinal axis A<NUM>.

The shaft <NUM> is an elongate member extending distally from the housing <NUM> and has at least one lumen extending therethrough along its axial length. In some embodiments, the shaft <NUM> may be fixed to the housing <NUM>, but could alternatively be rotatably mounted to the housing <NUM> to allow the shaft <NUM> to rotate about the longitudinal axis A<NUM>. In yet other embodiments, the shaft <NUM> may be releasably coupled to the housing <NUM>, which may allow a single housing <NUM> to be adaptable to various shafts having different end effectors.

The end effector <NUM> can exhibit a variety of sizes, shapes, and configurations. In the illustrated embodiment, the end effector <NUM> comprises a combination tissue grasper and vessel sealer that include opposing jaws <NUM>, <NUM> configured to move (articulate) between open and closed positions. As will be appreciated, however, the opposing jaws <NUM>, <NUM> may alternatively form part of other types of end effectors such as, but not limited to, a surgical scissors, a clip applier, a needle driver, a babcock including a pair of opposed grasping jaws, bipolar jaws (e.g., bipolar Maryland grasper, forceps, a fenestrated grasper, etc.), etc. One or both of the jaws <NUM>, <NUM> may be configured to pivot to articulate the end effector <NUM> between the open and closed positions.

<FIG> illustrates the potential degrees of freedom in which the wrist <NUM> may be able to articulate (pivot). The wrist <NUM> can have any of a variety of configurations. In general, the wrist <NUM> comprises a joint configured to allow pivoting movement of the end effector <NUM> relative to the shaft <NUM>. The degrees of freedom of the wrist <NUM> are represented by three translational variables (i.e., surge, heave, and sway), and by three rotational variables (i.e., Euler angles or roll, pitch, and yaw). The translational and rotational variables describe the position and orientation of the end effector <NUM> with respect to a given reference Cartesian frame. As depicted in <FIG>, "surge" refers to forward and backward translational movement, "heave" refers to translational movement up and down, and "sway" refers to translational movement left and right. With regard to the rotational terms, "roll" refers to tilting side to side, "pitch" refers to tilting forward and backward, and "yaw" refers to turning left and right.

The pivoting motion can include pitch movement about a first axis of the wrist <NUM> (e.g., X-axis), yaw movement about a second axis of the wrist <NUM> (e.g., Y-axis), and combinations thereof to allow for <NUM>° rotational movement of the end effector <NUM> about the wrist <NUM>. In other applications, the pivoting motion can be limited to movement in a single plane, e.g., only pitch movement about the first axis of the wrist <NUM> or only yaw movement about the second axis of the wrist <NUM>, such that the end effector <NUM> moves only in a single plane.

Referring again to <FIG>, the surgical tool <NUM> may also include a plurality of drive cables (obscured in <FIG>) that form part of a cable driven motion system configured to facilitate movement and articulation of the end effector <NUM> relative to the shaft <NUM>. Moving (actuating) one or more of the drive cables moves the end effector <NUM> between an unarticulated position and an articulated position. The end effector <NUM> is depicted in <FIG> in the unarticulated position where a longitudinal axis A<NUM> of the end effector <NUM> is substantially aligned with the longitudinal axis A<NUM> of the shaft <NUM>, such that the end effector <NUM> is at a substantially zero angle relative to the shaft <NUM>. Due to factors such as manufacturing tolerance and precision of measurement devices, the end effector <NUM> may not be at a precise zero angle relative to the shaft <NUM> in the unarticulated position, but nevertheless be considered "substantially aligned" thereto. In the articulated position, the longitudinal axes A<NUM>, A<NUM> would be angularly offset from each other such that the end effector <NUM> is at a non-zero angle relative to the shaft <NUM>.

In some embodiments, the surgical tool <NUM> may be supplied with electrical power (current) via a power cable <NUM> coupled to the housing <NUM>. In other embodiments, the power cable <NUM> may be omitted and electrical power may be supplied to the surgical tool <NUM> via an internal power source, such as one or more batteries or fuel cells. In such embodiments, the surgical tool <NUM> may alternatively be characterized and otherwise referred to as an "electrosurgical instrument" capable of providing electrical energy to the end effector <NUM>.

The power cable <NUM> may place the surgical tool <NUM> in electrical communication with a generator <NUM> that supplies energy, such as electrical energy (e.g., radio frequency energy), ultrasonic energy, microwave energy, heat energy, or any combination thereof, to the surgical tool <NUM> and, more particularly, to the end effector <NUM>. Accordingly, the generator <NUM> may comprise a radio frequency (RF) source, an ultrasonic source, a direct current source, and/or any other suitable type of electrical energy source that may be activated independently or simultaneously.

In applications where the surgical tool <NUM> is configured for bipolar operation, the power cable <NUM> will include a supply conductor and a return conductor. Current can be supplied from the generator <NUM> to an active (or source) electrode located at the end effector <NUM> via the supply conductor, and current can flow back to the generator <NUM> via a return electrode located at the end effector <NUM> via the return conductor. In the case of a bipolar grasper with opposing jaws, for example, the jaws serve as the electrodes where the proximal end of the jaws are isolated from one another and the inner surface of the jaws (i.e., the area of the jaws that grasp tissue) apply the current in a controlled path through the tissue. In applications where the surgical tool <NUM> is configured for monopolar operation, the generator <NUM> transmits current through a supply conductor to an active electrode located at the end effector <NUM>, and current is returned (dissipated) through a return electrode (e.g., a grounding pad) separately coupled to a patient's body.

<FIG> is an enlarged isometric view of the distal end of the surgical tool <NUM>. More specifically, <FIG> depicts an enlarged view of the end effector <NUM> and the wrist <NUM>, with the jaws <NUM>, <NUM> of the end effector <NUM> in the closed position. The wrist <NUM> operatively couples the end effector <NUM> to the shaft <NUM>. In some embodiments, however, a shaft adapter may be directly coupled to the wrist <NUM> and otherwise interpose the shaft <NUM> and the wrist <NUM>. Accordingly, the wrist <NUM> may be operatively coupled to the shaft <NUM> either through a direct coupling engagement where the wrist <NUM> is directly coupled to the distal end of the shaft <NUM>, or an indirect coupling engagement where a shaft adapter interposes the wrist <NUM> and the distal end of the shaft <NUM>. As used herein, the term "operatively couple" refers to a direct or indirect coupling engagement between two components.

To operatively couple the end effector <NUM> to the shaft <NUM>, the wrist <NUM> includes a first or "distal" clevis 402a and a second or "proximal" clevis 402b. The clevises 402a,b may alternatively be referred to as "articulation joints" or "linkages. " As described herein, the clevises 402a,b are operatively coupled to facilitate articulation of the wrist <NUM> relative to the shaft <NUM>, thereby allowing the end effector <NUM> to articulate in yaw, pitch, or a combination of both yaw and pitch.

As illustrated, the proximal end of the distal clevis 402a may be rotatably mounted to the distal end of the proximal clevis 402b at a first pivot axis P<NUM> of the wrist <NUM>. First and second pulleys 404a and 404b (only the first pulley 404a is visible in <FIG>; see <FIG>) may be rotatably mounted to the distal end of the distal clevis 402a at a second pivot axis P<NUM> of the wrist <NUM>. The first pivot axis P<NUM> is substantially perpendicular (orthogonal) to the longitudinal axis A<NUM> of the shaft <NUM>, and the second pivot axis P<NUM> is substantially perpendicular (orthogonal) to both the longitudinal axis A<NUM> and the first pivot axis P<NUM>. Movement of the end effector <NUM> about the first pivot axis P<NUM> provides "yaw" articulation of the wrist <NUM>, and movement about the second pivot axis P<NUM> provides "pitch" articulation of the wrist <NUM>.

A plurality of drive members, shown as drive members 406a, 406b, 406c, and 406d, extend longitudinally within a lumen <NUM> defined by the shaft <NUM> (or a shaft adaptor) and extend at least partially through the wrist <NUM>. The drive members 406a-d may form part of the actuation systems housed within the drive housing <NUM> (<FIG>), and may comprise cables, bands, lines, cords, wires, woven wires, ropes, strings, twisted strings, elongate members, belts, shafts, flexible shafts, drive rods, or any combination thereof. The drive members 406a-d can be made from a variety of materials including, but not limited to, a metal (e.g., tungsten, stainless steel, nitinol, etc.) a polymer (e.g., ultra-high molecular weight polyethylene), a synthetic fiber (e.g., KEVLAR®, VECTRAN®), etc.), an elastomer, or any combination thereof. While four drive members 406a-d are depicted in <FIG>, more or less than four may be employed, without departing from the scope of the disclosure.

The drive members 406a-d extend proximally from the end effector <NUM> and the wrist <NUM> toward the drive housing <NUM> (<FIG>) where they are operatively coupled to various actuation mechanisms or devices that facilitate longitudinal movement (translation) of the drive members 406a-d within the lumen <NUM>. Selective actuation of the drive members 406a-d applies tension (i.e., pull force) to the given drive member 406a-d in the proximal direction, which urges the given drive member 406a-d to translate longitudinally within the lumen <NUM>.

In the illustrated embodiment, the drive members 406a-d each extend longitudinally through the proximal clevis 402b, and the distal end of each drive member 406a-d terminates at the first or second pulleys 404a,b, thus operatively coupling each drive member 406a-d to the end effector <NUM>. In some embodiments, the distal ends of the first and second drive members 406a,b may be coupled to each other and terminate at the first pulley 404a, and the distal ends of the third and fourth drive members 406c,d may be coupled to each other and terminate at the second pulley 404b (<FIG>). In at least one embodiment, the distal ends of the first and second drive members 406a,b and the distal ends of the third and fourth drive members 406c,d may each be coupled together at a corresponding ball crimp <NUM> (only one shown) mounted to the first or second pulley 404a,b, respectively.

In the illustrated embodiment, the drive members 406a-d operate "antagonistically". More specifically, when the first drive member 406a is actuated (moved in tension), the second drive member 406b naturally follows as coupled to the first drive member 406a, and vice versa. Similarly, when the third drive member 406c is actuated (moved in tension), the fourth drive member 406d naturally follows as coupled to the third drive member 406c, and vice versa. Antagonistic operation of the drive members 406a-d can open or close the jaws <NUM>, <NUM> and can further cause the end effector <NUM> to articulate at the wrist <NUM>. More specifically, selective actuation of the drive members 406a-d in known configurations or coordination can cause the end effector <NUM> to articulate about one or both of the pivot axes P<NUM>, P<NUM>, thus facilitating articulation of the end effector <NUM> in both pitch and yaw directions. Moreover, selective actuation of the drive members 406a-d in other known configurations or coordination will cause the jaws <NUM>, <NUM> to open or close. Antagonistic operation of the drive members 406a-d advantageously reduces the number of cables required to provide full wrist <NUM> motion, and also helps eliminate slack in the drive members 406a-d, which results in more precise motion of the end effector <NUM>.

In the illustrated embodiment, the end effector <NUM> is able to articulate (move) in pitch about the second or "pitch" pivot axis P<NUM>, which is located near the distal end of the wrist <NUM>. Thus, the jaws <NUM>, <NUM> open and close in the direction of pitch. Moving both articulation axes P<NUM>, P<NUM> closer to the therapeutic jaw surface enables minimization of the distance between the remote center of motion, therapeutic surface, and articulation axis. Having the pitch pivot axis P<NUM> as far distal as possible may be advantageous in providing a geometric advantage that helps an operator more easily get under vessels and facilitate blunt (touch) and spread dissection. This may also reduce the overall length of the end effector <NUM> and thereby improve surgeon access to patient anatomy during surgery by allowing discrete motion in smaller surgical spaces. This may also improve the robotic control of the instrument making user-applied motions seem more natural. This may further result in providing better reach to anatomy during dissection, such as for lymph node removal or other tissue mobilization. In other embodiments, however, the wrist <NUM> may alternatively be configured such that the second pivot axis P<NUM> facilitates yaw articulation of the jaws <NUM>, <NUM>, without departing from the scope of the disclosure.

In the illustrated embodiment, first and second electrical conductors 412a and 412b also extend longitudinally within the lumen <NUM>, through the wrist <NUM>, and terminate at the end effector <NUM> to supply electrical energy thereto. More particularly, the first electrical conductor 412a terminates at a first or "upper" electrode 414a secured to the upper jaw <NUM>, and the second electrical conductor 412b terminates at a second or "lower" electrode 414b secured to the lower jaw <NUM>. In some embodiments, the electrical conductors 412a,b may each comprise a wire, but may alternatively comprise a rigid or semi-rigid shaft, rod, or strip (ribbon) made of a conductive material. The electrical conductors 412a,b may be partially covered with an insulative covering (overmold) made of a non-conductive material. Routing the electrical conductors 412a,b to the corresponding electrodes 414a,b, respectively, allows the end effector <NUM> to operate in bipolar RF operation.

In at least one embodiment, the electrical energy conducted through the electrical conductors 412a,b exhibits a frequency between about <NUM> and <NUM>. In a process known as Joule heating (resistive or Ohmic heating) the RF energy is transformed into heat within target tissue grasped between the jaws <NUM>, <NUM> due the tissue's intrinsic electrical impedance, thereby increasing the temperature of the target tissue. Heating the target tissue achieves various tissue effects such as cauterization and/or coagulation, and thus may be particularly useful for sealing blood vessels or diffusing bleeding during a surgical procedure. Heating the target tissue may also cause desiccation of the tissue, which allows the tissue to be cut (dissected) more easily.

<FIG> is another enlarged isometric view of the end effector <NUM>. The upper jaw <NUM> (<FIG>) is omitted in <FIG> to enable viewing of various component parts of the lower jaw <NUM>. In the illustrated embodiment, the end effector <NUM> comprises a combination tissue grasper and vessel sealer and includes a knife <NUM> (mostly occluded), alternately referred to as a "cutting element" or "blade. " The knife <NUM> is aligned with and configured to traverse a guide track or "knife slot" <NUM> defined longitudinally in both the upper and lower jaws <NUM>, <NUM>. The knife <NUM> may be operatively coupled to the distal end of a drive rod <NUM> (alternately referred to as "knife rod," "actuation rod," or "push rod") that extends longitudinally within the lumen <NUM> and passes through the wrist <NUM>. Longitudinal movement (translation) of the drive rod <NUM> correspondingly moves the knife <NUM> within the knife slot <NUM>.

The drive rod <NUM> may comprise a rigid or semi rigid elongate member, such as a rod or shaft (e.g., a hypotube, a hollow rod, a solid rod, etc.), a wire, a ribbon, a push cable, or any combination thereof. The drive rod <NUM> can be made from a variety of materials including, but not limited to, metal (e.g., tungsten, nitinol, stainless steel, etc.), a polymer, or a composite material. The drive rod <NUM> may have a circular cross-section, but may alternatively exhibit a polygonal cross-section without departing from the scope of the disclosure.

Similar to the drive members 406a-d, the drive rod <NUM> may form part of the actuation systems housed within the drive housing <NUM> (<FIG>). Selective actuation of a corresponding drive input will cause the drive rod <NUM> to move distally or proximally within the lumen <NUM>, and correspondingly move the knife <NUM> in the same longitudinal direction.

In the illustrated embodiment, the knife <NUM> is shown received within a knife housing <NUM> pivotably mounted to the end effector <NUM>. As described in more detail below, the knife housing <NUM> defines a central passageway through which the knife <NUM> and the drive rod <NUM> are able to extend to move the knife <NUM> into and along the knife slot <NUM>. Upon firing the end effector <NUM>, the drive rod <NUM> is moved (urged) distally, which correspondingly moves the knife <NUM> out of the knife housing <NUM> and into the knife slot <NUM>. After firing is complete, the drive rod <NUM> is retracted proximally, which pulls the knife <NUM> proximally and back into the knife housing <NUM> until it is desired to again fire the end effector <NUM>.

Referring again to <FIG>, with continued reference to <FIG>, in example operation of the end effector <NUM>, the jaws <NUM>, <NUM> may be actuated to close and grasp onto tissue, following which the electrodes 414a,b may be supplied with electrical energy, which is transformed into heat within the grasped tissue to cauterize, coagulate, and/or otherwise seal the tissue. The knife <NUM> may then be advanced distally along the knife slot <NUM> to cut (transect) and simultaneously seal the grasped tissue. Alternatively, in other applications, the knife <NUM> may be advanced prior to the application of electrical energy to cut unsealed tissue to facilitate dissection of non-vascular tissue.

According to embodiments of the present disclosure, the electrodes 414a,b provided in the end effector <NUM> may be designed to be thermally and mechanically symmetric and thereby configured to optimize performance of the end effector <NUM> when treating and cutting tissue grasped between the jaws <NUM>, <NUM>. Prior vessel sealer designs commonly include only a single, isolated electrode positioned on only one of the jaws, and the opposing jaw operates as the return path on the opposite side. This design configuration results in a difference in thermal mass causing asymmetric heat signatures on opposing sides of the tissue grasped between the jaws, which may affect tissue sealing performance. In contrast, the thermally and mechanically symmetric jaws <NUM>, <NUM> described herein each include a corresponding powered electrode 414a,b, which results in a thermally balanced thermal mass on both sides (e.g., above and below) of the grasped tissue. The presently-disclosed electrodes 414a,b facilitate consistent and efficient heating of the electrodes 414a,b and the corresponding grasped tissues due to low and equal thermal mass on both sides of the tissue.

<FIG> are partial cross-sectional isometric and end views, respectively, of the end effector <NUM>, as taken along the plane indicated in <FIG>, according to one or more embodiments. The upper and lower jaws <NUM>, <NUM> are shown in <FIG> in the closed position. In the closed position, the upper jaw <NUM> extends substantially parallel to the lower jaw <NUM> and the electrodes 414a,b interpose at least a portion of the interface between the upper and lower jaws <NUM>, <NUM>. Each electrode 414a,b is mounted to the corresponding jaw <NUM>, <NUM> in conjunction with a corresponding insulator 502a and 502b, which operates to isolate the RF energy supplied to the electrodes 414a,b from the corresponding bodies of the jaws <NUM>, <NUM> during operation.

As illustrated, the upper insulator 502a may be overmolded onto the upper electrode 414a, and the lower insulator 502b may be overmolded onto the lower electrode 414b. Each insulator 502a,b may comprise a non-conductive material mated or otherwise coupled to the corresponding jaw <NUM>, <NUM>. Suitable non-conductive materials include, but are not limited to, nylon, polyphthalamide (PPA; e.g., GRIVORY® or THERMEC™), or a combination thereof.

The electrodes 414a,b and the insulators 502a,b may cooperatively define the knife slot <NUM> that guides the knife <NUM> (<FIG> and <FIG>) along the jaws <NUM>, <NUM>. More specifically, the upper insulator 502a and the upper electrode 414a may cooperatively define a first or "upper" slot portion 504a, and the lower insulator 502b and the lower electrode 414b may cooperatively define a second or "lower" slot portion 504b. When the jaws <NUM>, <NUM> are closed, the upper and lower slot portions 504a,b are aligned such that the knife <NUM> extends partially into each slot portion 504a,b as the knife <NUM> traverses the knife slot <NUM>. The slot portions 504a,b cooperatively direct the travel path of the knife <NUM> and help prevent the knife <NUM> from twisting or otherwise falling (leaning) to one side or the other.

The upper and lower electrodes 414a,b constitute mirror images of each other, and each electrode 414a,b provides and otherwise defines a planar sealing surface <NUM>. When the jaws <NUM>, <NUM> are closed, the planar sealing surfaces <NUM> are arranged substantially parallel to each other and a small gap is defined therebetween to receive (accommodate) tissue. The upper slot portion 504a bifurcates the planar sealing surface <NUM> of the upper electrode 414a, thereby defining left (first) and right (second) portions 508a and 508b of the upper electrode 414a. Similarly, the lower slot portion 504b bifurcates the planar sealing surface <NUM> of the lower electrode 414b, thereby defining left (first) and right (second) portions 510a and 510b of the lower electrode 414b.

The design and configuration of the lateral extents of the left and right portions 508a,b and 510a,b may be optimized for efficient thermal management. More specifically, the left and right portions 508a,b and 510a,b of each electrode 414a,b provide and otherwise define an outer lateral extent <NUM> extending from the corresponding planar sealing surface <NUM>. In the illustrated embodiment, the outer lateral extent <NUM> (alternately referred to as the "perimeter" or "boundary") extends away from the planar sealing surface <NUM> and away from the opposing jaw <NUM>, <NUM>; e.g., out of the plane of the planar sealing surface <NUM> and toward the body of the corresponding jaw <NUM>, <NUM>. In at least one embodiment, as illustrated, the outer lateral extent <NUM> extends from the corresponding planar sealing surface <NUM> at about a <NUM>° angle, but could alternatively extend at an angle greater or less than <NUM>°, without departing from the scope of the disclosure.

In some embodiments, as illustrated, one or more of the outer lateral extents <NUM> of the electrodes 414a,b may be embedded within a portion of the corresponding insulator 502a,b. As will be appreciated, this may help retain (secure) the electrode 414a,b to the insulator 502a,b without requiring mechanical fasteners, adhesives, or an interference fit. Moreover, embedding the outer lateral extents <NUM> in the insulator 502a,b may also be advantageous in reducing the conductive pathway through tissue extending on either lateral side of the jaws <NUM>, <NUM>. More specifically, embedding at least a portion of the outer lateral extents <NUM> within the insulator 502a,b may result in cooler tissue protruding out each lateral side of the jaws <NUM>, <NUM> as compared to end effectors with entirely exposed lateral extents.

In the illustrated embodiment, the insulator 502a,b extends toward but stops short of the planar sealing surface <NUM>. As a result the electrodes 414a,b may provide an electrically exposed edge <NUM> (e.g., radius, curvature, etc.) that provides the transition between the planar sealing surface and the lateral extent <NUM>. In other embodiments, however, and as described in more detail below, the insulator 502a,b may extend to and terminate at the planar sealing surface <NUM>, thus covering and otherwise encapsulating the edge <NUM>. In such embodiments, the heat difference in the portions of the tissue protruding out each lateral side of the jaws <NUM>, <NUM> may be even cooler as compared to temperatures where the electrodes 414a,b directly contact the tissue during sealing.

The left and right portions 508a,b and 510a,b of each electrode 414a,b may further provide and otherwise define an inner lateral extent <NUM> extending from the corresponding planar sealing surface <NUM> at the knife slot <NUM>. The inner lateral extent <NUM> could alternately be referred to as or characterized as an inner lateral "perimeter," "boundary," or "face". Similar to the outer lateral extents <NUM>, each inner lateral extent <NUM> extends away from the planar sealing surface <NUM> and also away from the opposing jaw <NUM>, <NUM>; e.g., out of the plane of the planar sealing surface <NUM> and toward the body of the corresponding jaw <NUM>, <NUM>). In at least one embodiment, as illustrated, the inner lateral extent <NUM> extends away from the corresponding planar sealing surface <NUM> at about a <NUM>° angle, but could alternatively extend at an angle greater or less than <NUM>°, without departing from the scope of the disclosure.

One or more of the inner lateral extents <NUM> may be at least partially embedded within a portion of the corresponding insulator 502a,b. As will be appreciated, this may help retain (secure) the electrode 414a,b to the insulator 502a,b without the need of mechanical fasteners or an interference fit.

As forming integral parts of the corresponding upper and lower slot portions 504a,b, the inner lateral extents <NUM> help define the knife slot <NUM>. In at least one embodiment, when the jaws <NUM>, <NUM> are closed, the electrodes 414a,b at the inner lateral extents <NUM> cooperatively define a generally diamond-shaped cross-section <NUM> (<FIG>). The diamond-shaped cross-section <NUM> of the knife slot <NUM> may be sized to provide adequate space for the knife <NUM> (<FIG>) and the drive rod <NUM> (<FIG>) to extend therethrough while firing the end effector <NUM>.

Moreover, the diamond-shape <NUM> of the electrodes 414a,b at the knife slot <NUM> is electrically exposed (e.g., not overmolded with the insulators 502a,b), which may provide a conductive pathway that creates uniform heating of tissue across the knife slot <NUM>. This may create a thermal effect that helps desiccate tissue in the center of the knife slot <NUM>, which makes the tissue easier to cut and ensures that the grasped tissue is fully sealed up to the cut location. Electrodes without the diamond-shaped cross-section <NUM> (i.e., entirely flat sealing surfaces) can fail to communicate sufficient thermal energy to the tissue at the knife slot. Having the diamond-shaped <NUM> knife slot <NUM>, however, allows the thermal energy to radiate to and thereby efficiently desiccate the grasped tissue.

In some embodiments, one or both of the insulators 502a,b may provide or otherwise define a floor or "trough" section <NUM> extending laterally across the knife slot <NUM> and thereby structurally connecting the lateral sides of the corresponding insulators 502a,b. Each trough section <NUM> may form the bottom of the upper and lower slot portions 504a,b. Prior art insulators are often disconnected (separated) at the knife slot, but the insulators 502a,b described herein comprise monolithic components that extend across the knife slot <NUM> and opposing lateral sides are interconnected at the trough section <NUM>. As will be appreciated, the trough section <NUM> may prove advantageous in simplifying the manufacture of the insulators 502a,b.

Referring specifically to <FIG>, the inner lateral extents <NUM> each provide an exposed surface area extending from the corresponding planar sealing surface <NUM> and toward the trough section <NUM>, and thereby help form a portion of the knife slot <NUM>. In some embodiments, as illustrated, the length L of one or both of the inner lateral extents <NUM> may be greater than a thickness T of the corresponding electrode 414a,b. This may prove advantageous in providing extra surface area for sealing through the knife zone.

<FIG> is an isometric view of a portion of the lower jaw <NUM>, according to one or more additional embodiments, and <FIG> is a cross-sectional view of the portion of the lower jaw <NUM> of <FIG> taken along the indicated plane in <FIG>. More specifically, <FIG> depict the lower electrode 414b and the lower insulator 502b of the lower jaw <NUM>. The configuration of the upper jaw <NUM> (<FIG> and <FIG>) may be substantially similar, thus the following discussion may be equally applicable to the upper jaw <NUM>. The lower jaw <NUM> shown in <FIG> may be similar in some respects to the lower jaw <NUM> shown in <FIG> and therefore may be best understood with reference thereto, where like numerals will represent similar components that may not be described again in detail.

As illustrated, the lower insulator 502b may be overmolded onto the lower electrode 414b, and the lower electrode 414b and the lower insulator 502b cooperatively define the lower slot portion 504b of the knife slot <NUM>. The lower slot portion 504b bifurcates the planar sealing surface <NUM> of the lower electrode 414b, thereby defining the left and right portions 510a,b of the lower electrode 414b.

As best seen in <FIG>, the outer lateral extents <NUM> of the lower electrode 414b extend away from the planar sealing surface <NUM> and toward the body of the lower jaw <NUM> at about a <NUM>° angle, but could alternatively extend at an angle greater or less than <NUM>°, without departing from the scope of the disclosure. The outer lateral extents <NUM> may also be embedded within the lower insulator 502b, which encapsulates the lateral extents <NUM> by extending to and terminating at the planar sealing surface <NUM>. As a result, the lower insulator 502b may provide a generally flush interface and finish with the planar sealing surface <NUM>. In the embodiment shown in <FIG>, the lower insulator 502b stops short of the planar sealing surface <NUM>, which leaves the edge <NUM> (radius, corner, etc.) of the lower electrode 414b exposed. In the illustrated embodiment, however, the edge <NUM> of the lower electrode 414b is covered by the lower insulator 502b, which finishes flush with the planar sealing surface <NUM>.

<FIG> are side and isometric views, respectively, of the upper and lower electrodes 414a,b, according to one or more embodiments. As indicated above, the upper and lower electrodes 414a,b may constitute mirror images of each other. In <FIG>, the electrodes 414a,b are depicted in a configuration when the jaws <NUM>, <NUM> (<FIG>, <FIG>, <FIG>) are in the closed position. In the closed position, the electrodes 414a,b are arranged substantially parallel to each other and a small gap <NUM> (<FIG>) is defined therebetween to receive (accommodate) tissue.

As illustrated, each electrode 414a,b includes an elongate body <NUM> having a first or "distal" end 706a and a second or "proximal" end 706b opposite the distal end 706a. The body <NUM> may be made of a variety of rigid, conductive materials, such as a metal. Example conductive materials include, but are not limited to, stainless steel, aluminum, silver, copper, and alloys thereof. Alternatively, stainless steel could also be used as a substrate over which gold, silver, or platinum could be applied through a plating process. An elongate channel <NUM> (<FIG>) is defined in the body <NUM> of each electrode 414a,b and extends between the distal and proximal ends 706a,b. The elongate channel <NUM> helps define the knife slot <NUM> (<FIG>) in the upper and lower jaws <NUM>, <NUM> (<FIG>, <FIG>, <FIG>). As best seen in <FIG>, the elongate channels <NUM> substantially align when the jaws <NUM>, <NUM> are closed.

Each electrode 414a,b may provide an electrical connector <NUM> positioned at and otherwise extending from the proximal end 706b. The electrical connector <NUM> provides a location where the first and second electrical conductors 412a,b can be placed in electrical communication with the electrodes 414a,b, respectively. More specifically, the first electrical conductor 412a terminates at and is electrically coupled to the electrical connector <NUM> of the upper electrode 414a, and the second electrical conductor 412b terminates at and is electrically coupled to the electrical connector <NUM> of the lower electrode 414b. In contrast to vessel sealers that incorporate a single electrical conductor and relies on a mechanical metallic drive train for the conductive return pathway on an opposing jaw, the presently-described electrical conductors 412a,b are routed directly to the corresponding electrodes 414a,b. While the upper and lower electrodes 414a,b may be mirror images of each other, each electrode 414a,b exhibits a different polarity. As will be appreciated, this direct routing and electrical communication minimizes electrical losses, which enables better signal integrity for driving system response and ensures more controlled impedance values that improve the ability to do distal sensing of tissue properties, and better detection of seal progression.

In some embodiments, the electrical connectors <NUM> may form an integral part of the corresponding electrode 414a,b from which it extends. In such embodiments, each electrode 414a,b and corresponding electrical connector <NUM> may comprise a stamped, metal part, which may prove advantageous in simplifying the manufacturing process of the electrodes 414a,b.

Moreover, in at least one embodiment, as illustrated, the elongate channel <NUM> defined in each electrode 414a,b may extend into the electrical connector <NUM>, which forms or otherwise defines a generally U-shaped passage <NUM> (<FIG>). Consequently, the electrodes 414a,b may be bridged (connected) at both ends 706a,b, which allows for centered, embedded connection of the electrical conductors 412a,b for both electrodes 414a,b.

As best seen in <FIG>, the electrical connectors <NUM> may extend away from the corresponding electrodes 414a,b and, more particularly, away from the plane of the corresponding planar sealing surface <NUM>. In such embodiments, the electrical connectors <NUM> may extend at about a <NUM>° angle, but could alternatively extend at an angle greater or less than <NUM>°, without departing from the scope of the disclosure. The electrical connectors <NUM> may extend below the corresponding planar sealing surface <NUM> such that a gap <NUM> (<FIG>) is defined between the electrical connectors <NUM>. The gap <NUM> may prove advantageous in providing space to accommodate the knife <NUM> (<FIG> and <FIG>) and the knife housing <NUM> (<FIG>). Moreover, the knife <NUM> may be able to pass through the U-shaped passage <NUM> provided by each electrical connector <NUM> as it traverses the knife slot <NUM> operation.

<FIG> are isometric, partially exploded views of the end effector <NUM> and the wrist <NUM> of <FIG> and <FIG>, as taken from right and left vantage points, respectively. In <FIG>, the distal clevis 402a is shown exploded vertically from the remaining portions of the wrist <NUM>, thus exposing various internal parts of the wrist <NUM>. The drive members 406a-d (<FIG>) and the electrical conductors 412a,b (<FIG>) are omitted from <FIG> to enable better viewing of the component parts of the wrist <NUM>.

In the illustrated embodiment, the distal clevis 402a is depicted as a monolithic, one-piece structure, but could alternatively be made of two or more component parts, without departing from the scope of the disclosure. As discussed in more detail below, the proximal end of the distal clevis 402a may be rotatably mounted to the distal end of the proximal clevis 402b, and vice versa, which allows the wrist <NUM> to articulate in "yaw" about the first pivot axis P<NUM> (<FIG>).

The distal clevis 402a provides and otherwise defines a pair of outer lobes 802a and 802b and a pair of inner lobes 804a and 804b. The outer and inner lobes 802a,b and 804a,b each extend distally, and the inner lobes 804a,b interpose the outer lobes 802a,b. Each outer lobe 802a,b defines an axle aperture <NUM>, and each inner lobe 804a,b defines a pin aperture <NUM>. The axle and pin apertures <NUM>, <NUM> are co-axially aligned along the second pivot axis P<NUM> of the wrist <NUM> and configured to support first and second axles 810a (<FIG>) and 810b (<FIG>). More specifically, an outer end of the first axle 810a may be configured to be received within the axle aperture <NUM> of the first outer lobe 802a, and an inner end of the first axle 810a may be configured to be received within the pin aperture <NUM> of the first inner lobe 804a. Similarly, an outer end of the second axle 810b may be configured to be received within the axle aperture <NUM> of the second outer lobe 802b, and an inner end of the second axle 810b may be configured to be received within the pin aperture <NUM> of the second inner lobe 804b.

The first and second pulleys 404a,b may be rotatably mounted to the distal clevis 402a at the first and second axles 810a,b, thereby being able to rotate about the second pivot axis P<NUM>. More specifically, the first pulley 404a may be received within a gap 812a defined between the first outer and inner lobes 802a, 804a and rotatably mounted to the first axle 810a, and the second pulley 404b may be received within a gap 812b defined between the second outer and inner lobes 802b, 804b and configured to be rotatably mounted to the second axle 810b.

In some embodiments, the first and second axles 810a,b may be secured (e.g., welded) to one or both of the axle and pin apertures <NUM>, <NUM>. In such embodiments, the pulleys 404a,b may be rotatably mounted to the first and second axles 810a,b, respectively, such that they are free to rotate. In other embodiments, however, the pulleys 404a,b may be secured (e.g., welded) to the first and second axles 810a,b. In such embodiments, the first and second axles 810a,b may be freely rotatable within the corresponding axle and pin apertures <NUM>, <NUM>. In yet other embodiments, the first and second axles 810a,b may be freely rotatable and not secured to any other component of the wrist <NUM>, without departing from the scope of the disclosure.

As illustrated, a central gap <NUM> may be defined between the inner lobes 804a,b. The central gap <NUM> may be configured to accommodate the drive rod <NUM> and the electrical conductors 412a,b (<FIG>) as extending to the end effector <NUM>.

<FIG> are additional isometric, exploded views of the end effector <NUM> and the wrist <NUM> from right and left vantage points, respectively. In <FIG>, the distal clevis 402a (<FIG>) is omitted for simplicity, and the first and second pulleys 404a,b and the drive members 406a-d are shown exploded laterally from the remaining portions of the end effector <NUM> and the wrist <NUM>. As illustrated, the jaws <NUM>, <NUM> may be pivotably and rotatably coupled to each other at a third pivot axis P<NUM>, alternately referred to as a "jaw pivot axis". The third pivot axis P<NUM> may be parallel to the second pivot axis P<NUM> and orthogonal to the first pivot axis P<NUM> (<FIG>). In at least one embodiment, the longitudinal axes A<NUM>, A<NUM> of the shaft <NUM> (<FIG>) and the end effector <NUM>, respectively, are perpendicular to and intersect the third pivot axis P<NUM>. In some embodiments, as illustrated, both jaws <NUM>, <NUM> may be configured to simultaneously move and pivot about the jaw pivot axis P<NUM> to pivot the jaws <NUM>, <NUM> between the open and closed positions, and may thus be referred to as "bifurcating" jaws. In other embodiments, however, one of the jaws <NUM>, <NUM> may be configured to pivot or rotate while the other jaw <NUM>, <NUM> remains stationary, without departing from the scope of the disclosure.

Referring briefly to <FIG>, illustrated are isometric exploded views of the end effector <NUM> from left and right vantage points, respectively, according to one or more embodiments. In <FIG>, the upper and lower jaws <NUM>, <NUM> are shown exploded vertically from each other. As illustrated, the upper jaw <NUM> provides and otherwise defines first and second jaw axle apertures 1002a and 1002b (<FIG>) located at or near the proximal end of the upper jaw <NUM>. Similarly, the lower jaw <NUM> includes first and second jaw axle apertures 1004a and 1004b located at or near the proximal end of the lower jaw <NUM>.

The jaw axle apertures 1002a,b of the upper jaw <NUM> are coaxially aligned, and the jaw axle apertures 1004a,b of the lower jaw <NUM> are also coaxially aligned. When the end effector <NUM> is properly assembled, the jaw axle apertures 1002a,b of the upper jaw <NUM> will be aligned coaxially with the jaw axle apertures 1004a,b of the lower jaw <NUM>. More particularly, when the end effector <NUM> is assembled, the first jaw axle apertures 1002a, 1004a will be juxtaposed against each other, and the second jaw axle apertures 1002b, 1004b will be juxtaposed against each other such that all jaw axle apertures 1002a,b and 1004a,b will be axially aligned along the third pivot axis P<NUM>.

The jaws <NUM>, <NUM> may be pivotably coupled along the third pivot axis P<NUM> using one or more jaw axles, shown as a first jaw axle 1006a and a second jaw axle 1006b. The first jaw axle 1006a may be configured to be received within the axially aligned first jaw axle apertures 1002a, 1004a, and the second jaw axle 1006b may be configured to be received within the axially aligned second jaw axle apertures 1002b, 1004b. Once the first and second jaw axles 1006a,b are properly installed, the jaws <NUM>, <NUM> will be pivotable about the third pivot axis P<NUM> between the open and closed positions.

Having the jaws <NUM>, <NUM> rotatably (pivotably) coupled together at the third pivot axis P<NUM> may prove advantageous for a variety of reasons. First, this can ensure that the center plane, the sealing surfaces (e.g., the planar sealing surfaces <NUM> of <FIG>), and yaw position of the jaws <NUM>, <NUM> all remain centered and controlled between the two drive pulleys; e.g., the pulleys 404a,b of <FIG> and <FIG>. Second, this also reduces components and assembly complexity of the end effector <NUM>, which can result in significant cost savings. Reduction in components will also help to reduce the tolerance stack-ups on jaw gap, which is critical for sealing. And third, this can reduce interfaces for positioning the yaw plane of the end effector <NUM>, thus lowering backlash and reducing sliding friction in closure and yaw motions of the jaws <NUM>, <NUM>.

Moreover, as mentioned above, the longitudinal axes A<NUM>, A<NUM> (<FIG>) of the shaft <NUM> (<FIG>) and the end effector <NUM>, respectively, may perpendicularly intersect (cross through) the third pivot axis P<NUM>. Consequently, the sealing plane of the end effector <NUM> (e.g., the plane formed by the planar sealing surfaces <NUM> of <FIG>) may be centered relative to the end effector <NUM> and the shaft <NUM> to balance the symmetric jaws <NUM>, <NUM> that both carry an electrode 414a,b. Having the sealing plane of the end effector <NUM> at the centerline of the device also allows for equal stiffness of the jaws <NUM>, <NUM>, and thus equal deflection of the jaws <NUM>, <NUM> under loading.

Referring again to <FIG>, the upper jaw <NUM> provides a first jaw extension 902a and the lower jaw <NUM> provides a second jaw extension 902b (<FIG>), and each jaw extension 902a,b extends proximally from the corresponding jaws <NUM>, <NUM>. The second pulley 404b may be rotatably coupled (e.g., pinned) to the first jaw extension 902a such that movement (rotation) of the second pulley 404b correspondingly pivots the upper jaw <NUM> about the third pivot axis P<NUM>. Similarly, the first pulley 404a may be rotatably coupled (e.g. pinned) to the second jaw extension 902b such that movement (rotation) of the first pulley 404a correspondingly pivots the lower jaw <NUM> about the third pivot axis P<NUM>.

More particularly, in the illustrated embodiment, the first pulley 404a may provide or define a first drive pin 904a (<FIG>) configured to mate with a first jaw aperture 906a (<FIG>) defined on the second jaw extension 902b, and the second pulley 404b may provide or define a second drive pin 904b configured to mate with a second jaw aperture 906b defined on the first jaw extension 902a. The first and second drive pins 904a,b are eccentric to the second pivot axis P<NUM> when the pulleys 404a,b are mounted to the jaw axles 810a,b. Consequently, mating the first and second drive pins 904a,b with the second and first jaw apertures 906b,a, respectively, allows the pulleys 404a,b to rotate about the second pivot axis P<NUM> and simultaneously pivot the jaws <NUM>, <NUM> about the third pivot axis P<NUM> and between the open and closed positions.

In an alternative embodiment, the first and second drive pins 904a,b may be provided on the first and second jaw extensions 902a,b, and the first and second jaw apertures 906a,b may be provided on the pulleys 404a,b, or any combination thereof. Moreover, the jaw apertures 906a,b need not be through-holes, as depicted, but could alternatively comprise recesses defined in the jaw extensions 902a,b (or the pulleys 404a,b) and sized and otherwise configured to receive the drive pins 904a,b.

Selective actuation and antagonistic operation of the drive members 406a-d can open or close the jaws <NUM>, <NUM>. More specifically, because the jaws <NUM>, <NUM> are eccentrically pinned to the pulleys 404a,b, as generally described above, selectively actuating the drive members 406a-d such that the pulleys 404a,b rotate in opposite angular directions may result in the jaws <NUM>, <NUM> opening or closing about the third pivot axis P<NUM>. Selective actuation and antagonistic operation of the drive members 406a-d may also cause the end effector <NUM> to articulate at the wrist <NUM> in both pitch and yaw directions. More particularly, selectively actuating the drive members 406a-d such that the pulleys 404a,b rotate in the same angular direction may result in the jaws <NUM>, <NUM> pivoting about the second pivot axis P<NUM> and thereby moving the end effector <NUM> up or down in pitch. Moreover, selective actuation of a first connected pair of drive members 406a-d while relaxing a second pair of connected drive members 406a-d may cause the end effector <NUM> to pivot about the first pivot axis P<NUM> (<FIG>) and thereby move in yaw (left or right). The drive pins 904a,b may be optimized to deliver consistent tension in the drive members 406a-d at clamping loads, while maximizing movement.

Still referring to <FIG>, the first jaw extension 902a may further define a first arcuate slot 908a (<FIG>), and the second jaw extension 902b may similarly define a second arcuate slot 908b (<FIG>). The first axle 810a may be configured to extend through the second arcuate slot 908b, and the second axle 810b may be configured to extend through the first arcuate slot 908a. As the jaws <NUM>, <NUM> pivot between the closed and open positions, the axles 810a,b traverse the corresponding arcuate slots 908a,b.

In some embodiments, the arcuate slots 908a,b may be used to help prevent over-rotation of the jaws <NUM>, <NUM> during operation. More specifically, each end of the arcuate slots 908a,b provides and otherwise defines a mechanical hard stop. As the jaws <NUM>, <NUM> move to the open position, the axles 810a,b will traverse the corresponding arcuate slots 908a,b and may eventually engage the mechanical hard stop at an end of the arcuate slot 908a,b. Engaging the hard stop will prevent the jaws <NUM>, <NUM> from pivoting further in the open direction, which could result in over-rotation and inadvertently achieving a controls singularity, which could lock the jaws <NUM>, <NUM>. If the drive pins 904a,b are over-rotated to a point that they rotate past (cross over) the longitudinal axis A<NUM> of the shaft or the longitudinal axis A<NUM> of the end effector <NUM> or otherwise become co-axially aligned, this could result in controls singularity, which creates unstable yaw positioning. Reaching controls singularity theoretically provides the jaws <NUM>, <NUM> with the ability to rotate about different axes, thus eliminating finite control of yaw.

In other embodiments, however, the robotic controllers of the surgical tool <NUM> (<FIG>) may be programmed and otherwise configured to prevent over-rotation of the jaws <NUM>, <NUM> via selective actuation of the drive members 406a,b. In such embodiments, the mechanical hard stops of the arcuate slots 908a,b may serve as a fail-safe mechanism that prevents over-rotation in the event the robotic controllers or programming malfunction.

<FIG> are cross-sectional side views of the end effector <NUM> in the closed and open positions, respectively, according to one or more embodiments. In <FIG>, the second pulley 404b is shown pinned to the first jaw extension 902a of the upper jaw <NUM>, but the following discussion is equally applicable to the first pulley 404a (<FIG>) being pinned to the second jaw extension 902b (<FIG>) of the lower jaw <NUM>. As described above, the second drive pin 904b of the second pulley 404b is configured to mate with the second jaw aperture 906b defined on the first jaw extension 902a such that movement (rotation) of the second pulley 404b correspondingly pivots the upper jaw <NUM> about the third pivot axis P<NUM>. Moreover, the second axle 810b extends through and traverses the first arcuate slot 908a of the first jaw extension 902a as the jaws <NUM>, <NUM> pivot between the closed and open positions.

With reference to <FIG>, the end effector <NUM> may be operated in such a manner so as to prevent the second drive pin 904b from rotating "over-center" when approaching or reaching the fully closed position. More particularly, the controls system operating the end effector <NUM> or the configuration of the first arcuate slot 908a may be configured to prevent the second driver pin 904b from reaching or rotating past a centerline <NUM> of the second pulley 404b, where the centerline <NUM> is a plane passing through the second pivot axis P<NUM> and perpendicular to the longitudinal axis A<NUM> of the shaft <NUM> (<FIG>) or the longitudinal axis A<NUM> of the end effector <NUM>. Approaching the "over-center" condition at the closed position, while not surpassing it, ensures low tension in the drive members 406a-d (<FIG>), while balancing the motion of the drive pin 904b such that jaws <NUM>, <NUM> do not inadvertently lock in the closed position and instead remain reactive to user input requests for jaw motion. If the second drive pin 904b were somehow able to rotate over-center and past the centerline <NUM>, the jaws <NUM>, <NUM> could lock and would require a large amount of force to return from the over-center condition.

In <FIG>, the end effector <NUM> may be operated in such a manner so as to prevent the second drive pin 904b from rotating past (crossing over) a plane extending through the longitudinal axes A<NUM>, A<NUM>, which could result in controls singularity. More particularly, the controls system operating the end effector <NUM> or the configuration of the first arcuate slot 908a may be configured to prevent the second driver pin 904b from over-rotating past the longitudinal axes A<NUM>, A<NUM>, which could also result in the second drive pin 904b becoming concentrically aligned with the first drive pin 904a (<FIG>) and thereby achieving controls singularity that could lock up the end effector <NUM> and create unstable yaw positioning.

<FIG> is a schematic side view of the end effector <NUM> and the wrist <NUM>, according to one or more embodiments. As illustrated, and as discussed above, the distal and proximal clevises 402a,b may be rotatably mounted to each other at the first pivot axis P<NUM> of the wrist <NUM>, which provide "yaw" articulation of the wrist <NUM>, and the jaws <NUM>, <NUM> are rotatably mounted to the distal clevis 402a at the second or pivot axis P<NUM>, which provides "pitch" articulation of the wrist <NUM>. Moreover, the jaws <NUM>, <NUM> are pivotably coupled to each other at the third pivot axis P<NUM>, alternately referred to as a "jaw pivot axis".

The first and second pivot axes P<NUM>, P<NUM> are separated from each other by a first axial length L<NUM>, and the jaw pivot axis P<NUM> is separated from the second pivot axis P<NUM> by a second axial length L<NUM>. According to embodiments of the present disclosure, the second axial length L<NUM> may be equal to or smaller (shorter) than the first axial length L<NUM>. In combination with reduced compliments and simplified linkage of the jaws <NUM>, <NUM> directly to each other, allows for a shorter mechanism that provides better access and dissection in the articulated postures. Accordingly, having a second axial length L<NUM> equal to or shorter than the first axial length L<NUM>, may prove advantageous in providing easier access into tight anatomy.

Moreover, in combination with the knife <NUM> (<FIG> and <FIG>) and its corresponding knife housing <NUM> (<FIG>) being centrally located within the end effector <NUM>, having the second axial length L<NUM> equal to or shorter than the first axial length L<NUM> is an improvement over prior or conventional end effectors. As will be described in greater detail below, the unique architecture and internal structure of the end effector <NUM> and the distal clevis 402a, and how they are operatively coupled, allows for an open central area that accommodates the knife <NUM> and the knife housing <NUM>. In contrast, prior end effectors have architecture and internal structure that occludes or extends across any central area, thus eliminating the potential to include a centrally-located knife and knife housing. Attempts to include the knife and knife housing would necessarily result in the second axial length L<NUM> being longer than the first axial length L<NUM>.

Referring again to <FIG>, with continued reference to <FIG>, in some embodiments the end effector <NUM> may be designed such that the pulleys 404a,b need only rotate between the centerline <NUM> and the longitudinal axes A<NUM>, A<NUM> (e.g., less than <NUM>°) to obtain about <NUM>-<NUM> Newtons of clamping force.

<FIG> are exploded, isometric views of the distal and proximal clevises 402a,b of the wrist <NUM>, as taken from right and left vantage points, according to one or more embodiments. As mentioned above, the proximal end of the distal clevis 402a may be rotatably mounted to the distal end of the proximal clevis 402b, which allows the wrist <NUM> to articulate in "yaw" about the first pivot axis P<NUM> (<FIG>). As illustrated, both clevises 402a,b include or define a central passageway <NUM> sized to accommodate the electrical conductors 412a,b (<FIG>) and the drive rod <NUM> (<FIG>). The central passageway <NUM> of the distal clevis 402a transitions to the central gap <NUM> provided on the distal end of the distal clevis 402a. The distal and proximal clevises 402a,b also define a plurality of cable passages <NUM> sized to accommodate the drive members 406a-d (<FIG>). When the clevises 402a,b are rotatably coupled and unarticulated, the central passageways <NUM> will axially align to enable the electrical conductors 412a,b and the drive rod <NUM> to extend through the wrist <NUM>, and corresponding cable passages <NUM> will axially align to allow the drive members 406a-d to extend through the wrist <NUM>.

In the illustrated embodiment, the distal clevis 402a may provide and otherwise define one or more camming tabs <NUM> (two shown in <FIG>) configured to be received within and otherwise mated with one or more corresponding camming slots <NUM> (shown in <FIG>) defined on the proximal clevis 402b. When the clevises 402a,b are rotatably coupled, the camming tabs <NUM> will be received within the corresponding camming slots <NUM>, which may help provide vertical joint alignment. In alternative embodiments, the camming tabs <NUM> may be provided on the proximal clevis 402b, and the camming slots <NUM> may be provided on the distal clevis 402a, or a combination thereof, without departing from the scope of the disclosure.

In some embodiments, the distal clevis 402a may provide and otherwise define one or more first camming surfaces 1210a (two shown in <FIG>), and the proximal clevis 402B may provide and otherwise define one or more second camming surfaces 1210b (two shown in <FIG>). The camming surfaces 1210a,b may comprise opposing arcuate or curved surfaces. When the clevises 402a,b are rotatably coupled, the opposing camming surfaces 1210a,b may be in rolling or camming engagement as the wrist <NUM> articulates. As illustrated, each of the camming surfaces 1210a,b are located above or below the instrument axis B<NUM>.

In the illustrated embodiment, the distal clevis 402a may provide and otherwise define one or more first spur gears 1212a (two shown in <FIG>), and the proximal clevis 402b may provide and otherwise define one or more corresponding second spur gears 1212b (two shown in <FIG>) configured to interact with the one or more first spur gears 1212a. When the clevises 402a,b are rotatably coupled, the opposing spur gears 1212a,b help the wrist <NUM> articulate in a controlled manner. As illustrated, the spur gears 1212a,b are each located above or below the instrument axis B<NUM>, which helps improve rotational backlash and better resist torsional loads. Moreover, in at least one embodiment, the cable passages <NUM> may be located in the same plane as the spur gears 1221a,b.

<FIG> is an enlarged side view of the wrist <NUM> in an articulated state, and <FIG> is a cross-sectional top view of the wrist <NUM> in the articulated state, according to one or more embodiments. In <FIG>, the distal clevis 402a is rotatably coupled to the proximal clevis 402b, thereby providing the first pivot axis P<NUM>. As illustrated, the camming tabs <NUM> provided by the distal clevis 402a are received within and otherwise mated with the corresponding camming slots <NUM> provided by the proximal clevis 402b. Moreover, the camming surfaces 1210a,b are in cammed (rolling) engagement with each other as the wrist <NUM> articulates about the first pivot axis P<NUM>. Furthermore, the spur gears 1212a,b are inter-meshed to help provide the wrist <NUM> with controlled articulation about the first pivot axis P<NUM>.

In <FIG>, the wrist <NUM> is shown in an articulated state as the distal clevis 402a is rotated relative to the proximal clevis 402b about the first pivot axis P<NUM>. In the illustrated embodiment one of the drive cables 406a-d is shown extended through corresponding cable passages <NUM> that allow the drive cable 406a-d to extend through the wrist <NUM>. In at least one embodiment, the drive cable 406a-d may prove advantageous in blocking tissue from becoming entangled in the intermeshed spur gears 1212a,b.

<FIG> is another enlarged isometric view of the end effector <NUM>, according to one or more embodiments of the present disclosure. The upper jaw <NUM> (<FIG>, <FIG>, <FIG>, and <FIG>) is omitted from <FIG> to enable viewing of various internal features of the end effector <NUM> and the wrist <NUM>.

As mentioned above, the knife <NUM> (mostly occluded) is aligned with and configured to traverse the knife slot <NUM> defined longitudinally in both the upper and lower jaws <NUM>, <NUM>. The knife housing <NUM> defines a cavity <NUM> sized to receive and "stow" the knife <NUM> when not in use. The knife <NUM> is shown in <FIG> in a "stowed" position and otherwise received within the cavity <NUM>. The cavity <NUM> provides a conduit through which the drive rod <NUM> (see <FIG>) is able to extend to move the knife <NUM> into and along the knife slot <NUM>.

The knife housing <NUM> may be pivotably mounted to the end effector <NUM>. More particularly, the knife housing <NUM> may be rotatably mounted between the upper and lower jaws <NUM>, <NUM> when the jaws <NUM>, <NUM> are pivotably coupled as described herein with reference to <FIG>. As illustrated, the knife housing <NUM> may define and otherwise provide opposing first and second bosses 1404a and 1404b (mostly occluded) that laterally protrude from opposing sides of the knife housing <NUM>. When the jaws <NUM>, <NUM> are pivotably coupled using the first and second jaw axles 1006a,b, as described herein, the bosses 1404a,b will be captured between opposing (e.g., upper and lower) portions of the jaws <NUM>, <NUM>, thus axially securing the knife housing <NUM> at the end effector <NUM>, but simultaneously allowing the knife housing <NUM> to pivot relative to the jaws <NUM>, <NUM> about the third pivot axis P<NUM>.

Accordingly, the knife housing <NUM> is not fixed (e.g., immovably secured) to any portion of the end effector <NUM> or the wrist <NUM>, but is instead pivotably secured between opposing central portions of the jaws <NUM>, <NUM> when the end effector <NUM> is assembled. Allowing the knife housing <NUM> to pivot about the third pivot axis P<NUM> (e.g., due to yaw) may prove advantageous in reducing strain on the knife housing <NUM> during use.

<FIG> is an isometric top view of the lower jaw <NUM>, according to one or more embodiments. For purposes of the present discussion, the upper jaw <NUM> (<FIG>) will include similar features. Consequently, the following discussion of the lower jaw <NUM> will similarly apply to the upper jaw <NUM>.

As indicated above, the knife housing <NUM> (<FIG>) may be pivotably mounted and captured between opposing portions of the jaws <NUM>, <NUM>. As illustrated, the lower jaw <NUM> includes and otherwise defines one or more arcuate sections <NUM> (two shown). In the illustrated embodiment, the arcuate section(s) <NUM> are defined by the lower insulator 502b, but could alternatively be provided by other portions of the lower jaw <NUM>, without departing from the scope of the disclosure. The upper jaw <NUM> (<FIG>, <FIG>, <FIG>, and <FIG>) provides corresponding arcuate section(s) opposing the arcuate sections(s) <NUM> when the jaws <NUM>, <NUM> are pivotably coupled, as described above with reference to <FIG>. Upon pivotably coupling the jaws <NUM>, <NUM>, the opposing first and second bosses 1404a,b (<FIG>) of the knife housing <NUM> (<FIG>) will be received between the corresponding arcuate sections <NUM> of the upper and lower jaws <NUM>, <NUM>. This will axially secure the knife housing <NUM> at the end effector <NUM> (<FIG>), while simultaneously allowing the bosses 1404a,b to slidingly engage the opposing arcuate sections <NUM> as the end effector <NUM> is articulated in "pitch" about the third pivot axis P<NUM>.

<FIG> are enlarged isometric views of the knife <NUM> and the knife housing <NUM>, according to one or more embodiments. In <FIG>, the knife <NUM> is shown in a first or "stowed" position, where the knife <NUM> is fully received within the cavity <NUM> of the knife housing <NUM>. In <FIG>, the knife <NUM> is shown in a second or "extended" position, where the knife <NUM> is extended distally out of the cavity <NUM>. <FIG> also more fully depict the first and second bosses 1404a,b that laterally protrude from opposing sides of the knife housing <NUM>.

As mentioned above, the knife <NUM> may be operatively coupled to the distal end of the drive rod <NUM> (shown in dashed lines in <FIG>). In some embodiments, the drive rod <NUM> may comprise a solid shaft, but may alternatively comprise a tube or tubular structure. Moreover, the drive rod <NUM> may be made of a variety of flexible materials including, but not limited to, a metal or metal alloy (e.g., a nickel-titanium alloy or "nitinol"), a plastic or thermoplastic material, a composite material, or any combination thereof. The drive rod <NUM> may also comprise a braided cable construction of a metal (e.g., stainless steel), or any of the aforementioned materials, and such braided cable may be designed and radially constrained to support axial loads.

In some embodiments, as illustrated, a flexible sheath <NUM> (e.g., a hypotube or the like) may cover all or a portion of the drive rod <NUM>. The sheath <NUM> may support and help prevent buckling of the drive rod <NUM> upon assuming compressive loads during articulation of the wrist <NUM> and opening and closure of the jaws <NUM>, <NUM>. Similar to the drive rod <NUM>, the flexible sheath <NUM> may be made of a variety of flexible materials including, but not limited to, a metal or metal alloy (e.g., a nickel-titanium alloy or "nitinol"), a metallic coil, a plastic or thermoplastic material, a composite material, or any combination thereof.

Upon firing the end effector <NUM> (<FIG>), the drive rod <NUM> is moved (urged) distally, which correspondingly moves the knife <NUM> to the extended position and otherwise out of the cavity <NUM> and into the knife slot <NUM> (<FIG>). As the drive rod <NUM> translates distally, the sheath <NUM> supports the drive rod <NUM> against axial buckling resulting from compressive loading on the drive rod <NUM>. After firing is complete, the drive rod <NUM> is retracted proximally, which correspondingly pulls the knife <NUM> proximally and back to the stowed position and otherwise into the cavity <NUM> until it is desired to again fire the end effector <NUM>.

As best seen in <FIG>, the knife <NUM> may be attached to the distal end of the drive rod <NUM> at a retention feature <NUM>. The retention feature <NUM> may comprise any attachment or coupling means that removably or permanently fixes the knife <NUM> to the drive rod <NUM>. For example, the retention feature <NUM> may comprise, but is not limited to, a welded interface, an adhesive attachment, an interference or shrink fit, an overmold (e.g., a shaped block of material or a support block), one or more mechanical fasteners, or any combination thereof. In at least one embodiment, the retention feature <NUM> may comprise a formed shape on the drive rod <NUM> or alternatively on the knife <NUM>.

<FIG> is an enlarged cross-sectional side view of portions of the end effector <NUM> and the wrist <NUM>, according to one or more embodiments. As illustrated, the knife <NUM> is at least partially received within the cavity <NUM> of the knife housing <NUM>, and the drive rod <NUM> is at least partially received within the flexible sheath <NUM>.

The knife housing <NUM> may define a central conduit <NUM> that extends to and communicates with the cavity <NUM>. The drive rod <NUM> is extendable through the central conduit <NUM> and able to translate longitudinally therethrough when transitioning the knife <NUM> between the stowed and extended positions. In some embodiments, the distal end of the sheath <NUM> may be received within the central conduit <NUM>. In at least one embodiment, for example, the knife housing <NUM> may be secured to the distal end of the sheath <NUM>, such as being overmolded onto the sheath <NUM>. In other embodiments, the knife housing <NUM> may be secured to the distal end of the sheath <NUM> via welding, an adhesive, a shrink-fit or interference engagement, or any combination of the foregoing.

In <FIG>, the end effector <NUM> is articulated in pitch and the knife <NUM> is in the process of transitioning from the stowed position to the extended position. Articulating the end effector <NUM> also causes the knife housing <NUM> to pivot about the third pivot axis P<NUM> (<FIG>), which results in a line of action <NUM> (dashed lines) of the drive rod <NUM> becoming non-parallel to a line of action <NUM> (dashed lines) of the knife <NUM> when the knife <NUM> exits the knife housing <NUM> and transitions into the knife slot <NUM>.

In some embodiments, to help ease the transition from the cavity <NUM> to the knife slot <NUM> when the end effector <NUM> is articulated, at least one of the leading corners <NUM>, <NUM> of the knife <NUM> may be rounded or chamfered. In the illustrated embodiment, the lower leading corner <NUM> of the knife <NUM> is rounded, while the upper leading corner <NUM> defines a sharp angle. As will be appreciated, the rounded, lower leading corner <NUM> may prove advantageous in creating a smooth sliding transition for the knife <NUM> as it enters the knife track <NUM>.

In other embodiments, the lower leading corner <NUM> may define a sharp angle, and the upper leading corner <NUM> may alternatively be rounded or chamfered. In yet other embodiments, both leading corners <NUM>, <NUM> may be rounded or chamfered, without departing from the scope of the disclosure.

As illustrated, the drive rod <NUM> is directly pushed without any redirect pulleys being used in the end effector <NUM>. Those skilled in the art will readily appreciate that this can simplify the proximal end of the wrist <NUM> and the instrument as a whole, which can reduce costs.

<FIG> is a cross-sectional end view of the wrist <NUM> as taken through the first pivot axis P<NUM> (<FIG>), according to one or more embodiments. As discussed above, the proximal end of the distal clevis 402a is rotatably mounted to the distal end of the proximal clevis 402b at the first pivot axis P<NUM>, which allows the wrist <NUM> to articulate in "yaw" about the first pivot axis P<NUM>. A cross-section of the first spur gears 1212a of the distal clevis 402a are shown intermeshed with a cross-section of the second spur gears 1212b of the proximal clevis 402b, as generally described above.

Also shown in <FIG> is the central passageway <NUM> of the proximal clevis 402b, which is sized to accommodate the electrical conductors 412a,b and the drive rod <NUM>. While not shown, a similar central passageway may be defined in the distal clevis 402a and may axially align with the central passageway <NUM> of the proximal clevis 402b. In some embodiments, as illustrated, the central passageway <NUM> may flare open and define one or more arcuate transition surfaces, shown as a first arcuate transition surface 1702a, a second arcuate transition surface 1702b, and a third arcuate transition surface 1702c. The arcuate transition surfaces 1702a-c may be configured to receive and engage the electrical conductors 412a,b and the drive rod <NUM> as the wrist <NUM> articulates in "yaw" about the first pivot axis P<NUM>. The arcuate transition surfaces 1702a-c may prove advantageous in providing a smooth and curved transition for the electrical conductors 412a,b and the drive rod <NUM> as the wrist <NUM> articulates in "yaw," as opposed to sharp transition surfaces, which could fatigue the material of the electrical conductors 412a,b and the drive rod <NUM> over time.

As illustrated, the drive rod <NUM> extends along the instrument axis B<NUM>, and the electrical conductors 412a,b are arranged on radially opposite sides (e.g., above and below) of the drive rod <NUM>. In the illustrated embodiment, the electrical conductors 412a,b are arranged above and below the drive rod <NUM>, but could alternatively be arranged on opposing left and right sides of the drive rod <NUM>, without departing from the scope of the disclosure. Accordingly, the drive rod <NUM> may be centered (centrally-located) relative to the cross-section of the wrist <NUM>, which can help ensure that the controls length compensation is symmetric and the parasitic load imparted on the articulation system is symmetric, such that clamp force variation relative to a particular pose of the end effector <NUM> is consistent and predictable.

<FIG> is a schematic flowchart of an example process algorithm <NUM> in accordance with one or more embodiments of the present disclosure. The process algorithm <NUM> may be used to infer jaw position based on closure cable position and load, which can ensure that the tips of the jaws <NUM>, <NUM> are fully approximated and at an angle safe for firing. As will be appreciated, this can help prevent the knife <NUM> from escaping the knife slot <NUM> in an over-stuffed jaw condition.

As shown in the process algorithm <NUM>, a user sends a command signal to request firing of the knife <NUM>, as at <NUM>. The user may send the command signal to the robotic surgical system <NUM> (<FIG>), for example, and more particularly, to the control computer <NUM> (<FIG>). The system will read the torque and the position of the drive members in preparation for closure of the jaws <NUM>, <NUM>, as at <NUM>. Based on the measured torque, the system will calculate cable stretch, as at <NUM>, and based on the calculated cable length, and the actuator position relative to home, the position of the jaws <NUM>, <NUM> (the real aperture angle between the two jaws <NUM>, <NUM>) may then be calculated by the system, as at <NUM>. If the jaw angle between the jaws <NUM>, <NUM> is determined to be acceptably closed, as at <NUM>, then the system will proceed to fire the knife <NUM>, as at <NUM>.

If, however, the jaw angle between the jaws <NUM>, <NUM> is determined to be un-acceptably closed, as at <NUM>, the system may be programmed to disable the knife <NUM>, as at <NUM>. As will be appreciated, if the knife <NUM> were to be fired (extended along the knife slot <NUM>) with the jaws <NUM>, <NUM> open past a predetermined angle, the knife <NUM> could be completely exposed and potentially dislodge from the knife slot <NUM>. Upon disablement of the knife <NUM>, the user may then be prompted to reengage the tissue between the jaws <NUM>, <NUM> or re-energize the electrodes 414a,b, as at <NUM>. The process algorithm <NUM> may then return to the first step, as at <NUM>, and the process will repeat itself.

Each of embodiments A and B may have one or more of the following additional elements in any combination: Element <NUM>: wherein the first insulator and the first electrode cooperatively define a first slot portion that bifurcates a first planar surface of the first electrode into first left and right portions, and the second insulator and the second electrode cooperatively define a second slot portion that bifurcates a second planar surface of the second electrode into second left and right portions, and wherein the first and second slot portions cooperatively define the knife slot when the first and second jaws are in the closed position. Element <NUM>: wherein the first left and right portions each provide an outer lateral extent extending away from the first planar surface and embedded within the first insulator, and the second left and right portions each provide an outer lateral extent extending away from the second planar surface and embedded within the second insulator. Element <NUM>: wherein each outer lateral extent provides an electrically exposed edge that provides a transition between the outer lateral extent and the first and second planar sealing surfaces. Element <NUM>: wherein the outer lateral extents are embedded within the first and second insulators such that the first and second insulators provide a flush interface with the first and second planar sealing surfaces, respectively. Element <NUM>: wherein the first left and right portions each provide the inner lateral extent extending away from the first planar surface, and the second left and right portions each provide the inner lateral extent extending away from the second planar surface. Element <NUM>: wherein the inner lateral extents of the first and second left and right portions cooperatively define the diamond-shape cross-section when the first and second jaws are in the closed position. Element <NUM>: wherein each of the insulators defines a trough section extending laterally across the knife slot and thereby structurally connecting lateral sides of the first and second insulators. Element <NUM>: wherein each electrode provides an elongate body with opposing distal and proximal ends, and an elongate channel is defined in the body and extends between the distal and proximal ends to form part of the knife slot. Element <NUM>: further comprising a first electrical connector extending from the proximal end of the first electrode and configured to receive a first electrical conductor to provide electrical energy to the first electrode, and a second electrical connector extending from the proximal end of the second electrode and configured to receive a second electrical conductor to provide electrical energy to the second electrode. Element <NUM>: wherein each electrical connector defines a generally U-shaped passage such that each electrode is connected at both the distal and proximal ends, and wherein the knife is extendable into the knife slot by extending at least partially through the U-shaped passage of each electrical connector. Element <NUM>: wherein the first and second electrical connectors extend away from corresponding planar sealing surfaces of the first and second electrodes, respectively, such that a gap is defined between the first and second electrical connectors that accommodates the knife.

Element <NUM>: wherein the first insulator and the first electrode cooperatively define a first slot portion that bifurcates a first planar surface of the first electrode, and the second insulator and the second electrode cooperatively define a second slot portion that bifurcates a second planar surface of the second electrode, and wherein the first and second slot portions cooperatively define the knife slot when the first and second jaws are in the closed position. Element <NUM>: wherein the first planar surface provides opposing outer lateral extents extending away from the first planar surface and embedded within the first insulator, and the second planar surface provides opposing outer lateral extents extending away from the second planar surface and embedded within the second insulator. Element <NUM>: wherein the inner lateral extent of each electrode is provided by the first and second planar surfaces and each inner lateral extent extends away from the first and second planar surfaces, respectively. Element <NUM>: wherein each electrode provides an elongate body with opposing distal and proximal ends, and an elongate channel is defined in the body and extends between the distal and proximal ends to form part of the knife slot. Element <NUM>: further comprising a first electrical connector extending from the proximal end of the first electrode, a first electrical conductor extending from the drive housing and coupled to the first electrical connector to provide electrical energy to the first electrode, a second electrical connector extending from the proximal end of the second electrode, and a second electrical conductor extending from the drive housing and coupled to the second electrical connector to provide electrical energy to the second electrode. Element <NUM>: wherein each electrical connector defines a generally U-shaped passage such that each electrode is connected at both the distal and proximal ends, and wherein the knife is extendable into the knife slot by extending at least partially through the U-shaped passage of each electrical connector. Element <NUM>: wherein the first and second electrical connectors extend away from corresponding planar sealing surfaces of the first and second electrodes, respectively, such that a gap is defined between the first and second electrical connectors that accommodates the knife.

By way of non-limiting example, exemplary combinations applicable to A and B include: Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; Element <NUM> with Element <NUM>; and Element <NUM> with Element <NUM>.

Therefore, the disclosed systems and methods are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of "comprising," "containing," or "including" various components or steps, the compositions and methods can also "consist essentially of" or "consist of" the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, "from about a to about b," or, equivalently, "from approximately a to b," or, equivalently, "from approximately a-b") disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles "a" or "an," as used in the claims, are defined herein to mean one or more than one of the elements that it introduces.

Claim 1:
An end effector, comprising:
a first jaw (<NUM>) having a first electrode (414a) and a first insulator (502a) secured thereto;
a second jaw (<NUM>) having a second electrode (414b) and a second insulator (502b) secured thereto, the first and second jaws (<NUM>, <NUM>) being pivotable between open and closed positions; and
a knife slot (<NUM>) cooperatively defined in the first and second jaws (<NUM>, <NUM>) and defining a diamond-shape cross-section when the first and second jaws are in the closed position,
wherein each electrode provides an inner lateral extent (<NUM>) that cooperatively defines the diamond-shape cross-section, and
wherein a length of at least one of the inner lateral extents (<NUM>) is greater than a thickness of a corresponding one of the first or second electrodes (414a, 414b).