Patent Description:
A surgical forceps is a pliers-like instrument that relies on mechanical action between its jaw members to grasp, clamp, and constrict tissue. Electrosurgical forceps utilize both mechanical clamping action and energy to heat tissue to treat, e.g., coagulate, cauterize, dissect or seal, tissue. Typically, prior to tissue being treated, a surgeon must dissect portions of the tissue to orient the tissue for treatment. Examples of dissection include "blunt" dissection wherein the end of the end effector is used to bluntly separate tissue. Other examples include "poke and spread" dissection wherein the tissue is engaged and then the jaw members of the end effector are opened to spread the tissue. Still in other instances, a surgeon may have to finely dissect tissue in a grasp and pull manner.

Once the tissue is treated, the surgeon may have to accurately sever the treated tissue or further dissect portions thereof. Accordingly, many electrosurgical forceps are designed to incorporate a knife that is advanced between the jaw members to cut the treated tissue. As an alternative to a mechanical knife, an energy-based tissue cutting element may be provided to cut the treated tissue using energy, e.g., thermal, electrosurgical, ultrasonic, light, or other suitable energy.

<CIT> describes an end effector assembly with first and a second jaws having a U-shaped proximal flanges to support a pivot and a pivoting bar therein.

As used herein, the term "distal" refers to the portion that is being described which is further from a user, while the term "proximal" refers to the portion that is being described which is closer to a user. Further, to the extent consistent, any or all of the aspects detailed herein may be used in conjunction with any or all of the other aspects detailed herein.

Provided in accordance with aspects of the present disclosure is an electrosurgical instrument that includes a housing having a handle and an elongated shaft extending therefrom supporting an end effector assembly at a distal end thereof. The end effector assembly includes a first jaw member having a jaw housing supporting an electrically conductive tissue engaging surface thereon. The jaw housing has a U-shaped proximal flange including opposing sides defining a cuff therebetween. Each side has a cradle defined therein configured to secure a pivot bar therein. The proximal flange of the first jaw member is configured to operably support a pivot therein.

The end effector assembly also includes a second jaw member having a jaw housing supporting an electrically conductive tissue engaging surface thereon in opposition to the tissue engaging surface of the first jaw member. The jaw housing includes a U-shaped proximal flange having opposing sides defining a cuff therebetween configured to receive the proximal flange of the first jaw member. Each side of the second proximal flange includes a cradle defined therein configured to operably support the pivot and the proximal flange is configured to operably engage the distal end of the elongated shaft.

A drive tube is selectively translatable within the elongated shaft and includes a drive member disposed at a distal end thereof operably secured to the pivot bar. Actuation of the handle translates the drive member which, in turn, translates the pivot bar to rotate the first jaw member relative to the second jaw member about the pivot.

In aspects according to the present disclosure, the pivot bar is welded to the cradle of each side of the proximal flange of the first jaw member. In other aspects according to the present disclosure, the first jaw member moves relative the second jaw member upon actuation of the drive member.

In aspects according to the present disclosure, the second jaw member defines a longitudinal axis therethrough and the pivot is disposed on one side of the longitudinal axis and the pivot bar is offset from the pivot on the other side of the longitudinal axis. In other aspects according to the present disclosure, the cradle of the second jaw member is defined in an upper edge of the proximal flange thereof maximizing the offset between the pivot and the pivot bar increasing mechanical advantage therebetween. In yet other aspects according to the present disclosure, the offset between the pivot and the pivot bar provides a substantially constant closure force between the first and second jaw members through the range of motion therebetween. In still other aspects according to the present disclosure, the offset between the pivot and the pivot bar provides a substantially constant opening and closing force between the first and second jaw members through the range of motion therebetween.

In aspects according to the present disclosure, the elongated shaft defines an outer periphery and wherein the proximal flanges of the first and second jaw members remain inside the outer periphery during the range of motion between jaw members.

Provided in accordance with aspects of the present disclosure is an end effector assembly for an electrosurgical instrument that includes a first jaw member having a jaw housing supporting an electrically conductive tissue engaging surface thereon. The jaw housing includes a U-shaped proximal flange having opposing sides defining a cuff therebetween. Each side includes a cradle defined therein configured to secure a pivot bar therein and the proximal flange is configured to operably support a pivot therein.

The end effector assembly includes a second jaw member having a jaw housing supporting an electrically conductive tissue engaging surface thereon in opposition to the tissue engaging surface of the first jaw member. The jaw housing includes a U-shaped proximal flange having opposing sides defining a cuff therebetween configured to receive the proximal flange of the first jaw member. Each side of the second proximal flange includes a cradle defined therein configured to operably support the pivot. A drive member is operably secured to the pivot bar such that actuation the drive member translates the pivot bar to rotate the first jaw member relative to the second jaw member about the pivot.

In aspects according to the present disclosure, the second jaw member defines a longitudinal axis therethrough and the pivot is disposed on one side of the longitudinal axis and the pivot bar is offset from the pivot on the other side of the longitudinal axis. In other aspects according to the present disclosure, the cradle of the second jaw member is defined in an upper edge of the proximal flange thereof maximizing the offset between the pivot and the pivot bar increasing mechanical advantage therebetween. In still other aspects according to the present disclosure, the offset between the pivot and the pivot bar provides a substantially constant closure force between the first and second jaw members through the range of motion therebetween. In yet other aspects according to the present disclosure, the offset between the pivot and the pivot bar provides a substantially constant opening and closing force between the first and second jaw members through the range of motion therebetween.

The above and other aspects and features of the present disclosure will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings wherein like reference numerals identify similar or identical elements.

Referring to <FIG>, a shaft-based electrosurgical forceps provided in accordance with the present disclosure is shown generally identified by reference numeral <NUM>. Aspects and features of forceps <NUM> not germane to the understanding of the present disclosure are omitted to avoid obscuring the aspects and features of the present disclosure in unnecessary detail.

Forceps <NUM> includes a housing <NUM>, a handle assembly <NUM>, a trigger assembly <NUM>, a rotating assembly <NUM>, a first activation switch <NUM>, a second activation switch <NUM>, and an end effector assembly <NUM>. Forceps <NUM> further includes a shaft <NUM> having a distal end portion <NUM> configured to (directly or indirectly) engage end effector assembly <NUM> and a proximal end portion <NUM> that (directly or indirectly) engages housing <NUM>. Forceps <NUM> also includes cable "C" that connects forceps <NUM> to an energy source, e.g., an electrosurgical generator "G. " Cable "C" includes a wire (or wires) (not shown) extending therethrough that has sufficient length to extend through shaft <NUM> in order to connect to one or both tissue-treating surfaces <NUM>, <NUM> of jaw members <NUM>, <NUM>, respectively, of end effector assembly <NUM> (see <FIG> and <FIG>) to provide energy thereto. First activation switch <NUM> is coupled to tissue-treating surfaces <NUM>, <NUM> (<FIG>, <FIG> and <FIG>) and the electrosurgical generator "G" for enabling the selective activation of the supply of energy to jaw members <NUM>, <NUM> for treating, e.g., cauterizing, coagulating/ desiccating, and/or sealing, tissue. Second activation switch <NUM> is coupled to thermal cutting element (not shown) of jaw member <NUM> and the electrosurgical generator "G" for enabling the selective activation of the supply of energy to thermal cutting element <NUM> for thermally cutting tissue. Details relating to various envisioned thermal cutting elements are disclosed in commonly-owned <CIT>.

Handle assembly <NUM> of forceps <NUM> includes a fixed handle <NUM> and a movable handle <NUM>. Fixed handle <NUM> is integrally associated with housing <NUM> and handle <NUM> is movable relative to fixed handle <NUM>. Movable handle <NUM> of handle assembly <NUM> is operably coupled to a drive assembly <NUM> (shown generally in phantom) that, together, mechanically cooperate to impart movement of one or both of jaw members <NUM>, <NUM> of end effector assembly <NUM> about a pivot <NUM> between a spaced-apart position and an approximated position to grasp tissue between tissue-treating surfaces <NUM>, <NUM> of jaw members <NUM>, <NUM>. As shown in <FIG>, movable handle <NUM> is initially spaced-apart from fixed handle <NUM> and, correspondingly, jaw members <NUM>, <NUM> of end effector assembly <NUM> are disposed in the spaced-apart position. Movable handle <NUM> is depressible from this initial position to a depressed position corresponding to the approximated position of jaw members <NUM>, <NUM>. Rotating assembly <NUM> includes a rotation wheel <NUM> that is selectively rotatable in either direction to correspondingly rotate end effector assembly <NUM> relative to housing <NUM>.

Various drive assemblies <NUM> are envisioned such as those described in <CIT> and <CIT>. The various envisioned drive assemblies <NUM> are configured to translate a drive member <NUM> relative to the distal end <NUM> of the shaft <NUM> to actuate the jaw members <NUM>, <NUM> between open and closed positions (<FIG> and <FIG>). Unilateral and bilateral jaw members <NUM>, <NUM> are contemplated.

Referring to <FIG>, a robotic surgical instrument provided in accordance with the present disclosure is shown generally identified by reference numeral <NUM>. Aspects and features of robotic surgical instrument <NUM> not germane to the understanding of the present disclosure are omitted to avoid obscuring the aspects and features of the present disclosure in unnecessary detail.

Robotic surgical instrument <NUM> includes a plurality of robot arms <NUM>, <NUM>; a control device <NUM>; and an operating console <NUM> coupled with control device <NUM>. Operating console <NUM> may include a display device <NUM>, which may be set up in particular to display three-dimensional images; and manual input devices <NUM>, <NUM>, by means of which a surgeon may be able to telemanipulate robot arms <NUM>, <NUM> in a first operating mode. Robotic surgical instrument <NUM> may be configured for use on a patient <NUM> lying on a patient table <NUM> to be treated in a minimally invasive manner. Robotic surgical instrument <NUM> may further include a database <NUM>, in particular coupled to control device <NUM>, in which are stored, for example, pre-operative data from patient <NUM> and/or anatomical atlases.

Each of the robot arms <NUM>, <NUM> may include a plurality of members, which are connected through joints, and an attaching device <NUM>, <NUM>, to which may be attached, for example, an end effector assembly <NUM>, <NUM>, respectively. End effector assembly <NUM> is similar to end effector assembly <NUM> (<FIG> and <FIG>), although other suitable end effector assemblies for coupling to attaching device <NUM> are also contemplated. End effector assembly <NUM> may be any end effector assembly, e.g., an endoscopic camera, other surgical tool, etc. Robot arms <NUM>, <NUM> and end effector assemblies <NUM>, <NUM> may be driven by electric drives, e.g., motors, that are connected to control device <NUM>. Control device <NUM> (e.g., a computer) may be configured to activate the motors, in particular by means of a computer program, in such a way that robot arms <NUM>, <NUM>, their attaching devices <NUM>, <NUM>, and end effector assemblies <NUM>, <NUM> execute a desired movement and/or function according to a corresponding input from manual input devices <NUM>, <NUM>, respectively. Control device <NUM> may also be configured in such a way that it regulates the movement of robot arms <NUM>, <NUM> and/or of the motors.

Turning to <FIG> and <FIG>, one embodiment of a known end effector assembly <NUM>, as noted above, includes first and second jaw members <NUM>, <NUM>. Each jaw member <NUM>, <NUM> may include a structural support <NUM>, <NUM>, a jaw housing <NUM>, <NUM>, and a tissue-treating surface <NUM>, <NUM>, respectively. Alternatively, only one of the jaw members, e.g., jaw member <NUM>, may include the structural support <NUM>, jaw housing <NUM>, and tissue-treating surface <NUM>. In such embodiments, the other jaw member, e.g., jaw member <NUM>, may be formed as a single unitary body, e.g., a piece of conductive material acting as the structural support <NUM> and jaw housing <NUM> and defining the tissue-treating surface <NUM>. An outer surface of the jaw housing <NUM>, in such embodiments, may be at least partially coated with an insulative material or may remain exposed. Tissue-treating surfaces <NUM>, <NUM> may be pre-formed and engaged with jaw housings <NUM>, <NUM> via overmolding, adhesion, mechanical engagement, etc. The structural supports <NUM>, <NUM> for the jaw members <NUM>, <NUM> may also be engaged to the respective jaw housings <NUM>, <NUM> in a similar fashion via overmolding, adhesion, mechanical engagement, etc. as explained in more detail below.

As shown in <FIG> and <FIG>, jaw members <NUM> and <NUM> are pivotably supported for rotation about pivot <NUM> and may be unilateral or bilateral depending upon a particular purpose. Outer housing <NUM> of jaw member <NUM> is configured to mechanically engage structural support <NUM> via one or more detents <NUM>, <NUM> in a snap-fit manner or during an overmolding step. Jaw member <NUM> also includes a U-shaped proximal flange <NUM> having sides 113a and 113b that cooperatively define a cuff <NUM> configured to receive the drive member <NUM> as explained below. The sides 113a, 113b of flange <NUM> define opposing pivot bar cradles 113b' (other cradle defined in side 113a not shown) therein configured to receive a pivot bar 125a operably associated therewith.

Pivot bar 125a forms part of (or is welded, crimped or riveted or otherwise secured to) the respective cradles 113b' of sides 113a, 113b of the proximal flange <NUM> during a manufacturing step. The distal end of the drive member <NUM> is secured (or otherwise engaged) the pivot bar 125a while the opposite end of the drive member <NUM> is secured to or operably associated with the drive tube <NUM> slidably disposed within a bore 12a defined through shaft <NUM>. Upon actuation of the handle <NUM>, drive assembly <NUM> translate the drive tube <NUM>. The distal end of the drive member <NUM> may be rotatably secured to the pivot bar 125a in a snap-fit or other manner to facilitate smooth operation of the mechanical coupling.

Jaw member <NUM> includes outer housing <NUM> configured to mechanically engage structural support <NUM> via one or more detents <NUM>, <NUM> in a snap-fit manner or during an overmolding step. Jaw member <NUM> also includes a U-shaped proximal flange <NUM> having sides 123a and 123b that cooperatively define a cuff <NUM> configured to receive the proximal flange <NUM> of jaw member <NUM> as explained below. Flanges <NUM> and <NUM> may additionally act as tissue stops. The sides 123a, 123b of flange <NUM> define opposing pivot cradles 123b' (other cradle defined in side 123a not shown) therein configured to receive the pivot <NUM> operably associated with jaw member <NUM> (<FIG>). Pivot <NUM> is disposed through sides 113a, 113b of flange <NUM> towards an upper end thereof and is configured to allow rotation of jaw member <NUM>. The pivot <NUM> rotates within the cradles 123b' defined in sides 123a, 123b of proximal flange <NUM> of jaw member <NUM> upon translation of the drive member <NUM> and rotation of the jaw member <NUM>.

The second jaw member <NUM> defines a longitudinal axis A-A therethrough, the pivot <NUM> being disposed on one side the longitudinal axis A-A and the pivot bar 125a on the other to form an offset "O". Cradles 123b' (and other cradle defined in side 123a - not shown) may be defined in an uppermost edges of the proximal flanges 123a, 123b to maximize the distance or offset "O" between the pivot <NUM> and the pivot bar 125a to maximize the mechanical advantage therebetween. It is contemplated that the offset "O" between the pivot <NUM> and the pivot bar 125a provides a substantially constant opening and closure force between the first and second jaw members <NUM>, <NUM> through the range of motion therebetween.

Jaw member <NUM> is secured to the distal end <NUM> of shaft <NUM>. By mounting the pivot <NUM> within cradle 123b' (and cradle of side 123a) and securing jaw member <NUM> to the end <NUM> of the shaft <NUM>, the end effector assembly <NUM> is held secure relative to the shaft <NUM>. Actuating the handle <NUM> to translate drive tube <NUM> and, in turn, drive member <NUM>, will pivot jaw member <NUM> relative to jaw member <NUM> by virtue of pivot bar 125a camming within the sides 113a, 113b of the proximal flange <NUM> about pivot <NUM>.

Securing the pivot bar 125a to the sides 113a, 113b of the proximal flange <NUM> which, in turn, is directly coupled to the drive tube <NUM>, minimizes hysteresis between the various mechanical components allowing finer dissection capabilities and a more consistent jaw closure and opening force. Providing consistent jaw closure forces and resulting sealing pressures between jaw members <NUM>, <NUM> produces more consistent sealing and subsequent cutting of tissue and facilitates dissection. Moreover, with near constant closure forces throughout the entire handle <NUM> stroke, opening and closing the jaw members <NUM>, <NUM> during poke and spread type dissection, translates to a consistent force therebetween enhancing the overall feel of the instrument during use.

Further, the mechanical couplings, i.e., drive tube <NUM> to drive member <NUM> to pivot bar 125a to proximal flange <NUM>, do not extend outside the overall dimensions of the outer periphery of the elongated shaft <NUM> which reduces the chances of catching tissue during use while also maximizing the area for knife translation if used with a mechanical knife (Not shown).

The offset design of the pivot bar 125a and the pivot <NUM> provides a large mechanical advantage when the jaw members <NUM>, <NUM> are being approximated about tissue but less of a mechanical advantage when the jaw members <NUM>, <NUM> are moved to a fully open position. However, over the stroke of the closure of the jaw members <NUM>, <NUM>, the offset mechanical arrangement of the pivot bar 125a and the pivot <NUM> will yield more consistent closure pressure against tissues of varying sizes. Moreover, the near constant opening and closure forces provide the user with a consistent feel when opening and closing the jaw members <NUM>, <NUM> for fine dissection purposes.

Claim 1:
An end effector assembly (<NUM>) for an electrosurgical instrument, comprising:
a first jaw member (<NUM>) having a jaw housing (<NUM>) supporting an electrically conductive tissue engaging surface (<NUM>) thereon, the jaw housing including a U-shaped proximal flange (<NUM>) having opposing sides (113a, 113b) defining a cuff (<NUM>) therebetween, each side including a cradle (113a', 113b') defined therein configured to secure a pivot bar (125a) therein, the proximal flange configured to operably support a pivot (<NUM>) therein;
a second jaw member (<NUM>) having a jaw housing (<NUM>) supporting an electrically conductive tissue engaging surface <NUM>) thereon in opposition to the tissue engaging surface of the first jaw member. the jaw housing including a U-shaped proximal flange (<NUM>) having opposing sides (123a, 123b) defining a cuff (<NUM>) therebetween configured to receive the proximal flange of the first jaw member, each side of the second proximal flange including a cradle (123a, 123b) defined therein configured to operably support the pivot; and
a drive member (<NUM>) operably secured to the pivot bar wherein actuation the drive member translates the pivot bar to rotate the first jaw member relative to the second jaw member about the pivot wherein the second jaw member defines a longitudinal axis (A-A) therethrough, characterised by
the pivot being disposed on one side of the longitudinal axis and the pivot bar being offset from the pivot on the other side of the longitudinal axis wherein the cradle of the second jaw member is defined in an upper edge of the proximal flange thereof maximizing the offset between the pivot and the pivot bar increasing mechanical advantage therebetween.