Patent Description:
Electrosurgical apparatuses (e.g., electrosurgical forceps) are well known in the medical arts and typically include a handle, a shaft, and an end effector assembly operatively coupled to a distal end of the shaft that is configured to manipulate tissue (e.g., grasp and seal tissue). Electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect homeostasis by heating the tissue and blood vessels to coagulate, cauterize, fuse, seal, cut, desiccate, and/or fulgurate tissue.

Electrosurgical forceps may be open forceps for use when accessing open body cavities or open surgical access points, e.g., incisions, or endoscopic forceps for remotely accessing organs through smaller, puncture-like incisions. With endoscopic surgeries, patients tend to benefit from less scarring, less pain, and reduced healing time. The endoscopic forceps is inserted into the patient through one or more various types of cannulas or access ports (typically having an opening that ranges from about five millimeters to about fifteen millimeters) that has been made with a trocar.

Open and endoscopic forceps both utilize an end effector assembly disposed at a distal end thereof for treating tissue between a pair of opposing jaw members. Each jaw member includes an electrically conductive surface or sealing plate used to treat or seal tissue grasped therebetween. <CIT> refers to prior art relevant for the present invention.

The present invention is defined by the scope of appended claim <NUM>.

This disclosure generally relates to directing the flow of energy (e.g., bipolar energy) in an end effector assembly. Sealing plates of the end effector assembly are of variable thickness and/or incorporate conductive, semiconductive, or insulative materials on the sealing plates to direct the amount and flow of energy through the sealing plates and thus, through tissue thereby increasing seal reliability and/or biasing or decreasing thermal spread. The techniques of this disclosure may be utilized to improve sealing of tissue in cases of non-parallel closure of the end effector assembly when the tissue being treated is not centered between jaw members of the end effector assembly.

In one aspect, the disclosure provides a jaw member including a sealing plate and an insulator supporting the sealing plate thereon. The sealing plate has a length, a width, and a height. The height varies from a minimal height to a maximum height along the width or the length of the sealing plate.

The height of the sealing plate may vary across the width of the sealing plate and be consistent along the length of the sealing plate. The sealing plate may include a sealing surface and an outwardly facing surface tapering to an apex, and the maximum height of the sealing plate may extend from the sealing surface to the apex. The outwardly facing surface may include legs extending from outer edges of the sealing plate to the apex. The legs may be equal in length such that the apex is disposed in a central portion of the sealing plate, or the legs may have different lengths such that the apex is disposed in a side portion of the sealing plate.

The height of the sealing plate may vary along the length of the sealing plate and be consistent across the width of the sealing plate. The sealing plate may include a sealing surface and an outwardly facing surface tapering to an apex, and the maximum height of the sealing plate may extend from the sealing surface to the apex. The outwardly facing surface may include legs extending from proximal and distal ends of the sealing plate to the apex. The apex may be disposed in a tip portion of the sealing plate. The minimal height of the sealing plate may be defined in a heel portion of the sealing plate.

According to the invention, the disclosure provides a jaw member including a sealing plate and an insulator supporting the sealing plate thereon. The sealing plate includes a sealing surface having at least two impedance zones. The at least two impedance zones includes a first zone having a first impedance value and a second zone having a second impedance value that is different from the first impedance value.

The sealing surface includes an interphase disposed between the first and second zones. The interphase may have an impedance value that gradually transitions from the first zone to the second zone.

Each of the at least two impedance zones are homogeneous.

The first and second zones may be positioned longitudinally adjacent to each other. The sealing plate may further include a third zone having a third impedance value that is different from the first and second impedance values. The first zone may be disposed on a proximal portion of the sealing surface, the second zone may be disposed on an intermediate portion of the sealing surface, and the third zone may be disposed on a distal portion of the sealing surface. The third impedance value may be less than the second impedance value which may be less than the first impedance value.

The first and second zones may be concentric with each other. The first zone may be disposed inside of the second zone, and the first impedance value may be less than the second impedance value.

The at least two impedance zones may be coatings of conductive materials disposed on the sealing surface of the sealing plate.

In yet another aspect, the disclosure provides a jaw member including a support base, an insulator supported within the support base, and a sealing plate supported on the insulator. The sealing plate has a length, a width, and a height. The height varies from a minimal height to a maximum height along the width of the sealing plate.

The sealing plate may include a sealing surface and an outwardly facing surface positioned adjacent to the insulator. The outwardly facing surface may have at least one apex, and the maximum height of the sealing plate may extend from the sealing surface to the at least one apex.

The sealing plate may include two apexes. The outwardly facing surface of the sealing plate may include two sets of legs with each set of the two sets of legs extending to one of the two apexes. A first leg of each of the two sets of legs may extend from an outer edge of the sealing plate to the respective apex, and a second leg of each of the two sets of legs may extend from a central portion of the sealing plate to the respective apex. The first and second legs may have different lengths. At least one of the first or second legs may be non-linear.

A tissue contacting surface of the jaw member may define a length and width, and the width of the sealing plate may be less than the width of the jaw member. The tissue contacting surface may be nonplanar. The sealing plate may be offset in a height direction relative to the insulator.

In another aspect, the disclosure provides a jaw member including a support base, an insulator supported within the support base, and a sealing plate supported on the insulator. The sealing plate includes a sealing surface having at least two impedance zones. The at least two impedance zones have different impedance values.

The at least two impedance zones may be positioned longitudinally adjacent to each other. The at least two impedance zones may be concentric with each other. The at least two impedance zones may be formed from a material having a different thickness in each of the at least two impedance zones.

The sealing plate may include a first conductive material disposed at a proximal end of the sealing plate, and a second conductive material positioned over at least a portion of the first material and extending distally therefrom across the sealing surface to a distal end of the sealing plate. The first conductive material may have a resistivity lower than that of the second conductive material.

The sealing plate may include a first impedance region including the at least two impedance zones and a second impedance region including at least one impedance zone. The first impedance region may extend from a proximal end of the sealing plate towards a distal end of the sealing plate adjacent to a tip portion, and the second impedance region may be disposed at the tip portion of the sealing plate. The first impedance region may extend from a proximal end of the sealing plate to a central portion of the sealing plate, the second impedance region may be disposed about the central portion of the sealing plate, and a third impedance region may extend from the central portion to a distal end of the sealing plate. The first impedance region may be disposed within the second impedance region.

Embodiments of the disclosure are described hereinbelow with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure.

Like reference numerals may refer to similar or identical elements throughout the description of the figures. It should be understood that various components of the disclosure, such as those numbered in the <NUM> series, correspond to components of the disclosure similarly numbered in each of the <NUM> series, <NUM> series, <NUM> series, and so on such that redundant explanation of similar components of embodiments need not be repeated herein. As shown in the drawings and described throughout the following description, as is traditional when referring to relative positioning of a surgical instrument, the term "proximal" refers to a portion (e.g., an end) of the apparatus which is closer to the user and the term "distal" refers to a portion of the apparatus which is farther away from the user. The term "clinician" refers to any medical professional (e.g., doctor, surgeon, nurse, or the like) performing a medical procedure involving the use of embodiments described herein.

Turning now to <FIG>, an instrument generally identified as endoscopic bipolar forceps <NUM> may be used during various surgical procedures and includes a housing <NUM>, a handle assembly <NUM>, a rotating assembly <NUM>, a trigger assembly <NUM>, and an end effector assembly <NUM> that mutually cooperate to grasp, seal, and divide tubular vessels and vascular tissues. The forceps <NUM> includes a shaft <NUM> that has a distal end <NUM> dimensioned to mechanically engage the end effector assembly <NUM> and a proximal end <NUM> that mechanically engages the housing <NUM>. The proximal end <NUM> of the shaft <NUM> mechanically engages the rotating assembly <NUM> to facilitate rotation of a jaw assembly <NUM> of the end effector assembly <NUM>.

The handle assembly <NUM> includes a fixed handle <NUM> and a movable handle <NUM>. The fixed handle <NUM> is integrally associated with the housing <NUM> and the movable handle <NUM> is movable relative to the fixed handle <NUM> to actuate a pair of opposing jaw members <NUM>, <NUM> of the jaw assembly <NUM>. The movable handle <NUM> imparts movement of the jaw members <NUM>, <NUM> about a pivot pin <NUM> from an open position wherein the jaw members <NUM>, <NUM> are disposed in spaced relation relative to one another for approximating tissue, to a clamping or closed position wherein the jaw members <NUM>, <NUM> cooperate to grasp tissue therebetween (e.g., for sealing and/or dividing purposes).

The trigger assembly <NUM> is selectively movable by a clinician to energize the jaw assembly <NUM>. The movable handle <NUM> and the trigger assembly <NUM> are typically of unitary construction and are operatively connected to the housing <NUM> and the fixed handle <NUM> during the assembly process. The forceps <NUM> also includes an electrical interface or plug <NUM> which connects the forceps <NUM> to a source of electrosurgical energy, e.g., an electrosurgical generator (not shown). An electrical cable <NUM> extends from the plug <NUM> and is securely connected to the forceps <NUM>. The cable <NUM> is internally divided within the housing <NUM> to transmit electrosurgical energy through various electrical feed paths to the jaw assembly <NUM>.

The forceps <NUM> may be designed such that it is fully or partially disposable depending upon a particular purpose or to achieve a particular result. For example, the jaw assembly <NUM> may be selectively and releasably engageable with the distal end <NUM> of the shaft <NUM> and/or the proximal end <NUM> of the shaft <NUM> may be selectively and releasably engageable with the housing <NUM> and the handle assembly <NUM>. In either of these two instances, the forceps <NUM> would be considered "partially disposable" or "reposable", e.g., a new or different jaw assembly <NUM> (or jaw assembly <NUM> and shaft <NUM>) selectively replaces the old jaw assembly <NUM>, as needed.

Examples of forceps are shown and described in commonly-owned <CIT> entitled "VESSEL SEALER AND DIVIDER AND METHOD MANUFACTURING SAME" and commonly owned <CIT> (now <CIT>) entitled "VESSEL SEALER AND DIVIDER FOR USE WITH SMALL TROCARS AND CANNULAS",.

With regard to <FIG>, an open bipolar forceps <NUM> for use with various surgical procedures is shown. The forceps <NUM> includes a pair of opposing shafts 22a and 22b having an end effector assembly <NUM> attached to distal ends 24a and 24b thereof, respectively. The end effector assembly <NUM> is similar in design to the end effector assembly <NUM> and includes a jaw assembly <NUM> having a pair of opposing jaw members <NUM>, <NUM> that are pivotably connected about a pivot pin 15a and that are movable relative to one another to grasp tissue.

Each shaft 22a, 22b includes a handle 30a, 30b, respectively, disposed at the proximal end 26a, 26b thereof. Each handle 30a, 30b defines a finger hole 31a, 31b, respectively, therethrough for receiving a finger of a clinician. The finger holes 31a, 31b facilitate movement of the shafts 22a, 22b relative to one another which, in tum, pivot the jaw members <NUM>, <NUM> from an open position wherein the jaw members <NUM>, <NUM> are disposed in spaced relation relative to one another, to a clamping or closed position wherein the jaw members <NUM>, <NUM> cooperate to grasp tissue therebetween.

One of the shafts 22a, 22b includes a proximal shaft connector or flange <NUM> which is designed to connect the forceps <NUM> to a source of electrosurgical energy, such as an electrosurgical generator (not shown). The flange <NUM> mechanically secures an electrosurgical cable 62a to the forceps <NUM> such that a clinician may selectively apply electrosurgical energy as needed. The cable 62a includes a plug 60a, similar to plug <NUM> of <FIG>. A ratchet <NUM> is included for selectively locking the jaw members <NUM>, <NUM> relative to one another at various positions during pivoting.

Examples of forceps are shown and described in commonly-owned <CIT> (now <CIT>) entitled "VESSEL SEALING INSTRUMENT" and commonly owned <CIT> (now <CIT>) entitled "OPEN VESSEL SEALING INSTRUMENT",.

<FIG> show opposing jaw members <NUM>, <NUM> of a jaw assembly <NUM>. The jaw assembly <NUM> is contemplated for use with the endoscopic forceps <NUM> of <FIG> or the open forceps <NUM> of <FIG>. For the purposes herein, either an endoscopic instrument or an open instrument may be utilized with the end effector assembly described herein. Different electrical and/or mechanical connections and considerations apply to each particular type of instrument, as should be understood by one skilled in the art, however, the novel aspects with respect to the end effector assembly and its operating characteristics remain generally consistent with respect to both the endoscopic and open designs.

Similar to jaw members <NUM>, <NUM> of <FIG> and jaw members <NUM>, <NUM> of <FIG>, each of the jaw members <NUM>, <NUM> generally includes: electrically conductive sealing plates or substrates <NUM>, <NUM>, respectively; insulators <NUM>, <NUM>, respectively; and insulative support bases or frames <NUM>, <NUM>, respectively. The support bases <NUM>, <NUM> are dimensioned to support insulators <NUM>, <NUM> therein which, in turn, support the sealing plates <NUM>, <NUM> thereon. The sealing plates <NUM>, <NUM> may be affixed atop the insulators <NUM>, <NUM> and the support bases <NUM>, <NUM> in any manner within the purview of those skilled in the art, such as snap-fit, over-molding, stamping, ultrasonic welding, etc. It should be understood that the insulators <NUM>, <NUM> are configured and dimensioned to have a geometry complementary to the sealing plates <NUM>, <NUM> to support the sealing plates <NUM>, <NUM> thereon, and to the support bases <NUM>, <NUM> in which the insulators <NUM>, <NUM> are disposed.

The jaw members <NUM>, <NUM> are generally symmetrical and include similar component features which cooperate to permit facile rotation about a pivot (see e.g., pivot pin <NUM>, 15a of <FIG>, <FIG>) to effect the grasping of tissue. The jaw members <NUM>, <NUM> may be straight or may be curved to facilitate manipulation of tissue and to provide better "line of sight" for accessing targeted tissues. Either or both of the sealing plates <NUM>, <NUM> and, in some cases, the insulators <NUM>, <NUM> may include longitudinally-oriented knife slots (see e.g., knife slot <NUM> of <FIG>) defined therethrough for reciprocation of a knife blade (not shown). Either or both of the sealing plates <NUM>, <NUM> may have sealing surfaces <NUM>, <NUM> that are substantially planar, or the sealing surfaces <NUM>, <NUM> may have other configurations or features, such as stop members (not shown) to define a gap between the jaw members <NUM>, <NUM> during grasping, sealing, and/or cutting of tissue, and/or grooves, ridges, etc. (not shown) to enhance the gripping of tissue during the sealing process.

With continued reference to <FIG>, each of the sealing plates <NUM>, <NUM> has a longitudinally extending length "L" and a transversely extending width "W. " A vertical height or thickness of each of the sealing plates <NUM>, <NUM> varies from a nominal or minimal height "H1" to a maximum height "H2" across the width "W" of the sealing plate <NUM>, <NUM> and is consistent or uniform along the length "L" thereof. The sealing plates <NUM>, <NUM> include respective inwardly facing or sealing surfaces <NUM>, <NUM> and outwardly facing surfaces <NUM>, <NUM> that taper to apexes <NUM>, <NUM> disposed about central portions 322a, 332a of the sealing plates <NUM>, <NUM> such that the thickness of the sealing plates <NUM>, <NUM> is greatest about the central portions 322a, 332a of the sealing plates <NUM>, <NUM>.

Each of the sealing plates <NUM>, <NUM> includes a base <NUM>, <NUM> having the nominal height "H1" throughout the entire length "L" and width "W" of the sealing plate <NUM>, <NUM>. The base <NUM>, <NUM> extends from the sealing surface <NUM>, <NUM> outwardly towards the insulator <NUM>, <NUM> such that the height "H1" of the base <NUM>, <NUM> of the sealing plate <NUM>, <NUM> is uniform along the length "L" and width "W" of the base <NUM>, <NUM>. An extension or projection <NUM>, <NUM> extends from the base <NUM>, <NUM> and tapers towards the apex <NUM>, <NUM> such that the thickness of the extension <NUM>, <NUM> varies from the nominal height "H1" to the maximum height "H2" along the width "W" of the sealing plate <NUM>, <NUM> and is consistent along the length "L" of the sealing plate <NUM>, <NUM>. The maximum height "H2" at the apex <NUM>, <NUM> of the sealing plate <NUM>, <NUM> extends a majority of the height or thickness "T" of the jaw member <NUM>, <NUM> and in embodiments, the maximum height "H2" of the sealing plate <NUM>, <NUM> is almost the full height "T" of the jaw member <NUM>, <NUM> (e.g., about <NUM>% to about <NUM>% of the height "T" of the jaw member <NUM>, <NUM>).

The extension <NUM>, <NUM> includes legs 346a, 356a and 346b, 356b that taper linearly from outer edges 322c, 332c of the sealing plate <NUM>, <NUM> towards the central portion 322a, 332a of the sealing plate <NUM>, <NUM>. The legs 346a, 356a and 346b, 356b have equal lengths such that the apex <NUM>, <NUM> is centered about the sealing plate <NUM>, <NUM>. The legs 346a, 356a and 346b, 356b may be linear or non-linear (e.g., curved). Energy provided to the jaw assembly <NUM> is concentrated in the central portions 322a, 332a of the jaw members <NUM>, <NUM> (e.g., the thickest part of the sealing plate <NUM>, <NUM>) thereby reducing thermal spread outside of the jaw members <NUM>, <NUM>.

<FIG> shows opposing jaw members <NUM>, <NUM> of a jaw assembly <NUM>. The jaw members <NUM>, <NUM> include: electrically conductive sealing plates or substrates <NUM>, <NUM>; insulators <NUM>, <NUM>; and insulative support bases <NUM>, <NUM>. A vertical height or thickness of each of the sealing plates <NUM>, <NUM> varies from a nominal or minimal height "H1" to a maximum height "H2" across the width "W" of the sealing plate <NUM>, <NUM> and is consistent or uniform along the length "L" (<FIG>) thereof. The sealing plates <NUM>, <NUM> include inwardly facing or sealing surfaces <NUM>, <NUM> and outwardly facing surfaces <NUM>, <NUM> that taper to apexes <NUM>, <NUM> disposed about side portions 422b, 432b of the sealing plates <NUM>, <NUM> such that the thickness of the sealing plate <NUM>, <NUM> is greatest about one of the side portions 422b, 432b of the sealing plates <NUM>, <NUM>.

The outwardly facing surface <NUM>, <NUM> includes legs 446a, 456a and 446b, 456b that extend respectively from outer edges 422c, 432c of the sealing plates <NUM>, <NUM> adjacent the sealing surface <NUM>, <NUM> and taper towards the apexes <NUM>, <NUM> such that the thickness of the sealing plate <NUM>, <NUM> varies from the minimal height "H1" to the maximum height "H2". The maximum height "H2" at the apex <NUM>, <NUM> of the sealing plate <NUM>, <NUM> extends a majority of the height or thickness "T" of the jaw member <NUM>, <NUM> and in embodiments, the maximum height "H2" of the sealing plate <NUM>, <NUM> is almost the full height "T" of the jaw member <NUM>, <NUM>.

The legs 446a, 456a and 446b, 456b have different lengths such that the apex <NUM>, <NUM> is off-center of the sealing plate <NUM>, <NUM>. The legs 446a, 456a and 446b, 456b may be linear or non-linear (e.g., curved). Energy provided to the jaw assembly <NUM> more easily flows to the side portion 422b, 432b of the jaw member <NUM>, <NUM> containing the apex <NUM>, <NUM> (e.g., the thickest part of the sealing plate <NUM>, <NUM>) thus increasing thermal spread on the side portion 422b, 432b containing the apex <NUM>, <NUM>, with the other side portion 422b, 432b having minimal thermal spread.

<FIG> shows opposing jaw members <NUM>', <NUM>' of a jaw assembly <NUM>'. The jaw members <NUM>', <NUM>' include: electrically conductive sealing plates or substrates <NUM>', <NUM>'; insulators <NUM>', <NUM>'; and insulative support bases <NUM>', <NUM>'. Knife slots <NUM>', <NUM>' extend through each of the jaw members <NUM>', <NUM>' about a central portion 422a', 432a' of the sealing plates <NUM>', <NUM>'. A vertical height or thickness of each of the sealing plates <NUM>', <NUM>' varies between a nominal or minimal height "H1" and a maximum height "H2" across the width "W" of the sealing plate <NUM>', <NUM>' and is consistent or uniform along the length "L" (<FIG>) thereof. The sealing plates <NUM>', <NUM>' include inwardly facing or sealing surfaces <NUM>', <NUM>' and outwardly facing surfaces <NUM>', <NUM>' that taper to apexes <NUM>', <NUM>' disposed about each of the side portions 422b', 432b' of the sealing plates <NUM>', <NUM>' such that the thickness of the sealing plate <NUM>', <NUM>' is greatest about both of the side portions 422b', 432b' of the sealing plates <NUM>', <NUM>'.

The outwardly facing surface <NUM>', <NUM>' includes two sets <NUM>', <NUM>' of legs 446a', 456a' and 446b', 456b'. The first leg 446a', 456a' of each set <NUM>', <NUM>' extends respectively from an outer edge 422c', 432c' of the sealing plate <NUM>', <NUM>' adjacent the sealing surface <NUM>', <NUM>' to the respective apex <NUM>', <NUM>'. The second leg 446b', 456b' of each set <NUM>', <NUM>' extends respectively from the knife slot <NUM>', <NUM>', or in embodiments devoid of a knife slot <NUM>', <NUM>', from about the central portion 422a', 432a' of the sealing plate <NUM>', <NUM>' to the respective apex <NUM>', <NUM>'. The first and second legs 446a', 456a' and 446b', 456b' of each set <NUM>', <NUM>' tapers towards the respective apex <NUM>', <NUM>' such that the thickness of the sealing plate <NUM>', <NUM>' varies from the minimal height "H1" to the maximum height "H2". The maximum height "H2" at the apexes <NUM>', <NUM>' of the sealing plates <NUM>', <NUM>' extends a majority of the height or thickness "T" of the jaw member <NUM>', <NUM>' and in embodiments, the maximum height "H2" of the sealing plate <NUM>', <NUM>' is almost the full height "T" of the jaw member <NUM>', <NUM>'.

The first and second legs 446a', 456a' and 446b', 456b' of each set <NUM>', <NUM>' have different lengths such that the apexes <NUM>', <NUM>' are off-center and disposed closer to the outer edges 422c' 432c' of the sealing plates <NUM>', <NUM>' than the central portions 422a' 432a' of the sealing plates <NUM>', <NUM>'. It is envisioned that the first and second legs 446a', 456a' and 446b', 456b' of each set <NUM>', <NUM>' may have the same length such that the apexes <NUM>', <NUM>' are centered in each of the side portions 422b', 432b' of the sealing plates <NUM>', <NUM>'. The first and second legs 446a', 456a' and 446b', 456b' may be linear or non-linear (e.g., curved). Energy provided to the jaw assembly <NUM>' is transferred into the thickest part (e.g., the portions of the jaw members <NUM>', <NUM>' containing the apexes <NUM>', <NUM>') of the sealing plates <NUM>', <NUM>' (e.g., thermal energy is dissipated into the sealing plate <NUM>', <NUM>' cross-section and electrical energy rides the outer sealing plate surfaces) thereby minimizing thermal spread at the outer edges 422c', 432c' of the sealing plates <NUM>', <NUM>' and improving seal quality.

As shown in <FIG>, the sealing plates <NUM>, <NUM>' may have a width "W1" extending through a portion (e.g., a majority) of the width "W" of the jaw members <NUM>, <NUM>'. The outer edges 422c, 422c' of the sealing plates <NUM>, <NUM>' may be spaced inwardly of the outer edges of the jaw members <NUM>, <NUM>' such that the insulators <NUM>, <NUM>' are disposed outwardly of the sealing plates <NUM>, <NUM>' around the outer periphery of the tissue contacting surface <NUM>, <NUM>' of the jaw member <NUM>, <NUM>' at a width "W2. " As seen in <FIG>, the sealing plate <NUM>' may include inner edges <NUM>' spaced outwardly of the knife slot <NUM>' such that the insulator <NUM>' is disposed between to the knife slot <NUM>' and the sealing plate <NUM>'at a width "W3. " The width "W2," "W3" may be the same or different.

<FIG> show that the tissue contacting surface of the jaw members may be nonplanar. The sealing plate may extend outwardly beyond the insulator and the insulative support base of the jaw member. As seen in <FIG>, for example, the sealing plate <NUM>" may extend downwardly towards the opposing jaw member (not explicitly shown) in stepped relation relative to the insulator <NUM>" such that a height "H3" of the jaw member <NUM>" including the sealing plate <NUM>" is more than a height "H4" of the jaw member <NUM>" that does not include the sealing plate <NUM>".

Further still, as seen in <FIG>, one or more legs of the sealing plates may be contoured to achieve the desired geometry and thus, thermal effect. As seen in <FIG>, the first leg 446a" of each of the two sets <NUM>" of legs 446a", 446b" may extend linearly upwardly into the insulator <NUM>" and the second leg 446b" may include a first segment 447a" extending linearly upwardly into the jaw member <NUM>" adjacent to the knife slot <NUM>" and a second segment 447b" angled towards the apex <NUM>" of the sealing plate <NUM>". As seen in <FIG>, the first leg 446a" of the sealing plate <NUM>" may extend linearly upwardly to a rounded apex <NUM>" and the second leg 446b" may include a linear first segment 447a" and a contour second segment 447b". The contoured second segment 447b" may be concave, convex, or have other non-linear configurations. As seen in <FIG>, the first leg 446a" of the sealing plate <NUM>" may be convex and the second leg 446b" may be concave from the apex <NUM>" towards the sealing surface <NUM>". As seen in <FIG>, the first leg 446a" of the sealing plate <NUM>" may extend linearly upwardly and the second leg 446b" may include a plurality of stepped segments <NUM>" leading from the sealing surface <NUM>" to a substantially flat apex <NUM>". Other geometries are envisioned.

<FIG> illustrates opposing jaws members <NUM>, <NUM> of a jaw assembly <NUM>. The jaw members <NUM>, <NUM> include: electrically conductive sealing plates or substrates <NUM>, <NUM>; insulators <NUM>, <NUM>; and insulative support bases <NUM>, <NUM>. A vertical height or thickness of each of the sealing plates <NUM>, <NUM> varies from a minimal height "H1" to a maximum height "H2" across the length "L" of the sealing plate <NUM>, <NUM> and is consistent or uniform along the width "W" (<FIG>) thereof. The sealing plates <NUM>, <NUM> include inwardly facing or sealing surfaces <NUM>, <NUM> and outwardly facing surfaces <NUM>, <NUM> that taper to apexes <NUM>, <NUM> disposed about distal or tip portions 522d, 532d of the sealing plates <NUM>, <NUM> such that the thickness of the sealing plate <NUM>, <NUM> is greatest about the tip portions 522d, 532d of the sealing plates <NUM>, <NUM>.

The outwardly facing surface <NUM>, <NUM> includes legs 546a, 556a and 546b, 556b that extend respectively from proximal and distal ends 522e, 532e and 522f, 532f of the sealing plate <NUM>, <NUM> and taper towards the apexes <NUM>, <NUM> such that the thickness of the sealing plate <NUM>, <NUM> varies from a minimal height "H1" at a proximal or heel portion <NUM>, <NUM> of the sealing plate <NUM>, <NUM> to a maximum height "H2" at the tip portion 522d, 532d of the sealing plates <NUM>, <NUM>. The legs 546a, 556a and 546b, 556b have different lengths such that the apex <NUM>, <NUM> is disposed in the tip portion 522d, 532d of the sealing plate <NUM>, <NUM>. The thickness of the sealing plate <NUM>, <NUM> increases along a majority of the length "L" of the jaw member <NUM>, <NUM> such that energy is biased towards the tip portion 522d. 532d which improves tip sealing and overcomes non-parallel closure configurations.

It should be understood that the geometry of the sealing plate and/or the geometry, type, and/or location of the insulator relative to the sealing plate may be tailored to reduce thermal spread. For example, the geometry of the sealing plate (e.g., the position of the apex or apexes) may be optimized to control thermal mass location and thermal conductivity to minimize thermal spread by transferring heat into the sealing plate or away from the outer edges of the sealing plate. As another example, the type of insulator utilized in the jaw member, the insulator location relative to the sealing surface of the sealing plate, and/or the sealing plate and insulator geometry near the outer edges of the sealing plate may be tailored to control the current densities at the outer edges of the sealing plate, e.g., minimizing thermal spread at the outer edges of the sealing plate and thus, minimizing edge cutting.

With reference now to <FIG>, a top view of a sealing plate <NUM> of a jaw member <NUM> according to an embodiment of the present invention is shown. For the purposes, herein, one sealing plate <NUM> is described, however, both sealing plates of the jaw assemblies of the disclosure may be of the same or similar construction. The sealing plate <NUM> includes a longitudinally extending length "L" and a transversely extending width "W". The sealing plate <NUM> may have a generally flat or planar configuration, or may have a non-planar geometry such as those described above.

The sealing plate <NUM> includes a plurality of impedance zones <NUM> defined along the length "L" thereof. The impedance zones <NUM> are disposed adjacent each other along the entire length "L" of the sealing plate <NUM> from a proximal end 622e to a distal end 622f of the sealing plate <NUM>, with each of the impedance zones <NUM> extending the entire width "W" of the sealing plate <NUM>. The impedance zones <NUM> are formed by coating the sealing plate <NUM> with the same or different conductive, semiconductive, and/or insulative materials (e.g., conductors, such as stainless steel, semiconductors, such as silicon dioxide, or insulators) of the same or different thicknesses to achieve the desired thermal effect in each of the impedance zones <NUM>. The impedance zones <NUM> may be formed in any manner within the purview of those skilled in the art, such as sputter coating.

The impedance zones <NUM> include a first or proximal zone 660a, a second or intermediate zone 660b, and a third or distal zone 660c. The first zone 660a is a high impedance zone. In embodiments, the electrical impedance of the first zone 660a is about or greater than <NUM> ohms (e.g., about <NUM> ohms) thereby having nearly zero tissue effect. The second zone 660b is a medium impedance zone having an electrical impedance less than that of the first zone 660a. In embodiments, the electrical impedance of the second zone 660b is about <NUM> ohms to achieve some tissue sealing effect. The third zone 660c is a low impedance zone having an electrical impedance less than the second zone 660b. In embodiments, the electrical impedance of the third zone 660c is about <NUM> ohms to about <NUM> ohms, and in some embodiment, about <NUM> ohms, to achieve a tissue sealing effect. Energy provided to the jaw member <NUM> is biased towards the tip portion 622d of the sealing plate <NUM> to improve tip sealing.

Each impedance zone <NUM> is homogenous in that the impedance value is consistent throughout the impedance zone <NUM>. The impedance zones <NUM> are delineated by an interphase <NUM> between each adjacent impedance zone <NUM>. The interphase <NUM> is a gradual transition or gradient transition from one impedance zone <NUM> to another. For example, the first zone 660a may have an impedance value of <NUM> ohms, while the second zone 660b may have an impedance value of about <NUM> ohms. The interphase <NUM> separating the first and second zones 660a, 660b may include an impedance value that gradually transitions from the first zone 660a to the second zone 660b. In other words, the portion of the interphase <NUM> closer to the first zone 660a has a higher impedance value (closer to <NUM> ohms) while the portion of the interphase <NUM> closer to the second zone 660b has a lower impedance value (closer to <NUM> ohms).

Alternatively, not according to the invention, the impedance zones <NUM> may be separated by an interface. The interface is sharp transition at a common boundary between adjacent impedance zones <NUM>. It should be understood that other embodiments in accordance with the disclosure may include one or more interphases, one or more interfaces, or combinations of interphases and interfaces between impedance zones.

The impedance zones <NUM> are shown as being substantially equal in area across the sealing surface <NUM> of the sealing plate <NUM>. The impedance zones <NUM>, however, may cover different amounts of area of the sealing surface <NUM> depending upon the desired thermal effect, as is within the purview of those skilled in the art. Further, while three impedance zones <NUM> are shown, it should be understood that the number of impedance zones <NUM> of the sealing plate <NUM> may vary (e.g., the sealing plate may include two impedance zones or may include a multitude of impedance zones forming a smooth or continuous gradient transition across the entire sealing plate).

As shown in <FIG>, a sealing plate <NUM>' of a jaw member <NUM>' includes a plurality of impedance zones <NUM>' extending along a length "L" of the sealing plate <NUM>' from a proximal end 622e' to a distal end 622f' thereof. The impedance zones <NUM>' are disposed adjacent to each other and extend the entire width "W" of the sealing plate <NUM>'. The impedance zones <NUM>' form a gradient transition across the length "L" of the sealing plate <NUM>' that spans from an area of low resistance at the proximal end 622e' of the sealing plate <NUM>' to an area of high resistance at the distal end 622f' of the sealing plate <NUM>'.

The sealing plate <NUM>' includes a first material 661a', such as a conductive material (e.g., a metal) with low resistance characteristics, such as copper or aluminum, and a second material 661b', such as a conductive material (e.g., a metal) with high resistance characteristics, such as stainless steel. The first material 661a' is positioned at a proximal portion <NUM>' of the sealing plate <NUM>' over an insulator (not shown) and forms a wire connection "C" with an electrical jaw lead <NUM>' that supplies energy to the jaw member <NUM>'. The second material 661b' is positioned over a portion of the first material 661a' and extends distally therefrom across the sealing surface <NUM>' to the distal end 662f' of the sealing plate <NUM>'. The thickness of the second material 661b' varies to create the impedance zones <NUM>'. The sealing surface <NUM>' of the sealing plate <NUM>' is substantially planar, with the thickness of the second material 661b' varying inwardly towards an insulator over which the sealing plate <NUM>' is positioned (see e.g., <FIG>).

<FIG> shows a sealing surface <NUM> of a sealing plate <NUM> of a jaw member <NUM>. The sealing plate <NUM> includes a plurality of impedance zones <NUM> extending radially outwardly from a knife slot <NUM> defined therein, or in embodiments devoid of a knife slot <NUM>, from about a central portion 722a of the sealing plate <NUM>. The impedance zones <NUM> are concentric with each other and extend the length "L" of the entire circumference of the sealing plate <NUM>, although it is contemplated that at least one of the impedance zones <NUM> may extend along a portion or arc of the circumference. The impedance zones <NUM> are formed by coating the sealing plate <NUM> with the same or different conductive, semiconductive, and/or insulative materials (e.g., conductors, such as stainless steel, semiconductors, such as silicon dioxide, or insulators) of the same or different thicknesses to achieve the desired thermal effect in each of the impedance zones <NUM>.

The impedance zones <NUM> include a first or inner zone 760a and a second or outer zone 760b. The first and second zones 760a, 760b are generally ring-shaped in cross-sectional area and extend the length "L" of the sealing plate <NUM>. In general, the first zone 760a is at least partially or substantially inside the second zone 760b, and the knife slot <NUM> is inside the first zone 760a.

The first zone 760a is a low impedance zone, and the second zone 760b is a high impedance zone. In embodiments, the first zone 760a has an electrical impedance of about <NUM> ohms to about <NUM> ohms, and the second zone 760b has an electrical impedance of about <NUM> ohms. The first zone 760a is immediately adjacent to and extends radially outwardly from the knife slot <NUM>, and the second zone 760b is adjacent to and extends radially outwardly from the first zone 760a to outer edges 722c of the sealing plate <NUM>. The first and second zones 760a, 760b are homogenous, as described above with regard to sealing plate <NUM>, and include an interphase <NUM> disposed between the first and second zones 760a, 760b. Energy provided to the jaw member <NUM> is concentrated in the middle of the sealing plate <NUM> (about the first zone 760a), and the high impedance value of the second zone 760b reduces or eliminates thermal spread to surrounding tissue.

As shown in <FIG>, a sealing plate <NUM>' of a jaw member <NUM>' includes a plurality of impedance zones <NUM>' defined concentrically therein. The impedance zones <NUM>' extend the length "L" and the width "W" of the sealing plate <NUM>'. The impedance zones <NUM>' form a gradient transition outwardly from a central portion 722a' of the sealing plate <NUM>' to the outer edges 722c' that spans from an area of low resistance about the central portion 722a' to an area of high resistance at the outer edges 722c'.

The sealing plate <NUM>' includes a first material 761a', such as a conductive material (e.g., a metal) with low resistance characteristics, such as copper or aluminum, and a second material 761b', such as a conductive material (e.g., a metal) with high resistance characteristics, such as stainless steel. The first material 661a' forms a wire connection "C" with an electrical jaw lead <NUM>' that supplies energy to the jaw member <NUM>' at a proximal end 722e' of the sealing plate <NUM>' and extends distally through the central portion 722a' of the sealing plate <NUM>' adjacent to the distal end 722f' of the sealing plate <NUM>'. The second material 761b' is disposed over the first material 761a' and extends along and across the sealing surface <NUM>'. The thickness of the second material 761b' varies to create the impedance zones <NUM>' of the jaw member <NUM>'.

Turning now to <FIG>, sealing plates may include a plurality of impedance regions each having one or more impedance zones. As seen in <FIG>, a sealing plate <NUM> of a jaw member <NUM> includes a plurality of impedance regions <NUM> extending along a length "L" of the sealing plate <NUM> from a proximal end 822e to a distal end 822f thereof. The impedance regions <NUM> are disposed adjacent to each other and extend the entire width "W" of the sealing plate <NUM>. The impedance regions <NUM> includes a first impedance region 870a and a second impedance region 870b.

The first impedance region 870a extends from the proximal end 822e of the sealing plate <NUM> towards the distal end 822f adjacent to and proximal of the tip portion 822d. The first impedance region 870a includes a plurality of impedance zones <NUM> that forms a continuous gradient transition across the first impedance region 870a from a proximal impedance zone 860a that is a low impedance zone to a distal impedance zone 860b that is a high impedance zone. The second impedance region 870b is disposed at the tip portion 822d and has a single impedance zone 860c that may have an impedance value that is higher or lower than the distal impedance zone 860b of the first impedance region 870a depending upon the desired thermal effect. It should be understood that the plurality of impedance zones <NUM> in the first impedance region 870a may span, proximally to distally, from an area of high impedance to an area of low impedance and/or the second impedance region 870b may include more than one impedance zone <NUM>.

As should in <FIG>, a sealing plate <NUM>' includes a plurality of impedance regions <NUM>' extending along a length "L" (<FIG>) of the sealing plate <NUM>' from a proximal end 822e' to a distal end 822f' thereof. The impedance regions <NUM>' are disposed adjacent to each other and extend the entire width "W" (<FIG>) of the sealing plate <NUM>'. The impedance regions <NUM>' includes a first impedance region 870a', a second impedance region 870b', and a third impedance region 870c'.

The first impedance region 870a' extends from the proximal end 822e' of the sealing plate <NUM>' to about a central portion 822a' of the sealing plate <NUM>'. The first impedance region 870a' includes a plurality of impedance zones <NUM>' that forms a continuous gradient transition across the first impedance region 870a' from a proximal impedance zone 860a' that is a low impedance zone to a distal impedance zone 860b' that is a high impedance zone. The second impedance region 870b' is disposed about the central portion 822a' of the sealing plate <NUM>' and has a single impedance zone 860c' that may have an impedance value that is higher or lower than the distal impedance zone 860b' of the first impedance region 870a'. The third impedance region 870c' extends from the central portion 822a' of the sealing plate <NUM>' to the distal end 822f'. The third impedance region 870c' includes a plurality of impedance zones <NUM>' that forms a continuous gradient transition across the third impedance region 870c' from a proximal impedance zone 860d' that is a low impedance zone to a distal impedance zone 860e' that is a high impedance zone. It should be understood that the combinations and/or number of impedance zones <NUM>' within each impedance region <NUM>' may vary (e.g., increase or decrease proximally to distally).

Turning now to <FIG>, a sealing plate <NUM>" includes a plurality of impedance regions <NUM>" defined concentrically therein. The impedance regions <NUM>" includes a first impedance region 870a" and a second impedance region 870b". The first impedance region 870a" extend laterally outwardly from the knife slot <NUM>", or in embodiments devoid of a knife slot <NUM>", about the center portion 822a" of the sealing plate <NUM>". The second impedance region 870b" extends around the first impedance region 870a along the length "L" and the width "W" (<FIG>) of the sealing plate <NUM>".

The first impedance region 870a" includes a plurality of impedance zones <NUM>" forming a gradient transition that increases from an area of low impedance adjacent to the knife slot <NUM>" outwardly towards an area of high impedance in the direction of arrow "A. " The second impedance region 870b" includes a plurality of impedance regions <NUM>" that increase from an area of low impedance at the proximal end 822e" of the sealing plate <NUM>" to an area of high impedance at the distal end 822f" of the sealing plate <NUM>" in the direction of arrow "B. " While the first impedance region 870a" is shown longitudinally offset relative to each other on opposed sides of the knife slot <NUM>", it should be understood that the first impedance region 870a" may be symmetrical. Further, it should be understood that instead of a gradual transition, the impedance zones <NUM>" within each of the impedance regions <NUM>" may be separated by an interface or interphase and/or may increase or decrease proximally to distally and/or laterally.

It should be understood that the values, range of values of the impedance zones, and/or the configuration of the impedance zones on the sealing surface of the sealing plate depend on the specific energy application and desired tissue effect. For example, the impedance zones may be in pre-defined areas on the jaw member, such as along the tip portion or on one side of the sealing plate. As another example, the impedance zones may follow the jaw curvature or have a more complex contour. The impedance zones may be placed across from gap setting features.

Claim 1:
A jaw member comprising:
a sealing plate (<NUM>) including a sealing surface (<NUM>) having at least two electrical impedance zones (660a)(660b)(660c), the at least two impedance zones including a first zone having a first impedance value and a second zone having a second impedance value that is different from the first impedance value, wherein each impedance zone (<NUM>) is homogenous in that the impedance value over a thickness of the zone is consistent throughout the impedance zone; and
an insulator supporting the sealing plate thereon wherein the sealing surface further includes an interphase (<NUM>) disposed between the first and second zones, the interphase having an electrical impedance value over a thickness of the interphase that gradually transitions from the first zone to the second zone.