Patent Description:
In the last twenty years or more, the medical device industry has strived to provide reliable means to seal and divide tissue, including blood vessels. In some cases, vessel sealers have been offered that require the surgeon to repeatedly switch between a sealer and a cutting device. This method requires the surgeon first insert a sealer into the area, such as through a lumen, to seal tissue, then remove the device, and then re-enter with a cutting device. This method slows surgical procedures, so it is preferable to provide the sealing and dividing capabilities in a single device. Others require multiple activation steps, which increase the risk of error.

Some instruments provide a vessel sealer in combination with a mechanical (knife) cutting mechanism. Other devices (such as those disclosed in <CIT> and <CIT>) provide harmonic seal and cut operations, which also employ mechanical energy. For years, the industry has attempted without significant success to provide a vessel sealer with electronic (e.g., radiofrequency energy) cutting capability.

The present disclosure is directed towards a surgical system for sealing and severing tissue, the features of which are set out in the appended claims. In one embodiment of the inventions, a surgical system for sealing and severing tissue is disclosed. The system comprises a generator configured to output radiofrequency (RF) energy, including delivering a first RF power signal during a seal cycle, and delivering a second RF power signal during a cut cycle, and a surgical device electrically coupled to the generator output. The device comprises an elongate shaft; an end effector coupled to a distal end portion of the elongate shaft and defining a longitudinal axis, the end effector comprising first and second jaws configured to approximate each other in a closed position for compressing tissue extending therebetween and disposed transverse to the longitudinal axis, the first and second jaws having respective opposing conductive seal surface electrodes configured for sealing spaced apart first and second portions of the compressed tissue when the first RF power signal is conducted through a circuit including the respective seal surface electrodes during a seal cycle; and a cut electrode disposed within an interior region of the first jaw, wherein the cut electrode is aligned with the longitudinal axis and has an elongate conductive edge surface, the cut electrode having a height profile relative to the first jaw such that, when the first and second jaws are in the closed position compressing the tissue, the elongate conductive edge surface of the cut electrode presses against a third portion of the tissue located between the spaced apart first and second portions. The cut electrode is configured to sever the third portion of the tissue when the second RF power signal is conducted through a circuit including the cut electrode and a respective one of the seal surface electrodes during a cut cycle performed after the seal cycle is completed.

Optionally, the first RF power signal of the surgical system imparts a sealing power of no more than <NUM> Watts, with a current of no more than <NUM> Amperes rms, and a maximum voltage of <NUM> Volts rms. Optionally, the second RF power signal of the surgical system imparts a cutting power of no more than <NUM> Watts, with a current of no more than <NUM> Amperes rms, and a maximum voltage of <NUM> Volts rms.

In various embodiments of the surgical system, the generator maintains substantially constant output power by varying current or voltage in response to changes in impedance of the tissue during respective seal and cut cycles.

In some embodiments of the surgical system, wherein, when the first and second jaws are in the closed position compressing the tissue, the elongate conductive edge surface of the cut electrode stretches the third portion of the tissue.

In some embodiments, the surgical system further comprises a resilient member disposed in an interior region of the second jaw opposing the elongate conductive edge surface of the cut electrode, wherein when the first and second jaws are in the closed position compressing the tissue, the elongate conductive edge surface of the cut electrode and the resilient member are configured to compress the third portion therebetween. Optionally, the resilient member has a bias against the elongate conductive edge surface of the cut electrode so as to impose a restoring force that presses the third portion of the tissue against the elongate conductive edge surface of the cut electrode so as to maintain contact of the third portion of the tissue against the elongate conductive edge surface of the cut electrode during a cut cycle. Optionally, the resilient member comprises an elastomer. In some embodiments, when the first and second jaws are in the closed position compressing the tissue, a portion of the elastomer is deformed into an elastomer reservoir defined by the second jaw. Optionally, the resilient member comprises a non-conductive support surface that contacts the third tissue portion.

In some embodiments, the cut electrode is shaped and configured to uniformly distribute a current concentration along the elongate conductive edge surface during a cut cycle. Optionally, the elongate conductive edge surface of the cut electrode has a convex rounded cross-sectional profile.

In some embodiments, the respective seal surface electrode that forms the cut cycle circuit with the cut electrode comprises a seal surface profile, the seal surface profile having a tissue compression portion and a first rounded edge portion, the first rounded edge portion configured to minimize current concentrations during a cut cycle. Optionally, the respective conductive seal surface electrodes of the first and second jaws impart a bi-polar effect on the respective first and second portions of the tissue during a seal cycle. Optionally, the respective seal surface electrode that forms the cut cycle circuit with the cut electrode acts as a dispersive electrode such that the cut electrode imparts a monopolar effect on the third portion of the tissue during a cut cycle.

In some embodiments, the interior region of the first jaw defines at least one tissue reservoir disposed adjacent the cut electrode, wherein the tissue reservoir is configured to receive prolapsed tissue when the first and second jaws are in the closed position compressing the tissue. Optionally, the at least one tissue reservoir comprises a first tissue reservoir disposed adjacent a first side of the cut electrode, and a second tissue reservoir disposed adjacent a second side of the cut electrode opposite the first side.

In some embodiments, the end-effector has an envelope diameter of no more than eight millimeters when the first and second jaws are in the closed position.

In some embodiments, the cut cycle is no more than <NUM> seconds in duration.

In various embodiments, the generator is configured to vary one or both of a current and voltage of the first RF signal up to a predetermined maximum seal current in response to changes in impedance of the first and second tissue portions during a seal cycle, and the generator is configured to vary one or both of a current and voltage of the second RF signal up to a predetermined maximum cut current in response to changes in impedance of the third portion of the tissue during a cut cycle.

In some embodiments, the first RF power signal is maintained at a substantially constant power during the seal cycle, and the second RF power signal is maintained at a substantially constant power during the cut cycle. The substantially constant power level of the second RF power signal is greater than the substantially constant power level of the first RF power signal.

In some embodiments, the tissue comprises a blood vessel.

In some embodiments, the respective conductive seal surface electrodes of the first and second jaws impart a bi-polar effect on the respective first and second portions of the tissue during delivery of the first RF power signal.

The term "about" generally refers to a range of numbers that one of skilled in the art would consider equivalent to the recited value (i.e., having the same function or result).

The figures are not necessarily drawn to scale, the relative scale of select elements may have been exaggerated for clarity, and elements of similar structures or functions are represented by like reference numerals throughout the figures. It should also be understood that the figures are only intended to facilitate the description of the embodiments, and are not intended as an exhaustive description of the invention or as a limitation on the scope of the invention, which is defined only by the appended claims and their equivalents. An aspect or an advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in any other embodiments even if not so illustrated.

Before providing a more detailed description of the inventions and embodiments disclosed herein, it is expedient to describe some of the challenges faced when attempting to provide a reliable tissue sealer-divider.

The first problem is providing a reliable, safe tissue seal and addressing some biases in the medical device industry. For many years, it was believed that a very high power, often <NUM> Watts or more, was required to achieve tissue sealing. At such high powers, traditional devices were/are required to include a myriad of safety features to prevent tissue from being charred and/or preventing thermal spread - or damage to adjacent tissue. Some devices do so by rapidly turning the devices on and off. See, for example, <CIT>, which discloses a method of cycling a power application to tissue to prevent tissue necrosis, which is caused by the build-up of heat near tissue being treated. Power cycling, however, has its own side-effects, with one being the demand it places on programing and the power supply and hardware involved. The Applicant has overcome these and other problems in vessel sealing by providing a low power tissue sealing device, such as the one disclosed in commonly-owned <CIT>, and related applications, and commonly owned <CIT>.

The second problem is providing a safe, reliable cut after tissue is sealed, to separate the tissue. Historically, surgeons would remove the tissue sealing device from the patient after sealing, then insert a cutting device. This was cumbersome and extended the duration of surgeries. Vessel sealers with mechanical dividers have been developed to reduce the duration of surgeries. These devices typically function by moving a knife through sealed tissue to divide it. One exemplary device is shown and described in commonly-owned <CIT>, and related applications.

Such devices, however, limit flexibility in seal surface geometry and jaw manipulation because a knife must pass through the jaws. For example, these devices prevent or limit use with an articulating device and/or in a catheter setting.

Generally, it is desirable to limit the number of times a surgeon must manipulate the device, such as by providing a single-action device that performs two functions in response to a single action by a surgeon. In knife-based cutting systems, however, single-action operation may introduce the risk of a surgeon moving his or her hand between the seal and cut actions; on the other hand, automatic knife-actuation has the inherent risk of actuating the knife when the jaws are not closed, and the moving knife may also become lodged in the tissue or jaws, which requires an involved process to remove. It is therefore desirable to provide a device that is both "single action" in nature and overcomes the problems described above.

In an attempt to overcome these problems, numerous entities have attempted to develop what is known in the industry as e-cutting devices, such as the PKS™ OMNI™ device sold by Olympus (see e.g. www. olympusamerica. The PKS OMNI device, along with the related G400™ generator, applies high power in a cycling manner to seal tissue between the jaws.

However, none of the known devices currently available on the market can claim a <NUM>% cut performance. Instead, the devices typically only cut "most" of the tissue that is intended to be cut, but leave what is known in the industry as "tags" which must be cut separately by the surgeon, thus defeating the purpose of a "single action" device.

The Applicant has tested embodiments described herein and confirmed that embodiments described herein achieve a <NUM>% cut performance, which is the highest benchmark possible. This <NUM>% cut performance is in combination with low thermal spread, which the Applicant has proven to provide both a stronger seal and improved patient outcomes.

Embodiments of the present invention overcome the above-stated problems while providing other new and useful features.

<FIG> is a perspective view of a medical system <NUM>, in accordance with embodiments of the disclosed inventions. The system <NUM> includes a device <NUM> having a proximal portion <NUM>, a body portion <NUM> and a distal portion <NUM>. The proximal portion <NUM> of the device is configured to be coupled to an actuator <NUM>, such as a handle, a laparoscopic system, a surgical robotic system or the like. The body portion <NUM> of the medical device <NUM> comprises an inner tubular member <NUM> and an outer tubular member <NUM>, where the inner tubular member <NUM> is configured to translate relative to the outer tubular member <NUM>. The distal portion <NUM> of the medical device <NUM> comprises an end effector <NUM> having a first jaw <NUM> and a second jaw <NUM>. The actuator <NUM> is configured to actuate the medical device <NUM>, control physical movements (e.g., open and close jaws <NUM>, <NUM>), engage the end effector <NUM> with tissue of a patient, and electrically engage the end effector <NUM> to seal and divide tissue. An electrical wire or wires <NUM> extend from a power source <NUM>, such as a radio frequency generator, through the actuator <NUM> to the end effector <NUM>; the electrical wires <NUM> are configured to deliver energy to the end effector <NUM>. In an alternative embodiment, the electrical wires extend from the actuator <NUM> to the end effector <NUM>, and the connection of the medical device <NUM> to the power source <NUM> is wireless. The energy delivered may be radio-frequency (RF) energy or any other suitable energy for sealing and cutting tissue.

Referring back to the proximal portion <NUM> of the medical device <NUM>, the proximal portion <NUM> includes a spring cartridge <NUM> (or other suitable sealing mechanism) configured to exert a spring-limited sealing force when actuated by the actuator <NUM>, thereby compressing the spring and proximately translating (e.g., pulling) the inner tubular member <NUM>. The inner tubular member <NUM> of the medical device <NUM> comprises a bolt or cam pin <NUM> slidably disposed within a slot <NUM> of the outer tubular member <NUM> (<FIG>). The cam pin <NUM> is fixedly attached to the inner tubular member <NUM> and is configured to transfer forces to the end effector <NUM>, as the inner tubular member <NUM> longitudinally translates relative to outer tubular member <NUM>, allowing closing (<FIG>) or opening (<FIG>) of the jaws <NUM> and <NUM>. The slot <NUM> of the outer tubular member <NUM> is configured to allow movement of the cam pin <NUM> of the inner tubular member <NUM> without transferring forces to the outer tubular member <NUM>. The slot <NUM> of the outer tubular member <NUM> of the medical device <NUM> minimizes or avoids undesirable motion of the jaws <NUM> and <NUM> (e.g., rotation). The distal portion <NUM> of the medical device <NUM> further comprises a pivot pin <NUM> disposed between the jaws <NUM> and <NUM>. The pivot pin <NUM> is configured to serve as a bearing surface for the jaws <NUM> and <NUM> and as alignment for the components of the end effector <NUM>.

By way of further illustration, <FIG> depict the end effector <NUM> of the medical device <NUM> of the system <NUM>, having jaws <NUM> and <NUM> in a closed and opened configuration, respectively. As shown in <FIG>, the cam pin <NUM> slidably is disposed within the slot <NUM> of the outer tubular member <NUM> and proximately located when the jaws <NUM> and <NUM> are in a closed configuration. <FIG> shows the cam pin <NUM> is distally located within the slot <NUM> of the outer tubular member <NUM> when the jaws <NUM> and <NUM> are in an opened configuration. Both jaws <NUM> and <NUM> move relative to each other to form the opened configuration of the end effector <NUM> of the medical device <NUM>. In the opened configuration, the jaws <NUM> and <NUM> are configured to separate from each other in a range of <NUM> to <NUM> degrees. <FIG> illustrates an exemplary opened configuration having an angle θ of approximately <NUM>° between jaws <NUM> and <NUM>. In some embodiments, the angle θ of approximately <NUM>° between jaws <NUM> and <NUM> (not shown). In some embodiments, the length of the respective jaws <NUM> and <NUM> are in a range of <NUM> to <NUM> millimeters long, where the length is taken from the pivot pin <NUM> to the distal ends of each jaw (e.g., non-traumatic distal end portions <NUM> and <NUM> better shown in <FIG>). In some embodiments, the opened configuration of the jaws <NUM> and <NUM> have a working range of <NUM> to <NUM> millimeters long; where the working range is the length between the distal ends of each jaw in an opened configuration (e.g., distance between the distal end portions <NUM> and <NUM> of <FIG>). In an alternative embodiment, only one of the jaw move relative to the other jaw (not shown). Additionally, <FIG> depicts conductive core members <NUM>, <NUM>, and <FIG> depicts a cut electrode <NUM>, which will be described in further detail below.

<FIG> illustrates a perspective view of the end effector <NUM> of the medical device <NUM> of the system <NUM> in an opened configuration. The jaws <NUM> and <NUM> comprise a substantially elongated straight configuration, whereby the first jaw <NUM> extends along a longitudinal axis <NUM>. The jaws <NUM> and <NUM> further comprise respective curved, rounded, and/or non-traumatic distal end portions <NUM> and <NUM>. In alternative embodiments, the jaws <NUM> and <NUM> may comprise an elongated curved configuration (not shown), such as with a Maryland-style curve. In some embodiments, the jaws <NUM> and <NUM> are coupled to a flexible shaft (not shown) in the medical device <NUM>.

The jaws <NUM> and <NUM> comprise respective conductive core members <NUM> and <NUM>, which are configured to provide electrically conductive paths to the end effector <NUM>. The conductive core members <NUM> and <NUM> are composed of stainless steel or any other suitable conductive material. The conductive core members <NUM> comprises a seal surface <NUM> of the jaw <NUM>, and the conductive core members <NUM> comprises a seal surface <NUM> of the jaw <NUM>. The seal surfaces <NUM> and <NUM> are disposed along the perimeter of their respective jaw <NUM> and <NUM>, including along the curved distal end portions <NUM> and <NUM> of the jaws, as shown in <FIG>. The seal surfaces <NUM> and <NUM> are configured to contact and seal tissue, such as when the end effector <NUM> of the device <NUM> is in a closed configuration. The first jaw <NUM> further comprises an insulation element <NUM> disposed around and covering the conductive core member <NUM>, except for the seal surface <NUM>, as better appreciated in <FIG>, <FIG>. The second jaw <NUM> further comprises an insulation element <NUM> disposed around and covering the conductive core member <NUM>, except for the seal surface <NUM>, as better appreciated in <FIG>, <FIG>. The seal surfaces <NUM> and <NUM> are exposed (e.g., without insulation) to provide electrically conductive paths (e.g., bipolar) and seal tissue disposed between the seal surfaces <NUM> and <NUM>. The seal surface <NUM> includes one or more non-conductive stop members <NUM> composed of ceramic or any other suitable non-conductive material, to prevent direct contact between the seal surfaces <NUM> and <NUM> avoiding short outs, in a manner known to those skilled in the art. In some embodiments, the seal surface <NUM> may also include one or more non-conductive stop members <NUM>.

The first jaw <NUM> further comprises a cut electrode <NUM> and at least one tissue reservoir <NUM>. As shown in <FIG>, the cut electrode <NUM> is disposed within a tissue reservoir <NUM> and comprises an elongated blade-like configuration extending along the longitudinal axis <NUM> of the first jaw <NUM>. The cut electrode <NUM> includes an elongated profile or edge <NUM>, where the edge <NUM> is substantially curved, rounded or any other suitable configuration. The curved edge <NUM> of the cut electrode <NUM> is desirable to provide a relatively large cutting surface area and more uniform current density for tissue cutting (<FIG> and <FIG>). As better appreciated in <FIG>, the cut electrode <NUM> includes a non-conductive material <NUM>, such as a coating or insulation, except for the edge <NUM>. The conductive edge <NUM> of the cut electrode <NUM> is configured to provide uniform current density for tissue cutting, as it will be described in further detail below.

The elongated cut electrode <NUM> comprises a width in the range of <NUM> to <NUM> millimeters, sufficiently narrow to concentrate current to cut tissue near, adjacent or in contact with the edge <NUM>, yet wide enough to prevent an inadvertent mechanical cut of the tissue when compressed between the jaws <NUM> and <NUM> prior to the cut cycle. The cut electrode <NUM> is further configured to avoid or minimize deformation of the cut electrode <NUM> and/or edge <NUM> during use of the end effector <NUM> (e.g., seal and cut cycles). The elongated cut electrode <NUM> is fixedly disposed in the first jaw <NUM>. The elongated cut electrode <NUM> comprises a height profile wherein the edge <NUM> is disposed above or extending beyond the profiles of the seal surface <NUM> and stop members <NUM> (<FIG>, <FIG>, <FIG> and <FIG>). Optionally, those skilled in the art will also recognize that a moving cut electrode (e.g., slidably disposed) may be suitable for some applications.

In some embodiments, the tissue reservoir <NUM> is disposed on both sides along the length of the cut electrode <NUM> (<FIG>, <FIG>, <FIG> and <FIG>). The tissue reservoir <NUM> is configured to receive tissue that is displaced or prolapsed during the closed configuration of the end effector <NUM> and/or during cutting (e.g., cut cycle). The tissue reservoir <NUM> is further configured to allow the end effector <NUM> to obtain and/or maintain its closed configuration when tissue is grasped, held and/or retained between the jaws <NUM> and <NUM>, such that tissue is displaced to the tissue reservoir <NUM>, as it will be further described in <FIG>. The tissue reservoir <NUM> also is further configured to enhance compression on tissue between the seal surfaces <NUM> and <NUM>.

The second jaw <NUM> of the end effector <NUM> comprises an elongated cavity (element <NUM> in <FIG>) having a resilient member <NUM> therebetween. The resilient member <NUM> comprises an elastomer or any other suitable polymeric material having rubber-like elastic properties (e.g., silicone, fluoroelastomers, polyurethane, foams or the like). The resilient member <NUM> forms a non-conductive support surface <NUM>, shown in <FIG>, where the support surface <NUM> is configured to contact the cut electrode <NUM> in the first jaw <NUM> and/or contact tissue disposed therebetween. In some embodiments, the non-conductive support surface <NUM> may be formed as a coating on the resilient member <NUM>, or a different material from the resilient member <NUM>. The non-conductive support surface <NUM> and/or resilient member <NUM> have elastic properties, deforming and restoring forces, such as, deforming when the cut electrode <NUM> and/or tissue are pushed against them (e.g., end effector <NUM> in a closed configuration). Additionally, the non-conductive support surface <NUM> and/or resilient member <NUM> exert restoring force (e.g., push, spring-like) on the tissue against the conductive edge <NUM> of the cut electrode <NUM> configured to maintain uniform contact of the tissue against the cut electrode <NUM> for e-cutting (e.g., cut cycle), when the end effector <NUM> is in the closed configuration.

In some embodiments, the non-conductive support surface <NUM> and/or resilient member <NUM> may be configured to extend, occupy or move (partially or substantially) within the tissue reservoir <NUM> of the jaw <NUM>, such as, prior to application of the cut cycle (not shown). In some embodiments, the non-conductive support surface <NUM> and/or resilient member <NUM> is configured to give way during tissue sealing and to push back during tissue cutting to maintain an effective or sufficient pressure on tissue to be cut. In some embodiments, the non-conductive support surface <NUM> and/or resilient member <NUM> is provided in a pre-loaded formation (that is, the elastomer may be flush with the top of seal surface <NUM> to provide an immediate response to tissue during grasping of the tissue, and drive tissue into the reservoir <NUM>). In alternative embodiments, the resilient member <NUM> may include a relatively hard plate supported by a spring (not shown).

In some embodiments, a durometer of the non-conductive support surface <NUM> and/or resilient member <NUM> may be selected to maintain tissue contact with the cut electrode <NUM> as the tissue is cut and/or exhibits varying thicknesses. In some embodiments, the durometer may be selected to not inhibit closure of the jaws <NUM>, <NUM>. In some embodiments, the non-conductive support surface <NUM> and/or resilient member <NUM> may have a Shore A durometer up to <NUM>. In some embodiments, the Shore A durometer may be greater than <NUM>. In some embodiments, the durometer may be selected to maintain tissue contact with the cut electrode <NUM> during the cut cycle without biasing the jaws apart.

<FIG> illustrates a cross-sectional view of the end effector <NUM> of the medical device <NUM> of the system <NUM> in the closed configuration of <FIG>. The end effector <NUM> comprises a pair of jaws, including the first jaw <NUM> and the second jaw <NUM>. The jaws <NUM> and <NUM> are approximate one another, such as to grasp, hold and/or retain tissue therebetween, and move away from each other, such as to release tissue (not shown). The seal surfaces <NUM> and <NUM> of the respective first jaw <NUM> and second jaw <NUM> are configured for bipolar sealing of tissue disposed between the pair of jaws. The seal surfaces <NUM> and <NUM> seal tissue positioned therebetween by conducting bipolar energy through tissue grasped, held and/or retained between the jaws <NUM> and <NUM> during a seal cycle. In the bipolar sealing cycle, the current density is approximately the same between the seal surfaces <NUM> and <NUM>, since the exposed/conductive area of the seal surfaces <NUM> and <NUM> are approximately the same. In some embodiments, the seal cycle of the medical device <NUM> comprises applying a sealing power of <NUM> Watts nominal or less. In some embodiments, the sealing power has a current of <NUM> Amperes or less.

In some embodiments, the first seal surface <NUM> is the only exposed portion of the conductive core member <NUM>, and the second seal surface <NUM> is the only exposed portion of the conductive core member <NUM>.

In some embodiments, the jaws <NUM> and <NUM> are composed, formed and/or made by their respective conductive core members <NUM> and <NUM>. As shown in <FIG>, the conductive core members <NUM> and <NUM> are covered, coated, sandwiched and/or insulated with respective insulations <NUM> and <NUM>, except for their respective seal surfaces <NUM> and <NUM>, which are exposed and conductive. The seal surface <NUM> includes the one or more non-conductive stop members <NUM> composed of ceramic or any other suitable non-conductive material. The seal surfaces <NUM> and <NUM> are disposed along the perimeter of their respective jaw <NUM> and <NUM>, as better appreciated in <FIG>.

In some embodiments, the end effector <NUM> is configured to seal tissue grasped, held or restrained between the jaws <NUM> and <NUM>, then cut tissue. The seal and cut cycles are sequential, such that the tissue is first sealed, then cut. The end effector <NUM> comprises a distance between the cut electrode <NUM> and respective seal surfaces <NUM> and <NUM> (<FIG>, <FIG>, <FIG>, and <FIG>). The distance, shown as distance "D" in <FIG>, allows for a section of the tissue to be disposed between respective seal surfaces <NUM> and <NUM> and the cut electrode <NUM>, such that after the tissue is sealed by the seal cycle of the device <NUM>, the section of tissue would maintain some moisture to allow for current flow from the cut electrode <NUM> during the cut cycle of the device <NUM> to perform cutting of the tissue. Further, the distance "D", along with the force exerted by the non-conductive support surface <NUM> and/or resilient member <NUM> on the tissue when the end effector <NUM> is in a closed configuration, allows tissue movement into the tissue reservoir <NUM>. Distance "D" combined with the dimensions of the tissue reservoir <NUM> allow for an adequate amount of tissue overlaying and adjacent to the cut electrode <NUM> to avoid being desiccated during the seal cycle. In some embodiments, the distant "D" ranges between <NUM> to <NUM> millimeters. If the distance "D" is less than <NUM> millimeters, the sealed portion of the tissue would be too close to the cut electrode <NUM> during the seal cycle, then the impedance of tissue between the cut electrode <NUM> and the seal surface <NUM> or <NUM> will be too high, which will adversely affect the cut cycle. Additionally, if the distance "D" is less than <NUM> millimeters, for example, the cut electrode <NUM> may not cut tissue but rather simply char tissue, because there is little or no low-impedance path. In other words, the device <NUM> may be configured to provide a low-impedance path from the cut electrode edge <NUM> through a relatively large area of low-impedance tissue <NUM> (<FIG>) after tissue sealing; which may be referenced herein as a pillow. The resulting current concentration along the edge <NUM> of the cut electrode <NUM> during the cut cycle creates a "monopolar effect" as the current propagates through the relatively low-impedance tissue <NUM> to the respective one of the seal surfaces <NUM>, <NUM> that is functioning as the dispersive electrode.

As further shown in <FIG>, the pair of jaws <NUM> and <NUM> of the closed configuration of the end effector <NUM> comprises an envelope diameter <NUM> of <NUM> millimeters or less. Those skilled in the art will recognize that the term "envelope diameter" references to a substantially circular space within which the entirety of an object (e.g., jaws <NUM> and <NUM>) can fit, even if the object (e.g., end effector <NUM>) is not round. In some embodiments, the envelope diameter <NUM> is <NUM> millimeters or less. In some embodiments, the envelope diameter <NUM> is <NUM> millimeters or less. In some embodiments, the envelope diameter <NUM> is <NUM> millimeters or less.

<FIG> illustrate cross-sectional views of the first jaw <NUM> and components, in accordance with embodiments of the disclosed inventions. As disclosed above, the conductive core member <NUM> is covered, coated, sandwiched and/or insulated with insulation <NUM>, except for the seal surface <NUM>, which is exposed/conductive. <FIG> depicts the first jaw <NUM> of <FIG> where the conductive core member <NUM> comprises a continuous configuration (e.g., "U" shape cross-section). Alternatively, the conductive core member <NUM> may include sectional portions, as shown in <FIG>, as long as the conductive core member <NUM> is electrically engaged by the actuator <NUM> coupled to the power source <NUM> and is configured to deliver energy via the seal surface <NUM>.

The seal surface <NUM> of the conductive core member <NUM> of the first jaw <NUM> comprises a width "W1", as shown in <FIG>. In some embodiments, the width "W1" ranges between <NUM> and <NUM> millimeter. If the width "W1" of the seal surface <NUM> is less than <NUM> millimeters is considered a narrow width.

As shown in <FIG>, the cut electrode <NUM> is disposed within the tissue reservoir <NUM> and comprises the cut electrode edge <NUM>; the edge <NUM> having a substantially curved, rounded, convex configuration, as better appreciated in <FIG>. The cut electrode <NUM> includes a non-conductive material, coating or insulation <NUM>, except for the edge <NUM> (<FIG>) and except for a portion coupling the cut electrode <NUM> with the power source <NUM> (<FIG>). In some embodiments, the cut electrode <NUM> is insulated on all surfaces by insulation <NUM>, leaving the cut electrode edge <NUM> exposed and the coupling with the power source <NUM> without insulation. The edge <NUM> further comprises a conductive engagement surface <NUM> (<FIG>). The conductive engagement surface <NUM> comprises a convex and smooth configuration to prevent current concentrations on the edge <NUM> of the cut electrode <NUM>. The edge <NUM> of the cut electrode <NUM> may be curved laterally throughout the entire length of the cut electrode <NUM>, as better appreciated in <FIG>. Alternatively, the edge <NUM> of the cut electrode <NUM> may be curved throughout longitudinal portions or sections of the cut electrode <NUM> (not shown) and/or comprises other suitable configurations (<FIG> illustrates an alternative edge <NUM>' of the cut electrode <NUM>, where the edge <NUM>' comprises a beveled configuration having a rounded conductive engagement surface <NUM>' coupled to the beveled edges <NUM>'. The cut electrode <NUM> includes a non-conductive material, coating or insulation <NUM>, except for the beveled edges <NUM>' and the rounded conductive engagement surface <NUM>' (<FIG>).

Although, having a cut electrode <NUM> with rounded edge <NUM> and/or convex conductive engagement surface <NUM>, as shown in <FIG> may be considered counterintuitive (industry believes sharp edges on a cut blade would concentrate current and improve cutting ability), the curved edge <NUM> and/or convex conductive engagement surface <NUM> of the cut electrode <NUM> comprises a large radius, which creates a higher current concentration spread over surface area, thus providing improved cutting performance compared to a cut electrode with a sharp edge.

<FIG> illustrate cross-sectional views of the second jaw <NUM> and components, in accordance with embodiments of the disclosed inventions. As previously disclosed, the conductive core member <NUM> is covered, coated, sandwiched and/or insulated with insulation <NUM>, except for the seal surface <NUM>, which is exposed/conductive. <FIG> depicts the second jaw <NUM> of <FIG> where the conductive core member <NUM> comprises a continuous configuration (e.g., "∩" shape cross-section). Alternatively, the conductive core member <NUM> may include sectional portions, as shown in <FIG>, as long as the conductive core member <NUM> is electrically engaged by the actuator <NUM> coupled to the power source <NUM> and is configured to deliver energy via the seal surface <NUM>.

As shown in <FIG>, <FIG> the insulation <NUM> disposed on an outer surface 118a of the conductive core member <NUM> substantially, but not fully, covers the outer surface 118a, as better appreciated in <FIG>, exposing a conductive rounded edge portion <NUM> of the conductive core member <NUM>. Thus, the insulation <NUM> disposed on an outer surface 118a of the conductive core member <NUM> is set back slightly, as depicted in <FIG>, <FIG>, from the rounded edge portion <NUM> to expose conductive core member <NUM>. The rounded edge portion <NUM> extends longitudinally along the second jaw <NUM> and is configured to minimize any current concentration during the bipolar sealing cycle.

Referring back to first jaw <NUM>, <FIG>, <FIG> show the insulation <NUM> disposed in an outer surface 114a of the conductive core member <NUM> substantially, but not fully, covers the outer surface 114a, exposing a conductive rounded edge portion <NUM> of the conductive core member <NUM>. The rounded edge portion <NUM> extends longitudinally along the first jaw <NUM> and is configured to minimize current concentration and subsequent tissue effect.

In alternative embodiments, the insulations <NUM> and <NUM> fully cover their respective outer surface 114a and 118a of the conductive core members <NUM> and <NUM>, thus, the rounded edge portions <NUM> and <NUM> are not exposed (not shown).

The seal surface <NUM> of the conductive core member <NUM> of the second jaw <NUM> comprises a width "W2", as shown in <FIG>. In some embodiments, the width "W2" ranges between <NUM> and <NUM> millimeter. If the width "W2" of the seal surface <NUM> is less than <NUM> millimeters then W2 is considered a narrow width. In some embodiments, the respective seal surfaces <NUM> and <NUM> have widths W1 and W2 of <NUM> millimeters or less each. In some embodiments, the respective seal surfaces <NUM> and <NUM> have widths W1 and W2 of two millimeters or less each. In some embodiments, at least a portion of at least one seal surface <NUM>, <NUM> has width W1, W2 of <NUM> millimeters or less. In some embodiments, at least a portion of at least one seal surface <NUM>, <NUM> has width W1, W2 of <NUM> millimeters or less. In some embodiments, at least a portion of at least one seal surface <NUM>, <NUM> is a narrow seal surface.

The second jaw <NUM> comprises a cavity <NUM> having the resilient member <NUM> disposed therebetween (<FIG>). The cavity <NUM> comprises a relief space <NUM> for the resilient member <NUM> to occupy when the resilient member <NUM> is deformed by the cut electrode <NUM> and/or tissue such as when the end effector <NUM> in a closed configuration. In some embodiments, the resilient member <NUM> may deform and at least partially occupy the relief space <NUM> prior to the application of the cut cycle, such as during a seal cycle, or such as prior to a seal cycle as the end effector <NUM> is in a closed configuration (<FIG> and <FIG>). The relief space <NUM>, shown in <FIG>, is configured to prevent the resilient member <NUM> from cupping, whereby a gap forms between the cut electrode <NUM> and tissue disposed between the cut electrode <NUM> and the resilient member <NUM>. Therefore, the relief space <NUM> is configured to enhance tissue contact with the cut electrode <NUM> during the cut cycle. Cupping occurs in devices with no relief space, so the resilient member <NUM> would push the tissue against the cut electrode <NUM> in mostly one direction, in such a way that the tissue gets pinched and arches (i.e., cups) around the edge <NUM> of the cut electrode <NUM>, losing contact with the electrode edge <NUM>.

<FIG> illustrates a cross-sectional view of the interface between the end effector <NUM> of the medical device <NUM> and tissue <NUM> of a patient, in accordance with embodiments of the disclosed inventions. Selective components of the end effector <NUM> are partially shown in <FIG> for clarity and better view of the tissue <NUM>. As shown in <FIG>, the end effector <NUM> is in the closed configuration or substantially closed (e.g., jaws <NUM> and <NUM> near each other); the end effector <NUM> grasping, holding and/or restraining tissue <NUM> between jaws <NUM> and <NUM>. The end effector <NUM> is configured to apply pressure and compress the tissue <NUM> disposed between the jaws <NUM> and <NUM>, thereby creating compressed tissue portions <NUM> disposed between the sealing surfaces <NUM> and <NUM> and further creating a tented tissue portion <NUM> disposed between the support surface <NUM> and the cut electrode <NUM> (e.g., edge <NUM>). Notably, as the tissue <NUM> is compressed by the end effector <NUM>, tissue portions <NUM> (i.e., pillow) are pushed into the tissue reservoir <NUM> in both sides of the cut electrode <NUM>, as shown in <FIG>.

The system <NUM> is configured to apply RF energy to the compressed tissue portion <NUM> in the seal cycle via the device <NUM>. The power is selected and configured to limit current leakage beyond tissue that is not compressed between the seal surfaces <NUM> and <NUM>, in a manner described in Applicant's owned US patents and applications, previously incorporated by reference herein.

In some embodiments, the system <NUM> is configured to apply a seal cycle having a maximum power of <NUM> Watts or less, a maximum voltage of <NUM> Volts rms or less, and a maximum current of <NUM> Amperes rms or less. In some embodiments, the seal cycle has a maximum power of <NUM> Watts or less. In some embodiments, the system <NUM> is configured to apply a cut cycle having a maximum power of <NUM> Watts or less, a maximum voltage of <NUM> Volts rms or less, and a maximum current of <NUM> Amperes rms nominal or less. In some embodiments, the cut cycle has a maximum voltage of <NUM> Volts rms nominal or less. In some embodiments, the cut cycle has a maximum power of <NUM> Watts nominal or less. The system <NUM> may be configured to allow the power, voltage, and current to float up to the maximum values in response to tissue impedance changes during the seal cycle.

In some embodiments, the system <NUM> is configured to seal tissue to a burst strength of at least three times systolic pressure. In some embodiments, the system <NUM> is configured to seal a vessel having a diameter of at least <NUM> millimeters to a burst strength of at least three times systolic pressure. In some embodiments, the system <NUM> is configured to cause thermal spread of <NUM> millimeters or less during the seal cycle. In some embodiments, the system <NUM> is configured to cause thermal spread of <NUM> millimeter or less during the seal cycle.

In some embodiments, the tissue in the compressed tissue portion <NUM> develops a higher impedance after sealing than it had before sealing, which affects the impedance between the cut electrode <NUM> and either the first seal surface <NUM> or the second seal surface <NUM>. For example, prior to application of the seal cycle, the compressed tissue portion <NUM> typically has impedance of <NUM> Ohms or less, or between about <NUM> Ohms and about <NUM> Ohms. In some embodiments, it is desirable and efficient to provide a low-impedance path between the cut electrode <NUM> and the seal surface <NUM> or <NUM>.

In some embodiments, the system <NUM> is configured to apply a cutting power to the tissue <NUM> retained between the jaws <NUM> and104 during the cut cycle, and not during the seal cycle. In some embodiments, the system <NUM> is configured to apply a seal cycle followed by a cut cycle. In some embodiments, a thermal relaxation time is provided between the seal cycle and the cut cycle. In these embodiments, the seal and cut cycles are sequential, where the cut cycle occurs after the seal cycle is performed. In alternative embodiments, the seal and cut cycles are performed simultaneously.

It should be apparent from <FIG> that the end effector <NUM> is further configured to stretch (e.g., tent) the tissue <NUM> held between the pair of jaws against the cut electrode <NUM>. The tenting may be achieved through the combination of the jaws <NUM> and <NUM> compressing tissue <NUM>, as well as a slight contraction of tissue during a seal cycle and/or an effect of the support surface <NUM> and/or resilient member <NUM>. Tenting of tissue <NUM> increases when the tissue <NUM> is slightly contracted by the seal cycle because the combined action of the cut electrode <NUM> with the support surface <NUM> and/or resilient member <NUM> acts like pulling the tissue <NUM> in one direction while the slight contraction of the seal cycle acts like pulling the tissue <NUM> in the opposite direction. The support surface <NUM> and/or resilient member <NUM> are configured to bias tissue <NUM> against the cut electrode <NUM> and toward the reservoir <NUM>. The combination of tenting the tissue <NUM> and biasing tissue portions <NUM> into the tissue reservoir <NUM> during the cut cycle will inherently pull or move tissue away from the edge <NUM> of the cut electrode <NUM> as the tissue <NUM> is cut during the cut cycle, thereby promoting a monopolar tissue effect. Those skilled in the art know that monopolar operations such as tissue ablation require that the device remains in motion relative to the tissue being ablated - if the device stops the relative motion, further cutting of tissue is stopped and the tissue begins to desiccate and char; no cut. Currently, e-cutting devices on the market do not maintain this motion of tissue.

It should be appreciated that during the cut cycle, the tissue <NUM> clamped between jaws <NUM> and <NUM> begins to be electrically cut and divides from the cut electrode <NUM>, so the jaws <NUM> and <NUM> move closer together to a substantially closed configuration of the end effector <NUM>. The closing motion of the jaws <NUM> and <NUM> during the electrical cutting of tissue <NUM> causes the cut electrode <NUM> of the first jaw <NUM> to move closer to the second jaw <NUM>, as the tissue <NUM> is cut, divides and separates. Additionally, as the tissue <NUM> is electrically cut and divides, the resilient member <NUM> exerts a restoring force returning the resilient member <NUM> to a prior shape and/or position (e.g., before the resilient member <NUM> was compressed by the tissue <NUM> and the cut electrode <NUM>). The restoring force of the resilient member <NUM> is configured to push the tissue <NUM> towards the cut electrode <NUM>, particularly the edge <NUM> of the cut electrode <NUM>. The resilient member <NUM> comprises a high creep-recovery response, such that the resilient member <NUM> restoring force acts rapidly and does not lag or delay. A low creep-recovery response would cause undesirable loss of contact of the tissue <NUM> with the edge <NUM> of the cut electrode <NUM>.

During the cut cycle, the cut electrode <NUM> of the first jaw <NUM> is electrically coupled with either the first seal surface <NUM> or the second seal surface <NUM> to cut tissue held between the jaws <NUM> and <NUM>, such as cutting tissue tented between the cut electrode <NUM> and the non-conductive support surface <NUM>. Therefore, the cut electrode <NUM> and the first or second seal surfaces <NUM>, <NUM> are configured to conduct bipolar energy between the cut electrode <NUM> and the seal surfaces <NUM> or <NUM> during the cut cycle.

In some embodiments, during the cut cycle, the cut electrode <NUM> functions as an active electrode and the first or second seal surfaces <NUM>, <NUM> functions as a dispersive electrode. In some embodiments, the cut electrode <NUM> has a relatively small exposed conductive surface, while the seal surface <NUM>, <NUM> has a relatively large exposed conductive surface, whereby the current density drops significantly between the cut electrode <NUM> and the seal surface <NUM>, <NUM>, such that tissue near the seal surface <NUM>, <NUM> is not damaged, while tented tissue portion <NUM> adjacent the edge <NUM> of the cut electrode <NUM> is cut.

In some embodiments, the cutting power has a bipolar energy, but the cutting power and the pair of jaws <NUM> and <NUM> are configured to create a monopolar power tissue effect to the tissue restrained between the pair of jaws. Although the energy conducted is bipolar, current flow from the cut electrode <NUM> towards either one of the seal surfaces <NUM> or <NUM> may have a monopolar effect during the cut cycle. Since, the current density is larger at the edge <NUM> of the cut electrode <NUM> than in either of the seal surfaces <NUM> or <NUM>. Either of the seal surfaces <NUM> or <NUM> have a larger surface area compared to the smaller surface area of the edge <NUM>, thus the seal surfaces <NUM> or <NUM> have a smaller current density than the edge <NUM> of the cut electrode <NUM>.

The pillow tissue portions <NUM> comprise a relatively large area of low-impedance. The current density in the tented tissue portion <NUM> near the cut electrode edge <NUM> is higher than is the current density in the low-impedance tissue <NUM>, effectively dispersing nearly all current and promoting current flow toward the seal surface <NUM> or the seal surface <NUM>, rather than through pillow tissue portions <NUM>, due to the seal surfaces <NUM> or <NUM> functioning as a dispersive electrode in a cut cycle.

The resulting current differential in the high-impedance tented tissue portion <NUM> near the edge <NUM> of the cut electrode <NUM> and the low-impedance pillow tissue portions <NUM> promotes cutting of tissue near the edge <NUM> of the cut electrode <NUM>, rather than merely "cooking" or charring of tissue. In some embodiments, the system <NUM> may be configured to: (a) increase the impedance of compressed tissue portions <NUM> disposed between the jaws <NUM> and <NUM> during a seal cycle, (b) maintain a low impedance pillow tissue portions <NUM> during the seal cycle, and (c) subsequently apply a cutting power, with the cut electrode <NUM> being the active electrode, to cut tissue (e.g., tented tissue portion <NUM>). In some embodiments, the system <NUM> is configured to apply a seal cycle, whereby tissue impedance is raised to an impedance of no more than <NUM> Ohms.

In some embodiments, the system <NUM> is configured to cut through <NUM> centimeters of mesentery tissue in <NUM> seconds or less, without leaving any tissue tags.

<FIG> illustrate cross-sectional views of the edge <NUM> of the cut electrode <NUM> including a graphical representation of current density during the cut cycle, according to embodiments of the disclosed inventions. <FIG> depicts a zoomed-in cross-sectional view of the edge <NUM> of the cut electrode <NUM> of <FIG>, <FIG>, <FIG> and <NUM> having a rounded, curved, and/or convex profile. As shown in <FIG>, the cut electrode <NUM> is active during the cut cycle, such that current is distributed, substantially uniform, along the rounded conductive edge <NUM>. As previously disclosed, the cut electrode <NUM> comprises insulation <NUM>, making the sides of the cut electrode <NUM> non-conductive (<FIG> illustrates an alternative edge <NUM>" of the cut electrode <NUM>, where the edge <NUM>" comprises rounded corners 134a and a straight portion 134b therebetween. The alternative edge <NUM>" is prone to create current concentrations at the corners 134a (<FIG>); thus, edge <NUM>" includes a less uniform current distribution that the edge <NUM> of <FIG>. In prior art devices, the edge of the cut electrode is sharp (not shown), which creates current concentrations at the sharp edge, reducing the effectiveness of the cutting power.

In some embodiments, the cut electrode <NUM> is shaped and configured to maximize a current concentration at the edge <NUM> of the cut electrode <NUM> during the cut cycle, while the second seal surface <NUM> is shaped and configured to minimize a current concentration at the seal surface <NUM> during the cut cycle. In some embodiments, the cut electrode <NUM> and the second seal surface <NUM> may be configured to create a monopolar tissue effect during a cut cycle, as previously disclosed. In alternative embodiments of the cut cycle, one of the seal surfaces <NUM> or <NUM> is exposed/conductive, while the other one is insulated, such that the exposed/conductive seal surface acts as a dispersive or return electrode of the cut electrode <NUM> during the cut cycle.

During the cut cycle, the second seal surface <NUM> or core member <NUM> may function as a dispersive electrode. In some embodiments, the first seal surface <NUM> or core member <NUM> may function as a dispersive electrode. In some embodiments, the first seal surface <NUM> and the second seal surface <NUM>, or core members <NUM>, <NUM>, may both function as a dispersive electrode.

<FIG> illustrates a method <NUM> for sealing and cutting tissue, according to the embodiments of the inventions. The medical system <NUM> is configured to be used in the manner, actions, and/or steps described by method <NUM>.

The method <NUM> may include compressing <NUM> tissue grasped, held, disposed, and/or restrained between a pair of jaws of a medical device (e.g., surgical instrument). The method <NUM> may include applying a seal cycle <NUM> to the tissue held between the pair of jaws. The seal cycle having a maximum power of <NUM> Watts, to cause the tissue held between the pair of jaw to develop an impedance of <NUM> Ohms or less. After the seal cycle <NUM> is performed, the method <NUM> may include, applying a cut cycle <NUM> to the tissue held between the pair of jaws. The cut cycle having a maximum power of <NUM> Watts, to divide the tissue held between the pair of jaws, wherein the applying the cut cycle includes placing an active electrode and a dispersive electrode in contact with the tissue held between the pair of jaws. The seal cycle <NUM> may be configured to apply a sealing power selected to avoid causing thermal spread to tissue adjacent a cut electrode.

<FIG> illustrates a method <NUM> of dividing or cutting tissue, according to the embodiments of the inventions. The method <NUM> may be performed by the system <NUM> described herein and/or may be a method of applying a cut cycle. The method <NUM> may be performed in conjunction with method <NUM>.

The method <NUM> may include positioning <NUM> tissue in electrical communication with an active electrode and a dispersive electrode. The method <NUM> may include applying <NUM> RF energy to the tissue to divide or severed the tissue. The RF energy having a maximum power of <NUM> Watts or less, a maximum current of <NUM> Amperes RMS or less, and a maximum voltage of <NUM> Volts rms or less.

In some embodiments, the applying RF energy to divide the tissue <NUM> comprises dividing the tissue in <NUM> second or less. In some embodiments, the dividing the tissue <NUM> comprises dividing the tissue in <NUM> seconds or less. In some embodiments, the dividing the tissue <NUM> comprises dividing the tissue in <NUM> seconds or less. In some embodiments, the dividing the tissue <NUM> comprises dividing the tissue in <NUM> seconds or less. In some embodiments, the dividing the tissue <NUM> comprises dividing the tissue in <NUM> seconds or less. In some embodiments, the dividing the tissue <NUM> comprises dividing the tissue in about <NUM> seconds, or in between about <NUM> seconds and about <NUM> seconds.

In some embodiments, the RF energy <NUM> has a maximum power of <NUM> Watts. In some embodiments, the RF energy <NUM> has a maximum power of <NUM> Watts nominal. In some embodiments, the RF energy <NUM> has a maximum voltage of <NUM> Volts rms. In some embodiments, the RF energy <NUM> has a maximum voltage of <NUM> Volts rms nominal.

In some embodiments, the power, voltage, and current are allowed to float up to the maximum power, maximum voltage, and maximum current in response to a change in an impedance of the tissue during the application of the cut cycle.

In some embodiments, the positioning the tissue <NUM> comprises positioning tissue having a maximum impedance of <NUM> Ohms or less. In some embodiments, the positioning the tissue <NUM> comprises positioning tissue having a maximum impedance of <NUM> Ohms or less. In some embodiments, all tissue providing electrical continuity between the active electrode such as the cut electrode <NUM> and the dispersive electrode such as seal surface <NUM>, <NUM> or core member <NUM>, <NUM> has an impedance of <NUM> Ohms or less, or <NUM> Ohms or less, or <NUM> Ohms or less.

In some embodiments, the dividing the tissue <NUM> comprises raising the impedance of at least a portion of the tissue in electrical continuity between the active electrode and the dispersive electrode to <NUM>,<NUM> Ohms or more. In some embodiments, the dividing the tissue <NUM> comprises raising the impedance of the tissue to <NUM>,<NUM> Ohms or more.

It should be appreciated that the methods <NUM> and/or <NUM> may include other actions and/or steps disclosed throughout this application and/or in the patents and applications incorporated by reference herein.

In some embodiments, the system <NUM> and/or method <NUM> may include applying a first cut cycle for a period of time of between about <NUM> milliseconds and about <NUM> milliseconds, or about <NUM> milliseconds, followed by a rest period of between about <NUM> milliseconds and about <NUM> milliseconds, followed by a second cut cycle for a period of time of between about <NUM> milliseconds and about <NUM> milliseconds, or about <NUM> milliseconds. The power algorithm described or incorporated by references herein typically completes the tissue cut in the first cut cycle, but the second cut cycle may be applied without harm, to confirm the first cut cycle was successful. The application of two cut cycles in this manner may insure a <NUM>% cut success rate.

In some embodiments, the system <NUM> and method <NUM> may include applying a first seal cycle followed by two cut cycles and a second seal cycle, with a rest period between each cycle. In some embodiments, the second seal cycle may be followed by two cut cycles, with a rest period between each cycle. The rest periods may serve to limit thermal spread, thus improving the cut performance.

In some embodiments, the system <NUM> and/or method <NUM> and <NUM> include a single generator or providing a single generator configured to output a seal cycle followed by a cut cycle. The device <NUM> may include three electrodes (e.g., seal surfaces <NUM>, <NUM> and the cut electrode <NUM>) or any other suitable number of electrodes configured to apply seal and cut cycles.

In some embodiments, the system <NUM> and/or method <NUM> and <NUM> may include controlling a current density at or adjacent the cut electrode <NUM> during the cut cycle. The current density may be between about <NUM> Amperes per square inch and about <NUM> Amperes per square inch. The current density may be between <NUM> Amperes per square inch and about <NUM> Amperes per square inch. The current density may be greater than <NUM> Amperes per square inch during the application of the maximum power during the cut cycle. The current density may be greater than <NUM> Amperes per square inch during the application of the maximum power during the cut cycle.

<FIG> illustrate alternative embodiments of the end effector <NUM> of the medical device, according to the disclosed inventions. As shown in <FIG> and <FIG>-11E the seal surface <NUM> of the second jaw <NUM> comprises the first rounded edge portion <NUM> having a radius R1 (<FIG>). The first rounded edge portion <NUM> may be shaped to limit current concentrations near the seal surface <NUM>, such as, during the seal cycle. The radius R1 of the rounded edge portion <NUM> is configured to avoid current concentrations, thereby limiting tissue effects near the edge of the seal surface <NUM> during the seal cycle and/or during a cut cycle. Reducing current concentrations near the seal surface <NUM> may reduce thermal spread during the seal cycle. In some embodiments, the rounded edge portion <NUM> has a radius R1 of <NUM> millimeters or more. The first rounded edge portion <NUM> and radius R1 may be on an exterior wall (e.g., further away from the cut electrode <NUM>) of the jaw <NUM>.

Those skilled in the art will recognize that alternative end effector <NUM> and jaw configurations, such as <FIG>, may be provided to avoid current concentrations on an interior portion (e.g., near the cut electrode <NUM>) of one or both jaws <NUM>, <NUM> during the cut cycle. Optionally, the end effector <NUM> may comprise cut electrodes <NUM> of various heights (e.g., <FIG>) and/or various configurations of the core members <NUM>, <NUM> and/or width of the seal surfaces <NUM>, <NUM> (<FIG>).

For example, insulators <NUM>, <NUM> may be provided on the inner/interior corners of the dispersive electrode(s) (e.g. core members <NUM>, <NUM>) or seal surface(s) <NUM>, <NUM> of the jaw(s) <NUM>, <NUM>, so as to avoid current concentrations during the cut cycle, as shown in <FIG>, and better appreciated in <FIG>.

In another example, and as shown in <FIG>, the seal surfaces <NUM>, <NUM> or dispersive electrodes may include a second rounded edge portions <NUM>, <NUM> having a radius R3, R4 selected to limit current concentrations near the surfaces <NUM>, <NUM> during the cut cycle. In devices where the seal electrode edges are sharp, current concentration on the sharp edges can cause undesirable arcing, cutting and tissue sticking. In some embodiments, the second rounded edge portions <NUM>, <NUM> of the dispersive electrodes are selected to have a radius R3, R4 that is <NUM>% greater than a profile radius R2 of the edge <NUM> of the cut electrode <NUM>, or more. In some embodiments, the rounded edge portions <NUM>, <NUM> of the dispersive electrodes or core members <NUM>, <NUM> are selected to have a radius R3, R4 that is <NUM>% greater than a profile radius R2 of the edge <NUM> of the cut electrode <NUM>, or more. In some embodiments, the rounded edge portions <NUM>, <NUM> are selected to have a radius R3, R4 that is <NUM>% greater than a profile radius R2 of the edge <NUM> of the cut electrode <NUM>, or more. In some embodiments, the cut electrode <NUM> has a radius R2 of <NUM> inches or more.

<FIG> illustrates an exemplary seal cycle <NUM> of the medical system <NUM>, according to the disclosed inventions. When the system <NUM> is actuated and/or activated, such as by a user activating the actuator <NUM>, which activates the power source <NUM>, to perform the method <NUM>, or <NUM>, the system <NUM> applies a seal cycle, shown at time zero. The time scale of <FIG> is seconds. In <FIG>, the scale for power1 is times <NUM>, the scale for voltage1 is times <NUM>, the scale for current1 is times <NUM>, and the scale for impedance1 is <NUM>.

The system <NUM> is configured to detect the impedance <NUM> of tissue compressed between the jaws <NUM> and <NUM> (e.g., compressed tissue <NUM> in <FIG>). While the tissue impedance <NUM> is relatively low, the maximum power <NUM>, such as <NUM> Watts nominal (<FIG>), may be reached and controlled. To maintain the maximum power <NUM>, the voltage <NUM> and current <NUM> may fluctuate in response to changes in the impedance <NUM> of the compressed tissue <NUM> between the jaws <NUM> and <NUM>.

When the system <NUM> detects that the impedance <NUM> of the compressed tissue <NUM> has reached a threshold impedance level (e.g., a threshold between <NUM> to <NUM> Ohms), the system <NUM> is configured to discontinue applying the seal cycle <NUM>. In some embodiments, the time of the seal cycle <NUM> may be <NUM> seconds or less. Optionally, the time of the seal cycle <NUM> may be <NUM> second or less. Alternatively, the time of the seal cycle <NUM> may be <NUM> seconds or less for tissue having a larger cross section.

After the seal cycle <NUM> is applied to the tissue <NUM>, the system <NUM> may allow a rest time before applying a cut cycle. The rest time may be between <NUM> milliseconds and <NUM> milliseconds.

<FIG> illustrates an exemplary cut cycle <NUM> of the system <NUM>, according to the disclosed inventions. In <FIG>, the scale for power <NUM> is times <NUM>, the scale for voltage2 is times <NUM>, the scale for current2 is times <NUM>, and the scale for impedance2 is times <NUM>. After the seal cycle <NUM> (or after the rest time), the system <NUM> may apply a cut cycle <NUM> to the tissue restrained between the jaws <NUM> and <NUM>; particularly, to the tented tissue portion <NUM> disposed between the support surface <NUM> and the cut electrode <NUM> (e.g., edge <NUM>, as shown in <FIG>). The cut cycle <NUM> starts at time zero, as shown in <FIG>. The cut cycle <NUM> may be configured and applied as described with respect to method <NUM>. The cut cycle <NUM> may raise the tissue impedance <NUM> significantly, such as to over <NUM>,<NUM> Ohms, as shown in <FIG>. Alternatively, the cut cycle <NUM> may raise the tissue impedance <NUM> such as to <NUM>,<NUM> Ohms or more, or <NUM>,<NUM> Ohms or more, or to <NUM>,<NUM> Ohms or more. The system <NUM> is configured to discontinue the cut cycle <NUM> when the tissue impedance <NUM> is raised at the limits previously described, and/or after approximately <NUM> seconds to <NUM> seconds after starting the cut cycle <NUM>. The system <NUM> may stop the cut cycle after a successful cut, as shown in <FIG> by the quick drop in impedance <NUM> at about <NUM> seconds. The system <NUM> may apply a second cut cycle, such as to confirm the first cut cycle was successful, shown in <FIG> starting at about <NUM> seconds, shown by the quick rise in impedance <NUM> after the drop.

In some embodiments, the system <NUM> is configured to maintain a substantial constant power <NUM> during the seal cycle and/or cut cycle. In order to maintain the substantial constant power <NUM>, the system <NUM> will increase voltage <NUM> and decrease current <NUM> or decrease voltage <NUM> and increase current <NUM>, in response to changes in the impedance <NUM> of the compressed tissue <NUM> between the jaws <NUM> and <NUM>. For example, as shown in <FIG>, when impedance <NUM> drops, voltage <NUM> is increased and current <NUM> is decreased, so the slight drop in power <NUM> is adjusted back to remain substantially constant.

<FIG> illustrates a detailed view of the exemplary cut cycle <NUM> of <FIG>, according to the disclosed inventions. <FIG> graph omits portions of the impedance <NUM>. As shown in <FIG>, during a first cut cycle <NUM>, the system <NUM> will quickly increase power <NUM> to a maximum power (approximately <NUM> watts) while voltage <NUM> is relatively low. As the impedance <NUM> of the tissue changes, however, the power <NUM> will drop and the voltage <NUM> will increase. If the first cut cycle <NUM> is successful, a second cut cycle <NUM> will result in high impedance <NUM>, with the system <NUM> at maximum voltage <NUM>, maximum power <NUM>, and low current <NUM>. Note the difference between the power <NUM> output shown in <FIG> before the impedance <NUM> drops (e.g., signaling a break between the first cut cycle and the second cut cycle) and after the impedance <NUM> is raised once more.

In some embodiments, the power <NUM>, voltage <NUM>, and current <NUM> are allowed to float up to the maximum power, maximum voltage, and maximum current in response to a change in impedance <NUM> of the tissue <NUM> during the application of the cut cycle.

Claim 1:
A surgical system (<NUM>) for sealing and severing tissue, the system comprising:
a generator (<NUM>) configured to output radiofrequency, RF, energy, including delivering a first RF power signal during a seal cycle, and delivering a second RF power signal during a cut cycle; and
a surgical device (<NUM>) electrically coupled to the generator output, the device comprising
an elongate shaft (<NUM>);
an end effector (<NUM>) coupled to a distal end portion of the elongate shaft (<NUM>), wherein the elongate shaft defines a longitudinal axis (<NUM>), and wherein the end effector comprises first and second jaws (<NUM>, <NUM>) configured to approximate each other in a closed position for compressing tissue (<NUM>) extending therebetween, the first and second jaws (<NUM>, <NUM>) having respective opposing conductive seal surface electrodes (<NUM>, <NUM>) configured for sealing spaced apart first and second portions of the compressed tissue (<NUM>) when the first RF power signal is conducted through a circuit including the respective seal surface electrodes (<NUM>, <NUM>) during a seal cycle; and
a cut electrode (<NUM>) disposed within an interior region of the first jaw (<NUM>), wherein the cut electrode (<NUM>) is aligned with the longitudinal axis and has an elongate conductive edge (<NUM>) with a convex cross-section profile taken perpendicular to the longitudinal axis (<NUM>), the cut electrode having a height profile greater than the seal surface electrodes (<NUM>, <NUM>) of the first jaw (<NUM>), and wherein when the first and second jaws (<NUM>, <NUM>) are in the closed position compressing the tissue, the elongate conductive edge (<NUM>) of the cut electrode (<NUM>) presses against a third portion of the tissue (<NUM>) located between the spaced apart first and second portions (<NUM>),
wherein the cut electrode (<NUM>) is configured to sever the third portion of the tissue (<NUM>) when the second RF power signal is conducted through a circuit including the cut electrode (<NUM>) and a respective one of the seal surface electrodes (<NUM>, <NUM>) during a cut cycle.