WO2016100664A1

WO2016100664A1 - Surgical device

Info

Publication number: WO2016100664A1
Application number: PCT/US2015/066376
Authority: WO
Inventors: Ryan C. Abbott
Original assignee: Maquet Cardiovascular Llc
Priority date: 2014-12-17
Filing date: 2015-12-17
Publication date: 2016-06-23

Abstract

In accordance with one aspect of this disclosure, an end effector assembly for a surgical device includes: a first jaw having a first engagement surface; a second jaw having a second engagement surface, wherein the jaws are movable between open and closed configurations, and are arranged to receive tissue therebetween when open and to exert force on tissue when closed; and a drive assembly operatively connected to at least the first jaw to move at least the first jaw to transition the jaws between the open and closed configurations. The jaws variably exert force on tissue as a function of distance between engagement surfaces so forces applied to tissue by the jaws progressively increase when the engagement surfaces are spaced a first set of distances from each other and these forces substantially plateau when the engagement surfaces are spaced a second set of distances from each other, wherein the first distances are greater than the second distances. In accordance with another aspect of this disclosure, an end effector assembly for a surgical device includes first and second jaws having first and second engagement surfaces, respectively, wherein one or both jaws are movable with respect to the other jaw to transition between open and closed configurations. The jaws receive tissue therebetween when open and exert force on tissue via the engagement surfaces when closed. A drive assembly is operatively connected to at least one jaw, and is operable to transition the jaws between the open and closed configurations, so the jaws variably exert force on tissue as a function of distance between the first and second engagement surfaces. A first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw, so distance between the first and second electrodes varies along a width of the jaws to provide multiple varied distances along the width of the jaws. In accordance with yet another aspect of this disclosure, a surgical device includes a handle portion at a proximal portion, an elongated portion extending distally from the handle portion, and first and second jaws at a distal portion of the device, each jaw having an engagement surface. A drive assembly extends through the elongated portion, and is operable to move at least the first jaw to transition the jaws between open and closed positions. The jaws are arranged to receive tissue therebetween when in the open position and to exert force on tissue via the engagement surfaces when in the closed position. A first electrode is disposed on the first jaw, a second electrode is disposed on the second jaw, and a power switch positioned at the proximal portion is operable to supply energy to the first and second electrodes, although energy cannot be applied to the first and second electrodes unless the first and second jaws are closed. In accordance with still another aspect of this disclosure, a method for minimally invasively sealing parenchyma includes the steps of: preparing a device having a handle portion at a proximal portion, an elongated tubular portion extending distally from the proximal portion, and first and second jaws at a distal portion of the device; minimally invasively inserting the device so the first and second jaws are adjacent the parenchyma; positioning the jaws in an open position around the parenchyma; actuating a jaw actuator so the jaws transition to a closed position to clamp parenchyma, wherein force exerted by the jaws on parenchyma varies dependent on a gap between the jaws, the force increasing a first percentage upon initial clamping and subsequently varying a second percentage upon further clamping of the jaws, wherein the second percentage is substantially less than the first percentage; and applying energy to electrodes carried by the first jaw and by the second jaw.

Description

SURGICAL DEVICE

[0000] This application claims priority to, and the benefit of, the following United States Provisional Applications: United States Provisional Application No. 62/092,951, filed

December 17, 2014; United States Provisional Application No. 62/092,966, filed December 17, 2014; United States Provisional Application No. 62/092,974, filed December 17, 2014; and U.S. Provisional Application No. 62/092,981, filed December 17, 2014. The entire disclosures of the above applications are incorporated herein by reference.

BACKGROUND

[0001] Surgical devices are known in the health care industry for assisting medical professionals in the performance of a myriad of medical procedures. One type of device includes an end effector assembly at one end of a shaft that is controllable by a user holding or operating the device via a handle positioned at an opposite proximal end of the shaft. End effector assemblies may include jaws, staplers, bipolar sealers, monopolar sealers, and other components. There is an ever-present desire in the medical industry for new and alternate surgical devices, particularly those that enable procedures to be performed more effectively, efficiently, or under a wider array of scenarios and conditions. Certain devices are limited to a small range of tissue thicknesses. It would be beneficial to provide surgical devices with applications to a broad range of tissue thicknesses.

SUMMARY

[0002] The devices and methods of the present disclosure overcome the disadvantages and deficiencies of the prior art.

[0003] In accordance with a first aspect of the present disclosure an end effector assembly for a surgical device is provided comprising a first jaw having a first engagement surface and a second jaw having a second engagement surface. At least the first jaw is movable with respect to the second jaw to transition the first jaw and the second jaw between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert a force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration. A drive assembly is operatively connected to at least the first jaw. The drive assembly is operable to move at least the first jaw to transition the first jaw and the second jaw between the open configuration and the closed configuration, wherein the drive assembly moves the first jaw so that the first jaw and the second jaw variably exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve. The force curve is shaped so that the force exerted on the tissue is greater than a threshold force when the distance between the first engagement surface and the second engagement surface is less than a threshold distance and the force exerted on the tissue is less than the threshold force when the distance between the first engagement surface and the second engagement surface is greater than the threshold distance.

[0004] In some embodiments, in accordance with the first aspect, the threshold force is in a range of about 18 pounds to about 19 pounds and the threshold distance is between about 1.5 mm and about 3.5 mm, and in some embodiments, the threshold distance is between about 2.5mm and about 3.0 mm.

[0005] The force curve is preferably non-linear and in preferred embodiments, has a progressive slope when the first and second jaws are at a first range of distances and the force curve substantially plateaus when the first and second jaws are at a second range of distances.

[0006] In some embodiments, in accordance with the first aspect, a first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw so that thermal energy, or radiofrequency energy, or both the thermal energy and the radiofrequency energy, are communicated through the tissue to seal or weld the tissue. The first and second electrodes can extend in a substantially U-shape configuration spaced inwardly from a peripheral edge of the respective first and second jaws, and a non-conductive material can be positioned within the U- shape of the second electrode. [0007] In some embodiments, in accordance with the first aspect, a first slot is provided in the first jaw and a second slot is provided in the second jaw, the first jaw having a longitudinal axis and the first slot having a region angled with respect to the longitudinal axis of the first jaw, and a drive pin is movable within the first slot to rotate the first jaw toward the second jaw.

[0008] In preferred embodiments, in accordance with the first aspect, the drive assembly sets the force exerted by the first and second jaws on tissue in response to thickness of tissue.

[0009] In some embodiments, in accordance with the first aspect, both the first and second jaws are movable toward each other by the drive assembly; in other embodiments the second jaw is stationary and the first jaw is moved toward and away from the second jaw.

[0010] In accordance with a second aspect of the present disclosure, an end effector assembly for a surgical device is provided comprising a first jaw having a first engagement surface and a second jaw having a second engagement surface, at least the first jaw movable with respect to the second jaw to transition the first jaw and the second jaw between an open configuration and a closed configuration. The first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration. A drive assembly is operatively connected to at least the first jaw and operable to move at least the first jaw to transition the first jaw and the second jaw between the open configuration and the closed configuration, wherein the drive assembly moves at least the first jaw so that the first jaw and the second jaw variably exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface such that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

[0011] In some embodiments, in accordance with the second aspect, a threshold distance separates the first set of distances from the second set of distances. In some embodiments, the threshold distance is between about 3.0 mm and about 2.5 mm. Preferably, the forces exerted during the first set of distances varies greatly as compared to the forces exerted during the second set of distances which vary slightly. In some embodiments, the forces exerted during the first set of distances increases more than 25% and the forces exerted during the second set of distances changes less than 5%.

[0012] In preferred embodiments, in accordance with the second aspect, the first set of distances has a percentage force several times greater than a percentage force change over the second set of distances.

[0013] In some embodiments, in accordance with the second aspect, the variation of forces is obtained by a geometry of a first slot in the first jaw. The first slot in the first jaw can include an offset region offset from a longitudinal axis of the first jaw such that the slot is nonlinear, and the offset region effecting a degree of rotation of the first jaw with respect to the second jaw. The first jaw in some embodiments can include an arm and a float portion having a first electrode, wherein the float portion is rotatably connected to the first arm to enable the electrode to float with respect to the arm.

[0014] In some embodiments, in accordance with the second aspect, both the first and second jaws are movable toward each other by the drive assembly; in other embodiments the second jaw is stationary and the first jaw is moved toward and away from the second jaw.

[0015] In some embodiments, in accordance with the second aspect, a first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw. A spacer can be provided extending from the first jaw to maintain a minimum distance between the first and second engagement surfaces.

[0016] In accordance with a third aspect of the present disclosure, a surgical device is provided comprising a handle portion, an elongated tubular portion extending distally from the handle portion, a first jaw having a first engagement surface, and a second jaw having a second engagement surface. At least the first jaw is movable to transition the first jaw and the second jaws between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration. A drive assembly is operable to drive at least the first jaw to transition the first and second jaws between the open configuration and the closed configuration, wherein the drive assembly is operable so the first jaw and the second jaw variably exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that the force exerted on the tissue when the first engagement surface and second engagement surfaces are spaced a first range of distances changes a first percentage and the force exerted on the tissue when the first engagement surface and the second engagement surfaces are spaced a second range of distance changes a second percentage, the second percentage being less than the first percentage.

[0017] In preferred embodiments, in accordance with the third aspect, the forces exerted on tissue during the first range of distances progressively increases and the forces exerted on tissue during the second range of distances varies slightly. In some embodiments, the forces exerted on tissue during the second range of distances substantially plateaus.

[0018] In some embodiments, in accordance with the third aspect, the drive assembly includes a force transfer member extending through the elongated position and a compression spring biasing the force transfer member in a distal direction. A collar movable independently of the force transfer member could be provided.

[0019] In some embodiments, in accordance with the third aspect, the force transfer member is operatively connected to the first jaw, and the first jaw has a non-linear slot, and the force transfer member moves a drive pin within the non-linear slot to pivot the first jaw toward the second jaw. The force transfer member can be movable proximally to pivot the first jaw toward the second jaw. A movable handle can be provided that is operable to retract the force transfer member to move the first jaw toward the second jaw.

[0020] A movable cutting blade can be provided that is movable to sever tissue clamped between the first and second jaws. In some embodiments, a first electrode is disposed on the first jaw and a second electrode disposed on the second jaw. A spacer could be provided extending from the first jaw to maintain a minimum distance between the first and second electrodes.

[0021] In accordance with a fourth aspect of the present disclosure, an end effector assembly for a surgical device is provided comprising a first jaw having a first engagement surface and a second jaw having a second engagement surface, at least one of the first and second jaws movable toward the other jaw to transition the first and second jaws between an open configuration and a closed configuration. The first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration. A drive assembly is operatively connected to one or both of the first jaw and second jaw, the drive assembly operable to transition the first and second jaws between the open configuration and the closed configuration, wherein the drive assembly is operable so that the first jaw and the second jaw variably exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface. A first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw, at least one of the first electrode and second electrode being tapered radially outwardly in opposing directions from an intermediate portion so in the closed configuration the distance between the first electrode and second electrode is greater at a portion closer to a peripheral portion than at a portion closer to a center portion of the jaw.

[0022] In some embodiments, in accordance with the fourth aspect, both the first electrode and the second electrode are tapered radially outwardly in opposing directions from an intermediate portion. In some embodiments, one or both of the first and second electrodes is tapered in a distal direction at a distal tip. In some embodiments, one or both of the first and second electrodes is U-shaped in configuration. One or both of the first and second jaws can have an insulating material positioned within the U-shaped electrode. In some embodiments, one or both of first and second engagement surfaces is nonlinear.

[0023] In some embodiments, in accordance with the fourth aspect, a conductive protrusion extends from the first electrode to maintain a minimum spacing between the first and second electrodes. [0024] In some embodiments, in accordance with the fourth aspect, the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances. In preferred embodiments, the force curve is non-linear.

[0025] In accordance with a fifth aspect of the present disclosure, an end effector assembly for a surgical device is provided comprising a first jaw having a first engagement surface and a second jaw having a second engagement surface. At least one of the first jaw and second jaw is movable with respect to the other jaw to transition the first jaw and the second jaw between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration. A drive assembly is operatively connected to at least one of the first jaw and second jaw, the drive assembly operable to transition the first jaw and the second jaw between the open configuration and the closed configuration, wherein the drive assembly is operable so that the first jaw and the second jaw variably exert the force on the tissue as a function of distance between the first engagement surface and the second engagement surface. A first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw, wherein the distance between the first and second electrodes varies along a width of the jaws to provide multiple varied distance along the width of the jaws.

[0026] In some embodiments, in accordance with the fifth aspect, the first jaw is movable toward the second jaw and the second jaw is stationary; in other embodiments both jaws are movable toward each other.

[0027] In some embodiments, in accordance with the fifth aspect, the distance between the first and second electrodes varies along a length of the first and second jaws. In some embodiments, one or both of the first engagement surface and second engagement surface is nonlinear.

[0028] In some embodiments, in accordance with the fifth aspect, one or both of the first electrode and second electrode is non-linear and is tapered radially outwardly from an intermediate portion so in the closed configuration the distance between the first electrode and second electrode is greater at a portion closer to a periphery than at a portion closer to a center of the jaw to vary the distance along the width of the jaws.

[0029] In some embodiments, in accordance with the fifth aspect, the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

[0030] In some embodiments, in accordance with the fifth aspect, one or more conductive protrusions extends radially from the first electrode in a direction toward the second jaw when the first and second jaws are moved to the closed position to maintain a minimum spacing between the first and second electrodes.

[0031] In some embodiments, in accordance with the fifth aspect, one or both of the first and second electrodes extend in a substantially U-shape spaced inwardly from a peripheral edge of the respective first and second jaws. A non-conductive material can be positioned adjacent the second electrode and the conductive protrusion(s) can be engageable with the non-conductive material.

[0032] In accordance with a sixth aspect of the present disclosure, an end effector assembly for a surgical device is provided comprising a first jaw having a first engagement surface, and a second jaw having a second engagement surface. At least one of the first jaw and second jaw is movable with respect to the other jaw to transition the first jaw and the second jaw between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration. A drive assembly is operatively connected to at least one of the first jaw and second jaw, the drive assembly operable to transition the first jaw and the second jaw between the open configuration and the closed configuration, wherein the drive assembly is operable so that the first jaw and the second jaw variably exert the force on the tissue as a function of distance between the first engagement surface and the second engagement surface. A first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw. A first conductive protrusion extends radially from the first electrode in a direction toward the second jaw when the first and second jaws transition to the closed position to maintain a minimum spacing between the first and second electrodes.

[0033] In some embodiments, in accordance with the sixth aspect, the first conductive protrusion is integrally formed with the first electrode. In some embodiments, the first conductive protrusion is spaced proximally from a distal tip of the electrode. A second conductive protrusion could be provided, wherein the second conductive protrusion is spaced axially from the first conductive protrusion. The second conductive protrusion can be spaced distally from a proximal end of the first electrode. In some embodiments, the second jaw includes a non-conductive material adjacent the second electrode and the first protrusion is engageable with the non-conductive material. In some embodiments, the non-conductive material is substantially flush with the second engagement surface; in other embodiments it is recessed with respect to the second engagement surface.

[0034] In some embodiments, in accordance with the sixth aspect, one or both of the first electrode and second electrode tapers radially outwardly from an intermediate portion so the distance between the first electrode and second electrode is greater at a portion closer to a peripheral edge than at a portion closer to a center of the jaw.

[0035] In some embodiments, in accordance with the sixth aspect, the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances. In some embodiments, the variation of forces is obtained by a non-linear slot formed in the first jaw.

[0036] In some embodiments, in accordance with the sixth aspect, the first jaw includes an arm and a float portion having the first electrode, the float portion rotatably connected to the first arm to enable the first electrode to float with respect to the arm.

[0037] In accordance with a seventh aspect of the present disclosure a surgical device is provided comprising a handle portion at a proximal portion of the device, an elongated portion extending distally from the handle portion, and a first jaw and a second jaw at the distal portion of the device. The first jaw has a first engagement surface and the second jaw has a second engagement surface. A drive assembly extends through the elongated portion. The drive assembly is operable to move at least the first jaw to transition the first jaw and the second jaw between an open position and a closed position, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open position and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed position. A first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw. A power switch is positioned at the proximal portion of the device and is operable to supply energy to the first and second electrodes, wherein energy cannot be applied to the first and second electrodes unless the first and second jaws are in the closed position.

[0038] In some embodiments, in accordance with the seventh aspect, the handle portion includes a movable handle operably connected to the drive assembly and actuable from a first position to a second position to move the drive assembly to position the jaws in the closed position. In some embodiments, the movable handle moves the first jaw with respect to the second jaw between the open and closed position while the second jaw remains stationary. In other embodiments, both jaws move toward and away from each other.

[0039] In some embodiments, in accordance with the seventh aspect, the device includes an actuator for turning on the power switch and a cover adjacent the actuator, wherein the cover blocks user access to the actuator when the jaws are in the open position and enables user access to the actuator when the jaws are in the closed position. In some embodiments, the cover is attached to the movable handle and moves with movement of the movable handle. In some embodiments, in the first position of the movable handle the cover extends further distally than the actuator and in the second position of the handle the cover has moved proximally so the actuator extends distally of the cover. The cover can selectively block and unblock user access to the power switch.

[0040] The actuator can be in the form of an actuation button. The actuator can be recessed when the movable handle is in the first position. The actuator can be hidden when the movable handle is in the first position.

[0041] In some embodiments, in accordance with the seventh aspect, a cutting blade is provided which is movable with respect to the first and second jaws to sever tissue clamped between the first and second jaws.

[0042] In some embodiments, in accordance with the seventh aspect, the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

[0043] In accordance with an eighth aspect of the present disclosure, a surgical device is provided comprising a handle portion at a proximal portion of the device, an elongated portion extending distally from the handle portion, and a first jaw and a second jaw at the distal portion of the device. The first jaw has a first engagement surface and the second jaw has a second engagement surface. A drive assembly extends through the elongated portion, the drive assembly operable to transition the first jaw and the second jaw between an open position and a closed position, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open position and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed position. A first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw. An energy actuator is positioned at the proximal portion of the device and operable to supply energy to the first and second electrodes. A cover is movable with respect to the energy actuator to selectively block and unblock access to the energy actuator.

[0044] In some embodiments, in accordance with the eighth aspect, the drive assembly includes a force transfer member extending through the elongated portion and a jaw actuator for advancing and retracting the force transfer member, the cover extending from the jaw actuator so that movement of the jaw actuator moves the cover with respect to the energy actuator.

[0045] The device can further include a cutting blade movable with respect to the first and second jaws, and a blade actuator actuable independently from the jaw actuator to advance the blade to sever tissue clamped between the first and second jaws. A blade blocking mechanism can be provided which prevents movement of the cutting blade unless the first and second jaws are in the closed position.

[0046] In some embodiments, in accordance with the eighth aspect, the first and second jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

[0047] In accordance with a ninth aspect of the present disclosure, a surgical device is provided comprising a handle portion at a proximal portion of the device, an elongated portion extending distally from the handle portion, and a first jaw and a second jaw at the distal portion of the device. The first jaw has a first engagement surface and the second jaw has a second engagement surface. A drive assembly extends through the elongated portion, the drive assembly operable to transition the first jaw and the second jaw between an open position and a closed position, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open position and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed position. A first actuator at the handle portion is operably connected to the drive assembly to move the drive assembly between distal and proximal positions. A first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw. A power switch is positioned at the proximal portion of the device and operable to supply energy to the first and second electrodes. A blade is movable with respect to the first and second jaws to sever tissue clamped between the first and second jaws. A second actuator is operably connected to the blade to move the blade between proximal and distal positions. A blade lock prevents movement of the blade if the first and second jaws are not in the closed position, and the blade lock includes an engagement member so that when the first and second jaws are in the open position forces exerted on the second actuator are transferred to the first actuator in a direction substantially perpendicular to a direction of actuation of the first actuator so such forces will not move the first actuator.

[0048] In some embodiments, in accordance with the ninth aspect, the blade lock includes a blocking arm which blocks movement of the engagement member, and the blocking arm can extend from the first actuator and the engagement member can extend from the second actuator. In some embodiments, the first actuator includes a movable handle movable in a proximal direction to move the first and second jaws to the closed position and the second actuator is pivotable about an axis extending transverse to a longitudinal axis of the device.

[0049] In some embodiments, in accordance with the ninth aspect, the first actuator has a pair of arms extending distally therefrom, and the engagement member abuts the arms in the initial position of the first actuator.

[0050] In some embodiments, in accordance with the ninth aspect, energy cannot be applied to the first and second electrodes unless the first and second jaws are in the closed position. The device can further include a cover movable with respect to the power switch to prevent application of energy to the first and second electrodes if the first and second jaws are not in the closed position. The first actuator can include a movable handle, and the cover can extend from the movable handle and be movable along with movement of the handle member to selectively block and unblock access to the power switch. [0051] In some embodiments, in accordance with the ninth aspect, the first and second jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

[0052] In accordance with a tenth aspect of the present disclosure, a surgical device is provided comprising a handle portion at a proximal portion of the device, an elongated portion extending distally from the handle portion, and a first jaw and a second jaw at the distal portion of the device. The first jaw has a first engagement surface and the second jaw has a second engagement surface. A drive assembly extends through the elongated portion, the drive assembly operable to move at least the first jaw to transition the first jaw and the second jaw between an open position and a closed position, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open position and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed position. A first electrode is disposed on the first jaw and a second electrode is disposed on the second jaw. A blade is movable with respect to the first and second jaws to sever tissue clamped between the first and second jaws. A feedback mechanism indicates to a user that the blade has been moved with respect to the first and second jaws to sever tissue clamped between the first and second jaws.

[0053] The feedback mechanism can provide tactile feedback and/or audible feedback.

[0054] In some embodiments, in accordance with the tenth aspect, the surgical device includes a blade actuator and the feedback mechanism includes a flexible member, the blade actuator operably connected to the blade, wherein sufficient movement of the blade actuator causes the flexible member to buckle to increase resistance of the blade actuator. Further movement of the blade actuator can cause release of the flexible member. In some embodiments, the feedback mechanism provides feedback prior to full advancement of the blade. [0055] In some embodiments, in accordance with the tenth aspect, the feedback mechanism is positioned within a housing of the handle portion and can include a flexible member, wherein the flexible member resiliency deflects laterally to disengage from a support within the housing.

[0056] In some embodiments, in accordance with the tenth aspect, the device includes a blade actuator operably connected to the blade to move the blade between proximal and distal positions, and a blade lock to prevent actuation of the blade actuator unless the first and second jaws are in the closed position. In some embodiments, a jaw actuator is operably connected to the drive assembly to move the jaws between the open and closed position, wherein movement of the jaw actuator to transition the jaws to the closed position unblocks a blocking mechanism to enable actuation of the blade actuator.

[0057] In some embodiments, in accordance with the tenth aspect, the device can further include a power switch positioned at the proximal portion of the device and operable to supply energy to the first and second electrodes, wherein energy cannot be applied to the first and second electrodes unless the first and second jaws are in the closed position.

[0058] In some embodiments, in accordance with the tenth aspect, the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

[0059] In accordance with an eleventh aspect of the present disclosure, a surgical method for minimally invasively sealing parenchyma is provided comprising: (a) providing and/or preparing a device having a handle portion at a proximal portion, an elongated tubular portion extending distally from the proximal portion, and first and second jaws at the distal portion of the device; (b) minimally invasively inserting the device so the first and second jaws are adjacent the parenchyma; (c) positioning the jaws in an open position around the parenchyma; (d) actuating a jaw actuator so the first and second jaws transition to a closed position to clamp the parenchyma, the force exerted by the first and second jaws on the parenchyma varying dependent on the gap between the first and second jaws, the force increasing a first percentage upon initial clamping and subsequently varying a second percentage upon further clamping of the jaws, the second percentage being substantially less than the first percentage; and (e) applying energy to a first electrode carried by the first jaw and a second electrode carried by the second jaw.

[0060] In some embodiments, in accordance with the eleventh aspect, the step of actuating the jaw actuator moves a force transfer member within the elongated tubular portion to transition the first and second jaws to the closed position. The step of actuating the actuator can move the first jaw toward the second jaw, the second jaw remaining stationary, or alternatively, move both the first and second jaws toward each other.

[0061] In some embodiments, in accordance with the eleventh aspect, the step of moving the force transfer member moves a pin within a non-linear slot in the first jaw. The slot can be configured to control the force exerted by the jaws. In some embodiments, a spring for biasing the force transfer member is provided wherein compression of the spring controls the force exerted by the jaws.

[0062] In some embodiments, in accordance with the eleventh aspect, the force varies slightly once a threshold distance between the first and second jaws is reached. In some embodiments, the threshold distance is between about 2.5 mm and about 3.0 mm. In some embodiments, the force exerted by the first and second jaws in initial clamping is between about 14 pounds and about 19 pounds and the force exerted by the first and second jaws in the further (subsequent) clamping is between about 18 pounds and 19 pounds.

[0063] The method, in some embodiments of the eleventh aspect, further includes the step of advancing a blade to sever tissue clamped by the first and second jaws. The step of advancing the blade is preferably independent of movement of the force transfer member. In some embodiments, the step of advancing the blade cannot be performed if the first and second jaws are not in the closed position. In some embodiments, the step of applying energy cannot be performed unless the first and second jaws are in the closed position. [0064] In some embodiments, in accordance with the eleventh aspect, the gap between the jaws in the closed position varies along a width of the jaws so the gap is greater at a distance further from a center of the jaw than closer to the center of the jaw.

[0065] In accordance with a twelfth aspect of the present disclosure, a method for minimally invasively sealing organ tissue by applying electrosurgical energy to tissue while preventing excessive force on the tissue so that the tissue is not dissected is provided, the method comprising (a) providing and/or preparing a device having a handle portion, an elongated tubular portion extending distally from the proximal portion, a force transfer member extending through the tubular portion and first and second jaws at the distal portion of the device, at least one of the jaws having a slot configured to control forces applied to tissue; (b) minimally invasively inserting the device so the first and second jaws are adjacent the tissue; (c) positioning the first and second jaws in an open position around the tissue; (d) actuating a jaw actuator so the force transfer member engageable with the slot is retracted to move a drive pin proximally within the slot to clamp the first and second jaws on tissue with (i) a first force progressively increasing to a predetermined force when the first and second jaws move through a first range of distances spaced apart from each other (ii) and a second subsequent force which does not progressively increase when the first and second jaws move through a second range of distances to thereby control the forces on tissue and prevent dissection of the tissue; and (e) applying energy to a first electrode carried by the first jaw and a second electrode carried by the second jaw.

[0066] In some embodiments, in accordance with the twelfth aspect, the step of actuating the jaw actuator moves the first jaw toward the second jaw, the second jaw remaining stationary; in other embodiments, the step of actuating the jaw actuator moves both the first and second jaws toward each other.

[0067] In some embodiments, in accordance with the twelfth aspect, a spring is provided for biasing the force transfer member wherein compression of the spring controls the force exerted by the jaws.

[0068] In some embodiments, in accordance with the twelfth aspect, the first range of distances is between about 5.0 mm and about 2.75 mm. In some embodiments, the first force progressively increases from about 14 pounds to about 19 pounds and the second force varies between about 18 pounds and about 19 pounds.

[0069] The method, in some embodiments of the twelfth aspect, further comprises the step of advancing a blade to sever tissue clamped by the first and second jaws. Preferably, the step of advancing the blade is independent of movement of the force transfer member. In some embodiments, the step of advancing the blade cannot be performed if the first and second jaws are not in the closed position. In some embodiments, the step of applying energy cannot be performed unless the first and second jaws are in the closed position.

[0070] In some embodiments, in accordance with the twelfth aspect, the gap between the jaws in the closed position varies along a width of the jaws so the gap is greater at a distance further from a center of the jaw than closer to the center of the jaw.

[0071] In accordance with a thirteenth aspect of the present disclosure, a method for controlling clamping forces on tissue by an electrosurgical device to enable use of the device on a wide range of tissue and preventing dissection of tissue is provided, the method comprising the steps of (a) providing and/or preparing a device having a handle portion, an elongated tubular portion extending distally from the proximal portion, a force transfer member extending through the tubular portion and first and second jaws at the distal portion of the device, the first jaw having a first tissue engagement surface and a first electrode and the second jaw having a second tissue engagement surface and a second electrode, at least one of the jaws being movable to transition the jaws from an open position to a closed position; (b) positioning the first and second jaws in an open position around the tissue; (c) actuating a jaw actuator so the force transfer member engageable with at least the first jaw transitions at least the first jaw toward the second jaw so the first and second jaws (i) apply a first range of forces to tissue as the jaws transition through a first range of distances, the distances defined between the first and second engagement surfaces; and (ii) subsequently apply a second smaller range of forces to tissue as the jaws transition through a second range of distances less than the first range of distances; and (d) applying energy to a first electrode carried by the first jaw and a second electrode carried by the second jaw. [0072] In some embodiments, in accordance with the thirteenth aspect, the step of actuating the actuator moves the first jaw toward the second jaw, the second jaw remaining stationary. In other embodiments, the actuator moves both the first and second jaws toward each other.

[0073] In some embodiments, in accordance with the thirteenth aspect, the step of moving the force transfer member moves a pin within a non-linear slot in the first jaw, the slot configured to control the force exerted by the jaws. In some embodiments a spring is provided for biasing the force transfer member wherein compression of the spring controls the force exerted by the jaws.

[0074] In some embodiments, in accordance with the thirteenth aspect, the first range of forces progressively increases and the second range of forces varies slightly. In some embodiments, the second range of forces substantially plateaus. In some embodiments, the first range of forces is between about 14 pounds and about 19 pounds and the second range of forces is between about 18 pounds and 19 pounds.

[0075] The method, in accordance with the thirteenth aspect, can further comprise the step of independently advancing a blade to sever tissue clamped by the first and second jaws. In some embodiments, the step of advancing the blade cannot be performed if the first and second jaws are not in the closed position. In some embodiments, the step of applying energy cannot be performed unless the first and second jaws are in the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0076] The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

[0077] Figure 1 is a perspective view of a surgical device in accordance with one embodiment having an end effector assembly including a set of jaws shown in an open position and a trigger for a blade shown in an initial position;

[0078] Figure 2 is a perspective view of the handle portion of the surgical device of Figure 1 with a portion of the handle housing removed to illustrate internal components; [0079] Figure 3 is a cross-sectional view of the surgical device of Figure 1;

[0080] Figure 4 is a perspective view of the surgical device of Figure 1 with the jaws in a closed position and the blade trigger in the initial position;

[0081] Figure 5 is a perspective view of the handle housing of the surgical device of Figure 4 with a portion of the handle housing removed and corresponding to the position of Figure 4;

[0082] Figure 6 is a cross-sectional view of the handle portion of the surgical device of Figure 1 corresponding to the position of Figure 4;

[0083] Figure 7 is a perspective view of the surgical device of Figure 1 with the jaws in a closed configuration and the blade trigger in an actuated position;

[0084] Figure 8 is a perspective view of the handle housing of the surgical device of Figure 1 with a portion of the handle housing removed corresponding to the position of Figure 7;

[0085] Figure 9 is a cross-sectional view of the surgical device of Figure 1 corresponding to the position of Figure 7;

[0086] Figure 10A is a close up perspective view of the jaws of Figure 1 shown in an open position;

[0087] Figure 10B is a cross-sectional view of the jaws of Figure 1 shown in the open position;

[0088] Figure IOC is a cross-sectional view of the jaws of Figure 1 shown in the closed position;

[0089] Figure 10D is bottom perspective view of the upper jaw of Figure 1 shown in the open position;

[0090] Figure 11 is a perspective view of the circle area of Figure 7 showing jaws in the closed configuration; and

[0091] Figure 12 is a cross-sectional view of the circle area of Figure 3 showing the jaws in the open position; [0092] Figure 13 is a cross-sectional view of the circled area of Figure 9 showing the jaws in the closed position;

[0093] Figure 14 is a transverse cross-sectional view of the jaws taken generally along the line 14-14 in Figure 13;

[0094] Figure 15 is a cross-sectional view schematically illustrating a set of jaws clamping a representative hollow or layered tissue structure;

[0095] Figure 16 is a cross-sectional view schematically illustrating a set of jaws initially clamping a representative bulk tissue structure;

[0096] Figure 17 is a cross-sectional view of the jaws of Figure 16 after a clamping pressure of the jaws on the bulk tissue structure has been increased;

[0097] Figure 18 is a plot schematically illustrating a force curve for controlling the operation of jaws of a surgical device according to one embodiment;

[0098] Figure 19 is an enlarged view of the area generally circled in Figure 2;

[0099] Figure 20A is an enlarged view of the area of Figure 19 with the blade trigger in the actuated position;

[00100] Figure 20B is an enlarged bottom perspective view of the area of Figure

19 with the blade trigger in the actuated position.

[00101] Figure 21 is a perspective view of a feedback mechanism for indicating actuation of the trigger of the surgical device of Figure 1 ; and

[00102] Figure 22 is a cross-sectional view of a shaft of the surgical device taken generally along line 22-22 in Figure 13.

DETAILED DESCRIPTION

[00103] A detailed description of one or more embodiments of the disclosed device and method are presented herein by way of exemplification and not limitation with reference to the Figures. [00104] Referring now to the Figures, a surgical device 10 according to one embodiment is described with respect to Figures 1-22B. The surgical device 10 includes a body or housing 12 having a handle portion or handle assembly 14. The handle assembly 14 is intended to be held, gripped, grasped, operated, manipulated, etc., by a user, e.g., a medical professional, during use of the device 10. A shaft or elongated tubular portion 16 extends distally from the housing 12 along a longitudinal axis 17 and terminates at an end effector assembly 18. The terms distal and proximal as used herein are generally with reference to a user of the surgical device 10, with proximal denoting closer to the user and distal denoting further from the user, and it is accordingly to be appreciated that the housing 12 is said to be located at a proximal end of the shaft 16, while the end effector assembly 18 is located at a distal end of the shaft 16. Likewise, movement toward the end effector assembly 18, e.g., along the axis 17, is considered to be in the distal direction, while oppositely directed movement is considered to be in the proximal direction.

[00105] In one embodiment, the device 10 is used as a resection instrument, e.g., for sealing and/or cutting blood vessels, parenchyma, and/or other tissue. To this end, the end effector assembly 18 can include any desired tools or components, e.g., a pair of jaws clampable together to grip tissue therebetween, a blade or knife for cutting tissue, one or more electrodes for providing thermal energy to the tissue suitable for sealing the tissue, a stapler, etc., examples of which are described in more detail below. The terms seal, weld, bond, cauterize, fuse, etc. are generally interchangeable as used herein and refer to the sealing, welding, bonding, or fusing of tissue together, such as to prevent the flow of fluid through the seal or weld. For example, the application of heat can be used to coagulate compounds in the tissue, denature collagen and other proteins, etc. Proteins such as collagen are then entangled and re-crosslink to bond previously separate portions of the tissue together. Cutting or severing refers to the separation, e.g., mechanical separation, of portions of the tissue, e.g., by a blade, knife, or other cutting implement. By first sealing the tissue, e.g., via the application of heat from one or more electrodes, the seal will prevent fluids, e.g., blood through vessels, air through lung parenchyma, etc., from undesirably escaping from the tissue when the tissue is cut. [00106] In the illustrated embodiment, the end effector assembly 18 of the surgical device 10 positioned at the distal portion of device includes a set or pair of jaws identified individually as a jaw 20a and a jaw 20b, and which may be collectively referred to herein as "the jaws 20". In the illustrated embodiment, the jaw 20a is movable with respect to the shaft 16, while the jaw 20b is fixed with respect thereto. It is to be appreciated that in non-illustrated embodiments the jaw 20b can be movable and the jaw 20a fixed, or both of the jaws 20 can be movable toward and away from each other for movement between open and closed configurations (positions). Regardless of which of the jaws 20 is/are movable, relative motion between the jaws 20 is capable in order to transition the jaws 20 between an open configuration (e.g., as illustrated in Figures 1, 3, 10, 12) and a closed configuration (e.g., as illustrated in Figures 4, 7, 9, 11, 13).

[00107] As noted above, in one embodiment the end effector assembly 18 is arranged to seal a section of tissue. In the illustrated embodiment, the end effector assembly 18, shown best in Figures 10-14, includes an electrode 22a disposed with the jaw 20a and an electrode 22b disposed with the jaw 20b (collectively and/or generally, "the electrodes 22"). By providing the electrodes 22 with opposing polarities, radiofrequency (RF) energy can be communicated through the tissue clamped between the electrodes 22 by the jaws 20. As shown in Figure 10A, electrode 22b positioned on jaw 22a extends in a U-shape adjacent to, but spaced inwardly of a periphery of the jaw 20b. An insulating material or non-conductive base 80 is positioned within the "u" of electrode 22a, extending in the center of the jaw 20a along a longitudinal axis of jaw 20a. Similarly, electrode 22a of jaw 20a extends in a U-shape adjacent to, but spaced inwardly of a periphery of the jaw 20b. The RF energy will heat the tissue in order to create a seal or weld as described above. In one embodiment, the electrodes 22 are heating elements, e.g., resistance heaters, which generate heat via the resistance of current flowing therethrough as opposed to communicating RF energy through the tissue. In the illustrated embodiment, a single electrode is provided with the jaws 20 but in alternate embodiments multiple electrodes spaced apart can be provided in each jaw. In order to prevent the sticking of heated tissue to the outer surfaces of electrodes 22, the electrodes 22 and/or other outer surfaces of the jaws 20 can be coated with polytetrafluoroethylene (PTFE) or another "non-stick" material.

[00108] The handle assembly 14 is arranged to actuate, activate, or otherwise control operation of the end effector assembly 18, e.g., to move the jaws 20 between their open and close configurations (positions). To this end, the handle assembly 14 includes a fixed handle member 24 and a movable handle member 26. The jaws 20 are transitionable into the aforementioned open and closed configurations by respectively moving the movable handle member 26 relative to the fixed handle member 24 between an initial, default, or first position (e.g., as shown in Figures 1-3) and an actuated, activated, or second position (e.g., as shown in Figures 4-6). For example, a user can grip the surgical device 10 by placing a thumb of one hand around the fixed handle member 24 and other fingers of that hand around the movable handle member 26. The jaws 20 can then be transitioned by squeezing the thumb and fingers together to move the movable handle member 26 proximally between its initial or first and actuated or second positions. The user's index finger can be used for other and/or additional purposes described below, e.g., actuating a trigger to deploy a blade of the end effector assembly 18, activating a switch to power the electrodes 22, etc.

[00109] The movable handle member 26 of the handle assembly 14 in the illustrated embodiment includes a lever 28. The lever 28 is secured to the housing 12 at a pin or pivot 30 in order to enable rotational movement of the movable handle member 26 relative to the fixed handle member 24. A torsion spring 32 or other biasing element can be included for biasing the movable handle member 26 distally towards its initial position, thereby maintaining the movable handle member 26 in or toward its initial position when the movable handle member 26 is not being actuated.

[00110] The movable handle member 26 is coupled to the end effector assembly

18 via a drive assembly 34 in order to transition the jaws 20 between their respective open and closed configurations in response to the movable handle member 26 moving between its initial and actuated positions. The drive assembly 34 includes a follower member 36 movably mounted on the shaft 16 that is displaceable along the shaft 16 due to movement of the movable handle member 26. Movement of the follower member 36 results in compression of a spring 38 or other biasing element against a collar 40. As shown, spring 38 is positioned proximal of follower 36 and distal of collar 40. The collar 40 is also movably mounted on the shaft 16, but can move independent of the lever 28 and the follower member 36. Movement of the collar 40 relative to the shaft 16 is limited by a pin 42, fixed to the collar 40, located in an axially extending slot 44 formed in the shaft 16. The pin 42 is also secured to the proximal end of a force transfer member 46 that extends (Figure 3) through the shaft 16 to the end effector assembly 18. Thus, collar 42 is operatively connected to the jaws 20. In this way, the force applied, e.g., by a user, to the movable handle member 26 is received by the drive assembly 34 and ultimately transferred to the end effector assembly 18 via the force transfer member 46.

[00111] The drive assembly 34 additionally includes a jaw drive pin 48 secured to the distal end of the force transfer member 46. In order to effect movement of the jaw 20a relative to the jaw 20b, the drive pin 48 as shown in Figure 10-14 rides simultaneously in a slot 50 directed axially with respect to the axis 17 of the shaft 16 and a variable slot 52 that is curved, bent, angled, or otherwise misaligned or variable in angle with respect to the axis 17. Accordingly, the slot 52 may be referred to as the variable slot 52. The slot 50 is formed in the fixed jaw 20b, or in the movement for the fixed jaw 20a, which restricts the drive pin 48 to only axial movement with respect to the fixed jaw 20b, while the variable slot 52 is formed in the movable jaw 20a. As the movable jaw 20a is secured to the fixed jaw 20b at a pin or pivot 54, movement of the drive pin 48 along the axial slot 50 results in the movable jaw 20a rotating about the pivot 54 in order for the drive pin 48 to also travel along the variable slot 52. In this way, movement of the movable handle member 26 in the proximal direction (toward the fixed handle member 24) results in the force transfer member 46 moving proximally which moves the drive pin 48 proximally, which rotates the movable jaw 20a toward the fixed jaw 20b (to the closed configuration). Movement of the movable handle member 26 in the distal direction (away from the fixed handle member 24) results in the force transfer member 46 moving distally which moves the drive pin 48 distally, which rotates the movable jaw 20a away from the fixed jaw 20b (to the open configuration).

[00112] In the illustrated embodiment and as shown in Figures lOA-lOC, the variable slot is offset from a longitudinal axis of the jaw 20a. More particularly, the slot 52 has a varying curve configuration which controls the clamping forces on tissue. As shown, arcuate portion 52a of slot 52 has an increased radius of curvature as compared to portion 52 which can be linear or have a slight curvature. The effect of this slot geometry on clamping forces is described in more detail below in conjunction with the discussion of how the drive assembly 34 is structured to set desired forces exerted by the jaws on tissue.

[00113] When movable handle member 26 is pivoted proximally toward stationary handle member 24, lever 28 moves follower member 36 proximally which compresses spring 38 and moves collar 40 proximally to retract force transfer member 46 to move jaw 20a toward 20b. Release of movable member 26 causes the reverse motion, returning force transfer member 46 to its original distal position as spring 38 returns to its uncompressed position to open jaws 20. In the illustrated embodiment, the force transfer member 46 is formed by one or more drive ribbons, capable of transferring both compressive and tensile forces, although it is to be appreciated that any other structure capable of transferring force can be alternatively or additionally utilized, e.g., one or more rods, bars, wires, etc. Thus, the force transfer member 46 is moved in a proximal direction, i.e. pulled proximally, to effect jaw closure.

[00114] Representative sections of tissue are shown in Figures 15-17 being clamped by the jaws 20 and designated with the numerals 56a and 56b (collectively and/or generally, "the tissue 56")· In Figure 15, the tissue 56a schematically represents a blood vessel, a generally hollow structure having a lumen formed therethrough and/or some other multi-layered tissue structure. As illustrated, the clamping force exerted by the jaws 20 causes opposing wall portions of the tissue 56a, each having a wall thickness t, to contact together, creating a total cross-sectional thickness Tl of the tissue 56a clamped by the jaws 20 (with the thickness Tl equaling approximately twice that of the thickness t). By subjecting the tissue 56a to heat, e.g., via RF energy transferred between the electrodes 22, the opposing wall portions will denature, coagulate, etc., and become sealed or bonded together, e.g., in order to prevent blood from flowing through the sealed section of the tissue 56a.

[00115] The tissue 56b in Figures 16-17 is representative of a bulk of tissue, e.g., parenchyma, as opposed to the hollow structure represented by the tissue 56a. In some instances, particularly thick tissue may not be heated thoroughly therethrough, which may result in a poor or insufficient seal throughout the entire cross-section of the tissue 56b. Thus, in order to achieve a good seal with a relatively large bulk portion of tissue, in some situations, it may be desirable to perform several heating cycles with the electrodes 22. Figure 16 accordingly illustrates the tissue 56b being initially grabbed by the jaws 20 and only partially compressed therebetween. In this way, for example, the electrodes 22 can be powered a first time in order to heat the tissue 56b and begin sealing the cross-section of the tissue 56b clamped between the jaws 20. The denaturing, coagulating, re-crosslinking, etc., due to heating may result in a reduction of the cross-sectional thickness of the tissue 56b, as illustrated from a first thickness T2 shown in Figure 16 to a second thickness T3 shown in Figure 17. In some embodiments, the tissue 56b may be sufficiently sealed after one heating cycle, while in other embodiments it may be desired to power the electrodes 22 at least a second time in order to re -heat the now thinner cross-sectional portion of the tissue 56b and establish an improved seal.

[00116] It has been discovered by the inventors that certain tissue types, such as blood vessels and other relatively thin tissue structures (e.g., the thickness Tl of the representative tissue 56a, or the thickness T3 of the tissue 56b after undergoing a first heat cycle) may seal more favorably when subjected to relatively higher jaw forces. However, other tissue types, such as relatively thick sections of bulk or soft tissue, such as lung, liver, or other organ parenchyma (e.g., the thickness T2 of the representative tissue 56b before undergoing a first heat cycle), may undesirably blunt dissect at the same relatively high pressures that are desired to suitably seal blood vessels and other relatively thin tissue structures. Accordingly, the drive assembly 34, as discussed above, can be arranged to cause the jaws 20 to exert forces that are variable with respect to the cross-sectional thickness (e.g., the thickness Tl, T2, T3, etc.) of the tissue 56 being sealed. In lieu of directly measuring the cross-sectional thickness of the tissue, the jaws 20 can be arranged to exert different forces depending on the size of a gap 58 located between a tissue engagement or sealing surface 60a of the electrode 22a and a tissue engagement or sealing surface 60b of the electrode 22b (collectively and/or generally, "the surfaces 60"), as the distance of the gap 58 corresponds to the thickness of the tissue engaged between the surfaces 60. [00117] In one embodiment, the drive assembly 34 is arranged to at least partially define the operating characteristics of the jaws 20 in response to actuation of the movable handle member 26. For example, as noted above, the drive assembly 34 can be arranged to set the force exerted by the jaws 20 on the tissue 56 in response to the thickness of the tissue 56. An exemplary force curve 62 that defines operation of the jaws 20 according to one embodiment is illustrated in Figure 18. Specifically, the force curve 62 shows the force exerted by the jaws 20 with respect to the distance of the gap 58.

[00118] From the force curve 62 of Figure 18, it can be seen that a relatively large force is exerted by the jaws 20 when the jaws 20 are relatively close together, but that the exerted force decreases rapidly at gap distances above a certain point. In furtherance of explanation, dashed lines 64 and 66 are included with the force curve 62 to depict a threshold force Fx and a threshold distance Tx. Also included are labels corresponding to gap distances equaling the thicknesses Tl, T2, and T3 of the tissues 56a and 56b (shown in Figures 15-17), as well as a set of forces Fl, F2, and F3, corresponding respectively thereto. It can be seen that the force exerted by the jaws 20 is relatively consistent and greater than the threshold force Fx for gap distances less than the threshold distance Tx. For example, it can be seen that the thicknesses Tl and T3 correspond to distances of the gap 58 that are less than the threshold distance Tx, and thus the corresponding forces Fl and F3 are both greater than the threshold force Fx. It is noted that although the distance T3 is substantially greater than the distance Tl, e.g., multiple times greater, the forces Fl and F3 remain substantially similar in value and greater than the threshold force Fx. Oppositely, the thickness T2 corresponds to a distance of the gap 58 that is greater than the threshold distance Tx, and thus the force F2 exerted by the jaws 20 is significantly less than the threshold force Fx. Advantageously, controlling operation of the jaws 20 according to the force curve 62 enables a variety of tissue structures of various cross-sectional thicknesses to be suitably sealed by the device 10 without deleterious effects such as blunt dissection of the tissue.

[00119] Stated another way, when the jaws 20 are initially closed and moved toward each other so the tissue engagement surfaces of the jaws are separated by a first set of distances, the force exerted on tissue progressively increases. This is represented in the slope of the line on the force curve of Figure 18. However, once the jaws 20 are brought to a certain point, i.e., the tissue engagement surfaces are moved to a predetermined distance apart, the force exerted on tissue essentially plateaus so that as the jaws 20 move closer together along a second set of distances between the tissue engagement surfaces, the forces do not continue to progressively increase at the same rate. This is illustrated in the more horizontal line of the force curve of Figure 18. It should be understood, that substantial plateau means that the forces no longer increase as they did during the first set of distance. This plateau could be linear so the forces do not change or slightly variable as in the line of Figure 18. In fact, the forces can even slightly decrease during the plateau portion. With this force curve, the percentage change in forces during the first set of distances is much greater than the percentage change in forces over the second set of distances. Note if the forces continued on an upward slope without plateauing such that the forces progressively increased as the tissue engagement surfaces got closer together, the forces applied to the tissue could increase to as much as 40 pounds which could dissect the tissue in certain applications.

[00120] Figure 18 illustrates an example of the threshold force and distance values

In one embodiment, the threshold force Fx can be about 90% to about 95% of a maximum force 68 that is exertable by the jaws 20. In one embodiment by way of example, the threshold distance Tx can be the range of about 2.0 mm to about 3.5 mm and in a further embodiment can be in the range of about 2.5mm to about 3.0 mm. In other embodiments, the threshold distance Tx can be as low as about 1mm (thereby corresponding to typical vessel geometry, which is generally less than 1mm in total thickness as noted above), or as large as about 7mm (corresponding to larger vessels or other tissue bundles that would benefit from higher clamping forces). It should be appreciated that these are provided by way of example as other values distances are also contemplated. In one embodiment, the threshold force can be in the range of about 17 pounds to about 20 pounds, and in a further embodiment can be in the range of about 18 pounds to about 19 pounds, although it is to be appreciated that the force exerted by the jaws 20 can be modified to greater or lesser values in order to accommodate different types of tissue, different dimensions and/or geometries for the jaws 20, etc. Thus, in the example represented by the force curve of Figure 18, as the tissue engagement surfaces of the jaw 20 decrease from a distance apart of about 5mm to about 2.75 mm, the force exerted on the tissue increases from about 14 pounds to about 18.5 pounds. When the distance between the tissue engagement surfaces of the jaw 20 continues to decrease from about 2.75mm towards a minimal or no gap, the force exerted on tissue is only slight variable between about 18.5 to 19 pounds. It should be appreciated, that the numeric values shown in Figure 18 and described herein are provided by way of example for ease of understanding and applicable to only some embodiments, it being understood in alternate embodiments, the gap (distance) between the tissue engagement surfaces and the resulting forces applied by the jaws will have different values, although the forces would still follow a force curve of more rapidly increasing and then leveling off as described above.

[00121] In one embodiment, the curvature or angulation of the variable slot 52 is set in order to control the force exerted on the jaw 20a by the drive pin 48 at different points along the length of travel along the variable slot 52 of jaw 20a. The changing angle or curvature of the variable slot 52 results in the force transferred to the jaw 20a via the drive pin 48 to change with respect to the position of the drive pin 48 along the variable slot 52. For example, a relatively more axially orientated section of the variable slot 52 may have a slope, curvature, or angle with respect to the axis 17 that results in a relatively smaller degree of rotation of the jaw 20a, and thus, a relatively lower force exerted by the jaws 20, per unit length of movement of the force transfer member 46, with the slope, angle, or curvature of the variable slot 52 becoming steeper or resulting in greater forces to be transferred to the jaw 20a per unit length of movement of the pin 48 within the variable slot 52 as the jaws 20 become increasing closed. In this way, the force curve (e.g., the force curve 62) can be set to include a generally plateaued or constant range of forces in one gap distance range (e.g., the forces corresponding to gap distances below the threshold distance Tx in the force curve 62, which are all above the threshold force Fx), but with a significant change in force outside of that range (e.g., as seen in the relatively steep or sudden drop off in force for gap distances greater than the threshold distance Tx).

[00122] In addition to or in lieu of the using the geometry of the variable slot 52 to control the force, the properties of other components of the drive assembly 34 can be set to achieve the desired jaw force curve (e.g., the force curve 62), such as the properties of the spring or biasing element 38, e.g., spring constant, length, pre-load, etc. For example, the force exerted by the spring or biasing element 38 on the jaw 20a via the force transfer member 46 changes due to elongation and compression of the spring 38 as the follower member 36 (due to actuation of the movable handle member 26) moves toward and away from the collar 40. The jaws 20 of the end effector assembly 18 can be arranged to accommodate a number of different tissue arrangements in order to create high quality seals with the surgical device 10 under a variety of conditions. For example, in the illustrated embodiment, the jaw 20a is formed by an actuation arm 70 and a float portion 72. The actuation arm 70 includes the variable slot 52 and is pinned to the fixed jaw 20b at the pivot 54 as described above. The float portion 72 is connected rotatably to the actuation arm 70 at a pin or pivot 74 and includes the electrode 22a thereon in order to enable the electrode 22a to float with respect arm 70, i.e., rotate to some degree relative to the arm 70. The float portion 72 thereby enables, for example, the electrode 22a of the jaw 20a to more readily accommodate or conform to tissues of different and/or inconsistent thicknesses, shapes, or sizes, maintain parallelism with the electrode 22b, etc. Advantageously, this enables sufficiently high and/or consistent forces to be exerted on tissue clamped between the jaws 20, even if the tissue is of various cross- sectional shapes or thicknesses, which can promote better sealing.

[00123] It has also been found by the current inventors that the size of the gap 58 between the tissue engagement surfaces 60 of the electrodes 22 can be determinative of the quality of the seal created when communicating RF energy through each unique section of the tissue 56. For example, different tissue types (e.g., vessels as opposed to parenchyma) or different sections of the same tissue type (e.g., varying between different patients or even different locations within the same patient) can benefit from different distances for the gap 58 even when the same device and generator are used. To this end, in one embodiment, one or both of the electrodes 22 can be tapered, contoured, shaped, or otherwise arranged such that the gap 58 is variable across the width of the jaws 20. In other words, the electrodes 22 can be non- complementarily formed such that the distance defining the gap 58 changes with respect to the width of the jaws 20.

[00124] For example, the end effector assembly 18 is shown in cross-sectional across the width of the jaws 20 in Figure 14. By across the width, it is generally meant that the cross-section of Figure 14 is formed in a plane that is generally perpendicular to the proximal- distal direction, e.g., as represented by the line 14-14 in Figure 13. In this embodiment, the electrode gap 58 is defined by multiple distances that vary with the width of the electrodes 22. Specifically in the embodiment of Figure 14, the electrode 22b is shaped such that the engagement surface 60b is formed by a first inner surface portion 75 (closer to the center) and an outer second surface portion 76 (further from the center). The first surface portion 75 results in the electrode gap 58 being defined by a distance Dl between the engagement surface 60b of the electrode 22b and an engagement surface 60a of the electrode 22a, while the second surface portion 76 tapers or slopes away (radially outward) from the surface portion 75 so that the electrode gap 58 is defined by distances greater than Dl. Stated another way, the electrode 22b tapers laterally (in opposing directions from an intermediate portion of the electrode) so that the distance from electrode 22b to electrode 22a progressively increases toward the outer edge. The changing distance between the electrodes affects the force and energy applied to the clamped tissue, with a greater force toward the center of the clamped tissue. Thus, the taper causes the gap to increase away from the center line. Note that the taper region can be a flat angled surface or a curved surface, either one resulting in a changed distance between the electrodes. Additionally, although Figure 14 shows the tapered electrode on the stationary jaw 20b, it is also contemplated that the taper can be formed on the electrode of the movable jaw 20a either in addition to or instead of taper on the electrode of the stationary jaw 20b. As can be appreciated, the shape of the surface portion 76 results in the electrode gap 58 variably spanning a range of distances. By defining the electrode gap 58 to include multiple or a range of distances, the likelihood is increased the electrode gap 58 will include a distance at which the device 10 will suitably seal tissue, e.g., the tissue 56, regardless of the patient, tissue type, etc. The electrode 22a is illustrated with the engagement surface 60a being consistently substantially flat or proud (e.g., in a plane parallel to the axis 17 when the jaws 20 are fully closed), although it is noted that the electrode 22a can alternatively or additionally be contoured, tapered, shaped, or profiled to create the aforementioned variable distances for the gap 58. Additionally, the contours shown are according to just one example, and it is understood that the electrodes 22 can take other non- complementary shapes that result in a variable size for the electrode gap 58. [00125] A tip of the electrode 22b can be tapered in a distal direction, designated by region 29b in Figures 9, 10A and 13. A tip of the electrode 22a can also be tapered in a distal direction.

[00126] In addition to variability of the electrode (engagement surface) gap, a minimum size for the electrode gap 58 can be set by inclusion of one or more conductive protrusions 78 (see e.g., Figs. 10A, 10B, 12, and 14) extending between the electrodes 22. That is, even if the jaws 20 are fully closed, the protrusions 78 will support the jaws 20 against each other in order to maintain a minimum spacing between the electrodes 22. In the illustrated embodiment, the protrusions 78 extend from the electrode 22a toward the electrode 22b and contact the non-conductive base such as a ceramic insulator in jaw 20a, disposed oppositely therefrom. It should be understood that the conductive protrusions 78 can alternatively or additionally be formed extending from the electrode 22b toward the electrode 22a in which case electrode 22a would have an insulating material in receiving contact with the protrusions. In the illustrated embodiment, the protrusions 78 are integrally formed with the electrode 22a. The protrusions 78 can have any desired shape and/or size, and any number of the protrusions 78 can be included to properly support the jaws 20 when the jaws 20 are brought together. In the illustrated embodiment by way of example three sets of protrusions can be provided: one at a distal region of electrode 22a, one at an intermediate region of electrode 22a, and one at a proximal region of the electrode 22a. As shown, the protrusions 78 are slightly off center of the central longitudinal axis of the jaw 20a to accommodate a pair of protrusions side by side. Other numbers and locations of protrusions are also contemplated.

[00127] The protrusions 78 are arranged to prevent contact between the electrodes

22, as contact can result in malfunction of the device 10, e.g., an electrical short, charring or severing of the tissue clamped between the jaws 20, poor welds, etc. The protrusions 78 are offset from or misaligned with respect to the engagement surfaces 60 of the electrodes 22 such that when the jaws 20 are brought to the closed configuration the protrusions 78 engage against the non-conductive base 80, which is also offset from the surfaces 60. That is, for example, in the illustrated embodiment the surfaces 60 extend continuously distally to proximally, with the protrusions 78 and the non-conductive base 80 being offset in a direction transverse to the distal- proximal direction. More specifically, with respect to the illustrated embodiment, the electrodes 22 are generally U-shaped, with the protrusions 78 and the non-conductive base 80 offset to the inside of the 'LP. It is to be understood that in alternate embodiments, the offset can be to the outside of the U- shape or in some other direction with respect to other shapes for the electrodes 22. Additionally, the non-conductive base 80 is illustrated having a U-shape, but can be arranged in other embodiments as discrete structures aligned with each of the protrusions 78, strips aligned with each row of the protrusions 78, etc. As illustrated, the non-conductive base 80 can be flush with and/or slightly recessed from the engagement surface 60b of the electrode 22b, e.g., in order to reduce contact of the base 80 with tissue, e.g., the tissue 56, in order to control loading on the tissue, reduce sticking, etc.

[00128] The surgical device 10 includes a power switch 82 disposed within the housing 12. The power switch 82 is electrically coupled to the electrodes 22 via electrical conductors 83, e.g., electrical cables or wiring. The power switch 82 is arranged to be triggered by the user of the device 10, e.g., by pressing a button 84 (see e.g., Fig. 3). By triggering the power switch 82 via mechanical activation of the button 84, power can be selectively supplied from a generator 85 to the electrodes 22. The generator 85 can include or be in communication with a computer device or other control unit to control or set the power delivered by the generator 85, e.g., in response to parameters such as impedance, temperature, time, etc., sensed or measured by sensors in communication with the electrodes 22. For clarity of the other components, portions of the electrical conductors 83 are not shown in each drawing, but it is to be understood that the conductors 83 extend from the generator 85 to the power switch 82 and from the power switch 82 through the shaft 16 to each of the electrodes 22. It is to be appreciated that the generator 85 can be arranged to supply different levels of power to the electrodes 22, e.g., depending on input sensed or measured by the device 10 or input by a user of the device. For example, in one embodiment, the device 10 can be arranged such that pressing the button 84 multiple times cycles through a number of different power options for the generator 85. In one embodiment, the device 10 can include multiple buttons, or a single button having multiple settings, with the multiple buttons and/or settings corresponding to different power levels or modes of operation for the generator 85. [00129] The electrodes 22 are not intended to be powered prior to clamped engagement of tissue by the jaws 20. In order to prevent premature activation of the electrodes 22, the movable handle member 26 includes a cover 86 that selectively impedes access to the power switch 82. Namely, the cover 86 forms a cavity 88 into which the button 84 is recessed or hidden when the movable handle member 26 is in its initial position, e.g., as illustrated in Figure 1. As shown, in the position of Figure 1 the trigger 120 also blocks access to the button 84 recessed within the cover. When the jaws 20 are closed by moving the movable handle member 26 to its actuated position, e.g., as shown in Figure 4, ready access to the button 84 is enabled. In other words, moving the movable handle member 26 to its actuated position in order to transition the jaws 20 to their closed configuration results in the cover 86 moving relative to the button 84 to a position at which the button 84 extends at least partially out from the cavity 88 for access by the user. In this way, a user is effectively prevented from accessing the button 84 and activating the electrodes 22 via the button 84 of the power switch 82 until after the jaws 20 have been closed.

[00130] As noted above, the torsion spring 32 assists in maintaining the jaws 20 in their open configuration by biasing the movable handle member 26 toward its initial position when the movable handle member 26 is not being actuated. Similarly, the surgical device 10 can include a jaw lock mechanism 90, best seen in Figures 3 and 6, arranged to maintain the jaws 20 in the closed configuration even after a user releases pressure on the movable handle member 26. In the illustrated embodiment, the jaw lock mechanism 90 includes a cam 92 and a cam follower 94. The cam 92 includes a slot or groove 96 through which the cam follower 94 traverses as the movable handle member 26 is actuated toward the fixed handle member 24. The cam follower 94 is secured at the end of a cantilevered element 98 that is arranged to enable the cam follower 94 at the free end of the cantilevered element 98 to follow the groove 96 and then to be springingly or resiliency urged back to a default position by the element 98. In the illustrated embodiment, the cam 92 is formed in the movable handle member 26, and the cam follower 94 is secured to the fixed handle member 24, although it is to be appreciated that these components can be arranged oppositely (e.g., the cam follower 94 with the movable handle member 26) or between other pairs of components that experience relative movement with respect to the movable handle member 26.

[00131] In operation, movement of the movable handle member 26 toward the fixed handle member 24 results in the cam follower 94 encountering a first angled surface or ramp 100. The ramp 100 causes the cam follower 94 to move along the groove 96 in the generally downward direction with respect to the orientation of the device 10 in Figures 3 and 6. Continued actuation of the movable handle member 26 causes engagement of the cam follower 94 with a first stop 102 in the groove 96, preventing further movement of the movable handle member 26 toward the fixed handle member 24. Releasing the movable handle member 26 when the cam follower 94 is at the first stop 102 results in the torsion spring 32 or other biasing element urging the movable handle member 26 back away from the fixed handle member 24, while the cantilever element 98 urges the cam follower 94 in the generally upward direction with respect to the orientation of the device 10 in Figures 3 and 6, causing the cam follower 94 to engage and "climb" a second angled surface 104 until engaging with a second stop 106. When in the second stop 106, the torsion spring 32 or other biasing element holds the movable handle member 26 in its second, or actuated, position, as shown in Figure 6, which corresponds to the closed configuration of the jaws 20. Re-actuating the movable handle 24 causes the cam follower 94 to travel along the groove 96 until engagement with a third stop 108, preventing further actuation of the movable handle member 26. Releasing the movable handle member 26 when the cam follower 94 is at the third stop results in the torsion spring 32 or other biasing element again moving the movable handle member 26 away from the fixed handle member 24, thereby enabling the cam follower 94 to exit from the groove 96. This resets the jaw lock mechanism 90 such that it can re-lock the movable handle member 26 during each subsequent actuation thereof.

[00132] In addition to sealing tissue with the end effector assembly 18, as described above, the end effector assembly 18 may also be arranged to cut, sever, or dissect portions of tissue, e.g., the tissue 56. For this reason, the end effector assembly 18 optionally includes a blade, knife, or cutting implement 110, which can be best seen in the cross-sectional view of Figures 12 and 13. The cutting blade 110 is located at the distal end of a force transfer member 112, e.g., a drive ribbon, bar, rod, etc., that extends through the shaft 16. The proximal end of the force transfer member 112 is secured to a drive collar 114 (Figures 2 and 3) via a pin or fastener 116. Note the force transfer member 112 for the blade 110 is positioned radially spaced from the force transfer member 46 for jaw 20a, both extending within the shaft 16 and both radially spaced from a central longitudinal axis of the shaft 16. Movement of the pin 116 is delimited by the positioning of the pin 116 within an axially extending slot 118 formed in the shaft 16. A trigger 120, secured rotatably to the housing at a pivot 122, and in the illustrated embodiment positioned above (as viewed in the orientation of Figure 2) the movable handle 26 is operably coupled to the blade 110 such that actuation of the trigger 120, e.g., by a finger of a user of the surgical device 10, results in deployment of the blade 110 in order to cut tissue, e.g., the tissue 56. The trigger 120 is shown in a first or initial position in Figures 1-6, corresponding to the retracted position of the blade 110 shown in Figure 12 (the jaws 20 closed with the blade still retracted in the configuration of Figures 4-6), and in a second or actuated position in Figures 7-9, corresponding to the deployed position of the blade 110 shown in Figure 13. Thus, pulling the trigger 120 to move the blade 110 is actuable separately (independently) from jaw actuation.

[00133] The drive collar 114 is connected to the trigger 120 via an arm 124, extending from the trigger 120 opposite to the pivot 122, and a linkage 126 extending between the arm 124 and the collar 114. In this way, actuation of the trigger 120 rotates the arm 124 clockwise, which moves the collar 114 in the distal direction via the linkage 126. The connection of the collar 114 to the force transfer member 112 via the pin 116 causes the collar 114 to also move force transfer member 112, and thus the blade 110, in the distal direction. A cutting plane 127 is included in Figures 15 and 17 to illustrate one location and orientation for the blade 110 as it cuts through the tissue 56a and/or 56b due to actuation of the blade 110 via the trigger 120. A spring 128 or other biasing element can be included, e.g., between the housing 12 and the arm 124, in order to urge the trigger 120 and the blade 110 back toward the initial position when not actuated.

[00134] As discussed above, cover 86 prevents premature activation of the electrodes 22 before the jaws 20 are transitioned to the closed configuration. A blade lock mechanism 130 can also be included to prevent actuation of the blade 110 until the jaws 20 are closed. In the illustrated embodiment, the blade lock mechanism 130 includes one or more lock or blocking arms 132 extending toward the trigger 120 from the lever 28 of the movable handle member 26. When the movable handle member 26 is in the initial position, e.g., as shown in Figures 2 and 19, the lock (blocking) arms 132 engage with and support a locking feature or projection 134 projecting eccentrically from the trigger 120 in order to prevent rotation of the trigger 120 about the pivot 122 due to interference of the feature 134 with the lock arms 132. As shown in Figures 20B the engagement (or abutment) member 134 in the initial position rests on ledge 132a of arms 132. When the movable handle member 26 is moved to the actuated position, as shown in Figures 5, 8, and 20, and the jaws 20 are thus transitioned to their closed configuration, the lock arms 132 are moved proximally away from the trigger 120, removing blocking of the projection 134, which enables the trigger 120 to rotate about the pivot 122.

[00135] Additionally, as can be seen in Figure 19 and 20A, the lock arms 132 extend distally beyond the feature 134 when the movable handle member 26 is in its initial position such that the lock arms 132 advantageously remain engaged with the feature 134 over a degree of movement of the movable handle member 26 toward the actuated position from the initial position. This ensures that the trigger 120 and blade 110 are not free for movement if the movable handle member is moved only partially proximally to partially close the jaws, but only free for movement when movable handle member 26 has moved a sufficient distance to close the jaws.

[00136] It is also to be appreciated that the lock arms 132 and the feature 134 are arranged such that forces exerted on the trigger 120 (e.g., by a user purposely or inadvertently before the blade 110 is unlocked) are transferred to the arms 132 via the feature 134 in a direction substantially perpendicular to the direction of movement/actuation of the lever 28. Since the forces are perpendicularly directed with respect to the direction of actuation of the movable handle member 26, such forces will not readily cause actuation of the movable handle 24. In other words, the device 10 is arranged such that prematurely pulling the trigger 120 will not result in actuation of the movable handle member 26. This is due to the fact that engagement member 134 is positioned atop (as viewed in the orientation of Figures 19 and 20A) locking arms 132. Since the trigger 120 moves in a pivoting motion, if a user attempts to pull back on the trigger 120 it will only apply a downward force on the lock arm 132 and not a proximal force so that the lock arms 132 will not be moved proximally out of the way of the trigger 120.

[00137] It is additionally noted that the lock arms 132 are arranged to return the blade 110 to the retracted position when the movable handle member 26 is moved back to the initial position from the actuated position. That is, movement of the lock arms 132 toward the initial (distal) position from the actuated (proximal) position will cause the arms 132 to encounter the feature 134 and force rotation of the trigger 120, via engagement with the arms 132, back to its initial position and thereby retract the blade 110 as force transfer member 112 is pulled proximally via linkage 126 and collar 114.

[00138] The trigger 120 may also be equipped with a feedback mechanism 135 for indicating to the user when the blade 110 becomes fully deployed, i.e., reaches the position shown in Figure 13. In the illustrated embodiment, the feedback mechanism 135, shown in Figure 21, includes a resilient prong 136 secured to the housing 12 in a cantilevered manner and extending toward the arm 124 of the trigger 120. As the blade 110 approaches its fully deployed position, the trigger 120 reaches an intermediate position at which the arm 124 contacts the prong 136, as illustrated in Figure 21. Thus, prong 136 and arm 124 are initially spaced a distance corresponding to the distance trigger 120 and this arm 124 move to advance the blade 110 close to its fully deployed position The arm 124 may include a surface or feature 138 arranged to engage against the prong 136. Once contacted, continued actuation of the trigger 120 will cause the prong 136 to flex or buckle against the surface 138. This flexing or buckling may also increase the resistance felt by the user when further pulling the trigger 120. Further actuation of the trigger 120 toward the actuated position (e.g., toward the position of Figure 7) will result in the prong 136 disengaging or releasing from the arm 124. This disengagement or release is communicable to the user as a "pop" or "ping" in the trigger 120 as the buckled prong 136 suddenly and resiliency deflects off to the side of the arm 124. The change in resistance, sound, and/or the vibrations experienced by the user due to the prong 136 suddenly disengaging from the arm 124 indicates to the user that the blade 110 has reached its fully deployed position.

[00139] According to the illustrated embodiment, the surgical device 10 includes an articulation assembly 140 that is arranged to cause rotation of the shaft 16 about the axis 17 and/or rotation of the end effector assembly 18 about an axis oriented transversely with respect to the axis 17, e.g., about an axis 142 formed through a pin or pivot 144. The articulation assembly 140 includes a body 146 fixed to the shaft 16, e.g., via one or more keys (not shown) inserted into openings 148 of the shaft 16. In this way, rotation of the shaft 16 about the axis 17 is enabled by rotating the housing or body 146 of the articulation assembly 140 about the axis 17. Rotation of the shaft 16 likewise causes rotation of jaws 20. The body 146 in the illustrated embodiment includes a plurality of fins 150 (Figure 1), which are arranged to enable a user to securely grip the body 146 and rotate the body 146 in order to rotate the shaft 16 about the axis 17.

[00140] In the illustrated embodiment, the pivot 144 that enables rotation of the end effector assembly 18 about the axis 142 (Figure 12) is formed at the distal end of the shaft 16 where the shaft 16 is secured to the end effector assembly 18. It is to be appreciated that such a pivot can be included at any desired location along the length of the shaft 16, that the shaft 16 can be segmented including multiple pivots along the length of the shaft, etc. Articulation of the end effector assembly 18 is achievable by rotating a rotatable driver 152 of the articulation assembly 140. More specifically, one or more force transfer members 154 (see e.g., Figures 8 and 10A), two in the illustrated embodiment, extend from the rotatable driver 152 through the shaft 16, and connect to the end effector assembly 18. A single one of the force transfer members 154 can be included if arranged as a drive ribbon, rod, bar, etc., or other member capable of transferring both compressive and tensile forces.

[00141] The rotatable driver 152 is rotatable about an axis 156 (Figure 6) that is arranged in parallel with the axis 142 and perpendicularly with respect to the axis 17. The force transfer members 154 are eccentrically secured to the rotatable driver 152, which results in the force transfer members 154 translating axially with respect to the shaft 16 during rotation of the rotatable driver 152. Axial movement of the force transfer members 154 exerts compressive and/or tensile forces on one or both sides of the end effector assembly 18 (i.e., pushes and/or pulls) to cause the end effector assembly 18 to rotate (pivot) at the pivot 144 about the axis 142. A knob 158 is fixed to the rotatable driver 152 in order to enable a user to rotate the rotatable driver 152, and therefore articulate the end effector assembly 18, with the knob 158. The knob 158 in the illustrated embodiment is arranged substantially resembling one of the fins 150 so that the knob 158 can additionally be gripped by a user when causing rotation of the shaft 16 about the axis 17 with the body 146.

[00142] As discussed above, the force transfer members 46 and 112 for the jaws 20 and the blade 110, respectively, are formed as ribbons in the illustrated embodiment. The use of ribbons, or other thin bars, facilitates articulation of the end effector assembly 18 about the axis 142, as the ribbons can readily bend in the articulation directions while maintaining the ability to transfer compressive and tensile forces longitudinally therethrough (e.g., as opposed to wires or cables that can only transfer tensile forces). The ribbons are moved in a proximal, pulling direction to close the jaws rather than a pushing motion to facilitate bending around a corner as jaw closure through a pushing motion could cause the pushing member to buckle. Thus, articulation of the device can be effected to greater than 45 degrees and in some embodiments up to 60 degrees with respect to the longitudinal axis of shaft (elongated tubular portion) 16. To help support the force transfer members 46 and 112, and/or prevent buckling thereof, one or more guide blocks 160 can be included. The guide blocks 160 can include smoothly rounded surfaces that are arranged to receive the force transfer member 46 and/or force transfer member 112 when the end effector assembly 18 is articulated and be made from materials having low coefficients of friction, such as PTFE, with respect to the material of the force transfer members 46 and 112.

[00143] In one embodiment, the articulation assembly 140 is provided with preset discrete positions that correspond to varying degrees of rotation of the end effector assembly 18 about the axis 142. For example, in the illustrated embodiment, the rotatable driver 152 is provided with a plurality of detents 162 about its circumference. A ball 164 or other member as shown in Figure 3 formed for reception within and/or engagement with the detents 162 is biased, e.g., via a spring or other biasing element, into the detents 162. Rotation of the rotatable driver 152 results in the ball 164 being forced out of one of the detents 162 for reception in an adjacent one of the detents 162. The ball 164 and detents 162 accordingly resist disengagement in order to assist in maintaining the rotatable driver 152 in a selected position, which maintains the end effector assembly 18 at a selected angle (about the axis 142) with respect to the longitudinal axis of the shaft 16 until forced into a new position, e.g., by a user rotating the rotatable driver 152 via the knob 158.

[00144] Figure 22 illustrates a cross-section of the shaft 16. As discussed above, the force transfer members 46, 112, and 154 all extend through the shaft 16. The conductors 83 also extend through the shaft 16 in order to electrically couple the generator 85 and the power switch 82 to the electrodes 22. For example, two conductors designated with the numerals 83a and 83b are illustrated in Figure 14, with the conductor 83a providing power to the electrode 22a, and the conductor 83b providing power to the electrode 22b. In order to guide and support the force transfer members 46, 112, and 154, and the conductors 83a and 83b, and to prevent undesired or unintentional interaction between these components, the passage or lumen formed through the shaft can include a guide 166. In the illustrated embodiment, the guide 166 includes a jaw channel 168 in which the force transfer member 46 is positioned, a blade channel 170 in which the force transfer member 112 is positioned, a pair of articulation channels 172 in which the force transfer members 154 are positioned, and a pair of conductor channels 174 in which the conductors 83a and 83b are positioned. It is to be appreciated that other configurations are possible, e.g., the conductor channels 174 could be combined to hold both of the conductors 83a and 83b, or both of the conductors 83a and 83b combined in a single conductor that extends through the shaft 16 and splits as necessary at the distal end of the shaft 16, or only one of the articulation channels 172 would be needed in embodiments having only one force transfer member 154, etc.

[00145] While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purpose of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

Claims

IN THE CLAIMS

1. An end effector assembly for a surgical device comprising:

a first jaw having a first engagement surface;

a second jaw having a second engagement surface, at least the first jaw movable with respect to the second jaw to transition the first jaw and the second jaw between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert a force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration; and

a drive assembly operatively connected to at least the first jaw, the drive assembly operable to move at least the first jaw to transition the first jaw and the second jaw between the open configuration and the closed configuration, wherein the drive assembly moves at least the first jaw so that the first jaw and the second jaw variably exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that the force exerted on the tissue is greater than a threshold force when the distance between the first engagement surface and the second engagement surface is less than a threshold distance and the force exerted on the tissue is less than the threshold force when the distance between the first engagement surface and the second engagement surface is greater than the threshold distance.

2. The end effector assembly according to claim 1, wherein the threshold force is in a range of about 18 pounds to about 19 pounds.

3. The end effector assembly according to claim 1, wherein the threshold distance is between about 1.5 mm and about 3.5 mm.

4. The end effector assembly according to claim 3, wherein the threshold distance is between about 2.5mm and about 3.0 mm.

5. The end effector assembly according to claim 1, wherein the force curve is nonlinear.

6. The end effector assembly according to claim 1, wherein the force curve has a progressive slope when the first and second jaws are at a first range of distances and the force curve substantially plateaus when the first and second jaws are at a second range of distances.

7. The end effector assembly according to claim 1, wherein the force curve has a shape as shown in FIG. 18.

8. The end effector assembly according to claim 1, further comprising a first electrode disposed on the first jaw.

9. The end effector assembly according to claim 8, further comprising a second electrode disposed on the second jaw.

10. The end effector assembly according to claim 9, wherein the first and second electrodes extend in a substantially U-shape configuration spaced inwardly from a peripheral edge of the respective first and second jaws.

11. The end effector assembly according to claim 10, further comprising a non- conductive material positioned within the U-shape of the second electrode.

12. The end effector assembly according to claim 1, further comprising a first slot in the first jaw and a second slot in the second jaw, the first jaw having a longitudinal axis, the first slot having a region angled with respect to the longitudinal axis of the first jaw, and a drive pin movable within the first slot to rotate the first jaw toward the second jaw.

13. The end effector assembly according to claim 1, wherein the drive assembly sets the force exerted by the first and second jaws on tissue in response to thickness of tissue.

14. The end effector assembly according to claim 13, wherein the drive assembly includes a drive pin engageable with a first slot in the first jaw, the first slot having a non-linear configuration to set the force exerted by the first and second jaws on tissue.

15. The end effector assembly according to claim 1, further comprising a first electrode disposed on the first jaw and a second electrode disposed on the second jaw and opposite the one electrode so that thermal energy, or radiofrequency energy, or both the thermal energy and the radiofrequency energy, are communicated through the tissue to seal or weld the tissue.

16. The end effector assembly according to claim 1, wherein the second jaw is stationary while the first jaw is movable toward the second jaw.

17. The end effector assembly according to claim 1, wherein both the first and second jaws are movable toward each other by the drive assembly.

18. An end effector assembly for a surgical device comprising:

a first jaw having a first engagement surface;

a second jaw having a second engagement surface, at least the first jaw movable with respect to the second jaw to transition the first jaw and the second jaw between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration; and

a drive assembly operatively connected to at least the first jaw, the drive assembly operable to move at least the first jaw to transition the first jaw and the second jaw between the open configuration and the closed configuration, wherein the drive assembly moves at least the first jaw so that the first jaw and the second jaw variably exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface such that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

19. The end effector assembly according to claim 18, wherein a threshold distance separates the first set of distances from the second set of distances.

20. The end effector assembly according to claim 19, wherein the threshold distance is between about 2.5 mm and about 3.0 mm.

21. The end effector assembly according to claim 18, wherein the forces exerted during the first set of distances varies greatly as compared to the forces exerted during the second set of distance which vary slightly.

22. The end effector assembly according to claim 18, wherein the forces exerted during the first set of distances increases more than 25%.

23. The end effector assembly according to claim 18, wherein the forces exerted during the second set of distances changes less than 5%.

24. The end effector assembly according to claim 18, wherein the first set of distances has a percentage force change several times greater than a percentage force change over the second set of distances.

25. The end effector assembly according to claim 18, wherein the variation of forces is obtained by a geometry of a first slot in the first jaw.

26. The end effector assembly according to claim 25, wherein the first slot in the first jaw includes an offset region offset from a longitudinal axis of the first jaw such that the slot is non-linear, the offset region effecting a degree of rotation of the first jaw with respect to the second jaw.

27. The end effector assembly according to claim 26, wherein the first jaw includes an arm and a float portion having a first electrode, the float portion rotatably connected to the first arm to enable the electrode to float with respect to the arm.

28. The end effector assembly according to claim 18, wherein the second jaw is stationary as the first jaw is moved toward the second jaw by the drive assembly.

29. The end effector assembly according to claim 18, further comprising a first electrode disposed on the first jaw and a second electrode disposed on the second jaw.

30. The end effector assembly according to claim 29, further comprising a spacer extending from the first jaw to maintain a minimum distance between the first and second engagement surfaces.

31. A surgical device comprising:

a handle portion;

an elongated tubular portion extending distally from the handle portion;

a first jaw having a first engagement surface;

a second jaw having a second engagement surface, wherein at least the first jaw is movable to transition the first jaw and the second jaw between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration; and a drive assembly operable to drive at least the first jaw to transition the first and second jaws between the open configuration and the closed configuration, wherein the drive assembly is operable so the first jaw and the second jaw variably exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that the force exerted on the tissue when the first engagement surface and second engagement surfaces are spaced a first range of distances changes a first percentage and the force exerted on the tissue when the first engagement surface and the second engagement surfaces are spaced a second range of distance changes a second percentage, the second percentage being less than the first percentage.

32. The surgical device according to claim 31, wherein the forces exerted on tissue during the first range of distances progressively increases.

33. The surgical device according to claim 32, wherein the forces exerted on tissue during the second range of distances varies slightly.

34. The surgical device according to claim 32, wherein the forces exerted on tissue during the second range of distances substantially plateaus.

35. The surgical device according to claim 31, wherein the drive assembly includes a force transfer member extending through the elongated portion and a compression spring biasing the force transfer member in a distal direction.

36. The surgical device according to claim 35, further comprising a collar movable independently of the force transfer member.

37. The surgical device according to claim 31, wherein a force transfer member is operatively connected to the first jaw, and the first jaw has a non-linear slot, the force transfer member moving a drive pin within the non-linear slot to pivot the first jaw toward the second jaw.

38. The surgical device according to claim 31, further comprising a cutting blade movable to sever tissue clamped between the first and second jaws.

39. The surgical device according to claim 31, wherein a force transfer member is movable proximally to pivot the first jaw toward the second jaw.

40. The surgical device according to claim 31, further comprising a first electrode disposed on the first jaw and a second electrode disposed on the second jaw.

41. The surgical device assembly according to claim 40, further comprising a spacer extending from the first jaw to maintain a minimum distance between the first and second engagement surfaces.

42. The surgical device assembly according to claim 37, further comprising a movable handle operable to retract the force transfer member proximally to move the first jaw toward the second jaw.

43. An end effector assembly for a surgical device comprising:

a first jaw having a first engagement surface;

a second jaw having a second engagement surface, at least one of the first and second jaws movable toward the other jaw to transition the first and second jaws between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration; a drive assembly operatively connected to one or both of the first jaw and second jaw, the drive assembly operable to transition the first and second jaws between the open configuration and the closed configuration, wherein the drive assembly is operable so that the first jaw and the second jaw variably exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface; and

a first electrode disposed on the first jaw and a second electrode disposed on the second jaw, at least one of the first electrode and second electrode being tapered radially outwardly in opposing directions from an intermediate portion so in the closed configuration a distance between the first electrode and second electrode is greater at a portion closer to a peripheral portion than at a portion closer to a center portion of the jaw.

44. The end effector assembly according to claim 43, wherein both the first electrode and the second electrode are tapered radially outwardly in opposing directions from an intermediate portion.

45. The end effector assembly according to claim 43, wherein one or both of the first and second electrode is tapered in a distal direction at a distal tip.

46. The end effector assembly according to claim 44, wherein one or both of the first and second electrode is tapered in a distal direction at a distal tip.

47. The end effector assembly according to claim 44, wherein one or both of the first and second electrode has a non-linear engagement surface.

48. The end effector assembly according to claim 44, wherein one or both of the first and second electrodes is U-shaped in configuration.

49. The end effector assembly according to claim 43, wherein one or both of the first and second jaws has an insulating material positioned within the U-shaped electrode.

50. The end effector assembly according to claim 43, wherein the first engagement surface is nonlinear.

51. The end effector assembly according to claim 43, wherein the second engagement surface is nonlinear.

52. The end effector assembly according to claim 43, further comprising a conductive protrusion extending from the first electrode to maintain a minimum spacing between the first and second electrodes.

53. The end effector assembly according to claim 43, wherein the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

54. The end effector assembly of claim 53, wherein the force curve is non-linear.

55. An end effector assembly for a surgical device comprising:

a first jaw having a first engagement surface;

a second jaw having a second engagement surface, at least one of the first jaw and second jaw movable with respect to the other jaw to transition the first jaw and the second jaw between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration;

a drive assembly operatively connected to at least one of the first jaw and second jaw, the drive assembly operable to transition the first jaw and the second jaw between the open configuration and the closed configuration, wherein the drive assembly is operable so that the first jaw and the second jaw variably exert the force on the tissue as a function of distance between the first engagement surface and the second engagement surface; and

a first electrode disposed on the first jaw and a second electrode disposed on the second jaw, wherein the distance between the first and second electrodes varies along a width of the jaws to provide multiple varied distances along the width of the jaws.

56. The end effector assembly according to claim 55, wherein the first jaw is movable toward the second jaw and the second jaw is stationary.

57. The end effector assembly according to claim 55, wherein the distance between the first and second electrodes varies along a length of the first and second jaws.

58. The end effector assembly according to claim 55, wherein one or both of the first engagement surface and the second engagement surface is nonlinear.

59. The end effector assembly according to claim 55, wherein one or both of the first electrode and the second electrode tapers in a distal direction at a distal tip.

60. The end effector assembly according to claim 55, wherein the second electrode is nonlinear and is tapered radially outwardly from an intermediate portion so in the closed configuration the distance between the first electrode and second electrode is greater at a portion closer to a periphery than at a portion closer to a center of the second jaw to vary the distance along the width of the jaws.

61. The end effector assembly according to claim 60, wherein the first electrode is tapered radially outwardly.

62. The end effector assembly according to claim 55, wherein the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

63. The end effector assembly according to claim 55, further comprising a first conductive protrusion extending radially from the first electrode in a direction toward the second jaw when the first and second jaws are moved to the closed position to maintain a minimum spacing between the first and second electrodes.

64. The end effector assembly according to claim 63, further comprising a second conductive protrusion extending radially from the first electrode in a direction toward the second jaw.

65. The end effector assembly according to claim 63, wherein the first and second electrodes extend in a substantially U-shape spaced inwardly from a peripheral edge of the respective first and second jaws.

66. The end effector assembly according to claim 65, further comprising a non-conductive material positioned adjacent the second electrode and the first conductive protrusion is engageable with the non-conductive material.

67. An end effector assembly for a surgical device comprising: a first jaw having a first engagement surface;

a second jaw having a second engagement surface, at least one of the first jaw and second jaw is movable with respect to the other jaw to transition the first jaw and the second jaw between an open configuration and a closed configuration, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open configuration and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed configuration; and

a first electrode disposed on the first jaw and a second electrode disposed on the second jaw, and a first conductive protrusion extending radially from the first electrode in a direction toward the second jaw when the first and second jaws transition to the closed position to maintain a minimum spacing between the first and second electrodes.

68. The end effector assembly according to claim 67, wherein the first conductive protrusion is integrally formed with the first electrode

69. The end effector assembly according to claim 67, wherein the first conductive protrusion is spaced proximally from a distal tip of the electrode.

70. The end effector assembly according to claim 69, further comprising a second conductive protrusion, wherein the second conductive protrusion is spaced axially from the first conductive protrusion.

71. The end effector assembly according to claim 70, wherein the second conductive protrusion is spaced distally from a proximal end of the first electrode.

72. The end effector assembly according to claim 67, wherein the second jaw includes a non- conductive material adjacent the second electrode and the first conductive protrusion is engageable with the non-conductive material.

73. The end effector assembly according to claim 27, wherein the first protrusion is positioned in a central region of the first jaw.

74. The end effector assembly according to claim 67, wherein the second jaw includes a non- conductive base adjacent the second electrode, wherein the non-conductive base is substantially flush with the second engagement surface.

75. The end effector assembly according to claim 67, wherein the second jaw includes a non- conductive base, the non-conductive base is recessed with respect to the second engagement surface.

76. The end effector assembly according to claim 67, wherein one or both of the first electrode and second electrode tapers radially outwardly from an intermediate portion so the distance between the first electrode and second electrode is greater at a portion closer to a peripheral edge than at a portion closer to a center of the jaw.

77. The end effector assembly according to claim 67, wherein the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

78. The end effector assembly according to claim 77, wherein the variation of forces is obtained by a non-linear slot formed in the first jaw

79. The end effector assembly of claim 67, wherein the first jaw includes an arm and a float portion having a first electrode, the float portion rotatably connected to the first arm to enable the first electrode to float with respect to the arm.

80. A surgical device comprising:

a handle portion at a proximal portion of the device;

an elongated portion extending distally from the handle portion;

a first jaw and a second jaw at a distal portion of the device, the first jaw having a first engagement surface and the second jaw having a second engagement surface;

a drive assembly extending through the elongated portion, the drive assembly operable to move at least the first jaw to transition the first jaw and the second jaw between an open position and a closed position, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open position and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed position;

a first electrode disposed on the first jaw;

a second electrode disposed on the second jaw; and

a power switch positioned at the proximal portion of the device and operable to supply energy to the first and second electrodes, wherein energy cannot be applied to the first and second electrodes unless the first and second jaws are in the closed position.

81. The surgical device according to claim 80, wherein the handle portion includes a movable handle, the movable handle operably connected to the drive assembly and actuable from a first position to a second position to move the drive assembly to position the jaws in the closed position.

82. The surgical device according to claim 81, wherein the movable handle moves the first jaw with respect to the second jaw between the open and closed position and the second jaw remains stationary.

83. The surgical device according to claim 80, further comprising an actuator for turning on the power switch and a cover adjacent the actuator, the cover blocking user access to the actuator when the jaws are in the open position and enabling user access to the actuator when the jaws are in the closed position.

84. The surgical device according to claim 83, wherein the handle portion includes a movable handle, the movable handle operably connected to the drive assembly and actuable from a first position to a second position to move the drive assembly to position the jaws in the closed position, wherein the cover is attached to the movable handle and moves with movement of the movable handle.

85. The surgical device according to claim 83, wherein the actuator is in the form of an actuation button.

86. The surgical device of claim 84, wherein the actuator is recessed when the movable handle is in the first position.

87. The surgical device of claim 84, wherein the actuator is hidden when the movable handle is in the first position.

88. The surgical device of claim 83, wherein in the first position of the movable handle the cover extends further distally than the actuator and in the second position of the movable handle the cover has moved proximally so the actuator extends distally of the cover.

89. The surgical device according to claim 80, further comprising an actuator for actuating the drive assembly, the actuator including a cover extending therefrom to selectively block and unblock user access to the power switch.

90. The surgical device according to claim 80, further comprising a cutting blade movable with respect to the first and second jaws to sever tissue clamped between the first and second jaws.

91. The surgical device according to claim 80, wherein the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

92. A surgical device comprising:

a handle portion at a proximal portion of the device;

an elongated portion extending distally from the handle portion;

a drive assembly extending through the elongated portion, the drive assembly operable to transition the first jaw and the second jaw between an open position and a closed position, wherein the first jaw and the second jaw are arranged to receive tissue therebetween when in the open position and to exert force on the tissue via the first engagement surface and the second engagement surface when in the closed position;

a first electrode disposed on the first jaw;

a second electrode disposed on the second jaw;

an energy actuator positioned at the proximal portion of the device and operable to supply energy to the first and second electrodes; and

a cover movable with respect to the energy actuator to selectively block and unblock access to the energy actuator.

93. The surgical device according to claim 92, wherein the drive assembly includes a force transfer member extending through the elongated portion and a jaw actuator for advancing and retracting the force transfer member, the cover extending from the jaw actuator so that movement of the jaw actuator moves the cover with respect to the energy actuator.

94. The surgical device according to claim 92, wherein the cover includes first and second laterally extending portions with an open region therebetween.

95. The surgical device according to claim 92, further comprising a cutting blade movable with respect to the first and second jaws, and a blade actuator actuable independently from the jaw actuator to advance the blade to sever tissue clamped between the first and second jaws.

96. The surgical device according to claim 95, further comprising a blade blocking mechanism, the blade blocking mechanism prevents movement of the cutting blade unless the first and second jaws are in the closed position.

97. The surgical device according to claim 92, wherein the first and second jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

98. The surgical device according to claim 92, wherein the cover has a U-shaped configuration with the energy actuator positioned within the U.

99. A surgical device comprising:

a handle portion at a proximal portion of the device;

an elongated portion extending distally from the handle portion;

a first actuator at the handle portion operably connected to the drive assembly to move the drive assembly between distal and proximal positions;

a first electrode disposed on the first jaw;

a second electrode disposed on the second jaw;

a power switch positioned at the proximal portion of the device and operable to supply energy to the first and second electrodes,

a blade movable with respect to the first and second jaws to sever tissue clamped between the first and second jaws;

a second actuator operably connected to the blade to move the blade between proximal and distal positions; and a blade lock, the blade lock preventing movement of the blade when the first and second jaws are not in the closed position, and the blade lock includes an engagement member so when the first and second jaws are in the open position forces exerted on the second actuator are transferred to the first actuator in a direction substantially perpendicular to a direction of actuation of the first actuator so such forces will not move the first actuator.

100. The surgical device of claim 99, wherein the blade lock further includes a blocking arm that blocks movement of the engagement member.

101. The surgical device of claim 100, wherein the blocking arm extends from the first actuator and the engagement member extends from the second actuator.

102. The surgical device of claim 99, wherein the first actuator includes a movable handle, the handle movable in a proximal direction to move the first and second jaws to the closed position and the second actuator is pivotable about an axis extending transverse to a longitudinal axis of the device.

103. The surgical device of claim 99, wherein the first actuator has a pair of arms extending distally therefrom, and the engagement member abuts the arms in the initial position of the first actuator.

104. The surgical device of claim 102, wherein the first actuator has a pair of arms extending distally therefrom, and the engagement member abuts the arms in a distal position of the movable handle.

105. The surgical device of claim 99, wherein energy cannot be applied to the first and second electrodes unless the first and second jaws are in the closed position.

106. The surgical device of claim 99, further comprising a cover movable with respect to the power switch to prevent application of energy to the first and second electrodes when the first and second jaws are not in the closed position.

107. The surgical device of claim 99, wherein the first actuator includes a movable handle, and the cover extends from the movable handle and is movable along with movement of the handle member to selectively block and unblock access to the power switch.

108. The surgical device according to claim 99, wherein the first and second jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

109. A surgical device comprising:

a handle portion at a proximal portion of the device;

an elongated portion extending distally from the handle portion;

a first electrode disposed on the first jaw;

a second electrode disposed on the second jaw; a blade movable with respect to the first and second jaws to sever tissue clamped between the first and second jaws; and

a feedback mechanism to indicate to a user that the blade has been moved with respect to the first and second jaws to sever tissue clamped between the first and second jaws.

110. The surgical device of claim 109, wherein the feedback mechanism provides tactile feedback.

111. The surgical device of claim 109, wherein the feedback mechanism provides audible feedback.

112. The surgical device of claim 109, further comprising a blade actuator, and the feedback mechanism includes a flexible member, the blade actuator operably connected to the blade, wherein sufficient movement of the blade actuator causes the flexible member to buckle to increase resistance of the blade actuator.

113. The surgical device of claim 112, wherein further movement of the blade actuator causes release of the flexible member.

114. The surgical device of claim 109, wherein the feedback mechanism provides feedback prior to full advancement of the blade.

115. The surgical device of claim 109, wherein the feedback mechanism is positioned within a housing of the handle portion.

116. The surgical device of claim 115, wherein the feedback mechanism includes a flexible member, wherein the flexible member resiliently deflects laterally to disengage from a support within the housing.

117. The surgical device of claim 109, further comprising a blade actuator operably connected to the blade to move the blade between proximal and distal positions, and a blade lock to prevent actuation of the blade actuator unless the first and second jaws are in the closed position.

118. The surgical device of claim 117, further comprising a jaw actuator operably connected to the drive assembly to move the jaws between the open and closed position, wherein movement of the jaw actuator to transition the jaws to the closed position unblocks a blocking mechanism to enable actuation of the blade actuator.

119. The surgical device of claim 109, further comprising a power switch positioned at the proximal portion of the device and operable to supply energy to the first and second electrodes, wherein energy cannot be applied to the first and second electrodes unless the first and second jaws are in the closed position.

120. The surgical device of claim 117, further comprising a power switch positioned at the proximal portion of the device and operable to supply energy to the first and second electrodes, wherein energy cannot be applied to the first and second electrodes unless the first and second jaws are in the closed position.

121. The surgical device according to claim 109, wherein the jaws exert the force on the tissue as a function of a distance between the first engagement surface and the second engagement surface according to a force curve, wherein the force curve is shaped so that forces applied to the tissue by the jaws progressively increase when the first and second engagement surfaces are spaced any of a first set of distances from each other and the forces applied to tissue substantially plateaus when the first and second engagement surfaces are spaced any of a second set of distances from each other, the first set of distances being greater than the second set of distances.

122. A method for minimally invasively sealing parenchyma comprising the steps of: providing or preparing a device having a handle portion at a proximal portion, an elongated tubular portion extending distally from the proximal portion, and first and second jaws at a distal portion of the device;

minimally invasively inserting the device so the first and second jaws are adjacent the parenchyma;

positioning the jaws in an open position around the parenchyma;

actuating a jaw actuator so the first and second jaws transition to a closed position to clamp the parenchyma, wherein force exerted by the first and second jaws on the parenchyma varies dependent on a gap between the first and second jaws, the force increasing a first percentage upon initial clamping and subsequently varying a second percentage upon further clamping of the jaws, the second percentage being substantially less than the first percentage; and

applying energy to a first electrode carried by the first jaw and a second electrode carried by the second jaw.

123. The method according to claim 122, further comprising the step of actuating the jaw actuator to move a force transfer member within the elongated tubular portion to transition the first and second jaws to the closed position.

124. The method according to claim 123, wherein the step of actuating the actuator moves the first jaw toward the second jaw, the second jaw remaining stationary.

125. The method according to claim 123, wherein the step of actuating the actuator moves both the first and second jaws toward each other.

126. The method according to claim 123, wherein the step of moving the force transfer member moves a pin within a non-linear slot in the first jaw.

127. The method according to claim 126, wherein the slot is configured to control the force exerted by the jaws.

128. The method according to claim 123, further comprising a spring for biasing the force transfer member wherein compression of the spring controls the force exerted by the jaws.

129. The method according to claim 122, wherein the force varies slightly once a threshold distance between the first and second jaws is reached.

130. The method according to claim 129, wherein the threshold distance is between about 2.5 mm and about 3.0 mm.

131. The method according to claim 122, wherein the force exerted by the first and second jaws in the initial clamping is between about 14 pounds and about 19 pounds.

132. The method according to claim 131, wherein the force exerted by the first and second jaws in the further clamping is between about 18 pounds and 19 pounds.

133. The method according to claim 123, further comprising the step of advancing a blade to sever tissue clamped by the first and second jaws.

134. The method according to claim 133, wherein the step of advancing the blade is independent of movement of the force transfer member.

135. The method according to claim 134, wherein the step of advancing the blade cannot be performed when the first and second jaws are not in the closed position.

136. The method according to claim 122, wherein the step of applying energy cannot be performed unless the first and second jaws are in the closed position.

137. The method according to claim 122, wherein the gap between the jaws in the closed position varies along a width of the jaws so the gap is greater at a distance further from a center of the jaw than closer to the center of the jaw.

138. A method for minimally invasively sealing organ tissue by applying electrosurgical energy to tissue while preventing excessive force on the tissue so that the tissue is not dissected, the method comprising the steps of:

providing or preparing a device having a handle portion, an elongated tubular portion extending distally from the handle portion, a force transfer member extending through the tubular portion and first and second jaws at a distal portion of the device, at least one of the jaws having a slot configured to control forces applied to tissue;

minimally invasively inserting the device so the first and second jaws are adjacent the tissue;

positioning the first and second jaws in an open position around the tissue;

actuating a jaw actuator so the force transfer member engageable with the slot is retracted to move a drive pin proximally within the slot to clamp the first and second jaws on tissue with a first force progressively increasing to a predetermined force when the first and second jaws move through a first range of distances spaced apart from each other and a second subsequent force that does not progressively increase when the first and second jaws move through a second range of distances to thereby control the forces on tissue and prevent dissection of the tissue; and

139. The method according to claim 138, wherein the step of actuating the jaw actuator moves the first jaw toward the second jaw, the second jaw remaining stationary.

140. The method according to claim 138, wherein the step of actuating the jaw actuator moves both the first and second jaws toward each other.

141. The method according to claim 138, further comprising a spring for biasing the force transfer member wherein compression of the spring controls the force exerted by the jaws.

142. The method according to claim 138, wherein the first range of distances is between about 5.0 mm and about 2.75 mm.

143. The method according to claim 138, wherein the first force progressively increases from about 14 pounds to about 19 pounds.

144. The method according to claim 143, wherein the second force varies between about 18 pounds and about 19 pounds.

145. The method according to claim 138, further comprising the step of advancing a blade to sever tissue clamped by the first and second jaws.

146. The method according to claim 145, wherein the step of advancing the blade is independent of movement of the force transfer member.

147. The method according to claim 146, wherein the step of advancing the blade cannot be performed when the first and second jaws are not in the closed position.

148. The method according to claim 138, wherein the step of applying energy cannot be performed unless the first and second jaws are in the closed position.

149. The method according to claim 138, wherein the gap between the jaws in the closed position varies along a width of the jaws so the gap is greater at a distance further from a center of the jaw than closer to the center of the jaw.

150. A method for controlling clamping forces on tissue by an electrosurgical device to enable use of the device on a wider range of tissue and preventing dissection of tissue, the method comprising the steps of:

providing or preparing a device having a handle portion, an elongated tubular portion extending distally from the handle portion, a force transfer member extending through the tubular portion and first and second jaws at a distal portion of the device, the first jaw having a first tissue engagement surface and a first electrode and the second jaw having a second tissue engagement surface and a second electrode, wherein at least one of the jaws is movable to transition the jaws from an open position to a closed position;

positioning the first and second jaws in an open position around the tissue;

actuating a jaw actuator so the force transfer member engageable with at least the first jaw transitions at least the first jaw toward the second jaw so the first and second jaws apply a first range of forces to tissue as the jaws transition through a first range of distances, wherein the distances are defined between the first and second engagement surfaces, and subsequently applying a second smaller range of forces to tissue as the jaws transition through a second range of distances less than the first range of distances; and

151. The method according to claim 150, wherein the step of actuating the actuator moves the first jaw toward the second jaw, the second jaw remaining stationary.

152. The method according to claim 150, wherein the step of actuating the actuator moves both the first and second jaws toward each other.

153. The method according to claim 150, wherein the step of moving the force transfer member moves a pin within a non-linear slot in the first jaw, the slot configured to control the force exerted by the jaws.

154. The method according to claim 150, further comprising a spring for biasing the force transfer member wherein compression of the spring controls the force exerted by the jaws.

155. The method according to claim 150, wherein the first range of forces progressively increases.

156. The method according to claim 155, wherein the second range of forces varies slightly.

157. The method according to claim 150, wherein the second range of forces varies slightly.

158. The method according to claim 150, wherein the second range of forces substantially plateaus.

159. The method according to claim 150, wherein the first range of forces is between about 14 pounds and about 19 pounds.

160. The method according to claim 150, wherein the second range of forces is between about 18 pounds and 19 pounds.

161. The method according to claim 150, further comprising the step of independently advancing a blade to sever tissue clamped by the first and second jaws.

162. The method according to claim 161, wherein the step of advancing the blade cannot be performed when the first and second jaws are not in the closed position.

163. The method according to claim 150, wherein the step of applying energy cannot be performed unless the first and second jaws are in the closed position.