Destruction of vessel walls for energy-based vessel sealing enhancement

An end effector assembly for use with an electrosurgical instrument is provided. The end effector assembly includes a pair of opposing jaw members configured to grasp tissue therebetween, at least one jaw member adapted to connect to a source of electrosurgical energy to seal tissue disposed between jaw members during a sealing process. At least one of the jaw members includes an activator configured to selectively impart mechanical perturbations to the at least one jaw member during the sealing process.

BACKGROUND

1. Technical Field

The present disclosure relates to electrosurgical instruments used for open and endoscopic surgical procedures for sealing or fusing tissue. More particularly, the present disclosure relates to a bipolar forceps for sealing vessels, vascular tissues and soft tissues by applying mechanical vibrations and/or acoustic vibrations to destroy vessel walls and facilitate extraction of collagen and elastin during an electrosurgical procedure.

2. Background of the Related Art

Open or endoscopic electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis. The electrode of each opposing jaw member is charged to a different electric potential such that when the jaw members grasp tissue, electrical energy can be selectively transferred through the tissue. A surgeon can cauterize, coagulate/desiccate and/or simply reduce or slow bleeding, by controlling the intensity, frequency and duration of the electrosurgical energy applied between the electrodes and through the tissue.

Certain surgical procedures require more than simply cauterizing tissue and rely on the combination of clamping pressure, electrosurgical energy and gap distance to “seal” tissue, vessels and certain vascular bundles. More particularly, vessel sealing or tissue sealing utilizes a unique combination of radiofrequency (RF) energy, clamping pressure and precise control of gap distance (i.e., distance between opposing jaw members when closed about tissue) to effectively seal or fuse tissue between two opposing jaw members or sealing plates. Vessel or tissue sealing is more than “cauterization”, which involves the use of heat to destroy tissue (also called “diathermy” or “electrodiathermy”). Vessel sealing is also more than “coagulation”, which is the process of desiccating tissue wherein the tissue cells are ruptured and dried. “Vessel sealing” is defined as the process of liquefying the collagen, elastin and ground substances in the tissue so that the tissue reforms into a fused mass with significantly-reduced demarcation between the opposing tissue structures.

Energy based vessel sealing consists of a few steps. During a vessel sealing procedure, opposing vessel walls are moved closer together. Then, the inner layer of the vessel walls that normally prevent adhesion of the vessel walls are destroyed. Elastin and collagen are released, mixed and exposed to energy to seal the vessel. Moving the vessel walls together, destruction of the inner layer of the vessel walls and releasing and mixing of collagen are traditionally achieved by pressurizing vessels between jaws. Destruction of the inner layer of the vessel wall requires application of a significant amount of force. If the vessel is located in a relatively thick layer of the tissue, the significant amount of force may damage and even break the upper tissue layers before sealing is completed.

SUMMARY

In an embodiment of the present disclosure, an end effector assembly is provided. The end effector assembly includes a pair of opposing jaw members configured to grasp tissue therebetween, at least one jaw member adapted to connect to a source of electrosurgical energy to effectively seal tissue disposed between jaw members during a sealing process. At least one of the jaw members includes an activator configured to selectively impart mechanical perturbations to the at least one jaw member during the sealing process.

In another embodiment of the present disclosure, an electrosurgical instrument for sealing tissue is provided. The electrosurgical instrument may include at least one shaft that supports an end effector assembly at a distal end thereof, the end effector assembly including a pair of opposing jaw members, at least one of the jaw members moveable relative to the other for grasping tissue therebetween, at least one of the jaw members adapted to connect to a source of electrosurgical energy to effectively seal tissue disposed between jaw members during a sealing process. At least one of the jaw members includes an activator configured to selectively impart mechanical perturbations to the at least one jaw member during the sealing process.

In yet another embodiment of the present disclosure, a method for sealing tissue using an end effector assembly having a pair of opposing jaw members wherein at least one jaw member has a member configured to impart mechanical perturbations to the at least one jaw member is provided. The method includes grasping tissue between the pair of opposing jaw members, activating the activator to move the at least one jaw member and applying electrosurgical energy to seal the tissue disposed between the jaw members.

The activator may provide a shearing force caused by the forward and/or backward movement of the at least one jaw member along a longitudinal axis. Alternatively, the activator may be a transducer that provides ultrasound to impart mechanical perturbations to the at least one jaw member.

DETAILED DESCRIPTION

Electromagnetic energy is generally classified by increasing frequency or decreasing wavelength into radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma-rays. As used herein, the term “microwave” generally refers to electromagnetic waves in the frequency range of 300 megahertz (MHz) (3×108cycles/second) to 300 gigahertz (GHz) (3×1011cycles/second). As used herein, the term “RF” generally refers to electromagnetic waves having a lower frequency than microwaves. As used herein, the term “ultrasound” generally refers to cyclic sound pressure with a frequency greater than the upper limit of human hearing. The terms “tissue” and “vessel” may be used interchangeably since it is believed that the present disclosure may be employed to seal and cut tissue or seal and cut vessels utilizing the same principles described herein.

As will be described in more detail below with reference to the accompanying figures, the present disclosure is directed to the use mechanical or acoustic vibrations to destroy vessel walls and intensify release of collagen and elastin.

Referring now toFIGS. 1 and 2,FIG. 1depicts a bipolar forceps10for use in connection with endoscopic surgical procedures andFIG. 2depicts an open forceps100contemplated for use in connection with traditional open surgical procedures. For the purposes herein, either an endoscopic instrument or an open instrument may be utilized with the electrode assembly described herein. Different electrical and mechanical connections and considerations may apply to each particular type of instrument; however, the aspects with respect to the electrode assembly and its operating characteristics remain generally consistent with respect to both the open or endoscopic designs.

FIG. 1shows a bipolar forceps10for use with various endoscopic surgical procedures and generally includes a housing20, a handle assembly30, a rotating assembly80, a knife actuator70and an electrode assembly105having opposing jaw members110and120that mutually cooperate to grasp, seal and divide tubular vessels and vascular tissue. The jaw members110and120are connected about pivot pin19, which allows the jaw members110and120to pivot relative to one another from the first to second positions for treating tissue. More particularly, forceps10includes a shaft12that has a distal end16configured to mechanically engage the electrode assembly105and a proximal end14that mechanically engages the housing20. The shaft12may include one or more suitable mechanically-engaging components that are designed to securely receive and engage the electrode assembly105such that the jaw members110and120are pivotable relative to one another to engage and grasp tissue therebetween.

The proximal end14of shaft12mechanically engages the rotating assembly80to facilitate rotation of the electrode assembly105. In the drawings and in the descriptions that follow, the term “proximal”, as is traditional, will refer to the end of the forceps10that is closer to the user, while the term “distal” will refer to the end that is further from the user. Details relating to the mechanically cooperating components of the shaft12and the rotating assembly80are described in commonly-owned U.S. patent application Ser. No. 10/460,926, now U.S. Pat. No. 7,156,846, entitled “VESSEL SEALER AND DIVIDER FOR USE WITH SMALL TROCARS AND CANNULAS” filed on Jun. 13, 2003.

Handle assembly30includes a fixed handle50and a movable handle40. Fixed handle50is integrally associated with housing20and handle40is movable relative to fixed handle50to actuate the opposing jaw members110and120of the electrode assembly105as explained in more detail below. Movable handle40and knife actuator70are of unitary construction and are operatively connected to the housing20and the fixed handle50during the assembly process. Housing20is constructed from two component halves20aand20bthat are assembled about the proximal end14of shaft12during assembly. Switch assembly200is configured to selectively provide electrical energy to the electrode assembly105.

As mentioned above, electrode assembly105is attached to the distal end16of shaft12and includes the opposing jaw members110and120. Movable handle40of handle assembly30imparts movement of the jaw members110and120from an open position wherein the jaw members110and120are disposed in spaced relation relative to one another, to a clamping or closed position wherein the jaw members110and120cooperate to grasp tissue therebetween.

Referring now toFIG. 2, an open forceps100includes a pair of elongated shaft portions112aand112beach having a proximal end114aand114b, respectively, and a distal end116aand116b, respectively. The forceps100includes jaw members120and110that attach to distal ends116aand116bof shafts112aand112b, respectively. The jaw members110and120are connected about pivot pin119that allows the jaw members110and120to pivot relative to one another from the first to second positions for treating tissue. The electrode assembly105is connected to opposing jaw members110and120and may include electrical connections through or around the pivot pin119. Examples of various electrical connections to the jaw members are shown in commonly-owned U.S. patent application Ser. Nos. 10/474,170, 10/284,562 10/472,295, 10/116,944 and 10/179,863, now U.S. Pat. Nos. 7,582,087, 7,267,677, 7,101,372, 7,083,618 and 7,101,371 respectively.

Each shaft112aand112bincludes a handle117aand117bdisposed at the proximal end114aand114bthereof that each define a finger hole118aand118b, respectively, therethrough for receiving a finger of the user. As can be appreciated, finger holes118aand118bfacilitate movement of the shafts112aand112brelative to one another, which, in turn, pivot the jaw members110and120from the open position wherein the jaw members110and120are disposed in spaced relation relative to one another to the clamping or closed position wherein the jaw members110and120cooperate to grasp tissue therebetween. A ratchet130may be included for selectively locking the jaw members110and120relative to one another at various positions during pivoting.

More particularly, the ratchet130includes a first mechanical interface130aassociated with shaft112aand a second mating mechanical interface130bassociated with shaft112b. Each position associated with the cooperating ratchet interfaces130aand130bholds a specific, i.e., constant, strain energy in the shaft members112aand112b, which, in turn, transmits a specific closing force to the jaw members110and120. The ratchet130may include graduations or other visual markings that enable the user to easily and quickly ascertain and control the amount of closure force desired between the jaw members110and120.

As best seen inFIG. 2, forceps100also includes an electrical interface or plug200that connects the forceps100to a source of electrosurgical energy, e.g., an electrosurgical generator similar to generator500shown inFIG. 1. Plug202includes at least two prong members202aand202bthat are dimensioned to mechanically and electrically connect the forceps100to the electrosurgical generator500(SeeFIG. 1). An electrical cable210extends from the plug202and securely connects the cable210to the forceps100. Cable210is internally divided within the shaft112bto transmit electrosurgical energy through various electrical feed paths to the electrode assembly105.

One of the shafts, e.g.112b, includes a proximal shaft connector/flange140that is designed to connect the forceps100to the source of electrosurgical energy such as electrosurgical generator500. More particularly, flange140mechanically secures electrosurgical cable210to the forceps100such that the user may selectively apply electrosurgical energy as needed.

Referring toFIG. 3, an end effector assembly according to an embodiment of the present disclosure is shown generally as end effector300. End effector assembly300is substantially similar to electrode assembly105shown at the distal end of forceps10and/or forceps100. End effector assembly300includes an upper jaw member310and lower jaw member320. Jaw members310and320are used to grasp vessel301therebetween. Jaw members310and320may include one or more electrodes (not shown) to provide RF energy to vessel301to seal vessel301.

As shown inFIG. 3, jaw member310includes an activator305that imparts mechanical perturbations to jaw member310. Activator305may be mechanically or magnetically coupled to jaw member310. For example, activator305may have an adhesive applied thereon before inserted into jaw member310or activator305may be soldered onto jaw member310. Additionally, activator305may have a mechanical interface, e.g., a notch or protrusion that cooperates with a corresponding mechanical interface in jaw member310. Although not shown, activator305may also be included in jaw member320or both jaw members310and320. Activator305provides forward and/or backward movement of jaw member310along a longitudinal axis “A” defined therethrough relative to jaw member320(see arrow “X” onFIG. 3). The forward and/or backward movements of jaw members310and320relative to each other deforms vessel301due to compressing and shearing forces. The application of the compressing and shearing forces leads to the destruction of inner layer302of vessel301which releases and mixes elastin and/or collagen during a sealing cycle.

The shearing forces are produced by movement of jaw member310along longitudinal axis “A”. The maximum deformation of inner layer302occurs where the curvature of the compressed vessel is at its maximum (307). The shearing forces extend area307and accelerate destruction of inner layer302as well as accelerating the release of elastin and collagen disposed therein. Additionally, friction between inner walls of vessel301created in the tissue by the forward and backward movements of jaw members320contributes to the destruction of inner layer302.

Activator305may be mechanically, electrically, or magnetically coupled to an actuator330. Actuator330may be a motor, electromagnet or any other device that imparts motion to activator305, thereby causing activator305to move in a longitudinal direction along axis “A”. Actuator330may be controlled by generator500or may be controlled by a user.

Generator500includes a memory510and a processor520. Memory510may store a program or routine for performing a vessel sealing procedure that is executed by processor520. Generator500provides electrosurgical energy to end effector assembly300according to the program or routine stored in memory510. Generator500also controls actuator330according to a program or routine stored in memory510. To avoid damaging outer tissue layers before sealing is completed, generator500may control actuator330to limit the movement of activator305.

Referring toFIG. 4, an end effector assembly according to another embodiment of the present disclosure is shown generally as400. End effector assembly400includes upper jaw member410and lower jaw member420. Upper jaw member410includes a transducer405that receives electrical energy from energy source430and converts the electrical energy into ultrasound to impart mechanical perturbations to jaw member410, Energy source430may be a stand-alone unit, built into the forceps10or forceps100or may be included in generator500.

Transducer405may be mechanically or magnetically coupled to jaw member410. For example, transducer405may have an adhesive applied thereon before inserted into jaw member410or transducer405may be soldered onto jaw member410. Additionally, transducer405may have a mechanical interface, e.g., a notch or protrusion that cooperates with a corresponding mechanical interface in jaw member410.

Ultrasound provided by transducer405causes periodic movement in upper jaw member410resulting additional heating and destruction of inner layer302of vessel301. Transducer405may be located in upper jaw member310, lower jaw member320or both jaw members.

As described above, generator500includes a memory510and a processor520. Memory510may store a program or routine for performing a vessel sealing procedure that is executed by processor520. Generator500provides electrosurgical energy to end effector assembly400according to the program or routine stored in memory510. Generator500also controls energy source430according to a program or routine stored in memory510. To avoid damaging outer tissue layers before sealing is completed, generator500may control energy source430to limit the amplitude of periodic movements of transducer405.

While several embodiments of the disclosure have been shown in the drawings and/or discussed herein, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. The claims can encompass embodiments in hardware, software, or a combination thereof. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.