Surgical instrument for energy-based tissue treatment

A forceps includes a drive assembly and an end effector assembly having first and second jaw members movable between a spaced-apart position, a first approximated position, and a second approximated position. The drive assembly includes a drive housing and a drive bar. The proximal end of the drive bar is coupled to the drive housing, while the distal end of the drive bar is coupled to at least one of the jaw members. The drive housing and the drive bar are selectively movable in conjunction with one another between a first position and a second position to move the jaw members between the spaced-apart position and the first approximated position. The drive assembly is selectively activatable to move the drive bar independent of the drive housing from the second position to a third position to move the jaw members from the first approximated position to the second approximated position.

BACKGROUND

Technical Field

The present disclosure relates to surgical instruments and, more particularly, to surgical instrument for treating tissue with energy.

Background of Related Art

A forceps is a plier-like instrument which relies on mechanical action between its jaws to grasp, clamp and constrict vessels or tissue. Energy-based forceps utilize both mechanical clamping action and energy, e.g., RF energy, ultrasonic energy, microwave energy, thermal energy, light energy, etc., to affect hemostasis by heating tissue and blood vessels to coagulate and/or cauterize tissue. Certain surgical procedures require more than simply cauterizing tissue and rely on the unique combination of clamping pressure, precise energy control and/or gap distance (i.e., distance between opposing jaw members when closed about tissue) to “seal” tissue, vessels, and certain vascular bundles. Typically, once a vessel is sealed, the surgeon has to accurately sever the vessel along the newly formed tissue seal. Accordingly, many forceps have been designed which incorporate a knife or blade member that effectively severs the tissue along the tissue seal. Alternatively, or additionally, energy may be utilized to facilitate tissue division.

SUMMARY

As used herein, the term “distal” refers to that portion that is further from an operator while the term “proximal” refers to that portion that is closer to an operator. As used herein, the term “treat” refers to performing a surgical treatment to tissue using energy, e.g. heating, sealing, or energized cutting of tissue. As used herein, the term “energy” refers broadly to include all types of energy used to treat tissue, e.g., RF energy, ultrasonic energy, microwave energy, thermal energy, light energy, etc. As used herein, the term “light energy source” refers broadly to include all types of devices that produce light for medical use (e.g., tissue treatment). These devices include lasers, light emitting diodes (LEDs), lamps, and other accessories that produce light anywhere along an appropriate electromagnetic spectrum (e.g., from infrared to ultraviolet).

Any or all of the aspects described herein, to the extent consistent with one another, may be used in conjunction with any of the other aspects described herein.

In accordance with one aspect of the present disclosure, a forceps is provided. The forceps generally includes an end effector assembly and a drive assembly. The end effector assembly includes first and second jaw members movable relative to one another between a spaced-apart position, a first approximated position, and a second approximated position. The drive assembly includes a drive housing and a drive bar. The proximal end of the drive bar is coupled to the drive housing, while the distal end of the drive bar is coupled to one or both of the jaw members. The drive housing and the drive bar are selectively movable, in conjunction with one another, between a first position and a second position to move the jaw members between the spaced-apart position and the first approximated position. The drive assembly is selectively activatable to move the drive bar independent of the drive housing from the second position to a third position to move the jaw members from the first approximated position to the second approximated position.

In one aspect, one or both of the jaw members is adapted to connect to a source of energy for treating tissue disposed between the jaw members.

In another aspect, a plunger is coupled to the drive housing and is selectively movable between a proximal position and a distal position for moving the jaw members between the spaced-apart position and the first approximated position. Alternatively, a handle is coupled to the drive housing and is selectively movable between an initial position and an actuated position for moving the jaw members between the spaced-apart position and the first approximated position.

In another aspect, the drive housing defines an internal chamber and the drive bar includes a proximal stop disposed at the proximal end thereof. The proximal stop is disposed within the internal chamber of the drive housing and is movable within the internal chamber upon activation of the drive assembly to move of the drive bar from the second position to the third position.

In yet another aspect, the drive housing further includes a spring disposed within the internal chamber of the drive housing. The spring is configured, upon activation of the drive assembly, to bias the drive bar distally relative to the drive housing to thereby move the drive bar from the second position to the third position.

In some aspects, the spring is initially encased in a thermally-activateable material disposed within the internal chamber to inhibit movement of the drive bar from the second position to the third position. One or more heaters may be coupled to the internal chamber and configured such that, upon activation of the drive assembly, the heaters melt the material to thereby permit movement of the drive bar from the second position to the third position under the bias of the spring.

In other aspects, the proximal stop divides the internal chamber into a proximal portion and a distal portion and includes a valve that is transitionable between a closed condition, inhibiting passage of fluid through the valve from the distal portion to the proximal portion, and an open condition, permitting passage of fluid through the valve from the distal portion to the proximal portion. The valve may initially be disposed in the closed condition such that the fluid substantially fills the proximal portion of the internal chamber, thus inhibiting movement of the drive bar from the second position to the third position. Upon activation of the drive assembly, the valve is transitioned to the open condition to permit fluid to flow therethrough to thereby permit movement of the drive bar from the second position to the third position under the bias of the spring.

In accordance with another aspect of the present disclosure, a forceps is provided. The forceps includes an end effector assembly and a drive assembly. The end effector assembly includes first and second jaw members movable relative to one another between a spaced-apart position, a first approximated position, and a second approximated position. The drive assembly includes a drive housing defining an internal chamber and a drive bar coupled to the end effector assembly at a distal end thereof and defining a proximal stop at the proximal end thereof. The proximal stop is slidably disposed within the internal chamber of the drive housing. The drive bar and drive housing are movable in conjunction with one another between a first position and a second position for moving the jaw members between the spaced-apart position and the first approximated position. A spring is disposed within the internal chamber of the drive housing and is configured to bias the drive bar distally relative to the drive housing. A thermally-activateable material is disposed within the internal chamber of the drive housing and encases the spring so as to inhibit the spring from biasing the drive bar distally relative to the drive housing. One or more heaters is thermally coupled to the internal chamber. The heater(s) is selectively activatable to melt the material to thereby permit the spring to bias the drive bar distally relative to the drive housing from the second position to a third position to move the jaw members from the first approximated position to the second approximated position.

In one aspect, one or both of the jaw members is adapted to connect to a source of energy for treating tissue disposed between the jaw members. The heater(s) may be adapted to connect to the source of energy for melting the material.

In another aspect, the heater(s) is configured to melt the material according to a pre-determined function such that the jaw members are moved between the first approximated position and the second approximated position in accordance with the pre-determined function.

In accordance with yet another aspect of the present disclosure, a forceps is provided. The forceps includes an end effector assembly and a drive assembly. The end effector assembly includes first and second jaw members movable relative to one another between a spaced-apart position, a first approximated, and a second approximated position. The drive assembly includes a drive housing defining an internal chamber and a drive bar coupled to the end effector assembly at a distal end thereof. A proximal end of the drive bar defines a proximal stop slidably disposed within the internal chamber of the drive housing. The drive bar and drive housing are movable in conjunction with one another between a first position and a second position for moving the jaw members between the spaced-apart position and the first approximated position. A spring is disposed within the internal chamber of the drive housing and is configured to bias the drive bar distally relative to the drive housing. A fluid substantially fills the proximal portion of the internal chamber defined between a distal end of the internal chamber and the proximal stop so as to inhibit the spring from biasing the drive bar distally relative to the drive housing. A valve is disposed within an aperture extending through the proximal stop and is transitionable between a closed condition inhibiting the spring from biasing the drive bar distally relative to the drive housing, and an open condition permitting fluid to pass through the valve from the proximal portion of the internal chamber to a distal portion of the internal chamber defined between the proximal stop and a proximal end of the internal chamber. In the open condition of the valve, the spring is permitted to bias the drive bar distally relative to the drive housing from the second position to a third position to move the jaw members from the first approximated position to the second approximated position.

In one aspect, one or both of the jaw members is adapted to connect to a source of energy for treating tissue disposed between the jaw members.

In another aspect, the valve is configured to transition between the closed condition and the open condition according to a first pre-determined function such that the jaw members are moved between the first approximated position and the second approximated position in accordance with the first pre-determined function. Additionally or alternatively, the fluid is configured to flow through the valve according to a second pre-determined function such that the jaw members are moved between the first approximated position and the second approximated position in accordance with the second pre-determined function.

DETAILED DESCRIPTION

The present disclosure relates generally to apparatus, systems and methods for treating tissue, e.g., heating, sealing, and/or dividing tissue using energy. The present disclosure is particularly advantageous for treating tissue using light energy, although the present disclosure is equally applicable for use with various other forms of energy, e.g., RF energy, ultrasonic energy, microwave energy, thermal energy, etc. However, while different considerations may apply depending on the particular form of energy used, the novel aspects of the present disclosure remain generally consistent regardless of the form of energy used. For simplicity and consistency purposes, the various aspects of the present disclosure will be described hereinbelow with respect to treating tissue using light energy.

Various drive assemblies and end effector assemblies configured for use with forceps10(FIG. 1), forceps10′ (FIGS. 8A-8B), or any other suitable surgical instrument, are described in detail hereinbelow with reference toFIGS. 1-9B. In particular, the drive assemblies and end effector assemblies described herein each include features that are configured to vary the pressure exerted on tissue disposed between the jaw members thereof while treating tissue in order to facilitate sealing and/or cutting of tissue. As will be described below, such a feature is particularly advantageous with respect to tissue treatment using light energy. However, the present disclosure is equally applicable for treating tissue using other forms of energy.

Light energy is suitable for sealing tissue since it is converted into heat energy by absorption at a molecular level. That is, light energy at optical wavelengths (e.g., from about 200 nm to about 11,000 nm) is used to heat tissue due to absorption of light energy at these wavelengths. However, optical properties of tissue are known to change during heating. For example, properties such as the absorption coefficient (μa), scattering coefficient (μs), and anisotropy coefficient (g) have been shown to change as a function of temperature and time. These properties, in turn, affect the transmission and reflection of light as it interacts with tissue.

It has been found that, due to the above, varying the pressure exerted on tissue during the application of light energy to tissue facilitates the formation of a tissue seal and/or the division of tissue along the tissue seal. More specifically, it has been found that initially applying a relatively smaller pressure to tissue allows for maximum absorption of light energy by tissue and that, once tissue has absorbed a sufficient amount of energy, i.e., once tissue has been sufficiently heated, increasing the pressure applied to tissue facilitates formation of the tissue seal. Further, it has also been found that increasing the pressure applied to tissue, e.g., after formation of a tissue seal, facilitates the cutting of tissue using light energy. The drive assemblies and end effector assemblies described hereinbelow implement these advantageous findings by providing features that are configured to vary the pressure exerted on tissue disposed between the jaw members thereof during the application of light energy to tissue in order to facilitate sealing and/or cutting of tissue.

Referring now toFIGS. 1-3, a forceps is shown generally identified by reference numeral10. Forceps10defines a longitudinal axis “X-X” and includes a handle assembly100, a plunger200extending proximally from handle assembly100, a shaft300extending distally from handle assembly100, an end effector assembly400disposed at distal end302of shaft300, and a drive assembly500(FIGS. 4A, 5A, and 6A) operably coupled to plunger200and end effector assembly400. End effector assembly400includes a pair of opposed jaw members410,420movable relative to one another between a spaced-apart position (FIG. 1) and one or more approximated positions (FIG. 2) for grasping tissue therebetween. Plunger200is selectively translatable relative to handle assembly100between an extended or proximal position (FIG. 1), wherein plunger200substantially extends proximally from handle assembly100, and an inserted or distal position (FIG. 2), wherein plunger200is substantially disposed within handle assembly100. More specifically, as will be described in greater detail below, plunger200and drive assembly500(FIGS. 4A, 5A, and 6A) cooperate with one another to effect movement of jaw members410,420relative to one another between the spaced-apart position (FIG. 1) and one or more approximated positions (FIG. 2) upon movement of plunger200between the proximal position (FIG. 1) and the distal position (FIG. 2).

Forceps10further includes a cable600extending from handle assembly100. Cable600includes a plurality of wires610extending therethrough that separate within handle assembly100to provide energy to handle assembly100and/or to extend through shaft300to provide energy, e.g., light energy, to end effector assembly400, as will be described in greater detail below. Cable600is adapted to connect to a generator (not shown) or other suitable power source, although forceps10may alternatively be configured as a battery powered instrument (seeFIGS. 8A-8B).

With continued reference toFIGS. 1-3, handle assembly100is formed from first and second housing parts110,120that are engagable with one another to form handle assembly100. More specifically, each housing part110,120includes a plurality of posts112,122disposed on engaging surfaces114,124, respectively, thereof and extending therefrom. Housing part110includes a plurality of apertures (not shown) defined within engaging surface114thereof, and housing part120similarly includes a plurality of apertures126defined within engaging surface124thereof. Posts112of housing part110are positioned to oppose apertures126of housing part120and, similarly, posts122of housing part120are positioned to oppose the apertures (not shown) of housing part110such that, upon approximation of housing parts110,120, posts112are engaged within apertures126and posts122are engaged within different apertures (not shown) defined within housing part110to engage first and second housing parts110,120, respectively, to one another.

Each housing part110,120further includes an elongated body portion117,127and an ergonomically-configured handle118,128extending outwardly therefrom. Each handle118,128defines a finger hole119,129therethrough for receiving a finger of the user. As can be appreciated, finger holes119,129facilitate grasping of handle assembly100during translation of plunger200relative to handle assembly100between the proximal and distal positions to transition jaw members410,420of end effector assembly400between the spaced-apart and approximated positions.

Continuing with reference toFIGS. 1-3, and toFIG. 3in particular, body portions117,127of housing parts110,120, respectively, cooperate with one another to define a longitudinally-extending lumen130therethrough. Lumen130is disposed about longitudinal axis “X-X” and is configured to house drive assembly500and at least a portion of plunger200therein. More specifically, lumen130is configured to permit reciprocation of drive assembly500and plunger200at least partially therethrough to transition jaw members410,420between the more spaced-apart position and the one or more approximated positions. One or both of housing parts110,120may further include one or more switch assemblies, e.g., first and second switch assemblies132,134, respectively, that are ergonomically disposed on handle assembly100and are coupled to cable600for selectively controlling the supply of energy to jaw members410,420, and/or for selectively activating other components of forceps10, e.g., heaters540of drive assembly500(as will be described in greater detail below (seeFIGS. 4A, 5A, and 6A).

Plunger200generally includes a rod210and a knob220disposed at a proximal end of rod210. Rod210further defines an engagement feature216at distal end214thereof that is configured to engage plunger200and drive assembly500to one another, as will be described in greater detail below. Knob220is configured for single handed-used, e.g., where knob220is grasped, or palmed by the user, while the user grasps handle assembly100by engagement of the user's fingers within finger holes119,129of handles118,128, respectively, to facilitate translation of plunger200relative to handle assembly100, e.g., between the proximal position (FIG. 1) and the distal position (FIG. 2), although other grasping configurations, e.g., two-handed operation, are also contemplated.

Continuing with reference toFIG. 3, shaft300is coupled to handle assembly100at proximal end304thereof and operably engages jaw members410,420of end effector assembly400at distal end302thereof. More specifically, shaft300extends into lumen130of handle assembly100formed via the engagement of first and second housing parts110,120, respectively, and includes an annular flange306disposed at proximal end304thereof that is received within annular slot136(FIG. 4A) defined within handle assembly100and disposed about lumen130. The engagement of annular flange306within annular slot136(FIG. 4A), upon engagement of first and second housing parts110,120to one another, secures proximal end304of shaft300and handle assembly100to one another.

Shaft300further includes a lumen308extending longitudinally therethrough from proximal end304to distal end302thereof. A pivot pin310extends transversely through lumen308of shaft300towards distal end302of shaft300. Pivot pin310is configured to rotatably support first and second jaw members410,420of end effector assembly400at distal end302of shaft300. However, although end effector assembly400is shown as a bilateral assembly, i.e., wherein both jaw members410,420are movable relative to one another and with respect to shaft300, end effector assembly400may alternatively be configured as a unilateral assembly, i.e., wherein one of the jaw members, e.g., jaw member420, is fixed relative to shaft300, while the other jaw member, e.g., jaw member410, is movable about pivot310relative to both jaw member420and shaft300. Lumen308may further be configured to route one or more wires610afrom cable600to end effector assembly400for selectively energizing jaw member410and/or jaw member420of end effector assembly400.

With continued reference toFIG. 3, drive assembly500generally includes a drive housing502and a drive bar504coupled to and extending distally from drive housing502. Drive housing502is slidably positioned within lumen130of handle assembly100, while drive bar504extends distally from drive housing502and though shaft300, ultimately engaging jaw members410,420via cam pin506. As such, longitudinal translation of drive bar504relative to end effector assembly400pivots jaw members410,420relative to one another between the spaced-apart position (FIG. 4B) and one or more approximated positions, e.g., a first approximated position (FIG. 5B) and a second approximated position (FIG. 6B). More specifically, drive bar504is longitudinally translatable, in conjunction with plunger200and drive housing502, between a first position, corresponding to the spaced-apart position of jaw members410,420(FIG. 4B), and a second position, corresponding to the first approximated position of jaw members410,420(FIG. 5B). Drive bar504is further translatable, independent of plunger200and drive housing502, from the second position, to a third position, corresponding to the second approximated position of jaw members410,420(FIG. 6B).

Drive housing502of drive assembly500may be formed at least partially from a thermally conductive material and defines a proximal end507, a distal end509, and an internal chamber510. Proximal end507of drive housing502includes an engagement feature516configured complementary to engagement feature216of rod210of plunger200for engaging drive housing502and rod210to one another, e.g., via snap-fit engagement. However, rod210and drive housing502may alternatively be engaged to one another in any other suitable fashion, e.g., via adhesion, friction-fitting, welding, etc., or may be monolithically formed with one another as a single component. Distal end509of drive housing502defines an aperture511therethrough that is centered about longitudinal axis “X-X” and is configured to receive proximal end505of drive bar504therethrough.

Proximal end505of drive bar504, as mentioned above, extends proximally through aperture511of drive housing502and into internal chamber510of drive housing502to divide internal chamber510into a proximal portion518and a distal portion522. More specifically, drive bar504includes a proximal stop524disposed at proximal end507thereof that generally approximates the cross-sectional area of internal chamber510so as to function as a piston disposed within internal chamber510. Proximal stop524is longitudinally translatable within and relative to internal chamber510of drive housing502to translate drive bar504relative to drive housing502between the second and third positions (FIGS. 5A and 6A, respectively). As can be appreciated, distal translation of proximal stop524within internal chamber510and relative to drive housing502increases the volume of proximal portion518while correspondingly decreasing the volume of distal portion522(and vice versa, e.g., proximal translation of proximal stop524within internal chamber510and relative to drive housing502decreases the volume of proximal portion518while correspondingly increasing the volume of distal portion522). Proximal stop524may be formed at least partially from a resilient material, or may otherwise be configured, to establish a sealing relation with drive housing502, such that proximal and distal portions518,522, respectively, of internal chamber510remain substantially sealed from one another.

With continued reference toFIG. 3, proximal portion518of drive housing502includes a biasing member, e.g., a spring526, longitudinally positioned between proximal end507of drive housing502and proximal stop524of drive bar504. Proximal portion518of drive housing502further includes a thermally-activatable material530, e.g., a wax, oil, or any other other suitable material having a thermally-dependent viscosity. Thermally-activatable material530is initially disposed in a solid (or more viscous) state that substantially fills the volume of proximal portion518. Spring526is encased within the solid (or more viscous) thermally-activatable material530and is retained in a compressed, or loaded position. That is, although spring526is loaded, spring526is inhibited from biasing proximal stop524distally relative to drive housing502due to the encasement of spring526within the solid (or more viscous) thermally-activatablematerial530. Rather, thermally-activatable material530retains spring526in its loaded position. Thermally-activatable material530, in its solid (or more viscous) state, may further be configured to couple proximal end507of drive housing502and proximal stop524of drive bar504to one another to inhibit relative movement therebetween when material530is disposed in its solid (or more viscous) state. As such, material530, in its solid (or more viscous) state, inhibits drive bar504from being translated relative to drive housing502from the second position (FIG. 5A) to the third position (FIG. 6A).

As shown inFIG. 3, drive housing502additionally includes a pair of heaters540(although greater or fewer than two heaters may also be provided) disposed on either side of proximal portion518of drive housing502. Each heater540is coupled to a wire610bthat extends through cable600to couple heaters540to the generator (not shown) used for providing energy to jaw members410,420, or any other suitable energy source. Alternatively, heaters540may be self-powered, e.g., via a battery (not explicitly shown) disposed within or adjacent to heaters540. Heaters540may include any suitable mechanism for selectively heating proximal portion518of drive housing502, e.g., heaters540may include heating coils, transistors, resistive heaters, etc. Positioning heaters540on the exterior of drive housing502is sufficient to heat the thermally-activatable material530disposed within proximal portion518of drive housing502due to the formation of drive housing502from a thermally conductive material. However, in embodiments where drive housing502is formed from an insulative material, heaters540may be disposed within drive housing502to permit sufficient heating of material530. Heaters540, as will be described below, are configured to heat the thermally-activatable material530sufficiently so as to activate, or transition material530from the solid (or more viscous) state to a fluid (or less viscous) state, thereby permitting spring526to bias drive bar504distally to transition drive bar from the second position (FIG. 5A) to the third position (FIG. 6A).

Heaters540may be activated manually, e.g., upon translation of plunger200from the proximal position to the distal position, via activating one or more switch assemblies132,134disposed on handle assembly100, via activating one or more controls on the generator (not shown) or other energy source, or via any other suitable mechanism. Alternatively, heaters540may be automatically actuated, e.g., via one or more sensors (not explicitly shown) configured to sense the properties of jaw members410,420and/or tissue disposed therebetween.

Referring again toFIGS. 1-3, end effector assembly400, as mentioned above, includes first and second jaw members410,420, respectively, that are moveable relative to one another between a spaced-apart position (FIG. 4B), a first approximated position (FIG. 5B), and a second approximated position (FIG. 6B). Each jaw member410,420includes an opposed, tissue contacting surface412,422, respectively. One or both of the jaw members, e.g., jaw member410, includes a tissue contacting member414disposed on or along tissue contacting surface412that is configured to facilitate the transmission of light energy from the light energy source, e.g., the generator (not shown), to tissue grasped between jaw members410,420. More specifically, cable600and wires610a(which extend distally through shaft300) couple tissue contacting member414of jaw member410to the light energy source such that light energy may be transmitted between jaw members410,420, as indicated by arrows “A” (FIGS. 5B and 6B) and through tissue grasped therebetween (although energy may be transmitted between jaw members410,420and through tissue in the opposite direction, in both directions, and/or in a transverse direction). The other jaw member, e.g., jaw member420, may alternatively or additionally include a tissue contacting member424disposed on or along tissue contacting surface422that is configured to receive, absorb, or reflect the light energy transmitted from jaw member410and through tissue.

Turning now toFIGS. 1, 2 and 4A-6B, the use and operation of forceps10is described. Initially, as shown inFIGS. 1 and 4A-4B, plunger200is disposed in the proximal position and drive bar504and drive housing502of drive assembly500are disposed in the first position. Accordingly, at this point, jaw members410,420of end effector assembly400are disposed in the spaced-apart position. In this position, forceps10may be manipulated and/or maneuvered to position end effector assembly400such that tissue to be treated, e.g., sealed and/or cut, is disposed between jaw members410,420.

Turning now toFIGS. 4A-4Bin conjunction withFIGS. 5A-5B, with jaw members410,420of end effector assembly400in position, the surgeon, while grasping both handle assembly100and plunger200, translates knob230of plunger200distally relative to handle assembly100, thereby translating plunger200from the proximal position to the distal position. Translation of plunger200from the proximal position to the distal position, in turn, effects cooperative translation of drive bar504and drive housing502from the first position to the second position, such that jaw members410,420are pivoted relative to one another from the spaced-apart position to the first approximated position (FIG. 4B) to grasp tissue therebetween. A transversely-positioned wall138disposed within handle assembly100inhibits further distal translation of drive housing502beyond the second position and, thus, inhibits further distal translation of plunger200beyond the distal position. However, wall138includes an aperture139defined therethrough to permit passage of drive bar504distally beyond wall138. In other words, wall138functions as a stop, thus defining the distal position of plunger200, the second position of drive housing502, and correspondingly, the first approximated position of jaw members410,420. In this first approximated position, tissue contacting members414,424of jaw members410,420, respectively, define a gap distance “G” therebetween.

At this point, the material530disposed within proximal portion518of drive housing502remains in the solid state such that spring526remains encased therein in the loaded position. Further, as mentioned above, material530, in its solid (or more viscous) state, retains drive bar504in fixed position relative to drive housing502. As such, at this point, with material530in its solid (or more viscous) state, and with drive housing502disposed in the second position and inhibited by wall138from translating further distally, drive bar504is likewise inhibited from being translated beyond the second position (FIG. 5A).

With jaw members410,420disposed in the first approximated position defining gap distance “G” therebetween, as shown inFIG. 5B, a relatively smaller pressure is applied to tissue grasped therebetween. That is, with a relatively larger gap distance “G” between jaw members410,420, the pressure exerted on tissue grasped therebetween is relatively smaller. As will be described below, upon translation of drive bar504from the second position to the third position, jaw members410,420are permitted to further approximate relative to one another to the second approximated position (FIG. 6B), wherein a smaller gap distance “g” is defined between jaw members410,420and, thus, a greater pressure is applied to tissue grasped between jaw members410,420.

Referring toFIGS. 5A-5B, with jaw members410,420disposed in the first approximated position and grasping tissue between tissue contacting members414,424, respectively, thereof, energy may be transmitted from tissue contacting member414of jaw member410, through tissue, to tissue contacting member424of jaw member420, as indicated by arrows “A” (although energy may alternatively be transmitted between one or both of tissue contacting members414,424in either or both directions). Activation of the energy may be effected via actuating one or more of first and second switch assemblies132and134(FIG. 1). At this point, with jaw members410,420disposed in the first approximated position defining first gap distance “G” therebetween, a relatively smaller pressure is applied to tissue, and, thus, the absorption of light energy by tissue is maximized at this beginning stage of tissue treatment.

With reference also toFIGS. 6A-6B, once tissue has absorbed a sufficient amount of energy, upon satisfaction of a pre-determined condition, time, and/or function, upon other suitable automatic activation, or upon manual activation, e.g., via actuation of one or more of switch assemblies132,134(FIG. 1), heaters540are activated. Upon activation of heaters540, as mentioned above, proximal portion518of drive housing502is heated such that material530begins to melt (or become less viscous) from its solid (more viscous) state to a more fluid (less viscous) state. As material530melts, the loaded spring526is no longer fixed in encasement within the material530, but is permitted to elongate under bias back towards its at-rest state. As spring526is elongated back towards its at-rest position, the distal end of spring526eventually contacts proximal stop524and, upon further elongation of spring526, proximal stop524is urged distally towards distal end509of drive housing502. More specifically, as proximal stop524is urged distally, drive bar504is likewise urged distally independent of drive housing502from the second position towards the third position, as progressively shown fromFIG. 5AtoFIG. 6A, such that proximal stop524is moved to distal end509of drive housing502and such that jaw members410,420are moved to the second approximated position defining gap distance “g” therebetween. Since jaw members410,420are approximated further about tissue, a greater pressure is applied to tissue grasped between jaw members410,420.

As can be appreciated, at the beginning of the melting of material530, e.g., where material530is still substantially solid, material530is relatively more viscous, thus dampening, or slowing the return of spring526back towards its at-rest position. As material530is melted further, e.g., as material530becomes more fluid, material530is less viscous and, as a result, spring526is permitted to elongated further and at an increased rate. Accordingly, heaters540may be controlled to heat and, ultimately, melt material530at a pre-determined rate, according to a predetermined function, or in any other suitable fashion so as to control the translation of drive bar504from the second position to the third position, thus controlling the movement of jaw members410,420from the first approximated position to the second approximated position. Alternatively, the wax, oil, or other material used to form thermally-activatable material530may be configured to likewise achieve a desired rate of movement of jaw member410,420as the material530is transitioned from its more viscous state to its less viscous state.

With jaw members410,420disposed in the second approximated position, as shown inFIG. 6B, second gap distance “g,” which is smaller than first gap distance “G,” is defined between tissue contacting members414,424of jaw members410,420, respectively, and, as a result, a relatively larger pressure is applied to tissue grasped therebetween. With jaw members410,420disposed in this second approximated position applying an increased pressure to tissue, the transmission of energy from tissue contacting member414of jaw member410, through tissue, to tissue contacting member424of jaw member420may be continued to complete formation of a tissue seal and/or to divide tissue along the previously formed tissue seal. Alternatively, jaw members410,420may be moved to an intermediate approximated position for completion of the tissue seal, and may then be moved to the second approximated position for cutting tissue along the previously formed tissue seal. Further, heaters540may be activated automatically upon supplying energy to jaw members410,420such that jaw members410,420are continuously moved from the first approximated position to the second approximated position to seal tissue, seal and cut tissue, or otherwise treat tissue.

At the completion of tissue treatment, e.g., sealing and/or cutting of tissue, jaw members410,420are returned to the spaced-apart position, e.g., via translating plunger200proximally back to the proximal position, and end effector assembly200is removed from the surgical site (or is repositioned adjacent other tissue to be treated).

Turning now toFIGS. 7A-7C, in conjunction withFIGS. 1-2, another embodiment of a drive assembly configured for use with forceps10, or any other suitable surgical instrument, is shown generally identified by reference numeral700. Drive assembly700is similar to drive assembly500(FIGS. 3, 4A, 5A and 6A) and is likewise configured for use with forceps10and end effector assembly400(although drive assembly700may alternatively be configured for use with forceps10′ (FIGS. 8A-8B) or any other suitable surgical instrument and/or end effector assembly). Thus, only the differences between drive assembly700and drive assembly500(FIGS. 3, 4A, 5A and 6A) will be described in detail hereinbelow, while the similarities will be summarized or omitted entirely.

Drive assembly700generally includes a drive housing702and a drive bar704coupled to and extending distally from drive housing702. Drive bar704extends distally from drive housing702, though shaft300, ultimately engaging jaw members410,420. As such, longitudinal translation of drive bar704relative to end effector assembly400pivots jaw members410,420relative to one another between the spaced-apart position (FIG. 4B), the first approximated position (FIG. 5B), and the second approximated position (FIG. 6B). Similar to drive bar504of drive assembly500(FIGS. 3, 4A, 5A and 6A), drive bar704is longitudinally translatable, in conjunction with drive housing702, between a first position (FIG. 7A), corresponding to the spaced-apart position of jaw members410,420(FIG. 4B), and a second position (FIG. 7B), corresponding to the first approximated position of jaw members410,420(FIG. 5B). Drive bar704is further translatable, independent of drive housing702, from the second position (FIG. 7B), to a third position (FIG. 7C), corresponding to the second approximated position of jaw members410,420(FIG. 6B).

Proximal end705of drive bar704extends proximally through aperture707of drive housing702and into internal chamber710of drive housing702to divide internal chamber710into a proximal portion718and a distal portion722. More specifically, drive bar704includes a proximal stop724disposed at proximal end705thereof that is longitudinally translatable within and relative to internal chamber710of drive housing702to translate drive bar704relative to drive housing702between the second and third positions (FIGS. 7B and 7C, respectively). Proximal stop724establishes a sealing relation with drive housing702such that proximal and distal portions718,722, respectively, of internal chamber710remain substantially sealed from one another. Proximal stop724further includes a valve740disposed within an aperture725extending longitudinally therethrough that, as will be described in greater detail below, selectively permits fluid730to flow between the proximal and distal portions718,722, respectively, of drive housing702. Valve740may be manually mechanically or electrically actuated via one or more wires710bcoupling valve740to a control, e.g., one or more of switch assembly132,134(FIGS. 1-2), and/or an energy source, e.g., a generator (not shown), or may be automatically activated.

With continued reference toFIGS. 7A-7C, in conjunction withFIGS. 1-2, proximal portion718of drive housing702includes a biasing member, e.g., a spring726, longitudinally positioned between proximal end709of drive housing702and proximal stop724of drive bar704. Spring726is initially disposed in a compressed, or loaded condition, as shown inFIG. 7A. Distal portion722of drive housing702, initially, is substantially filed with a fluid730, e.g., air or any other suitable gas; water, saline, oil, or any other suitable liquid; or any suitable liquid-gas mixture. Further, valve740of proximal stop724is initially disposed in a closed condition so as to inhibit the passage of fluid730from distal portion722of drive housing702to proximal portion718of drive housing702(and vice versa). That is, with proximal portion718substantially filled with fluid730and with valve740closed, spring726is retained in the loaded condition since, due to the substantial filling of proximal portion718of drive housing702with fluid730, proximal stop724is inhibited from being translated further distally under the bias of spring726. Rather, spring726is retained in its loaded position.

With reference toFIGS. 7A-7C, in conjunction withFIGS. 4B, 5B and 6B, respectively, the use and operation of drive assembly700is described. Initially, drive assembly700is disposed in the first position, as shown inFIG. 7Aand, correspondingly, jaw members410,420of end effector assembly400are disposed in the spaced-apart position, as shown inFIG. 4B. In this position, forceps10may be manipulated and/or maneuvered to position end effector assembly400such that tissue to be treated, e.g., sealed and/or cut, is disposed between jaw members410,420.

Upon translation of drive assembly700to the second position, e.g., upon translation of plunger200from the proximal position to the distal position, drive bar704and drive housing702are cooperatively translated from the first position to the second position, such that jaw members410,420are pivoted relative to one another from the spaced-apart position (FIG. 4B) to the first approximated position (FIG. 5B) to grasp tissue therebetween. More specifically, drive bar704and drive housing702are moved in cooperation with one another since, at this point, valve740remains closed, thus inhibiting spring726from elongating and urging proximal stop724and drive bar704distally relative to drive housing702.

With jaw members410,420disposed in the first approximated position defining gap distance “G” therebetween, as shown inFIG. 5B, a relatively smaller pressure is applied to tissue grasped therebetween. In this position, with jaw members410,420grasping tissue between tissue contacting members414,424, respectively, thereof, energy may be transmitted from the energy source (not shown) to tissue contacting member414of jaw member410, e.g., via wires710a, through tissue, to tissue contacting member424of jaw member420, as indicated by arrows “A” (although energy may alternatively be transmitted between one or both of tissue contacting members414,424in either or both directions) such that, due to the relatively small pressure being applied to tissue, maximum absorption of light energy by tissue at the beginning of tissue treatment is facilitated.

Once tissue has absorbed a sufficient amount of energy, upon satisfaction of a pre-determined condition, time, and/or function, upon other suitable automatic activation, or upon manual activation, e.g., via actuation of one or more of switch assemblies132,134(FIG. 1), valve740may be opened. When valve740is opened, fluid730is permitted to flow through proximal stop724from proximal portion718of drive housing to distal portion722thereof, ultimately allowing spring726to elongate back towards its at-rest position, thereby urging proximal stop724distally towards distal end711of drive housing702. As proximal stop724is urged distally, drive bar704is likewise urged distally, independent of drive housing702, from the second position towards the third position, as shown progressively fromFIG. 7BtoFIG. 7C, wherein proximal stop724is disposed at distal end711of drive housing702and wherein jaw members410,420are moved to the second approximated position defining gap distance “g” therebetween (seeFIG. 6B). With jaw members410,420approximated to this second approximated position defining a smaller gap distance “g” therebetween, a greater pressure is applied to tissue grasped between jaw members410,420. As can be appreciated, valve740may be opened to various different positions, thus allowing a greater or lesser amount of fluid730to pass therethrough in order to control the rate at which the pressure applied to tissue is increased, e.g., the rate at which drive bar704is translated between the second and third positions. Further, valve740may be selectively controlled, e.g., incrementally opened and closed, to define various incremental steps for incrementally increasing the pressure applied to tissue grasped between jaw members410,420. The viscosity of the fluid730chosen also effects the rate that fluid730flows between proximal and distal portions718,722, respectively, of drive housing702and, thus, may be selected in accordance with a desired rate of approximation of jaw members410,420from the first approximated position (FIG. 5B) to the second approximated position (FIG. 6B).

With jaw members410,420disposed in the second approximated position, as shown inFIG. 6B, second gap distance “g,” which is smaller than first gap distance “G,” is defined between tissue contacting members414,424of jaw members410,420, respectively, and, as a result, a relatively larger pressure is applied to tissue grasped therebetween. With jaw members410,420disposed in this second approximated position applying an increased pressure to tissue, the transmission of energy from tissue contacting member414of jaw member410, through tissue, to tissue contacting member424of jaw member420may be continued to complete formation of a tissue seal and/or to divide tissue along the previously formed tissue seal. Thereafter, plunger200may be retracted back to the proximal position to open jaw members410,420and release the previously treated tissue grasped therebetween such that jaw members410,420may be removed from the surgical site (or repositioned adjacent other tissue to be treated).

Turning now toFIGS. 8A-8B, another embodiment of a forceps10′ is shown generally including a housing800, an elongated shaft810, an end effector assembly820disposed at distal end812of shaft810, and a drive assembly830disposed within housing800and operably coupled to end effector assembly820for controlling operation of end effector assembly820. End effector assembly820may be similar to end effector assembly400, described above (seeFIGS. 3, 4B, 5B and 6B), or may be any other suitable end effector assembly. Housing800houses drive assembly830therein, which may be configured similarly to either of drive assemblies500and700, discussed above (seeFIGS. 3, 4A, 5A, 6AandFIGS. 7A-7C, respectively). More specifically, drive assembly830is housed within distal portion802of housing800. Housing800further includes a generally hollow proximal portion704that is configured to receive a portable generator850therein, and a generally hollow fixed handle portion806that is configured to receive a battery860therein. Generator850and battery860are coupled to one another, to drive assembly830, and to end effector assembly820for controlling the supply of energy to jaw members822,824of end effector assembly820and/or drive assembly830to facilitate treating tissue. As can be appreciated, the relatively compact configuration of drive assembly830(which is similar to drive assembly500or drive assembly700(FIGS. 3, 4A, 5A, 6AandFIGS. 7A-7C, respectively)), permit positioning of the drive assembly830in distal portion802of housing800while leaving sufficient space for generator850and battery806to also be positioned within housing800. Thus, forceps10′ provides a relatively compact, portable surgical instrument (e.g., a surgical instrument incorporating a generator and battery into the housing thereof) having a drive assembly830that facilitates movement of jaw members822,824between a spaced-apart position and first and second approximated positions for energy-based tissue treatment.

In use, forceps10′ functions similar to forceps10(FIGS. 1-3), described above. However, rather than providing a plunger200(FIGS. 1-3), forceps10′ includes a movable handle808movable between an initial position (FIG. 8A) and an actuated position (FIG. 8B) for moving drive assembly830from a first position to a second position and, correspondingly moving jaw members822,824from the spaced-apart position (FIG. 8A) and the first approximated position (FIG. 8B). Thereafter, drive assembly830is further operable, as described above with respect to drive assemblies500,700(FIGS. 3, 4A, 5A, 6AandFIGS. 7A-7C, respectively), to translate drive bar834, independent of drive housing832, from the second position to a third position corresponding to the second approximated position of jaw members822,824. Any or all of the features of forceps10(FIGS. 1-3) and/or drive assemblies500,700(FIGS. 3, 4A, 5A, 6AandFIGS. 7A-7C, respectively) described above may also be incorporated into forceps10′.

Turning now toFIGS. 9A-9B, another embodiment of a forceps provided in accordance with the present disclosure is shown generally identified by reference numeral900. Forceps900includes a housing910, a shaft920extending distally form housing910, and an end effector assembly930disposed at distal end922of shaft920. Housing910is formed from cooperating housing parts912,914(although other configurations are contemplated) and includes a cable916extending therefrom that ultimately connects to an energy source (not shown) for providing energy to end effector assembly930. Alternatively, housing910may be configured to retain a portable energy source (not shown) therein. Housing910is particularly suitable for retaining a portable energy source therein in that housing910does not include any of the drive assembly or movable handle components typically associated with the housing of a forceps. Alternatively, housing910may simply configured as a small, lightweight instrument configured to connect to an external energy source, e.g., via cable916. Both of these configurations are facilitated because, as will be described in greater detail below, the components of forceps900are static, i.e., forceps900does not require moving components.

With continued reference toFIGS. 9A-9B, shaft920includes a bifurcated distal end922defining the first and second jaw members932,934, respectively, of end effector assembly930. Each jaw member932,934defines a diverging opposed surface936,938. More specifically, diverging opposed surfaces936,938of jaw members932,934, respectively, extend outwardly and distally from heel940of end effector assembly930to distal ends933a,935aof jaw members932,934, respectively, such that jaw members932,934define a first gap distance “G” therebetween at distal ends933a,935a, respectively, thereof, and a second, smaller gap distance “g” therebetween at proximal ends933b,935b, respectively, thereof. Heel940of end effector assembly930may define a cutting blade942that, as will be described in greater detail below, is configured to cut tissue disposed between jaw members932,934. Cutting blade942may also be coupled to the energy source (not shown), e.g., via wire944, to facilitate energy-based cutting of tissue. One or both of the jaw members, e.g., jaw member932, may further include a tissue contacting member937coupled to the source of energy, e.g., via wire936, such that light energy may be transmitted between jaw members932,934, as indicated by arrows “A,” and through tissue disposed therebetween (although energy may be transmitted between jaw members932,934and through tissue in the opposite direction or in both directions).

Continuing with reference toFIGS. 9A-9B, the use and operation of forceps900is described. Initially, forceps900is positioned such that jaw members932,934are positioned proximally of tissue to be treated. In instances where the tissue to be treated is underlying other tissue, forceps900may be advanced distally to dissect through the overlying tissue, e.g., such that the overlying tissue is passed between jaw members932,934and, due to the configuration of jaw members932,934, is directed into contact with cutting blade942of heel940of end effector assembly930to dissect the tissue.

Once jaw members932,934of end effector assembly930of forceps900are positioned proximally adjacent the tissue to be treated, energy may be supplied to jaw member932, e.g., via activating one or more of switch assemblies952,954, such that light energy is transmitted between jaw members932,934in the direction of arrows “A.” Next, end effector assembly930may be advanced distally towards and, eventually, about tissue such that tissue enters the gap between jaw members932,934and is moved proximally therethrough. Initially, when tissue is disposed towards distal tips ends933a,935aof jaw members932,934, respectively, a relatively small pressure is applied to tissue between jaw members932,934, due to the relatively larger gap distance “G” between jaw members932,934. Thus, at the beginning of the tissue treatment process, absorption of light energy by tissue is maximized.

As end effector assembly930is advanced further distally relative to tissue, the pressure applied to tissue is increased due to the fact that tissue is moved proximally between jaw members932,934towards proximal ends933b,935b, respectively, thereof, wherein the gap distance “g” between jaw members932,934is relatively small. Accordingly, as tissue is moved proximally relative to and between jaw members932,934, the pressure applied to tissue disposed therebetween is increased. As mentioned above, increasing the pressure after sufficient energy absorption has been achieved facilitates completion of the tissue seal.

Upon further advancement of end effector assembly930relative to tissue, tissue contacts cutting blade942of heel940of end effector assembly930, which divides the tissue along the previously-formed tissue seal. As mentioned above, cutting blade942may be energized to facilitate cutting of tissue. Thereafter, end effector assembly930may be repositioned adjacent other tissue to be treated, and the above-described process can be repeated to treat, e.g., seal and/or cut, additional tissue.

Although the above is described in terms of three steps, it is envisioned that end effector assembly930be advanced continuously through tissue such that the application of energy under the first, relatively small pressure during the initial phase of tissue treatment; the application of energy under the second, increased pressure to complete formation of the tissue seal; and the cutting of tissue along the previously-formed tissue seal are segments of a continuous process, rather than incremental, discrete steps. As such, the surgeon may advance end effector assembly930through tissue to rapidly treat, e.g., seal and cut, one or more portions of tissue in a single, continuous motion.