Patent ID: 12214222

DETAILED DESCRIPTION

Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the term “clinician” refers to a doctor, a nurse, or any other care provider and may include support personnel. Throughout this description, the term “proximal” will refer to the portion of the device or component thereof that is closest to the clinician and the term “distal” will refer to the portion of the device or component thereof that is furthest from the clinician. Throughout the drawings, the arrows within and adjacent to portions of the cooling system indicate the direction of the flow of the cooling fluid.

Referring now toFIG.1, one exemplary embodiment of an ultrasonic surgical instrument configured for use in accordance with the present disclosure is shown generally identified by reference numeral10, although it is also envisioned that the aspects and features of the present disclosure be similarly incorporated into any suitable ultrasonic surgical instrument. Ultrasonic surgical instrument10generally includes a handle assembly12, an elongated body portion14, and a tool assembly16. Handle assembly12supports a battery assembly18and an ultrasonic transducer and generator assembly (hereinafter “TAG”)20. Handle assembly12includes a rotatable nozzle22, an activation button24, and a clamp trigger26. Battery assembly18and TAG20are each releasably secured to a central body28of handle assembly12and are removable from central body28to facilitate disposal of the entire device, with the exception of battery assembly18and TAG20.

With additional reference toFIG.2, elongated body portion14includes a waveguide30which extends from handle assembly12to tool assembly16(FIG.1). A distal end of waveguide30defines a blade32, which will be discussed in further detail below. A proximal end of waveguide30has a threaded extension34for engaging TAG20. Waveguide30further includes a proximal tapered portion30aand distal tapered portions30band30c. A series of annular abutments31a-dare disposed along, e.g., machined onto, waveguide30at node points along waveguide30.

An inner tube36is positioned about waveguide30between proximal tapered portion30aand distal tapered portion30bof waveguide30. A distal seal member38is supported about waveguide30distally of a distal end of inner tube36and proximally of distal tapered portion30cof waveguide30to provide a fluid-tight seal at the distal end of elongated body portion14between waveguide30and an inner surface of a middle tube42. Ultrasonic energy is isolated from transfer to middle tube42by inner tube36. A series of splines44are formed at the proximal end of waveguide30. Splines44engage splines (not shown) formed on an inner surface of a torque adapter46to rotatably secure torque adapter46to waveguide30. Torque adapter46also includes diametrically opposed wings48which are positioned in recesses (not shown) in rotatable nozzle22to secure torque adapter46to rotatable nozzle22.

With additional reference toFIGS.3and3A, middle tube42is positioned about inner tube36and includes a distal end having a corset feature50and a pair of spaced clamp support arms52. Corset feature50is positioned to receive distal seal member38to maintain distal seal member38in the proper position about the distal end of waveguide30. Distal seal member38is positioned at a node point along waveguide30. An O-ring40is supported about corset feature50to provide a fluid-tight seal between an outer surface of middle tube42and an inner surface of an outer tube66.

With particular reference toFIGS.3and3A, spaced clamp support arms52each define an opening54for pivotally receiving pivot members56formed on a clamp member58of tool assembly16. Clamp member58of tool assembly16is pivotal between an open position (FIG.3), wherein clamp member58is spaced from blade member32, and a closed position (FIG.3A), wherein clamp member58is in juxtaposed alignment with blade member32. Clamp member58is moved between the open position and the closed position in response to actuation of clamp trigger26(FIG.1).

Outer tube66is slidably repositionable between an advanced position and a retracted position. Upon movement of outer tube66from the advanced position to the retracted position, clamp member58is moved from the open position (FIG.3) to the closed position (FIG.3A). A proximal end of outer tube66includes an elongated slot70(FIG.2) which receives projections (not shown) of rotatable nozzle22(FIG.1) such that outer tube66is rotatably secured to, but slidable about, the projections to facilitate movement of outer tube66between the advanced and retracted positions.

Referring again toFIG.2, the proximal end of outer tube66includes a bifurcated portion that defines an axially extending throughbore72that slidably receives wings48of torque adapter46. A pair of diametrically opposed windows74are formed in the proximal end of outer tube66. Windows74receive bosses (not shown) formed in handle assembly12(FIG.1) to couple outer tube66to handle assembly12(FIG.1).

Referring toFIG.4, one embodiment of a blade cooling system80incorporated into ultrasonic surgical instrument10(FIG.1) in accordance with the present disclosure is shown including an inflow conduit82and a blade lumen84. Inflow conduit82is annularly defined between middle tube42and waveguide30. Blade lumen84is formed within and extends substantially through the length of blade32. Blade lumen84includes one or more blade inlets84a, e.g., one or more blade inlets84aextending radially outwardly from blade lumen84, and a blade outlet84b. Blade inlet(s)84amay be positioned at an anti-node point along waveguide30or at any other suitable position therealong. Blade outlet84bis defined at the distal end of blade32. Blade lumen84is in fluid communication with inflow conduit82via blade inlet(s)84a. Blade outlet84bincludes an angled surface85bdisposed at an angle θ to the inner surface of blade lumen84as shown inFIG.5to facilitate the outflow of fluid from blade lumen84. Angle θ may be in a range of about 0° to about 45°. Blade lumen84may have a diameter in the range of about 0.25 mm to about 0.65 mm. In embodiments, blade inlet84amay have a diameter in the range of about 0.25 mm to about 1.00 mm. Other suitable configurations are also contemplated.

As noted above, inflow conduit82is defined between middle tube42and waveguide30. Alternatively or additionally, inflow conduit82may be defined between outer tube66and middle tube42. In such embodiments, inflow conduit82includes an input opening (not shown) in inner tube36and/or middle tube42, which provides fluid communication between inflow conduit82and blade inlet84a.

Annular abutment31dis positioned within inflow conduit82and configured to permit a cooling fluid89(FIG.1) to flow through inflow conduit82to blade inlet84a. In embodiments, as opposed to defining inflow conduit82annularly between middle tube42and waveguide30, inflow conduit82may comprise one or more polyimide microtubes (or other suitable microtubes) disposed between inner tube36and waveguide30and extending proximally from the proximal end of elongated body member14. In such configurations, annular abutment31dmay include a passage (or passages) dimensioned and configured to slidably receive the one or more microtubes.

Referring toFIGS.1-4, blade cooling system80further includes a fluid reservoir88in fluid communication with inflow conduit82. Fluid reservoir88may be positioned external to instrument10, positioned on handle assembly12, or positioned within handle assembly12. In embodiments where fluid reservoir88is external to instrument10, central body28of handle assembly12includes an inflow port81to provide fluid communication between fluid reservoir88and inflow conduit82. Fluid reservoir88is configured to hold a supply of cooling fluid89. Cooling fluid89can be any fluid capable of conductively and/or conventionally absorbing heat from a thermally conductive solid surface. Exemplary cooling fluids include but are not limited to water, saline, compressed air, compressed nitrogen, compressed oxygen, etc.

Blade cooling system80further includes a fluid control system90having a pump92. Pump92is configured to pump cooling fluid89from fluid reservoir88through inflow conduit82and blade lumen84such that cooling fluid89exits blade32through blade outlet84b. In embodiments, fluid control system90is selectively operated by a clinician. In some embodiments, fluid control system90is automatically operated by conditions of instrument10sensed by fluid control system90. Fluid control system90may include a plurality of sensors94a-dpositioned on and/or within instrument10to provide feedback of conditions of instrument10. Sensors94a-dmay include, for example, a blade thermocouple94aconfigured to measure the temperature of blade32, a clamp sensor94b(FIG.3) configured to determine the position of clamp58and/or the position of clamp trigger26, a waveguide thermocouple94cconfigured to measure the temperature of a portion of waveguide14, and an activation sensor94dconfigured to measure the position of activation button24. Other suitable sensors and/or combinations of sensors are also contemplated, as are any other suitable mechanisms for providing feedback and/or indicating a state, parameter, condition, etc. of a component of instrument10and/or the surrounding environment.

When pump92of fluid control system90is activated, pump92draws cooling fluid89from fluid reservoir88and pumps cooling fluid89through inflow conduit82and blade lumen84. When cooling fluid89is pumped through blade lumen84, cooling fluid89flows out of blade outlet84bformed through the distal surface of blade32(seeFIGS.3-3A). As cooling fluid89exits from blade outlet84b, cooling fluid89can form a mist. As angle θ of angled surface85bis decreased, the misting of cooling fluid89decreases. As cooling fluid89fluid flows through blade lumen84, cooling fluid89absorbs heat from blade32such that blade32is cooled by blade cooling system80. Cooling fluid89flowing through inflow conduit82also absorbs heat from waveguide30. Fluid control system90regulates the amount of cooling fluid89that pump92draws from fluid reservoir88and pumps through blade cooling system80thus controlling the cooling of blade32.

Fluid control system90may be configured to control the cooling of blade32via regulating pump92such as, for example, by: activating pump92to continually pump cooling fluid89through blade cooling system80; activating/deactivating pump92to pump cooling fluid89through blade cooling system80when activation button24(FIG.1) is depressed (actuated); activating/deactivating pump92to pump cooling fluid89through blade cooling system80when activation button24(FIG.1) is released (un-actuated); activating/deactivating pump92to pump cooling fluid89through blade cooling system80according to a predetermined schedule; activating/deactivating pump92to pump cooling fluid89through blade cooling system80once activation button24(FIG.1) has been depressed (actuated) for a predetermined period of time; activating/deactivating pump92to pump cooling fluid89through blade cooling system80once activation button24(FIG.1) has been released (un-actuated) for a predetermined amount of time; and/or activating/deactivating pump92to pump cooling fluid89through blade cooling system80based upon temperature feedback so as to maintain the temperature of blade32and/or waveguide30below a predetermined threshold temperature or within a predetermined temperature range. As described in detail below, fluid control system90may include sensors94a-d, or any other suitable mechanisms for providing feedback and/or indicating a state, parameter, condition, etc. of a component of instrument10and/or the surrounding environment, to facilitate controlling of pump92. Other control systems, mechanisms, methods, and/or protocols are also contemplated.

As mentioned above, in some embodiments, fluid control system90, together with blade cooling system80, may be configured to maintain blade32below a predetermined temperature. In such a configuration, the clinician inputs an upper temperature limit into fluid control system90. In embodiments, the upper temperature limit may also be preset at the time of manufacture of fluid control system90. Fluid control system90activates pump92when blade thermocouple94adetermines the temperature of blade32is approaching the upper temperature limit. When pump92is activated, pump92pumps cooling fluid89through blade cooling system80to prevent blade32from exceeding the upper temperature limit. The amount of fluid pumped through blade cooling system80may also be varied depending on the sensed temperature.

Additionally, blade32may be maintained within a range of predetermined temperatures. In such a configuration, the clinician inputs an upper and lower temperature limit of the range of predetermined temperatures into fluid control system90. Similar to the previous configuration, the upper and lower temperature limits can be preset. Fluid control system90activates pump92(or increases the rate at which fluid is pumped) when blade thermocouple94adetermines the temperature of blade32is approaching the upper temperature limit to cool or decrease the temperature of blade32. When fluid control system90determines the temperature of blade32is approaching the lower temperature limit, as measured by blade thermocouple94c, fluid control system90deactivates pump92(or decreases the rate at which fluid is pumped) stopping (or reducing) the flow of cooling fluid89through blade32.

Additionally or alternatively, blade cooling system80may be configured to cool blade32after a clinician has activated and deactivated blade32. In this configuration blade32is allowed to heat up when used to dissect and/or coagulate tissue, but is actively cooled via blade cooling system10once blade32is no longer in use. In such a configuration, fluid control system90activates pump92when blade thermocouple94adetermines the temperature of blade32exceeds an upper temperature limit and activation sensor94d(or other suitable mechanism) determines that activation button24is in the released (un-actuated) position. Fluid control system90may deactivate pump92when the temperature of blade32reaches a lower temperature limit, or when activation button24is in the depressed (actuated) position. Fluid control system90may further include a clamp sensor94b(or other suitable mechanism) to determine the position of clamp58, i.e. open or closed. When clamp58is in the open position, as determined by clamp sensor94b, and the temperature of blade32exceeds the upper temperature limit, fluid control system90activates pump92. On the other hand, when clamp58or the temperature of blade32is below the lower temperature limit, fluid control system90deactivates pump92.

Referring toFIGS.6and7, another ultrasonic surgical instrument110is provided in accordance with the present disclosure including a waveguide130and incorporating a blade cooling system180. Ultrasonic surgical instrument110and blade cooling system180are substantially similar to ultrasonic surgical instrument10and blade cooling system80(FIGS.1-5), with similar elements represented by similar numerals. As such only the differences are discussed in detail below.

Blade cooling system180is a closed circuit and includes an inflow conduit182, a blade lumen184, and a return conduit186. Inflow conduit182is defined between middle tube142and waveguide130. Inflow conduit182is in fluid communication with blade lumen184via one or more blade inlets184adisposed at an anti-node point along waveguide130. A seal is disposed about or in proximity to annular abutment131dto seal a distal end of inflow conduit182. In embodiments, annular abutment131dforms a seal at the distal end of inflow conduit182. Blade lumen184is defined within and extends through blade132. Blade lumen184includes blade inlet(s)184aand a blade outlet184b. Blade inlet(s)184ais proximal of the seal of, about, or in proximity to annular abutment131dto permit the inflow of fluid from inflow conduit182into blade inlet(s)184a. Blade lumen184extends distally from blade inlet184asuch that blade lumen184extends substantially along the length of blade132in a parallel orientation to the longitudinal axis. A distal section184cof blade lumen184is orthogonal to the longitudinal axis of blade132(or otherwise curved, bent, or angled) such that distal section184cof blade lumen184is parallel (or otherwise curved, bent, or angled) to a distal surface132aof blade132. Distal section184cis spaced-apart from distal surface132aof blade132and distal section184cdefining a gap187therebetween. Gap187may be in the range of about 0.005 to about 0.025 mm; however, larger and smaller dimensions for gap187are also contemplated. Blade lumen184returns along a length of blade132from distal section184cto blade outlet184b. Blade outlet184bmay be disposed at an anti-node point along waveguide130or any other suitable position therealong and is disposed in fluid connection with return conduit186, e.g., via positioning of blade outlet184bproximally of distal seal member138and distally of the seal of, about, or in proximity of annular abutment131d. Return conduit186is defined between middle tube142and outer tube166and is in fluid communication with blade outlet184bthrough a slot142aof middle tube142. An O-Ring140is positioned distal to slot142abetween middle tube142and outer tube166to seal the distal end of return conduit186.

Similar to inflow conduit82described above (FIG.4), inflow conduit182and return conduit186may alternatively be formed from polyimide microtubes. For example, inflow conduit182can be a polyimide microtube disposed between middle tube142and waveguide130and in fluid communication with blade inlet184aand return conduit186can be a polyimide microtube in fluid communication with blade outlet184bpassing through slot142aof middle tube142and extending proximally through a channel disposed between outer tube166and middle tube142. Moreover, as shown inFIGS.8and8A, in embodiments where microtubes are provided, conduits182,186of polyimide microtubes may be disposed within the same channel, e.g., between the middle tube142and the waveguide130, and blade outlet184bcan be proximal to annular abutment31d.

In embodiments, return conduit186is in fluid communication with inflow conduit182such that the fluid continually circulates through blade cooling system180. In some embodiments, blade cooling system180includes a fluid control system190having a pump192positioned between return conduit186and inflow conduit182to circulate cooling fluid189through blade cooling system180. Pump192can be disposed within central body128of handle assembly112. In certain embodiments, blade cooling system180further includes a fluid reservoir188positioned between and in fluid communication with return conduit186and inflow conduit182. Fluid reservoir188can be disposed within central body128or external to instrument110. When fluid reservoir188is disposed external to instrument110, central body128includes an inflow port182aand a return port186ain fluid communication with inflow conduit182and return conduit186, respectively. Fluid control system190may also include a sensors194a-dsimilar to the sensors94a-ddiscussed above with respect to instrument10(FIGS.1-5) and may also include a return conduit thermocouple194e(FIG.7) configured to measure the temperature of cooling fluid189in return conduit186.

Blade cooling system180of instrument110functions substantially similar to blade cooling system80of instrument10. However, as blade cooling system180is a closed system, cooling fluid189flows through inflow conduit182through blade lumen184and returns through return conduit186before recirculating through blade cooling system180. As cooling fluid189flows through blade cooling system180, cooling fluid189absorbs heat from waveguide130and/or blade132. The absorbed heat may be released to the surrounding environment through an outer surface of outer tube166, central portion128of housing assembly112, and/or from fluid reservoir188. Additionally, fluid reservoir188may be actively cooled to facilitate cooling of the fluid189returned from blade132prior to recirculation.

Referring toFIGS.9-10, another ultrasonic surgical instrument210is provided in accordance with the present disclosure including a waveguide230and incorporating a blade cooling system280. Ultrasonic surgical instrument210and blade cooling system280are substantially similar to ultrasonic surgical instrument10and blade cooling system80(FIGS.1-5), with similar elements represented by similar numerals. As such only the differences are discussed in detail below.

Blade cooling system280includes a blade lumen284and a cooling conduit286. It is envisioned that the distal end284aof blade lumen284is spaced from a distal surface232aof blade232by a gap287. Gap287may be in the range of about 0.005 to about 0.025 mm; however, larger and smaller dimensions for gap287are also contemplated. Blade lumen284extends proximally within and substantially along the length of blade232to a blade outlet284b. Cooling conduit286is disposed within blade lumen284and a longitudinal slot266ain the outer surface of outer tube266along a length of an elongated body portion214(seeFIG.9A). A proximal end286bof cooling conduit286may be sealed or may be configured to couple to a fluid reservoir similarly as described above with respect to previous embodiments. A distal end286aof cooling conduit286is proximate to distal end284aof blade lumen284. Cooling conduit286can be a polyimide tube.

Referring toFIG.11, a blade cooling system380is provided in accordance with the present disclosure incorporated within a waveguide330and blade332. Waveguide330and blade cooling system380are substantially similar to waveguide30and blade cooling system80(FIGS.1-5), with similar elements represented by similar numerals, and may be used with any of ultrasonic instruments10,110, and210. It is also contemplated that blade cooling system380can be used with other suitable ultrasonic instruments. As such only the differences are discussed in detail below.

Blade cooling system380is a closed heat pipe system and includes a blade lumen384and a cooling conduit386. It is envisioned that the distal end384aof blade lumen384is spaced from a distal surface332aof blade332by a gap387. Gap387may be in the range of about 0.005 to about 0.025 mm; however, larger and smaller dimensions for gap387are also contemplated. Blade lumen384extends proximally within and substantially along the length of blade332to a blade outlet384b. Blade outlet384bis in fluid communication with cooling conduit386, i.e., blade lumen384and cooling conduit386cooperate to define a heat pipe extending through and between at least a portion of both waveguide330and blade332. Cooling conduit386is disposed within waveguide330. Cooling conduit386includes a conduit opening386aat a distal end of waveguide330in fluid communication with blade outlet384band a proximal or closed end386bis proximate to the proximal end of waveguide330. Closed end386bof cooling conduit386is sealed. In embodiments, the inner wall of the blade lumen384and/or cooling conduit386includes a wick structure (not shown) configured to exert capillary pressure on the cooling fluid when the cooling fluid is in a liquid phase. The wick structure may be a series of grooves parallel to the longitudinal axis of waveguide330. Cooling conduit386is constructed of a material with a high thermal efficiency, e.g., copper, polyimide micro tubing, etc.

In use, as the temperature of blade332increases, cooling fluid389which is disposed within blade lumen384absorbs heat from blade332transitioning cooling fluid389from a liquid phase to a vapor phase. Cooling fluid389in the vapor phase travels through blade cooling system380from blade lumen384to cooling conduit386where the cooling fluid389releases the absorbed heat through the surface of cooling conduit386, i.e., waveguide330, to the surrounding environment. As cooling fluid389releases the absorbed heat, cooling fluid389returns from the vapor phase to the liquid phase. When cooling fluid389returns to the liquid phase, cooling fluid389returns to blade lumen384to repeat the cycle. As can be appreciated, the distal-to-proximal movement of the vapor and the proximal-to-distal movement of the liquid can be facilitated by gravity when in use as blade332is generally angled downwardly relative to waveguide330into the surgical site.

The present disclosure also provides methods of manufacturing ultrasonic surgical instruments including cooling systems, such as those instruments detailed above. The method may include fabricating a waveguide, fabricating two halves of a blade separated along the longitudinal axis of the blade, cutting a portion of a conduit in each half of the blade, welding the two halves of the blade into a blade, and welding the blade to the distal end of the waveguide. As such, the conduits extending through the blade, as detailed above, can be readily formed to a desired configuration.

Cutting a portion of the conduit in each half of the blade may particularly include cutting a half-cylindrical channel along the length of the blade half including an opening in the outer surface of the blade and at the distal end of the blade. Blade32(FIG.4) may be manufactured in this manner. Alternatively, to achieve blade132(FIG.7), the cutting a portion of the conduit in each half of the blade includes cutting a half-cylindrical channel along the length of the blade half from a first opening in the outer surface of the blade, along the length of the blade towards the distal end, continuing the channel substantially parallel to the distal end of the blade defining a gap between the channel and the distal end of the blade, continuing the channel back along the length of the blade towards the proximal end of the blade, continuing the channel out a second opening in the outer surface of the blade substantially opposing the first opening. The cutting in either of the above embodiments may be accomplished by laser cutting or etching.

Welding the two halves of the blade into a blade may include aligning the two halves of the blade such that the half-cylindrical channels in each blade are positioned adjacent to each other to form a continuous cylindrical conduit within the blade. Welding the two halves may include laser welding the two halves of the blade together. Welding the blade to the waveguide may include laser welding the proximal end of the blade to the distal end of the waveguide.

In embodiments, the distal end of the waveguide includes threads configured to cooperate with threads of the blade to secure the waveguide to the blade. In some embodiments, the blade lumen is formed by drilling through a portion of the blade such that the distal end of the blade remains closed and does not require welding. Electrical Discharge Machining (EDM) may alternatively be used to make the blade lumen, followed by the distal end of the blade being welded shut. Other suitable manufacturing methods are also contemplated.

Referring now toFIGS.12-14, another embodiment of an ultrasonic surgical instrument configured for use in accordance with the present disclosure is shown generally identified by reference numeral410. Ultrasonic surgical instrument410is similar to and may include any of the aspects and/or features of any of the instruments detailed above. Thus, for purposes of brevity, only the differences between ultrasonic surgical instrument410and the above instruments will be detailed below, while similarities will be summarily described or omitted entirely.

Ultrasonic surgical instrument410generally includes a handle assembly412, an elongated body portion414, a tool assembly416having a blade432, and a blade cooling system480. Blade cooling system480has a fluid reservoir488that may be separate from ultrasonic surgical instrument410(as shown), on handle assembly412, or within handle assembly412. Fluid reservoir488is configured to hold a supply of cooling fluid489, which can be any suitable fluid such as those detailed above.

Blade cooling system480further includes a fluid control system490having a pump492configured to pump cooling fluid489from fluid reservoir488through blade432of ultrasonic surgical instrument410via a cooling inflow conduit482. Cooling fluid489absorbs heat from blade432of ultrasonic surgical instrument410and is returned through a cooling return conduit486. Heated cooling fluid489may be returned to fluid reservoir488, thus forming a closed-loop system, or may be released into a separate return reservoir (not shown) as part of an open-loop system.

As shown inFIGS.12and12A, cooling inflow and return conduits482,486are disposed on the outer surface of elongated body portion414of ultrasonic surgical instrument410and extend substantially along the length thereof. Positioning conduits482,486on the exterior of elongated body portion414helps inhibit the heating of waveguide430(FIG.13) and other internal components extending through elongated body portion414via the heated fluid returning through the return conduit486. A proximal end482aof inflow conduit482is configured to couple to pump492via handle assembly412(as shown) or separately therefrom and a proximal end486aof return conduit486is configured to couple to fluid reservoir488(or a separate return fluid reservoir (not shown)) via handle assembly412(as shown) or separately therefrom. Distal and proximal apertures466a,466b, respectively, are defined within elongated body portion414to enable conduits482,486to exit and enter elongated body portion414, respectively. However, it is also contemplated that ultrasonic surgical instrument410be configured with conduits482,486extending within elongated body portion414.

Referring toFIGS.13and14, blade432defines a blade lumen434that is formed within and extends substantially along the length of blade432. Blade lumen434may be coaxial with or extend in a parallel orientation relative to a longitudinal axis defined by blade432. Blade lumen434defines a closed distal end. Inflow conduit482and return conduit486enter blade lumen434through a blade output460defined towards the proximal end of blade lumen434. A seal is formed about blade output460and around inflow and outflow conduits482,486to inhibit the escape of fluid thereform. The seal may be affixed to the blade output460and conduits482,486. Alternatively, the seal may be releasably attached to blade output460permitting access to blade lumen434. Blade output460may be positioned at an anti-node point along waveguide430of ultrasonic surgical instrument410or at any other suitable position therealong. Inflow conduit482is disposed within and extends distally through blade lumen434. Return conduit486is disposed within the proximal end of blade lumen434. Inflow conduit482has a smaller diameter than blade lumen434leaving an annular gap436(FIG.14) between the inner surface of blade432defining blade lumen434and the outer surface of inflow conduit482. Blade lumen434may have a diameter in the range of about 0.25 mm to about 0.65 mm; however, other suitable configurations are also contemplated. During operation, cooling fluid489is pumped or otherwise circulated distally through inflow conduit482, exits a distal end of inflow conduit482at the distal end of blade lumen434, and travels proximally back through blade lumen434within annular gap436, ultimately being received by return conduit486, e.g., under suction force or under urging from the pumped inflowing fluid. Inflow and return conduits482,486may comprise one or more polyimide microtubes (other suitable microtubes, or may be formed in any other suitable fashion).

Referring again toFIGS.12-14, the fluid control system490is similar to the fluid control systems described above except for the relative positions of inflow and return conduit482,486and the flow path of cooling fluid489. When pump492of fluid control system490is activated, pump492draws cooling fluid489from fluid reservoir488and pumps cooling fluid489through inflow conduit482into the distal end of blade lumen434. As cooling fluid489fluid flows proximally back through blade lumen434within annular gap436, cooling fluid489absorbs heat from blade432such that blade432is cooled. The cooling fluid489is then pushed and/or pulled through the return conduit486into fluid reservoir488, creating a closed circuit, or pushed and/or pulled into a return reservoir (not shown) creating an open circuit. Fluid control system490regulates the amount of cooling fluid489that pump492draws from fluid reservoir488and pumps through blade cooling system480, thus controlling the cooling of blade432. Control may be performed similarly as detailed above with respect to the previous embodiments, or in any other suitable fashion.

Referring toFIG.15, another ultrasonic surgical instrument510is provided in accordance with the present disclosure incorporating a blade cooling system580. Ultrasonic surgical instrument510is similar to ultrasonic surgical instrument410(FIGS.12-14), except for the configuration of blade cooling system580, as detailed below.

Blade cooling system580includes an inflow conduit582, a return conduit586, an inflow pump592, and a return pump594. Inflow conduit582and return conduit586may be formed from polyimide microtubes (or in any other suitable manner).

Similar to the cooling systems described above, return conduit586is in fluid communication with inflow conduit582such that the fluid continually circulates through blade cooling system580. Blade cooling system580includes a fluid control system590having an inflow pump592positioned between a fluid reservoir588and inflow conduit582and a return pump594positioned between return conduit586and fluid reservoir588. Alternatively, return pump594may be positioned between return conduit584and a separate return reservoir (not shown) to define an open-loop system. Inflow and return pumps592,594can be externally disposed (as shown), or may be disposed within central body528of handle assembly512. Fluid control system590may also include sensors (not shown) similar to the sensors discussed above to enable feedback-based control.

Similar to the fluid control systems detailed above, when inflow pump592of fluid control system590is activated, inflow pump592draws cooling fluid589from fluid reservoir588and pumps cooling fluid589through inflow conduit582and the blade of ultrasonic surgical instrument510. As cooling fluid589fluid flows through blade lumen (not shown) of the blade, return pump594is activated to draw the heated cooling fluid589from the blade lumen (not shown), through the return conduit586, and into the fluid reservoir588or alternatively the return reservoir (not shown). The inflow and return pumps592,594may operate simultaneously. However, the operation times of pumps592,594may also be staggered. Fluid control system590may include sensors (not shown), or any other suitable mechanisms for providing feedback and/or indicating a state, parameter, condition, etc. of a component of surgical instrument510and/or the surrounding environment, to facilitate controlling of inflow and return pumps592,594. Fluid control system490(FIG.12) may similarly include such features. Other control systems, mechanisms, methods, and/or protocols are also contemplated for either or both embodiments.

While several embodiments of the disclosure have been shown in the drawings, 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. Any combination of the above embodiments is also envisioned and is within the scope of the claimed invention. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.