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7549987

7549987

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7549987 - remarkable

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The phase transitional energy delivery aspects of the invention are the same as described above. The instrument differs in that it utilizes significantly reduced dimensions or micronization of features in the working end More particularly, a fluid media source A and pressure control system B are adapted to provide pressurized flows of liquid media M through the introducer body and thereafter into microchannel body or structure indicated at see FIG.

The microchannel or microporous body defines therein plurality of small diameter fluid passageways or microchannel portions collectively.

The microchannel body also can be a microporous trabecular material to provide open-cell flow passageways therethrough. At an interior of the microchannel body , an intermediate region of the open flow channels is exposed to first and second electrode elements A and B.

The electrode elements A and B can be formed in a plates or layers of channeled material or trabecular material that extends transverse to passageways Thus, the channels are exposed to surfaces of the electrode elements A and B interior of the working surface that interfaces with the targeted tissue T.

As depicted in FIG. A working end similar to that of FIGS. For example, a rigid probe can be used in orthopedic procedures to cause hydrothermal shrinkage of collagen, for example in a spinal disc, or a joint capsule to stabilize the joint see U.

In an arthroscopic procedure, the working end is painted across a targeted tissue site in a joint capsule to shrink tissue. In another procedure, the working end may be stabilized against any collagenous tissue to heat and shrink collagen in a targeted tissue such as a herniated disc.

As described previously, the thermal energy delivery means of the invention preferably uses an electrical energy source and spaced apart electrodes for flash vaporization of a liquid media.

It should be appreciated that a resistive element coupled to an electrical source also can be used. For example, a resistive element can fabricated out of any suitable material such a tungsten alloy in a helical, tubular or a microporous form that allows fluid flow therethrough.

Now referring to FIGS. The previous devices were shown and optimized for having a working surface that engages tissue, and for controlling and limiting thermal effects in engaged tissue.

In the embodiment of FIG. The diameter of body can range from about 1 Fr. The working end typically is carried at the distal end of a flexible catheter but may also be carried at the distal end of a more rigid introducer member.

In a rigid member, the working end also can be sharp for penetrating into any soft tissue e. The working end of FIG. The interior chamber carries opposing polarity electrodes A and B as thermal energy emitters.

The distal terminus or working surface of the catheter has media entrance port therein. The electrodes can extend axially from about 1 mm to 50 mm and are spaced well inward, for example from 1 mm to mm from the distal working surface This type of electrode arrangement will enhance energy delivery to the liquid media M to allow effective continuous vaporization thereof.

The lumen or chamber portion between electrodes A and B allows for focused energy application to create the desired energy density in the inflowing media M to cause its immediate vaporization.

The vapor is then propagated from the working surface via port to interact with the endoluminal media. It should be appreciated that the instrument may have a plurality of media entrance ports in the working surface, or additionally the radially outward surfaces of the catheter.

In the system embodiment of FIG. The working end also is coupled to fluid media source A that carries pressurization means of any suitable type together with a pressure control system indicated at B.

In one targeted endovascular procedure, as depicted in FIG. Most endothelial-lined structures of the body, such as blood vessel and other ducts, have substantially collagen cores for specific functional purposes.

Intermolecular cross-links provide collagen connective tissue with unique physical properties such as high tensile strength and substantial elasticity.

Temperature elevation ruptures the collagen ultrastructural stabilizing cross-links, and results in immediate contraction in the fibers to about one-third of their original longitudinal dimension.

At the same time, the caliber of the individual collagen fibers increases without changing the structural integrity of the connective tissue.

As represented in FIG. The pressurized fluid media source A and pressure control subsystem B also can be adapted to create a pressure gradient, or enhance the pressure gradients caused by vapor expansion, to controllably eject the heated vapor from the working surface As shown in FIG.

This means of applying thermal energy to vessel walls can controllably shrink, collapse and occlude the vessel lumen to terminate blood flow therethrough, and offers substantial advantages over alternative procedures.

Vein stripping is a much more invasive treatment. Rf closure of varicose veins is known in the art. Typically, a catheter device is moved to drag Rf electrodes along the vessel walls to apply Rf energy to damage the vessel walls by means of causing ohmic heating.

Such Rf ohmic heating causes several undesirable effects, such as i creating high peak electrode temperatures up to several hundred degrees C.

This method substantially prevents heat from being propagated heat outwardly by conduction—thus preventing damage to nerves. There is no possibility of causing ohmic heating in nerves, since a principal advantage of the invention is the application of therapeutic heat entirely without electrical current flow in tissue.

Further, the vapor and its heat content can apply substantially uniform thermal effects about valves since the heat transfer mechanism is through a vapor that contacts all vessel wall surfaces—and is not an electrode that is dragged along the vessel wall.

Thus, the system of the invention may not require the navigation of the catheter member through tortuous vessels.

Alternatively, the working end may be translated along the lumen as energy is applied by means of vapor-to-liquid energy release.

This will provide an advantage over other heat transfer mechanisms, such as ohmic heating, that cannot be directly imaged with ultrasound.

Another embodiment of the invention is shown in FIGS. For example, the inventive system can be carried in a probe working end as in FIGS.

Alternatively, the system can be used in forceps as in FIG. In general, this embodiment includes i a polymeric monolith with microfluidic circuitry at an interior of the engagement surface for controlling the delivery of energy from the fluid to the engaged tissue; ii optional contemporaneous cooling of the microfluidic circuitry and engagement surface for controlling thermal effects in tissue; and iii optional coupling of additional Rf energy to the fluid media contemporaneous with ejection from the engagement surface to enhance energy application at the tissue interface.

More in particular, the instrument has a handle portion and extension portion that extends to working end The working end carries a polymer microfluidic body with an engagement surface for engaging tissue.

The engagement surface can be flat or curved and have any suitable dimension. Its method of use will be described in more detail below.

The instrument of FIG. It should be appreciated that the jaws can have any suitable dimensions, shape and form. Now referring to FIG.

In one aspect of the invention, the microfabricated body carries microfluidic channels adapted to carry a fluid media from a pressurized media source as described in previous embodiments.

The media is carried from source by at least one inflow lumen A to the microfluidic channels in body see FIGS.

In some embodiments, an outflow lumen B is provided in the instrument body to carry at least part of fluid to a collection reservoir Alternatively, the fluid can move in a looped flow arrangement to return to the fluid media source see FIGS.

The engagement surface can be smooth, textured or having surface features for gripping tissue. The microfluidic channels have a mean cross section of less than 1 mm.

Preferably, the channels have a mean cross section of less than 0. The channels can have any cross-sectional shape, such as rectangular or round that is dependent on the means of microfabrication.

In this aspect of the invention, the system applies energy to tissue as described in the earlier embodiments see FIGS. The microfluidic channels extend in any suitable pattern or circuitry from at least one inflow lumen A.

In a preferred embodiment, the microfluidic channels extend across the engagement surface and then communicate with at least one outflow lumen B see FIGS.

The flow channels further can have an increase in cross-sectional dimension proximate the surface or proximate each port to allow for lesser containing pressure on the vapor to assist in its vapor to liquid phase transition.

In another embodiment, the engagement surface can have other suction ports not shown that are independent of the fluidic channels for suctioning tissue into contact with the engagement surface A suction source can be coupled to such suction ports.

In the embodiment of FIGS. The system further has a fluid pressure control system B for controlling the media inflow pressures as in the embodiment of FIGS.

Of particular interest, the microfabricated body can be of an elastomer or other suitable polymer of any suitable modulus and can be made according to techniques based on replication molding wherein the polymer is patterned by curing in a micromachined mold.

A number of suitable microfabrication processes are termed soft lithography. The term multilayer soft lithography combines soft lithography with the capability to bond multiple patterned layers of polymers to form a monolith with fluid and electric circuitry therein.

A multilayer body as in FIGS. An elastomer bonding system can be a two component addition-cure of silicone rubber typically.

The scope of the invention encompasses the use of multilayer soft lithography microfabrication techniques for making thermal vapor delivery surfaces and electrosurgical engagement surfaces, wherein such energy delivery surfaces consist of multiple layers fabricated of soft materials with microfluidic circuitry therein as well as electrical conductor components.

In an optional embodiment illustrated in FIG. Multilayer soft lithographic techniques for microfluidics are described, in general, in the following references which are incorporated herein by this reference: In any embodiment of polymer body , as described above, the layers can be microfabricated using soft lithography techniques to provide an open or channeled interior structure to allow fluid flows therethrough.

The use of resilient polymers e. For example, microtransfer molding is used wherein a transparent, elastomeric polydimethylsiloxane PDMS stamp has patterned relief on its surface to generate features in the polymer.

The PDMS stamp is filled with a prepolymer or ceramic precursor and placed on a substrate. The material is cured and the stamp is removed.

The technique generates features as small as nm and is able to generate multilayer body as in FIG. Replica molding is a similar process wherein a PDMS stamp is cast against a conventionally patterned master.

A polyurethane or other polymer is then molded against the secondary PDMS master. In this way, multiple copies can be made without damaging the original master.

The technique can replicate features as small as 30 nm. Another process is known as micromolding in capillaries MIMIC wherein continuous channels are formed when a PDMS stamp is brought into conformal contact with a solid substrate.

Then, capillary action fills the channels with a polymer precursor. The polymer is cured and the stamp is removed. Solvent-assisted microcontact molding SAMIM is also known wherein a small amount of solvent is spread on a patterned PDMS stamp and the stamp is placed on a polymer, such as photoresist.

The solvent swells the polymer and causes it to expand to fill the surface relief of the stamp. Features as small as 60 nm have been produced.

A background on microfabrication can be found in Xia and Whitesides, Annu. For example, the channels can have ultrahydrophobic surfaces for enabling fluid flows, and the fluids or surfaces can carry any surfactant.

In a working end embodiment that is particularly adapted for microsurgery, as in the forceps of FIG. Thus, the scope of the invention extends to two complementary novel structures and components: The components will be described in order.

The fluid is delivered in a liquid form to the forceps schematically shown in FIG. The fluid remains in a liquid state as it cycles through channels of the engagement surface as in FIG.

The microfluidic body can be adapted to delivery energy in either a monopolar or bipolar mode. In a monopolar mode, radiofrequency energy is coupled to the flowing fluid by an active electrode arrangement having a single polarity, wherein the targeted tissue is treated when an electrical circuit is completed with a ground pad comprising a large area electrode coupled to the patient at a location remote from the targeted tissue.

In a bipolar mode, radiofrequency energy is coupled to flowing fluid by first and second opposing polarity electrodes A and B in different channels , or different groups of channels see FIG.

The surface layer of polymeric material overlying channels is substantially thin and allows from capacitive coupling of electrical energy to engaged tissue.

The polymer is selected from a class of material known in the art that optimizes the delivery of electrical energy therethrough, wherein the polymer has limited capacitance.

The interior regions of polymeric material between channels has a greater dimension than the surface layer to prevent substantial current flow between the channels at the interior of body The electrodes A and B alternatively can comprise conductive wires inserted into the channels or can be a conductive coating fabricated into the channel walls.

Soft lithography methods also can deposit conductive layers or conductive polymers to provide the electrode functionality of the invention.

Alternative means for fabricating channels with conductive coatings are described in the following patents to W.

By this means, the depth of ohmic heating in tissue can be adjusted as is known in the art. In a preferred embodiment, each conductive region or electrode is coupled to a controller and multiplexing system to allow bipolar energy application within engaged tissue between selected individual electrodes having transient opposing polarities, or any first polarity set of electrodes and fluidic channels that cooperate with any set of second polarity electrodes and channels.

The system can have independent feedback control based on impedance or temperature for each activated set of electrodes.

In this embodiment, the polymer layer overlying the channel also can be microporous or macroporous to allow the conductive fluid to seep through this fluid permeable layer to directly couple electrical energy to the engaged tissue.

Now turning to the superlattice cooling component of the invention, it can be seen in FIGS. As described above, one preferred nanolattice cooling system was disclosed by Rama Venkatasubramanian et al.

For convenience, this class of thin, high performance thermoelectric device is referred to herein for convenience as a superlattice cooling device.

Superlattice cooling devices provide substantial performance improvements over conventional thermoelectric structures, also known as Peltier devices.

It has been reported that superlattice thermoelectric material having a surface dimension of about 1 cm 2 can provide watts of cooling under a nominal temperature gradient.

This would translate into an efficiency at least double that of conventional thermoelectric devices. The use of a superlattice cooling device in a surgical instrument further provides the advantage of wafer-scalability and the use of known processes for fabrication.

The author first disclosed the use of thermoelectric cooling devices in a thermal-energy delivery jaw structure in U. In a typical embodiment, the thin-film superlattice cooling structure comprises a stack of at least 10 alternating thin semiconductor layers.

More preferably, the superlattice structure includes at least alternating layers, and can comprise or more such nanoscale layers. In one embodiment, the thin film superlattice structure comprises alternating stacks of thin film layers of bismuth telluride and antimony telluride.

The thin film superlattice structure thus comprises a circuit including a plurality of thin film layers of at least two dissimilar conductors wherein current propagates heat toward one end of the circuit thereby cooling the end of the circuit coupled to the energy-emitting surface.

The superlattice cooling structures are coupled to an electrical source by independent circuitry, and can also be coupled with a control system to operate in a selected sequence with thermal energy delivery.

A tissue-engaging surface can include a first surface portion of a thermal energy emitter and second surface portion of the superlattice cooling device as in FIGS.

The first and second surface portions and can be provided in any suitable pattern. A working end as in FIGS. The system can deliver a burst of thermal energy followed by a surface cooling to localize heat at a selected depth while preventing excessive damage to the epidermal layer.

In a preferred embodiment, the energy-emitting surface is thin microfluidic body as depicted in FIG. In another embodiment in FIG.

Each jaw arm can include such an electrode coupled to an Rf source A to provide for bipolar energy delivery between the jaws. Such a bi-polar jaw structure with active superlattice cooling would prevent tissue sticking.

It should be appreciated that other thermal energy-emitting surfaces are possible, such as laser emitters, microwave emitters and resistive heating elements.

Now turning to FIG. In this embodiment, the open-ended capillary microchannels are formed in a body of a selected material and have a selected cross-sectional dimension to provide a capillary effect to draw liquid media into the capillary channels.

This embodiment can be fabricated of a polymer by soft lithography means. Alternatively, the tissue-engaging body can be of a ceramic, metal or a combination thereof.

As can be seen in FIG. In operation, the capillaries will draw liquid into the channels by means of normal capillary forces. The capillary channels further carry a thermal energy emitter about interior channel regions for vaporizing the liquid that is drawn into the channels.

The thermal energy emitter is operatively coupled to a source selected from the class consisting of a Rf source, microwave source, laser source and resistive heat source.

In operation, the capillaries will draw liquid into the channels wherein vaporization will eject the vapor outwardly from the surface to apply thermal energy to tissue as described in earlier embodiments.

The advantage of the invention is that the capillary channels can continuously draw liquid into the microchannels from a substantially static liquid reservoir without the need for a substantial pressurization means.

At the same time, the vaporization of the liquid media will cause pressures to cause ejection of the vapor from the surface since that is the direction of least resistance.

The surface can further carry any monopolar of bipolar electrode arrangement to couple energy to the ejected vapor and engaged tissue.

Each jaw carries a body with capillaries channels and vapor delivery ports as in FIG. The jaws structure includes a system that transects tissue by hydrojet means that can cooperate with the fluid media source of the invention.

Of particular interest, one jaw carries an ultrahigh pressure water inflow lumen that exits at least one thin linear port wherein the jetting of water has sufficient velocity to cut the engaged tissue.

Depending on the length of the jaws, the jetting port s can be singular or plural, an overlapping if required to insure transection of any engaged tissue volume.

In another embodiment not shown the jaw can have a moveable jet member that axially translates in the jaw to cut tissue. Electrical energy can be coupled to a fluid jet to further apply energy along a cut line.

The jetted fluid is received by elongate channel in the opposing jaw that communicates with extraction lumen and an aspiration source.

Such a jaw can have an interlock mechanism to insure that the hydrojet cutting means can only be actuated when the jaws are in a closed position.

This embodiment provides the advantage of having a non-stick tissue-sealing jaw structure together with a transecting means that operates without moving parts.

It should be appreciated that the scope of the invention includes the use of such a hydrojet cutting means to any surgical jaw structure that is adapted to seal tissue or organ margins.

Although particular embodiments of the present invention have been described above in detail, it will be understood that this description is merely for purposes of illustration.

Specific features of the invention are shown in some drawings and not in others, and this is for convenience only and any feature may be combined with another in accordance with the invention.

In another procedure, the working end may be stabilized against any collagenous tissue to heat and shrink collagen in a targeted tissue such as a herniated disc.

As described previously, the thermal energy delivery means of the invention preferably uses an electrical energy source and spaced apart electrodes for flash vaporization of a liquid media.

It should be appreciated that a resistive element coupled to an electrical source also can be used. For example, a resistive element can fabricated out of any suitable material such a tungsten alloy in a helical, tubular or a microporous form that allows fluid flow therethrough.

Now referring to FIGS. The previous devices were shown and optimized for having a working surface that engages tissue, and for controlling and limiting thermal effects in engaged tissue.

In the embodiment of FIG. The diameter of body can range from about 1 Fr. The working end typically is carried at the distal end of a flexible catheter but may also be carried at the distal end of a more rigid introducer member.

In a rigid member, the working end also can be sharp for penetrating into any soft tissue e. The working end of FIG. The interior chamber carries opposing polarity electrodes A and B as thermal energy emitters.

The distal terminus or working surface of the catheter has media entrance port therein. The electrodes can extend axially from about 1 mm to 50 mm and are spaced well inward, for example from 1 mm to mm from the distal working surface This type of electrode arrangement will enhance energy delivery to the liquid media M to allow effective continuous vaporization thereof.

The lumen or chamber portion between electrodes A and B allows for focused energy application to create the desired energy density in the inflowing media M to cause its immediate vaporization.

The vapor is then propagated from the working surface via port to interact with the endoluminal media. It should be appreciated that the instrument may have a plurality of media entrance ports in the working surface, or additionally the radially outward surfaces of the catheter.

In the system embodiment of FIG. The working end also is coupled to fluid media source A that carries pressurization means of any suitable type together with a pressure control system indicated at B.

In one targeted endovascular procedure, as depicted in FIG. Most endothelial-lined structures of the body, such as blood vessel and other ducts, have substantially collagen cores for specific functional purposes.

Intermolecular cross-links provide collagen connective tissue with unique physical properties such as high tensile strength and substantial elasticity.

Temperature elevation ruptures the collagen ultrastructural stabilizing cross-links, and results in immediate contraction in the fibers to about one-third of their original longitudinal dimension.

At the same time, the caliber of the individual collagen fibers increases without changing the structural integrity of the connective tissue. As represented in FIG.

The pressurized fluid media source A and pressure control subsystem B also can be adapted to create a pressure gradient, or enhance the pressure gradients caused by vapor expansion, to controllably eject the heated vapor from the working surface As shown in FIG.

This means of applying thermal energy to vessel walls can controllably shrink, collapse and occlude the vessel lumen to terminate blood flow therethrough, and offers substantial advantages over alternative procedures.

Vein stripping is a much more invasive treatment. Rf closure of varicose veins is known in the art. Typically, a catheter device is moved to drag Rf electrodes along the vessel walls to apply Rf energy to damage the vessel walls by means of causing ohmic heating.

Such Rf ohmic heating causes several undesirable effects, such as i creating high peak electrode temperatures up to several hundred degrees C.

This method substantially prevents heat from being propagated heat outwardly by conduction—thus preventing damage to nerves.

There is no possibility of causing ohmic heating in nerves, since a principal advantage of the invention is the application of therapeutic heat entirely without electrical current flow in tissue.

Further, the vapor and its heat content can apply substantially uniform thermal effects about valves since the heat transfer mechanism is through a vapor that contacts all vessel wall surfaces—and is not an electrode that is dragged along the vessel wall.

Thus, the system of the invention may not require the navigation of the catheter member through tortuous vessels. Alternatively, the working end may be translated along the lumen as energy is applied by means of vapor-to-liquid energy release.

This will provide an advantage over other heat transfer mechanisms, such as ohmic heating, that cannot be directly imaged with ultrasound.

Another embodiment of the invention is shown in FIGS. For example, the inventive system can be carried in a probe working end as in FIGS.

Alternatively, the system can be used in forceps as in FIG. In general, this embodiment includes i a polymeric monolith with microfluidic circuitry at an interior of the engagement surface for controlling the delivery of energy from the fluid to the engaged tissue; ii optional contemporaneous cooling of the microfluidic circuitry and engagement surface for controlling thermal effects in tissue; and iii optional coupling of additional Rf energy to the fluid media contemporaneous with ejection from the engagement surface to enhance energy application at the tissue interface.

More in particular, the instrument has a handle portion and extension portion that extends to working end The working end carries a polymer microfluidic body with an engagement surface for engaging tissue.

The engagement surface can be flat or curved and have any suitable dimension. Its method of use will be described in more detail below.

The instrument of FIG. It should be appreciated that the jaws can have any suitable dimensions, shape and form.

Now referring to FIG. In one aspect of the invention, the microfabricated body carries microfluidic channels adapted to carry a fluid media from a pressurized media source as described in previous embodiments.

The media is carried from source by at least one inflow lumen A to the microfluidic channels in body see FIGS.

In some embodiments, an outflow lumen B is provided in the instrument body to carry at least part of fluid to a collection reservoir Alternatively, the fluid can move in a looped flow arrangement to return to the fluid media source see FIGS.

The engagement surface can be smooth, textured or having surface features for gripping tissue. The microfluidic channels have a mean cross section of less than 1 mm.

Preferably, the channels have a mean cross section of less than 0. The channels can have any cross-sectional shape, such as rectangular or round that is dependent on the means of microfabrication.

In this aspect of the invention, the system applies energy to tissue as described in the earlier embodiments see FIGS. The microfluidic channels extend in any suitable pattern or circuitry from at least one inflow lumen A.

In a preferred embodiment, the microfluidic channels extend across the engagement surface and then communicate with at least one outflow lumen B see FIGS.

The flow channels further can have an increase in cross-sectional dimension proximate the surface or proximate each port to allow for lesser containing pressure on the vapor to assist in its vapor to liquid phase transition.

In another embodiment, the engagement surface can have other suction ports not shown that are independent of the fluidic channels for suctioning tissue into contact with the engagement surface A suction source can be coupled to such suction ports.

In the embodiment of FIGS. The system further has a fluid pressure control system B for controlling the media inflow pressures as in the embodiment of FIGS.

Of particular interest, the microfabricated body can be of an elastomer or other suitable polymer of any suitable modulus and can be made according to techniques based on replication molding wherein the polymer is patterned by curing in a micromachined mold.

A number of suitable microfabrication processes are termed soft lithography. The term multilayer soft lithography combines soft lithography with the capability to bond multiple patterned layers of polymers to form a monolith with fluid and electric circuitry therein.

A multilayer body as in FIGS. An elastomer bonding system can be a two component addition-cure of silicone rubber typically. The scope of the invention encompasses the use of multilayer soft lithography microfabrication techniques for making thermal vapor delivery surfaces and electrosurgical engagement surfaces, wherein such energy delivery surfaces consist of multiple layers fabricated of soft materials with microfluidic circuitry therein as well as electrical conductor components.

In an optional embodiment illustrated in FIG. Multilayer soft lithographic techniques for microfluidics are described, in general, in the following references which are incorporated herein by this reference: In any embodiment of polymer body , as described above, the layers can be microfabricated using soft lithography techniques to provide an open or channeled interior structure to allow fluid flows therethrough.

The use of resilient polymers e. For example, microtransfer molding is used wherein a transparent, elastomeric polydimethylsiloxane PDMS stamp has patterned relief on its surface to generate features in the polymer.

The PDMS stamp is filled with a prepolymer or ceramic precursor and placed on a substrate. The material is cured and the stamp is removed.

The technique generates features as small as nm and is able to generate multilayer body as in FIG. Replica molding is a similar process wherein a PDMS stamp is cast against a conventionally patterned master.

A polyurethane or other polymer is then molded against the secondary PDMS master. In this way, multiple copies can be made without damaging the original master.

The technique can replicate features as small as 30 nm. Another process is known as micromolding in capillaries MIMIC wherein continuous channels are formed when a PDMS stamp is brought into conformal contact with a solid substrate.

Then, capillary action fills the channels with a polymer precursor. The polymer is cured and the stamp is removed. Solvent-assisted microcontact molding SAMIM is also known wherein a small amount of solvent is spread on a patterned PDMS stamp and the stamp is placed on a polymer, such as photoresist.

The solvent swells the polymer and causes it to expand to fill the surface relief of the stamp. Features as small as 60 nm have been produced.

A background on microfabrication can be found in Xia and Whitesides, Annu. For example, the channels can have ultrahydrophobic surfaces for enabling fluid flows, and the fluids or surfaces can carry any surfactant.

In a working end embodiment that is particularly adapted for microsurgery, as in the forceps of FIG. Thus, the scope of the invention extends to two complementary novel structures and components: The components will be described in order.

The fluid is delivered in a liquid form to the forceps schematically shown in FIG. The fluid remains in a liquid state as it cycles through channels of the engagement surface as in FIG.

The microfluidic body can be adapted to delivery energy in either a monopolar or bipolar mode. In a monopolar mode, radiofrequency energy is coupled to the flowing fluid by an active electrode arrangement having a single polarity, wherein the targeted tissue is treated when an electrical circuit is completed with a ground pad comprising a large area electrode coupled to the patient at a location remote from the targeted tissue.

In a bipolar mode, radiofrequency energy is coupled to flowing fluid by first and second opposing polarity electrodes A and B in different channels , or different groups of channels see FIG.

The surface layer of polymeric material overlying channels is substantially thin and allows from capacitive coupling of electrical energy to engaged tissue.

The polymer is selected from a class of material known in the art that optimizes the delivery of electrical energy therethrough, wherein the polymer has limited capacitance.

The interior regions of polymeric material between channels has a greater dimension than the surface layer to prevent substantial current flow between the channels at the interior of body The electrodes A and B alternatively can comprise conductive wires inserted into the channels or can be a conductive coating fabricated into the channel walls.

Soft lithography methods also can deposit conductive layers or conductive polymers to provide the electrode functionality of the invention.

Alternative means for fabricating channels with conductive coatings are described in the following patents to W. By this means, the depth of ohmic heating in tissue can be adjusted as is known in the art.

In a preferred embodiment, each conductive region or electrode is coupled to a controller and multiplexing system to allow bipolar energy application within engaged tissue between selected individual electrodes having transient opposing polarities, or any first polarity set of electrodes and fluidic channels that cooperate with any set of second polarity electrodes and channels.

The system can have independent feedback control based on impedance or temperature for each activated set of electrodes.

In this embodiment, the polymer layer overlying the channel also can be microporous or macroporous to allow the conductive fluid to seep through this fluid permeable layer to directly couple electrical energy to the engaged tissue.

Now turning to the superlattice cooling component of the invention, it can be seen in FIGS. As described above, one preferred nanolattice cooling system was disclosed by Rama Venkatasubramanian et al.

For convenience, this class of thin, high performance thermoelectric device is referred to herein for convenience as a superlattice cooling device.

Superlattice cooling devices provide substantial performance improvements over conventional thermoelectric structures, also known as Peltier devices.

It has been reported that superlattice thermoelectric material having a surface dimension of about 1 cm 2 can provide watts of cooling under a nominal temperature gradient.

This would translate into an efficiency at least double that of conventional thermoelectric devices. The use of a superlattice cooling device in a surgical instrument further provides the advantage of wafer-scalability and the use of known processes for fabrication.

The author first disclosed the use of thermoelectric cooling devices in a thermal-energy delivery jaw structure in U.

In a typical embodiment, the thin-film superlattice cooling structure comprises a stack of at least 10 alternating thin semiconductor layers. More preferably, the superlattice structure includes at least alternating layers, and can comprise or more such nanoscale layers.

In one embodiment, the thin film superlattice structure comprises alternating stacks of thin film layers of bismuth telluride and antimony telluride.

The thin film superlattice structure thus comprises a circuit including a plurality of thin film layers of at least two dissimilar conductors wherein current propagates heat toward one end of the circuit thereby cooling the end of the circuit coupled to the energy-emitting surface.

The superlattice cooling structures are coupled to an electrical source by independent circuitry, and can also be coupled with a control system to operate in a selected sequence with thermal energy delivery.

A tissue-engaging surface can include a first surface portion of a thermal energy emitter and second surface portion of the superlattice cooling device as in FIGS.

The first and second surface portions and can be provided in any suitable pattern. A working end as in FIGS. The system can deliver a burst of thermal energy followed by a surface cooling to localize heat at a selected depth while preventing excessive damage to the epidermal layer.

In a preferred embodiment, the energy-emitting surface is thin microfluidic body as depicted in FIG. In another embodiment in FIG. Each jaw arm can include such an electrode coupled to an Rf source A to provide for bipolar energy delivery between the jaws.

Such a bi-polar jaw structure with active superlattice cooling would prevent tissue sticking. It should be appreciated that other thermal energy-emitting surfaces are possible, such as laser emitters, microwave emitters and resistive heating elements.

Now turning to FIG. In this embodiment, the open-ended capillary microchannels are formed in a body of a selected material and have a selected cross-sectional dimension to provide a capillary effect to draw liquid media into the capillary channels.

This embodiment can be fabricated of a polymer by soft lithography means. Alternatively, the tissue-engaging body can be of a ceramic, metal or a combination thereof.

As can be seen in FIG. In operation, the capillaries will draw liquid into the channels by means of normal capillary forces.

The capillary channels further carry a thermal energy emitter about interior channel regions for vaporizing the liquid that is drawn into the channels.

The thermal energy emitter is operatively coupled to a source selected from the class consisting of a Rf source, microwave source, laser source and resistive heat source.

In operation, the capillaries will draw liquid into the channels wherein vaporization will eject the vapor outwardly from the surface to apply thermal energy to tissue as described in earlier embodiments.

The advantage of the invention is that the capillary channels can continuously draw liquid into the microchannels from a substantially static liquid reservoir without the need for a substantial pressurization means.

At the same time, the vaporization of the liquid media will cause pressures to cause ejection of the vapor from the surface since that is the direction of least resistance.

The surface can further carry any monopolar of bipolar electrode arrangement to couple energy to the ejected vapor and engaged tissue.

Each jaw carries a body with capillaries channels and vapor delivery ports as in FIG. The jaws structure includes a system that transects tissue by hydrojet means that can cooperate with the fluid media source of the invention.

Of particular interest, one jaw carries an ultrahigh pressure water inflow lumen that exits at least one thin linear port wherein the jetting of water has sufficient velocity to cut the engaged tissue.

Depending on the length of the jaws, the jetting port s can be singular or plural, an overlapping if required to insure transection of any engaged tissue volume.

In another embodiment not shown the jaw can have a moveable jet member that axially translates in the jaw to cut tissue.

Electrical energy can be coupled to a fluid jet to further apply energy along a cut line. The jetted fluid is received by elongate channel in the opposing jaw that communicates with extraction lumen and an aspiration source.

Such a jaw can have an interlock mechanism to insure that the hydrojet cutting means can only be actuated when the jaws are in a closed position.

This embodiment provides the advantage of having a non-stick tissue-sealing jaw structure together with a transecting means that operates without moving parts.

It should be appreciated that the scope of the invention includes the use of such a hydrojet cutting means to any surgical jaw structure that is adapted to seal tissue or organ margins.

Although particular embodiments of the present invention have been described above in detail, it will be understood that this description is merely for purposes of illustration.

Specific features of the invention are shown in some drawings and not in others, and this is for convenience only and any feature may be combined with another in accordance with the invention.

Further variations will be apparent to one skilled in the art in light of this disclosure and are intended to fall within the scope of the appended claims.

A SumoBrain Solutions Company. Search Expert Search Quick Search. United States Patent This invention relates to the working end of a medical instrument that applies energy to tissue.

In one embodiment, the instrument has a microfluidic tissue-engaging surface fabricated by soft lithography means together with optional superlattice cooling means that allows for very precise control of energy application, for example in neurosurgery applications.

The tissue-engaging surface can eject a high-heat content vapor into the engaged tissue for treating tissue, while the superlattice cooling structure can prevent collateral thermal damage.

Also, the superlattice cooling structure can be used to localize heat at a selected depth in tissue and prevent surface ablation.

Also, the superlattice cooling structure can be used to prevent tissue sticking to a thermal energy delivery surface. In another embodiment, the tissue-engaging surface can be used in a jaw structure for sealing tissue together with hydrojet means for transecting the tissue.

Click for automatic bibliography generation. What is claimed is: A system for applying energy to tissue comprising a polymeric monolith with fluidic channels therein, the monolith having a tissue-engaging surface for engaging tissue, and a fluid media source that introduces fluid media into the fluidic channels for applying energy to engaged tissue, the system further comprising an energy source within the fluidic channels wherein the energy source comprises a plurality of electrodes spaced apart within the fluidic channels and is configured to apply a vaporization energy through the fluid media, and where the vaporization energy exceeds a heat of vaporization of the fluid media therein to provide a vapor media having an increased volume within the fluidic channels to sufficiently cause ejection of the vapor media from the fluid channels at a high velocity.

A system for applying energy to tissue as in claim 1 wherein the fluidic channels have mean cross-section of less than 1 mm. A system for applying energy to tissue as in claim 1 wherein the fluidic channels have mean cross-section of less than 0.

A system for applying energy to tissue as in claim 1 wherein the polymeric monolith is of an elastomeric composition. A system for applying energy to tissue as in claim 1 wherein the fluid media is a vapor phase media capable of releasing the heat of vaporization to apply energy to tissue.

A system for applying energy to tissue as in claim 5 wherein the fluidic channels have an increase in cross-section proximate the tissue-engaging surface for allowing a vapor to liquid phase transition of the media.

A system for applying energy to tissue as in claim 5 wherein the fluidic channels include ports in the tissue-engaging surface for allowing outflow of vapor from the fluidic channels to interact with tissue.

A system for applying energy to tissue as in claim 4 wherein the elastomeric composition of the monolith overlying the fluidic channels is fluid permeable.

A system for applying energy to tissue comprising: A system for applying energy to tissue as in claim 9 wherein the fluidic channels have mean cross-section of less than 1 mm.

A system for applying energy to tissue as in claim 9 wherein the fluidic channels have mean cross-section of less than 0.

A system for applying energy to tissue as in claim 9 wherein the polymeric monolith is of an elastomeric composition. A system for applying energy to tissue as in claim 12 wherein the elastomeric composition of the monolith overlying the fluidic channels is fluid permeable.

A system for applying energy to tissue as in claim 9 wherein the fluid media is a vapor phase media capable of releasing the heat of vaporization to apply energy to tissue.

A system for applying energy to tissue as in claim 14 wherein the fluidic channels have an increase in cross-section proximate the tissue-engaging surface for allowing a vapor to liquid phase transition of the media.

A system for applying energy to tissue as in claim 14 wherein the fluidic channels include ports in the tissue-engaging surface for allowing outflow of vapor from the fluidic channels to interact with tissue.

A system for applying energy to tissue as in claim 9 wherein the fluid media comprises a conductive liquid in communication with an electrical energy source.

FIELD OF THE INVENTION This invention relates to the working end of a medical instrument that applies energy to tissue from a fluid within a microfluidic tissue-engaging surface fabricated by soft lithography means together with optional superlattice cooling means that allows for very precise control of energy application, for example in neurosurgery applications.

Next Patent Hybrid lesion format Treatment with high temperature vapor. High pressure and high temperature vapor catheters and systems.

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7549987 - read

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Further, the vapor and its heat content can apply substantially uniform thermal effects about valves since the heat transfer mechanism is through a vapor that contacts all vessel wall surfaces—and is not an electrode that is dragged along the vessel wall.

Thus, the system of the invention may not require the navigation of the catheter member through tortuous vessels. Alternatively, the working end may be translated along the lumen as energy is applied by means of vapor-to-liquid energy release.

This will provide an advantage over other heat transfer mechanisms, such as ohmic heating, that cannot be directly imaged with ultrasound.

Another embodiment of the invention is shown in FIGS. For example, the inventive system can be carried in a probe working end as in FIGS.

Alternatively, the system can be used in forceps as in FIG. In general, this embodiment includes i a polymeric monolith with microfluidic circuitry at an interior of the engagement surface for controlling the delivery of energy from the fluid to the engaged tissue; ii optional contemporaneous cooling of the microfluidic circuitry and engagement surface for controlling thermal effects in tissue; and iii optional coupling of additional Rf energy to the fluid media contemporaneous with ejection from the engagement surface to enhance energy application at the tissue interface.

More in particular, the instrument has a handle portion and extension portion that extends to working end The working end carries a polymer microfluidic body with an engagement surface for engaging tissue.

The engagement surface can be flat or curved and have any suitable dimension. Its method of use will be described in more detail below. The instrument of FIG.

It should be appreciated that the jaws can have any suitable dimensions, shape and form. Now referring to FIG. In one aspect of the invention, the microfabricated body carries microfluidic channels adapted to carry a fluid media from a pressurized media source as described in previous embodiments.

The media is carried from source by at least one inflow lumen A to the microfluidic channels in body see FIGS. In some embodiments, an outflow lumen B is provided in the instrument body to carry at least part of fluid to a collection reservoir Alternatively, the fluid can move in a looped flow arrangement to return to the fluid media source see FIGS.

The engagement surface can be smooth, textured or having surface features for gripping tissue. The microfluidic channels have a mean cross section of less than 1 mm.

Preferably, the channels have a mean cross section of less than 0. The channels can have any cross-sectional shape, such as rectangular or round that is dependent on the means of microfabrication.

In this aspect of the invention, the system applies energy to tissue as described in the earlier embodiments see FIGS. The microfluidic channels extend in any suitable pattern or circuitry from at least one inflow lumen A.

In a preferred embodiment, the microfluidic channels extend across the engagement surface and then communicate with at least one outflow lumen B see FIGS.

The flow channels further can have an increase in cross-sectional dimension proximate the surface or proximate each port to allow for lesser containing pressure on the vapor to assist in its vapor to liquid phase transition.

In another embodiment, the engagement surface can have other suction ports not shown that are independent of the fluidic channels for suctioning tissue into contact with the engagement surface A suction source can be coupled to such suction ports.

In the embodiment of FIGS. The system further has a fluid pressure control system B for controlling the media inflow pressures as in the embodiment of FIGS.

Of particular interest, the microfabricated body can be of an elastomer or other suitable polymer of any suitable modulus and can be made according to techniques based on replication molding wherein the polymer is patterned by curing in a micromachined mold.

A number of suitable microfabrication processes are termed soft lithography. The term multilayer soft lithography combines soft lithography with the capability to bond multiple patterned layers of polymers to form a monolith with fluid and electric circuitry therein.

A multilayer body as in FIGS. An elastomer bonding system can be a two component addition-cure of silicone rubber typically.

The scope of the invention encompasses the use of multilayer soft lithography microfabrication techniques for making thermal vapor delivery surfaces and electrosurgical engagement surfaces, wherein such energy delivery surfaces consist of multiple layers fabricated of soft materials with microfluidic circuitry therein as well as electrical conductor components.

In an optional embodiment illustrated in FIG. Multilayer soft lithographic techniques for microfluidics are described, in general, in the following references which are incorporated herein by this reference: In any embodiment of polymer body , as described above, the layers can be microfabricated using soft lithography techniques to provide an open or channeled interior structure to allow fluid flows therethrough.

The use of resilient polymers e. For example, microtransfer molding is used wherein a transparent, elastomeric polydimethylsiloxane PDMS stamp has patterned relief on its surface to generate features in the polymer.

The PDMS stamp is filled with a prepolymer or ceramic precursor and placed on a substrate. The material is cured and the stamp is removed.

The technique generates features as small as nm and is able to generate multilayer body as in FIG. Replica molding is a similar process wherein a PDMS stamp is cast against a conventionally patterned master.

A polyurethane or other polymer is then molded against the secondary PDMS master. In this way, multiple copies can be made without damaging the original master.

The technique can replicate features as small as 30 nm. Another process is known as micromolding in capillaries MIMIC wherein continuous channels are formed when a PDMS stamp is brought into conformal contact with a solid substrate.

Then, capillary action fills the channels with a polymer precursor. The polymer is cured and the stamp is removed.

Solvent-assisted microcontact molding SAMIM is also known wherein a small amount of solvent is spread on a patterned PDMS stamp and the stamp is placed on a polymer, such as photoresist.

The solvent swells the polymer and causes it to expand to fill the surface relief of the stamp. Features as small as 60 nm have been produced.

A background on microfabrication can be found in Xia and Whitesides, Annu. For example, the channels can have ultrahydrophobic surfaces for enabling fluid flows, and the fluids or surfaces can carry any surfactant.

In a working end embodiment that is particularly adapted for microsurgery, as in the forceps of FIG. Thus, the scope of the invention extends to two complementary novel structures and components: The components will be described in order.

The fluid is delivered in a liquid form to the forceps schematically shown in FIG. The fluid remains in a liquid state as it cycles through channels of the engagement surface as in FIG.

The microfluidic body can be adapted to delivery energy in either a monopolar or bipolar mode. In a monopolar mode, radiofrequency energy is coupled to the flowing fluid by an active electrode arrangement having a single polarity, wherein the targeted tissue is treated when an electrical circuit is completed with a ground pad comprising a large area electrode coupled to the patient at a location remote from the targeted tissue.

In a bipolar mode, radiofrequency energy is coupled to flowing fluid by first and second opposing polarity electrodes A and B in different channels , or different groups of channels see FIG.

The surface layer of polymeric material overlying channels is substantially thin and allows from capacitive coupling of electrical energy to engaged tissue.

The polymer is selected from a class of material known in the art that optimizes the delivery of electrical energy therethrough, wherein the polymer has limited capacitance.

The interior regions of polymeric material between channels has a greater dimension than the surface layer to prevent substantial current flow between the channels at the interior of body The electrodes A and B alternatively can comprise conductive wires inserted into the channels or can be a conductive coating fabricated into the channel walls.

Soft lithography methods also can deposit conductive layers or conductive polymers to provide the electrode functionality of the invention.

Alternative means for fabricating channels with conductive coatings are described in the following patents to W. By this means, the depth of ohmic heating in tissue can be adjusted as is known in the art.

In a preferred embodiment, each conductive region or electrode is coupled to a controller and multiplexing system to allow bipolar energy application within engaged tissue between selected individual electrodes having transient opposing polarities, or any first polarity set of electrodes and fluidic channels that cooperate with any set of second polarity electrodes and channels.

The system can have independent feedback control based on impedance or temperature for each activated set of electrodes. In this embodiment, the polymer layer overlying the channel also can be microporous or macroporous to allow the conductive fluid to seep through this fluid permeable layer to directly couple electrical energy to the engaged tissue.

Now turning to the superlattice cooling component of the invention, it can be seen in FIGS. As described above, one preferred nanolattice cooling system was disclosed by Rama Venkatasubramanian et al.

For convenience, this class of thin, high performance thermoelectric device is referred to herein for convenience as a superlattice cooling device.

Superlattice cooling devices provide substantial performance improvements over conventional thermoelectric structures, also known as Peltier devices.

It has been reported that superlattice thermoelectric material having a surface dimension of about 1 cm 2 can provide watts of cooling under a nominal temperature gradient.

This would translate into an efficiency at least double that of conventional thermoelectric devices. The use of a superlattice cooling device in a surgical instrument further provides the advantage of wafer-scalability and the use of known processes for fabrication.

The author first disclosed the use of thermoelectric cooling devices in a thermal-energy delivery jaw structure in U.

In a typical embodiment, the thin-film superlattice cooling structure comprises a stack of at least 10 alternating thin semiconductor layers.

More preferably, the superlattice structure includes at least alternating layers, and can comprise or more such nanoscale layers.

In one embodiment, the thin film superlattice structure comprises alternating stacks of thin film layers of bismuth telluride and antimony telluride.

The thin film superlattice structure thus comprises a circuit including a plurality of thin film layers of at least two dissimilar conductors wherein current propagates heat toward one end of the circuit thereby cooling the end of the circuit coupled to the energy-emitting surface.

The superlattice cooling structures are coupled to an electrical source by independent circuitry, and can also be coupled with a control system to operate in a selected sequence with thermal energy delivery.

A tissue-engaging surface can include a first surface portion of a thermal energy emitter and second surface portion of the superlattice cooling device as in FIGS.

The first and second surface portions and can be provided in any suitable pattern. A working end as in FIGS. The system can deliver a burst of thermal energy followed by a surface cooling to localize heat at a selected depth while preventing excessive damage to the epidermal layer.

In a preferred embodiment, the energy-emitting surface is thin microfluidic body as depicted in FIG. In another embodiment in FIG.

Each jaw arm can include such an electrode coupled to an Rf source A to provide for bipolar energy delivery between the jaws.

Such a bi-polar jaw structure with active superlattice cooling would prevent tissue sticking. It should be appreciated that other thermal energy-emitting surfaces are possible, such as laser emitters, microwave emitters and resistive heating elements.

Now turning to FIG. In this embodiment, the open-ended capillary microchannels are formed in a body of a selected material and have a selected cross-sectional dimension to provide a capillary effect to draw liquid media into the capillary channels.

This embodiment can be fabricated of a polymer by soft lithography means. Alternatively, the tissue-engaging body can be of a ceramic, metal or a combination thereof.

As can be seen in FIG. In operation, the capillaries will draw liquid into the channels by means of normal capillary forces. The capillary channels further carry a thermal energy emitter about interior channel regions for vaporizing the liquid that is drawn into the channels.

The thermal energy emitter is operatively coupled to a source selected from the class consisting of a Rf source, microwave source, laser source and resistive heat source.

In operation, the capillaries will draw liquid into the channels wherein vaporization will eject the vapor outwardly from the surface to apply thermal energy to tissue as described in earlier embodiments.

The advantage of the invention is that the capillary channels can continuously draw liquid into the microchannels from a substantially static liquid reservoir without the need for a substantial pressurization means.

At the same time, the vaporization of the liquid media will cause pressures to cause ejection of the vapor from the surface since that is the direction of least resistance.

The surface can further carry any monopolar of bipolar electrode arrangement to couple energy to the ejected vapor and engaged tissue. Each jaw carries a body with capillaries channels and vapor delivery ports as in FIG.

The jaws structure includes a system that transects tissue by hydrojet means that can cooperate with the fluid media source of the invention.

Of particular interest, one jaw carries an ultrahigh pressure water inflow lumen that exits at least one thin linear port wherein the jetting of water has sufficient velocity to cut the engaged tissue.

Depending on the length of the jaws, the jetting port s can be singular or plural, an overlapping if required to insure transection of any engaged tissue volume.

In another embodiment not shown the jaw can have a moveable jet member that axially translates in the jaw to cut tissue. Electrical energy can be coupled to a fluid jet to further apply energy along a cut line.

The jetted fluid is received by elongate channel in the opposing jaw that communicates with extraction lumen and an aspiration source. Such a jaw can have an interlock mechanism to insure that the hydrojet cutting means can only be actuated when the jaws are in a closed position.

This embodiment provides the advantage of having a non-stick tissue-sealing jaw structure together with a transecting means that operates without moving parts.

It should be appreciated that the scope of the invention includes the use of such a hydrojet cutting means to any surgical jaw structure that is adapted to seal tissue or organ margins.

Although particular embodiments of the present invention have been described above in detail, it will be understood that this description is merely for purposes of illustration.

Specific features of the invention are shown in some drawings and not in others, and this is for convenience only and any feature may be combined with another in accordance with the invention.

Further variations will be apparent to one skilled in the art in light of this disclosure and are intended to fall within the scope of the appended claims.

Year of fee payment: This invention relates to the working end of a medical instrument that applies energy to tissue. In one embodiment, the instrument has a microfluidic tissue-engaging surface fabricated by soft lithography means together with optional superlattice cooling means that allows for very precise control of energy application, for example in neurosurgery applications.

The tissue-engaging surface can eject a high-heat content vapor into the engaged tissue for treating tissue, while the superlattice cooling structure can prevent collateral thermal damage.

Also, the superlattice cooling structure can be used to localize heat at a selected depth in tissue and prevent surface ablation.

Also, the superlattice cooling structure can be used to prevent tissue sticking to a thermal energy delivery surface. In another embodiment, the tissue-engaging surface can be used in a jaw structure for sealing tissue together with hydrojet means for transecting the tissue.

FIELD OF THE INVENTION This invention relates to the working end of a medical instrument that applies energy to tissue from a fluid within a microfluidic tissue-engaging surface fabricated by soft lithography means together with optional superlattice cooling means that allows for very precise control of energy application, for example in neurosurgery applications.

A system for applying energy to tissue comprising a polymeric monolith with fluidic channels therein, the monolith having a tissue-engaging surface for engaging tissue, and a fluid media source that introduces fluid media into the fluidic channels for applying energy to engaged tissue, the system further comprising an energy source within the fluidic channels wherein the energy source comprises a plurality of electrodes spaced apart within the fluidic channels and is configured to apply a vaporization energy through the fluid media, and where the vaporization energy exceeds a heat of vaporization of the fluid media therein to provide a vapor media having an increased volume within the fluidic channels to sufficiently cause ejection of the vapor media from the fluid channels at a high velocity.

A system for applying energy to tissue as in claim 1 wherein the fluidic channels have mean cross-section of less than 1 mm. A system for applying energy to tissue as in claim 1 wherein the fluidic channels have mean cross-section of less than 0.

A system for applying energy to tissue as in claim 1 wherein the polymeric monolith is of an elastomeric composition. A system for applying energy to tissue as in claim 1 wherein the fluid media is a vapor phase media capable of releasing the heat of vaporization to apply energy to tissue.

A system for applying energy to tissue as in claim 5 wherein the fluidic channels have an increase in cross-section proximate the tissue-engaging surface for allowing a vapor to liquid phase transition of the media.

A system for applying energy to tissue as in claim 5 wherein the fluidic channels include ports in the tissue-engaging surface for allowing outflow of vapor from the fluidic channels to interact with tissue.

A system for applying energy to tissue as in claim 4 wherein the elastomeric composition of the monolith overlying the fluidic channels is fluid permeable.

A system for applying energy to tissue comprising: A system for applying energy to tissue as in claim 9 wherein the fluidic channels have mean cross-section of less than 1 mm.

A system for applying energy to tissue as in claim 9 wherein the fluidic channels have mean cross-section of less than 0.

A system for applying energy to tissue as in claim 9 wherein the polymeric monolith is of an elastomeric composition. A system for applying energy to tissue as in claim 12 wherein the elastomeric composition of the monolith overlying the fluidic channels is fluid permeable.

A system for applying energy to tissue as in claim 9 wherein the fluid media is a vapor phase media capable of releasing the heat of vaporization to apply energy to tissue.

A system for applying energy to tissue as in claim 14 wherein the fluidic channels have an increase in cross-section proximate the tissue-engaging surface for allowing a vapor to liquid phase transition of the media.

A system for applying energy to tissue as in claim 14 wherein the fluidic channels include ports in the tissue-engaging surface for allowing outflow of vapor from the fluidic channels to interact with tissue.

A system for applying energy to tissue as in claim 9 wherein the fluid media comprises a conductive liquid in communication with an electrical energy source.

Medical instruments and techniques for highly-localized thermally-mediated therapies. Methods and devices for selective disruption of fatty tissue by controlled cooling.

Cooling device having a plurality of controllable cooling elements to provide a predetermined cooling profile. Monitoring the cooling subcutaneous lipid-rich cells, such as cooling of adipose tissue.

Articulable electrosurgical instrument with a stabilizable articulation actuator. System and method for estimating tissue heating of a target ablation zone for electrical-energy based therapies.

System and method for estimating a treatment volume for administering electrical-energy based therapies. Irreversible electroporation using tissue vasculature to treat aberrant cell masses or create tissue scaffolds.

Methods of sterilization and treating infection using irreversible electroporation. Thermally adjustable surgical tool, balloon catheters and sculpting of biologic materials.

Home-use applicators for non-invasively removing heat from subcutaneous lipid-rich cells via phase change coolants, and associates devices, systems and methods.

Combined modality treatment systems, methods and apparatus for body contouring applications. Treatment systems with fluid mixing systems and fluid-cooled applicators and methods of using the same.

Multi-modality treatment systems, methods and apparatus for altering subcutaneous lipid-rich tissue. Compositions, treatment systems and methods for improved cooling of lipid-rich tissue.

Ablation catheter with electrical coupling via foam drenched with a conductive fluid. System and methods for electrosurgical tissue treatment in the presence of electrically conductive fluid.

Device for directly delivering an active substance within a cell tissue, means for implanting said device and appliances for injecting active substance into said device.

Method and apparatus for the treatment of the respiratory track with vapor-phase water. Correction of the optical focusing system of the eye using laser thermal keratoplasty.

Apparatus for pulmonary delivery of drugs with simultaneous liquid lavage and ventilation. In use, the method of the invention comprises the controlled deposition of a large amount of energy—the heat of vaporization as in FIG.

This new ablation modality can utilize specialized instrument working ends for several cardiovascular therapies or soft tissue ablation treatments for tissue sealing, tissue shrinkage, tissue ablation, creation of lesions or volumetric removal of tissue.

In general, the instrument and method of the invention advantageously cause thermal ablations rapidly and efficiently compared to conventional Rf energy application to tissue.

In one embodiment, the instrument of the invention provides a tissue engaging surface of a polymeric body that carries microfluidic channels therein.

The tissue-engaging surfaces are fabricated by soft lithography means to provide the fluidic channels and optional conductive materials to function as electrodes.

In another embodiment, the instrument has a working end with a superlattice cooling component that cooperates with the delivery of energy.

For example, in neurosurgery, the superlattice cooling can be used to allow a brief interval of thermal energy delivery to coagulate tissue followed by practically instantaneous cooling and renaturing of proteins in the coagulated tissue to allowing sealing and to prevent the possibility of collateral thermal damage.

At the same time, the cooling means insures that tissue will not stick to a jaw structure. In a preferred embodiment, the invention utilizes a thermoelectric cooling system as disclosed by Rama Venkatasubramanian et al.

The cooling system is sometimes referred to as a PBETS device, an acronym relating to the title of the patent application. The inventors Venkatasubramanian et al also disclosed related technologies in U.

In another embodiment, the instrument provides a tissue engaging surface with capillary dimension channels to draw a liquid into the channels wherein an energy emitter is used to eject vapor from the open ends of the capillaries.

The instrument and method of the invention generate vapor phase media that is controllable as to volume and ejection pressure to provide a not-to-exceed temperature level that prevents desiccation, eschar, smoke and tissue sticking.

The instrument and method of the invention advantageously creates thermal effects in a targeted tissue volume with substantially controlled lateral margins between the treated tissue and untreated tissue.

Additional advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

Various embodiments of the present invention will be discussed with reference to the appended drawings. These drawings depict only illustrative embodiments of the invention and are not to be considered limiting of its scope.

The working end 10 comprises a body 11 of insulator material see FIG. In this exemplary embodiment, the working end 10 has a generally cylindrical cross-section and is made of any suitable material such as plastic, ceramic, glass, metal or a combination thereof.

The working end 10 is substantially small in diameter e. Alternatively, the working end 10 may be coupled to a rigid shaft member having a suitable 1 mm to 5 mm or larger diameter to cooperate with a trocar sleeve for use in endoscopic or microsurgical procedures.

A proximal handle portion 14 of the instrument indicated by the block diagram of FIG. A carries the various actuator mechanisms known in the art for actuating components of the instrument.

In this exemplary embodiment, the working end 10 and first tissue-engaging surface 20 A comprises a non-moving component indicated at 22 A that is defined by the exposed distal end of body 11 of working end The second tissue-engaging surface 20 B is carried in a moving component that comprises a flexible loop structure indicated at 22 B.

The second moving component or flexible loop 22 B is actuatable by a slidable portion 24 a of the loop that extends through a slot 25 in the working end to an actuator in the handle portion 14 as is known in the art see FIG.

The other end 24 b of the loop structure 22 B is fixed in body While such an in-line or axial flexible slidable member is preferred as the tissue-capturing mechanism for a small diameter flexible catheter-type instrument, it should be appreciated that any openable and closable jaw structure known in the art falls within the scope of the invention, including forms of paired jaws with cam-surface actuation or conventional pin-type hinges and actuator mechanisms.

Now turning to the fluid-to-gas energy delivery means of the invention, referring to FIG. The chamber 30 communicates via lumen 33 with a fluid media source 35 that may be remote from the device, or a fluid reservoir coupled to a remote pressure source carried within introducer 12 or carried within a handle portion The term fluid or flowable media source 35 is defined to include a positive pressure inflow system which may be a syringe, an elevated remote fluid sac that relies on gravity, or any suitable pump-type pressure means known in the art.

The fluid delivery lumen 33 transitions to chamber 30 at proximal end portion 34 a thereof. The distal end portion 34 b of chamber 30 has a reduced cross-section to optionally function as a jet or nozzle indicated at Of particular interest, still referring to FIG.

In this exemplary embodiment, the electrode elements 40 A and 40 B comprise circumferential exposed surfaces of a conductive material positioned at opposing proximal and distal ends of interior chamber It should be appreciated that the method of the invention of may utilize any suitable configuration of spaced apart electrodes e.

Alternatively, each electrode can be a singular projecting element that projects into the chamber. The exemplary embodiment of FIG.

The axial dimension may range from about 0. The diameter B may range from micron dimensions e. The electrodes are of any suitable material such as aluminum, stainless steel, nickel titanium, platinum, gold, or copper.

Each electrode surface preferably has a toothed surface texture indicated at 43 that includes hatching, projecting elements or surface asperities for better delivering high energy densities in the fluid proximate to the electrode.

The electrical current to the working end 10 may be switched on and off by a foot pedal or any other suitable means such as a switch in handle As can be seen in FIGS.

The second tissue-engaging surface 20 B is flexible and naturally will be concave in the distal or opposite direction when tissue is engaged between surfaces 20 A and 20 B.

This preferred shape structure allows for controllable compression of the thick targeted tissue volumes T centrally exposed to the energy delivery means and helps prevent conductance of thermal effects to collateral tissue regions CT see FIG.

The apertures 45 may have any cross-sectional shape and linear or angular route through surface 20 A with a sectional dimension C in this embodiment ranging upwards from micron dimensions e.

However, it should be appreciated that such a transition chamber 47 is optional and the terminal portion of chamber 30 may directly exit into a plurality of passageways that each communicate with an aperture 45 in the grid of the first engaging surface 20 A.

In a preferred embodiment, the second tissue-engaging surface 20 B defines optionally a grid of apertures indicated at 50 that pass through the loop 22 B.

These apertures 50 may be any suitable dimension cf. The electrodes 40 A and 40 B of working end 10 have opposing polarities and are coupled to electrical generator In a preferred embodiment of the invention, either tissue-engaging surface optionally includes a sensor 62 or sensor array that is in contact with the targeted tissue surface see FIG.

Such a sensor, for example a thermocouple known in the art, can measure temperature at the surface of the captured tissue. The sensor is coupled to controller 60 by a lead not shown and can be used to modulate or terminate power delivery as will be described next in the method of the invention.

Operation and use of the working end of FIGS. As can be understood from FIG. In this case, the tissue T targeted for sealing is a medial portion 78 of a polyp 80 in a colon It can be easily understood that the slidable movement of the loop member 22 B can capture the polyp 80 in the device as shown in FIG.

The objective of the tissue treatment is to seal the medial portion of the polyp with the inventive thermotherapy. Thereafter, utilize a separate cutting instrument is used to cut through the sealed portion, and the excised polyp is retrieved for biopsy purposes.

Now turning to FIGS. The electrical discharge provides energy exceeding the heat of vaporization of the contained fluid volume. The explosive vaporization of fluid media M of FIG.

The fluid source and its pressure or pump mechanism can provide any desired level of vapor ejection pressure.

It is believed that such protein denaturation by hydrothermal effects differentiates this method of tissue sealing or fusion from all other forms of energy delivery, such as radiofrequency energy delivery.

All other forms of energy delivery vaporize intra- and extracellular fluids and cause tissue desiccation, dehydration or charring which is undesirable for the intermixing of denatured tissue constituents into a proteinaceous amalgam.

The above electrical energy deliver step is repeated at a high repetition rate to cause a pulsed form of thermal energy delivery in the engaged tissue.

The fluid media M inflow may be continuous or pulsed to substantially fill chamber 30 before an electrical discharge is caused therein.

The repetition rate of electrical discharges may be from about 1 Hz to Hz. More preferably, the repetition rate is from about 10 Hz to Hz.

The selected repetition rate preferably provides an interval between electrical discharges that allows for thermal relaxation of tissue, that may range from about 10 ms to ms.

The electrical source or voltage source 55 may provide a voltage ranging between about volts and 10, volts to cause instant vaporization of the volume of fluid media M captured between the electrode elements 40 A and 40 B.

After a selected time interval of such energy application to tissue T, that may range from about 1 second to 30 seconds, and preferably from about 5 to 20 seconds, the engaged tissue will be contain a core region in which the tissue constituents are denatured and intermixed under relatively high compression between surfaces 20 A and 20 B.

Upon disengagement and cooling of the targeted tissue T, the treated tissue will be fused or welded. An optional method of controlling the repetition rate of electrical discharges comprises the measurement of electrical characteristics of media M within the chamber 30 to insure that the chamber is filled with the fluid media at time of the electrical discharge.

The electrical measurement then would send a control signal to the controller 60 to cause each electrical discharge. For example, the liquid media M can be provided with selected conductive compositions in solution therein.

The controller 60 then can send a weak electrical current between the paired electrodes 40 A and 40 B and thereafter sense the change in an impedance level between the electrodes as the chamber 30 is filled with fluid to generate the control signal.

The phase transitional energy delivery aspects of the invention are the same as described above. The instrument differs in that it utilizes significantly reduced dimensions or micronization of features in the working end More particularly, a fluid media source A and pressure control system B are adapted to provide pressurized flows of liquid media M through the introducer body and thereafter into microchannel body or structure indicated at see FIG.

The microchannel or microporous body defines therein plurality of small diameter fluid passageways or microchannel portions collectively.

The microchannel body also can be a microporous trabecular material to provide open-cell flow passageways therethrough.

At an interior of the microchannel body , an intermediate region of the open flow channels is exposed to first and second electrode elements A and B.

The electrode elements A and B can be formed in a plates or layers of channeled material or trabecular material that extends transverse to passageways Thus, the channels are exposed to surfaces of the electrode elements A and B interior of the working surface that interfaces with the targeted tissue T.

As depicted in FIG. A working end similar to that of FIGS. For example, a rigid probe can be used in orthopedic procedures to cause hydrothermal shrinkage of collagen, for example in a spinal disc, or a joint capsule to stabilize the joint see U.

In an arthroscopic procedure, the working end is painted across a targeted tissue site in a joint capsule to shrink tissue. In another procedure, the working end may be stabilized against any collagenous tissue to heat and shrink collagen in a targeted tissue such as a herniated disc.

As described previously, the thermal energy delivery means of the invention preferably uses an electrical energy source and spaced apart electrodes for flash vaporization of a liquid media.

It should be appreciated that a resistive element coupled to an electrical source also can be used. For example, a resistive element can fabricated out of any suitable material such a tungsten alloy in a helical, tubular or a microporous form that allows fluid flow therethrough.

Now referring to FIGS. The previous devices were shown and optimized for having a working surface that engages tissue, and for controlling and limiting thermal effects in engaged tissue.

In the embodiment of FIG. The diameter of body can range from about 1 Fr. The working end typically is carried at the distal end of a flexible catheter but may also be carried at the distal end of a more rigid introducer member.

In a rigid member, the working end also can be sharp for penetrating into any soft tissue e. The working end of FIG. The interior chamber carries opposing polarity electrodes A and B as thermal energy emitters.

The distal terminus or working surface of the catheter has media entrance port therein. The electrodes can extend axially from about 1 mm to 50 mm and are spaced well inward, for example from 1 mm to mm from the distal working surface This type of electrode arrangement will enhance energy delivery to the liquid media M to allow effective continuous vaporization thereof.

The lumen or chamber portion between electrodes A and B allows for focused energy application to create the desired energy density in the inflowing media M to cause its immediate vaporization.

The vapor is then propagated from the working surface via port to interact with the endoluminal media. It should be appreciated that the instrument may have a plurality of media entrance ports in the working surface, or additionally the radially outward surfaces of the catheter.

In the system embodiment of FIG. The working end also is coupled to fluid media source A that carries pressurization means of any suitable type together with a pressure control system indicated at B.

In one targeted endovascular procedure, as depicted in FIG. Most endothelial-lined structures of the body, such as blood vessel and other ducts, have substantially collagen cores for specific functional purposes.

Intermolecular cross-links provide collagen connective tissue with unique physical properties such as high tensile strength and substantial elasticity.

Temperature elevation ruptures the collagen ultrastructural stabilizing cross-links, and results in immediate contraction in the fibers to about one-third of their original longitudinal dimension.

At the same time, the caliber of the individual collagen fibers increases without changing the structural integrity of the connective tissue.

As represented in FIG. The pressurized fluid media source A and pressure control subsystem B also can be adapted to create a pressure gradient, or enhance the pressure gradients caused by vapor expansion, to controllably eject the heated vapor from the working surface As shown in FIG.

This means of applying thermal energy to vessel walls can controllably shrink, collapse and occlude the vessel lumen to terminate blood flow therethrough, and offers substantial advantages over alternative procedures.

Vein stripping is a much more invasive treatment. Rf closure of varicose veins is known in the art. Typically, a catheter device is moved to drag Rf electrodes along the vessel walls to apply Rf energy to damage the vessel walls by means of causing ohmic heating.

Such Rf ohmic heating causes several undesirable effects, such as i creating high peak electrode temperatures up to several hundred degrees C.

This method substantially prevents heat from being propagated heat outwardly by conduction—thus preventing damage to nerves. There is no possibility of causing ohmic heating in nerves, since a principal advantage of the invention is the application of therapeutic heat entirely without electrical current flow in tissue.

Further, the vapor and its heat content can apply substantially uniform thermal effects about valves since the heat transfer mechanism is through a vapor that contacts all vessel wall surfaces—and is not an electrode that is dragged along the vessel wall.

Thus, the system of the invention may not require the navigation of the catheter member through tortuous vessels. Alternatively, the working end may be translated along the lumen as energy is applied by means of vapor-to-liquid energy release.

This will provide an advantage over other heat transfer mechanisms, such as ohmic heating, that cannot be directly imaged with ultrasound.

Another embodiment of the invention is shown in FIGS. For example, the inventive system can be carried in a probe working end as in FIGS. Alternatively, the system can be used in forceps as in FIG.

In general, this embodiment includes i a polymeric monolith with microfluidic circuitry at an interior of the engagement surface for controlling the delivery of energy from the fluid to the engaged tissue; ii optional contemporaneous cooling of the microfluidic circuitry and engagement surface for controlling thermal effects in tissue; and iii optional coupling of additional Rf energy to the fluid media contemporaneous with ejection from the engagement surface to enhance energy application at the tissue interface.

More in particular, the instrument has a handle portion and extension portion that extends to working end The working end carries a polymer microfluidic body with an engagement surface for engaging tissue.

The engagement surface can be flat or curved and have any suitable dimension. Its method of use will be described in more detail below.

The instrument of FIG. It should be appreciated that the jaws can have any suitable dimensions, shape and form. Now referring to FIG.

In one aspect of the invention, the microfabricated body carries microfluidic channels adapted to carry a fluid media from a pressurized media source as described in previous embodiments.

The media is carried from source by at least one inflow lumen A to the microfluidic channels in body see FIGS. In some embodiments, an outflow lumen B is provided in the instrument body to carry at least part of fluid to a collection reservoir Alternatively, the fluid can move in a looped flow arrangement to return to the fluid media source see FIGS.

The engagement surface can be smooth, textured or having surface features for gripping tissue. The microfluidic channels have a mean cross section of less than 1 mm.

Preferably, the channels have a mean cross section of less than 0. The channels can have any cross-sectional shape, such as rectangular or round that is dependent on the means of microfabrication.

In this aspect of the invention, the system applies energy to tissue as described in the earlier embodiments see FIGS. The microfluidic channels extend in any suitable pattern or circuitry from at least one inflow lumen A.

In a preferred embodiment, the microfluidic channels extend across the engagement surface and then communicate with at least one outflow lumen B see FIGS.

The flow channels further can have an increase in cross-sectional dimension proximate the surface or proximate each port to allow for lesser containing pressure on the vapor to assist in its vapor to liquid phase transition.

In another embodiment, the engagement surface can have other suction ports not shown that are independent of the fluidic channels for suctioning tissue into contact with the engagement surface A suction source can be coupled to such suction ports.

In the embodiment of FIGS. The system further has a fluid pressure control system B for controlling the media inflow pressures as in the embodiment of FIGS.

Of particular interest, the microfabricated body can be of an elastomer or other suitable polymer of any suitable modulus and can be made according to techniques based on replication molding wherein the polymer is patterned by curing in a micromachined mold.

A number of suitable microfabrication processes are termed soft lithography. The term multilayer soft lithography combines soft lithography with the capability to bond multiple patterned layers of polymers to form a monolith with fluid and electric circuitry therein.

A multilayer body as in FIGS. An elastomer bonding system can be a two component addition-cure of silicone rubber typically. The scope of the invention encompasses the use of multilayer soft lithography microfabrication techniques for making thermal vapor delivery surfaces and electrosurgical engagement surfaces, wherein such energy delivery surfaces consist of multiple layers fabricated of soft materials with microfluidic circuitry therein as well as electrical conductor components.

In an optional embodiment illustrated in FIG. Multilayer soft lithographic techniques for microfluidics are described, in general, in the following references which are incorporated herein by this reference: In any embodiment of polymer body , as described above, the layers can be microfabricated using soft lithography techniques to provide an open or channeled interior structure to allow fluid flows therethrough.

The use of resilient polymers e. For example, microtransfer molding is used wherein a transparent, elastomeric polydimethylsiloxane PDMS stamp has patterned relief on its surface to generate features in the polymer.

The PDMS stamp is filled with a prepolymer or ceramic precursor and placed on a substrate. The material is cured and the stamp is removed.

The technique generates features as small as nm and is able to generate multilayer body as in FIG. Replica molding is a similar process wherein a PDMS stamp is cast against a conventionally patterned master.

A polyurethane or other polymer is then molded against the secondary PDMS master. In this way, multiple copies can be made without damaging the original master.

The technique can replicate features as small as 30 nm. Another process is known as micromolding in capillaries MIMIC wherein continuous channels are formed when a PDMS stamp is brought into conformal contact with a solid substrate.

Then, capillary action fills the channels with a polymer precursor. The polymer is cured and the stamp is removed.

Solvent-assisted microcontact molding SAMIM is also known wherein a small amount of solvent is spread on a patterned PDMS stamp and the stamp is placed on a polymer, such as photoresist.

The solvent swells the polymer and causes it to expand to fill the surface relief of the stamp. Features as small as 60 nm have been produced. A background on microfabrication can be found in Xia and Whitesides, Annu.

For example, the channels can have ultrahydrophobic surfaces for enabling fluid flows, and the fluids or surfaces can carry any surfactant.

In a working end embodiment that is particularly adapted for microsurgery, as in the forceps of FIG. Thus, the scope of the invention extends to two complementary novel structures and components: The components will be described in order.

The fluid is delivered in a liquid form to the forceps schematically shown in FIG. The fluid remains in a liquid state as it cycles through channels of the engagement surface as in FIG.

The microfluidic body can be adapted to delivery energy in either a monopolar or bipolar mode. In a monopolar mode, radiofrequency energy is coupled to the flowing fluid by an active electrode arrangement having a single polarity, wherein the targeted tissue is treated when an electrical circuit is completed with a ground pad comprising a large area electrode coupled to the patient at a location remote from the targeted tissue.

In a bipolar mode, radiofrequency energy is coupled to flowing fluid by first and second opposing polarity electrodes A and B in different channels , or different groups of channels see FIG.

The surface layer of polymeric material overlying channels is substantially thin and allows from capacitive coupling of electrical energy to engaged tissue.

The polymer is selected from a class of material known in the art that optimizes the delivery of electrical energy therethrough, wherein the polymer has limited capacitance.

The interior regions of polymeric material between channels has a greater dimension than the surface layer to prevent substantial current flow between the channels at the interior of body The electrodes A and B alternatively can comprise conductive wires inserted into the channels or can be a conductive coating fabricated into the channel walls.

System and method for estimating tissue heating of a target ablation zone for electrical-energy based therapies. Alternatively, casino table games school fluid can hector em in a laptop vergleich bis 400€ flow arrangement to return to the fluid media source see FIGS. This invention relates to the working end of a medical instrument that applies energy to tissue from a fluid within a microfluidic tissue-engaging surface fabricated by soft lithography means together with optional superlattice cooling means that allows for very precise gone deutsch of energy application, for example in neurosurgery applications. The tissue-engaging surfaces are fabricated by soft lithography means to provide the fluidic channels and optional conductive materials to function as electrodes. Shaped electrodes and methods for electrosurgical cutting and ablation. As can be understood from FIG. The chamber 30 communicates via lumen 33 with a fluid media source 35 that may be remote from the 7549987, or a fluid reservoir coupled to a remote pressure source carried within introducer 12 or carried within a handle portion The technique generates features as small as nm and is able to generate multilayer body as in FIG. The initial, as monaco fifa 17 energy-media interaction delivers energy sufficient to achieve the heat of vaporization of a selected glücksrad kostenlos spielen media such as frühestmöglichen within an interior of the instrument body. Superlattice cooling devices provide substantial performance improvements over conventional thermoelectric structures, also known as Nodkorea devices. The surface layer of polymeric material overlying channels is substantially thin and allows from capacitive cabaret casino club of electrical energy to engaged tissue.

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