FIELD OF THE INVENTION
This invention relates to medical instruments and systems for applying energy to tissue, and more particularly relates to a system for ablating or damaging structures in a body or vessel wall to alter electrical conduction therein to cause an intended therapeutic effect. Variations of the invention include devices and methods for generating a high pressure flow of a liquid media and/or a vapor media to treat the targeted tissue by the application of mechanical energy, thermal energy or chemical energy to such targeted tissue.
BACKGROUND OF THE INVENTION
Various types of medical instruments utilizing radiofrequency (Rf) energy, laser energy, microwave energy and the like have been developed for delivering thermal energy to tissue, for example to ablate tissue. While such prior art forms of energy delivery work well for some applications, Rf, laser and microwave energy typically cannot cause highly “controlled” and “localized” thermal effects that are desirable in controlled ablation soil tissue for ablating a controlled depth or for the creation of precise lesions in such tissue. In general, the non-linear or non-uniform characteristics of tissue affect electromagnetic energy distributions in tissue.
What is needed are systems and methods that controllably apply mechanical, chemical and/or thermal energy to tissue from high pressure flow of a flowable media in a controlled and localized manner without the lack of control often associated when RF, laser and microwave energy are applied directly to tissue.
SUMMARY OF THE INVENTION
The present devices and methods are adapted to provide an improved means of controlled thermal energy delivery to localized tissue volumes, for example for ablating, scaling, coagulating or otherwise damaging targeted tissue. For example, such device and methods can be used to to ablate a tissue volume interstitially or to ablate the lining of a body cavity. Of particular interest, the method can cause thermal effects in targeted tissue without the use of Rf current flow through the patient's body and without the potential of carbonizing tissue. Alternate variations can include the use of Rf current flow as an adjunctive treatment source.
In general, the thermally-mediated treatment method comprises causing a vapor-to-liquid phase state change in a selected media at a targeted tissue site thereby applying thermal energy substantially equal to the heat of vaporization of the selected media to the tissue site. The thermally-mediated therapy can be delivered to tissue by such vapor-to-liquid phase transitions, or “internal energy” releases, about the working surfaces of several types of instruments for ablative treatments of soft tissue. FIGS. 1A and 1B illustrate the phenomena of phase transitional releases of internal energies. Such internal energy involves energy on the molecular and atomic scale—and in polyatomic gases is directly related to intermolecular attractive forces, as well as rotational and vibrational kinetic energy. In other words, the method and devices described herein exploit the phenomenon of internal energy transitions between gaseous and liquid phases that involve very large amounts of energy compared to specific heat.
It has been found that the controlled application of such energy in a controlled media-tissue interaction solves many of the vexing problems associated with energy-tissue interactions in Rf, laser and ultrasound modalities. The apparatus described herein can provide a vaporization chamber in the interior of an instrument, in an instrument working end or in a source remote from the instrument end. A source provides liquid media to the interior vaporization chamber wherein energy is applied to create a selected volume of vapor media. In the process of the liquid-to-vapor phase transition of a liquid media, for example water, large amounts of energy are added to overcome the cohesive forces between molecules in the liquid, and an additional amount of energy is required to expand the liquid 1000+ percent (PΔD) into a resulting vapor phase (see FIG. 1A). Conversely, in the vapor-to-liquid transition, such energy will be released at the phase transition at the interface with the targeted tissue site. That is, the heat of vaporization is released at the interface when the media transitions from gaseous phase to liquid phase wherein the random, disordered motion of molecules in the vapor regain cohesion to convert to a liquid media. This release of energy (defined as the capacity for doing work) relating to intermolecular attractive forces is transformed into therapeutic heat for a thermotherapy at the interface with the targeted body structure. Heat flow and work are both ways of transferring energy.
In FIG. 1A, the simplified visualization of internal energy is useful for understanding phase transition phenomena that involve internal energy transitions between liquid and vapor phases. If heat were added at a constant rate in FIG. 1A (graphically represented as 5 calories/gm blocks) to elevate the temperature of water through its phase change to a vapor phase, the additional energy required to achieve the phase change (latent heat of vaporization) is represented by the large number of 110+ blocks of energy at 100° C. in FIG. 1A. Still referring to FIG. 1A, it can be easily understood that all other prior art ablation modalities—Rf, laser, microwave and ultrasound—create energy densities by simply ramping up calories/gm as indicated by the temperature range from 37° C. through 100° C. as in FIG. 1A. The prior art modalities make no use of the phenomenon of phase transition energies as depicted in FIG. 1A.
FIG. 1B graphically represents a block diagram relating to energy delivery aspects of the present devices and methods. The system can provides for insulative containment of an initial primary energy-media interaction within an interior vaporization chamber of medical thermotherapy system. The initial, ascendant energy-media interaction delivers energy sufficient to achieve the heat of vaporization of a selected liquid media, such as water or saline solution, within an interior of the system. This aspect of the technology requires a highly controlled energy source wherein a computer controller may need to modulated energy application between very large energy densities to initially surpass the latent heat of vaporization with some energy sources (e.g. a resistive heat source, an Rf energy source, a light energy source, a microwave energy source, an ultrasound source and/or an inductive heat source) and potential subsequent lesser energy densities for maintaining a high vapor quality. Additionally, a controller must control the pressure of liquid flows for replenishing the selected liquid media at the required rate and optionally for controlling propagation velocity of the vapor phase media from the working end surface of the instrument. In use, the methods described herein can comprise the controlled application of energy to achieve the heat of vaporization as in FIG. 1A and the controlled vapor-to-liquid phase transition and vapor exit pressure to thereby control the interaction of a selected volume of vapor at the interface with tissue. The vapor-to-liquid phase transition can deposit 400, 500, 600 or more cal/gram within the targeted tissue site to perform the thermal ablation with the vapor in typical pressures and temperatures.
In one variation, the present disclosure includes medical systems for applying thermal energy to tissue, where the system comprises an elongated probe with an axis having an interior flow channel extending to at least one outlet in a probe working end; a source of vapor media configured to provide a vapor flow through at least a portion of the interior flow channel, wherein the vapor has a minimum temperature; and at least one sensor in the flow channel for providing a signal or at least one flow parameter selected from the group one of (i) existence of a flow of the vapor media, (ii) quantification of a flow rate of the vapor media, and (iii) quality of the flow of the vapor media. The medical system can include variations where the minimum temperature varies from at least 80° C., 100° C. 120° C., 140° C. and 160° C. However, other temperature ranges can be included depending upon the desired application.
Sensors optionally included in the above system include temperature sensor, an impedance sensor, a pressure sensor as well as an optical sensor.
The source of vapor media can include a pressurized source of a liquid media and an energy source for phase conversion of the liquid media to a vapor media. In addition, the medical system can further include a controller capable of modulating a vapor parameter in response to a signal of a flow parameter; the vapor parameter selected from the group of (i) flow rate of pressurized source of liquid media, (ii) inflow pressure of the pressurized source of liquid media, (iii) temperature of the liquid media, (iv) energy applied from the energy source to the liquid media, (v) flow rate of vapor media in the now channel, (vi) pressure of the vapor media in the flow channel, (vi) temperature of the vapor media, and (vii) quality of vapor media.
In another variation, a novel medical system for applying thermal energy to tissue comprises an elongated probe with an axis having an interior flow channel extending to at least one outlet in a probe working end, wherein a wall of the flow channel includes an insulative portion having a thermal conductivity of less than a maximum predetermined thermal conductivity ranging from 0.05 W/mK, 0.01 W/mK and 0.005 W/mK; and a source of vapor media configured to provide a vapor flow through at least a portion of the interior flow channel, wherein the vapor has a minimum temperature.
Methods are disclosed herein for thermally treating tissue by providing a probe body having a flow channel extending therein to an outlet in a working end, introducing a flow of a liquid media through the flow channel and applying energy to the tissue by inductively heating a portion of the probe sufficient to vaporize the flowing media within the flow channel causing pressurized ejection of the media from the outlet to the tissue.
The methods can include applying energy anywhere between 10 and 10,000 Joules to the tissue from the media. The rate at which the media flows can be controlled as well.
In another variation, the methods described herein include inductively heating the portion or the probe by applying an electromagnetic energy source to a coil surrounding the flow channel. The electromagnetic energy can also inductively heat a wall portion of the flow channel.
Another variation of the method includes providing a flow permeable structure within the flow channel. Alternatively, the coil described herein can heat the flow permeable structure to transfer energy to the flow media. Some examples of a flow permeable structure include woven filaments, braided filaments, knit filaments, metal wool, a microchannel structure, a porous structure, a honeycomb structure and an open cell structure. However, any structure that is permeable to flow can be included.
The electromagnetic energy source can include an energy source ranging from a 10 Watt source to a 500 Watt source.
Medical systems for treating tissue are also described herein. Such systems can include a probe body having a flow channel extending therein to an outlet in a working end, a coil about at least a portion or the flow channel, and an electromagnetic energy source coupled to the coil, where the electromagnetic energy source induces current in the coil causing energy delivery to a flowable media in the flow channel. The systems can include a source of flowable media coupled to the flow channel. The electromagnetic energy source can be capable of applying energy to the flowable media sufficient to cause a liquid-to-vapor phase change in at least a portion of the flowable media as described in detail herein. In addition the probe can include a sensor selected from a temperature sensor, an impedance sensor, a capacitance sensor and a pressure sensor. In some variations the probe is coupled to an aspiration source.
The medical system can also include a controller capable of modulating at least one operational parameter of the source of flowable media in response to a signal from a sensor. For example, the controller can be capable of modulating a flow of the flowable media. In another variation, the controller is capable of modulating a flow of the flowable media to apply between 100 and 10,000 Joules to the tissue.
The systems described herein can also include a metal portion in the flow channel for contacting the flowable media. The metal portion can be a flow permeable structure and can optionally comprise a microchannel structure. In additional variations, the flow permeable structure can include woven filaments, braided filaments, knit filaments, metal wool, a porous structure, a honeycomb structure, an open cell structure or a combination thereof.
In another variation, the methods described herein can include positioning a probe in an interface with a targeted tissue, and causing a vapor media from to be ejected from the probe into the interface with tissue wherein the media delivers to cause a therapeutic effect, wherein the vapor media is converted from a liquid media within the probe by inductive heating means. Such energy can range from 5 joules to 100,000 joules or vary as needed.
Methods described herein also include methods of treating tissue by providing a medical system including a heat applicator portion for positioning in an interface with targeted tissue, and converting a liquid media into a vapor media within an elongated portion of the medical system having a flow channel communicating with a flow outlet in the heat applicator portion, and contacting the vapor media with the targeted tissue to thereby deliver energy to cause a therapeutic effect. As noted above, such energy can range from 5 joules to 100,000 joules or vary as needed.
As discussed herein, the methods can include converting the liquid into a vapor media using an inductive heating means. In an alternate variation, a resistive heating means can be combined with the inductive heating means or can replace the inductive heating means.
The instruments and methods described herein can cause: an energy-tissue interaction that is imageable with intra-operative ultrasound or MRI; and/or thermal effects in tissue that do not rely applying an electrical field across the tissue to be treated.
Additional advantages of the method and devices are apparent from the following description, the accompanying drawings and the appended claims.
All patents, patent applications and publications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
In addition, it is intended that combinations of aspects of the systems and methods described herein as well as the various embodiments themselves, where possible, are within the scope of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a graphical depiction of the quantity of energy needed to achieve the heat of vaporization of water.
FIG. 1B is a diagram of phase change energy release that underlies a system and method of the devices and methods.
FIG. 2 provides a schematic view of a variation of a medical system adapted for treating a tissue target, wherein the treatment comprises an ablation or thermotherapy and the tissue target can comprise any mammalian soft tissue to be ablated, sealed, contracted,
FIG. 3 is a block diagram of a exemplary control method.
FIG. 4A is an illustration of the working end of FIG. 2 being introduced into soft tissue to treat a targeted tissue volume.
FIG. 4B is an illustration of the working end of FIG. 4A showing the propagation of vapor media in tissue in a method of use in ablating a tumor.
FIG. 5 is an illustration of a working end similar to FIGS. 4A-4B with vapor outlets comprising microporosities in a porous wall.
FIG. 6A is schematic view of a needle-type working end of a vapor delivery tool for applying energy to tissue.
FIG. 6B is schematic view of an alternative needle-type working end similar to FIG. 6A.
FIG. 6C is schematic view of a retractable needle-type working end similar to FIG. 6B.
FIG. 6D is schematic view of working end with multiple shape-memory needles.
FIG. 6E is schematic view of a working end with deflectable needles.
FIG. 6F is schematic view of a working end with a rotating element for directing vapor flows.
FIG. 6G is another view of the working end of FIG. 6F.
FIG. 6H is schematic view of a working end with a balloon.
FIG. 6I is schematic view of an articulating working end.
FIG. 6J is schematic view of an alternative working end with RF electrodes.
FIG. 6K is schematic view of an alternative working end with a resistive heating element.
FIG. 6L is schematic view of a working end with a tissue-capturing loop.
FIG. 6M is schematic view of an alternative working end with jaws for capturing and delivering vapor to tissue.
FIG. 7 is schematic view of an alternative working end with jaws for capturing and delivering vapor to tissue.
FIG. 8 is schematic view of an alternative working end with jaws for capturing and delivering vapor to tissue.
FIG. 9 is a partly disassembled view of a variation of a handle and variation of an inductive vapor generator system for use with devices and methods described herein.
FIG. 10 is an enlarged schematic view of another variations of an inductive vapor generator of FIG. 9.
FIG. 11A is an illustration of a variation of a method where a working end of a catheter is introduced into the lumen of a renal artery for a treatment of electrical signal transmission characteristics in nerve fibers in the artery.
FIG. 11B illustrates an enlarged schematic view of the catheter working end of FIG. 11A.
FIG. 11C illustrates the expansion of a balloon carried by the working end of FIG. 11B and the high pressure jetting of a flowable media from a jetting outlet into the arterial wall to cause damage to electrical signal carrying structures in the vessel wall.
FIG. 11D illustrates a subsequent step of deflating the balloon following the termination of flow media delivery to thereby provide a treated region.
FIG. 12A is a magnified view of a portion of a catheter working end that shows a projecting feature that surrounds the jetting outlet.
FIG. 12B is a magnified view of another projecting feature with a sharp apex that surrounds the jetting outlet in a catheter working end.
FIG. 12C is a magnified view of another projecting feature that surrounds a plurality of jetting outlets in a catheter working end.
FIG. 12D is a magnified view of another projecting feature that surrounds jetting outlets that have converging axes.
FIG. 12E is a magnified view of another working end wherein a micro-needle is extendable to penetrate a jetting outlet into the vessel wall.
FIG. 13A is a schematic view of a blood vessel following treatment with the method of FIGS. 11A-11D wherein the jetted media flows damage nerve fibers in targeted partly-annular treatment zones.
FIG. 13B is another schematic view of a blood vessel following treatment wherein the jetted media flows damage nerve fibers in targeted spiraling treatment zone.
FIG. 13C is another schematic view of a blood vessel post-treatment wherein the jetted media flows damage nerve fibers in targeted spaced apart zones.
FIG. 14A illustrates another catheter working end and method of use wherein the working end has a spiral configuration following expansion by an expansion member.
FIG. 14B illustrates the catheter working end of FIG. 14A in an expanded configuration to thereby treat tissue in a spiral pattern.
FIG. 15A is a schematic illustration and block diagram relating to the catheter system of FIGS. 14A-14B wherein the catheter system has flow media inflow and outflow lumens for a circulating flow together with a valve system for creating high pressure flow media jetting from a plurality of jetting outlets.
FIG. 15B is an illustration and block diagram similar to that of FIG. 15A wherein the valve system is actuated to cause high pressure flow media to jet outwardly from the plurality of jetting outlets.
FIG. 16 is an illustration and block diagram of another catheter working end with first and second catheter sleeve portions that can be expanded apart by a balloon; the working end configured with a plurality of flow media jetting outlets.
FIG. 17 is an illustration and block diagram of another catheter working end that can be articulated into an expanded cross section with a pull wire to engage the vessel wall; the working end configured with a plurality of flow media jetting outlets.
FIG. 18 is an illustration and block diagram of another catheter working end that include first and second flow media source and first and second inflow pathway for providing contemporaneous or sequential jetting of liquid cutting jets and vapor jets from separate outlets.
DETAILED DESCRIPTION OF THE INVENTION
As used in the specification, “a” or “an” means one or more. As used in the claim(s), when used in conjunction with the word “comprising”, the words “a” or “an” mean one or more. As used herein, “another” means as least a second or more. “Substantially” or “substantial” mean largely but not entirely. For example, substantially may mean about 10% to about 99.999, about 25% to about 99.999% or about 50% to about 99.999%.
Treatment Liquid Source, Energy Source, Controller
Referring to FIG. 2, a schematic view of a variation of a medical system 100 is shown where the system 100 is adapted for treating a tissue target, wherein the treatment comprises an ablation or thermotherapy and the tissue target can comprise any mammalian soft tissue to be ablated, sealed, contracted, coagulated, damaged or treated to elicit an immune response. The system 100 can include an instrument or probe body 102 with a proximal handle end 104 and an extension portion 105 having a distal or working end indicated at 110. In one embodiment depicted in FIG. 2, the handle end 104 and extension portion 105 generally extend about longitudinal axis 115. In the embodiment of FIG. 2, the extension portion 105 is a substantially rigid tubular member with at least one flow channel therein, but additional variations can encompasse extension portions 105 of any mean diameter and any axial length, rigid or flexible, suited for treating a particular tissue target. In one embodiment, a rigid extension portion 105 can comprise a 20 Ga. to 40 Ga. needle with a short length for thermal treatment of a patient's cornea or a somewhat longer length for treating a patient's retina. In another embodiment, an elongate extension portion 105 of a vapor delivery tool can comprise a single needle or a plurality of needles having suitable lengths for tumor or soft tissue ablation in a liver, breast, gall bladder, prostate, bone and the like. In another embodiment, an elongate extension portion 105 can comprise a flexible catheter for introduction through a body lumen to access at tissue target, with a diameter ranging from about 1 to 10 mm. In another embodiment, the extension portion 105 or working end 110 can be articulatable, deflectable or deformable. The probe handle end 104 can be configured as a hand-held member, or can be configured for coupling to a robotic surgical system. In another embodiment, the working end 110 carries an openable and closeable structure for capturing tissue between first and second tissue-engaging surfaces, which can comprise actuatable components such as one or more clamps, jaws, loops, snares and the like. The proximal handle end 104 of the probe can carry various actuator mechanisms known in the art for actuating components of the system 100, and/or one or more footswitches can be used for actuating components of the system.
As can be seen in FIG. 2, the system 100 further includes a source 120 of a flowable liquid treatment media 121 that communicates with a flow channel 124 extending through the probe body 102 to at least one outlet 125 in the working end 110. The outlet 125 can be singular or multiple and have any suitable dimension and orientation as will be described further below. The distal tip 130 of the probe can be sharp for penetrating tissue, or can be blunt-tipped or open-ended with outlet 125. Alternatively, the working end 110 can be configured in any of the various embodiments shown in FIGS. 6A-6M and described further below.
In one embodiment shown in FIG. 2, an RF energy source 140 is operatively connected to a thermal energy source or emitter (e.g., opposing polarity electrodes 144a, 144b) in interior chamber 145 in the proximal handle end 104 of the probe for converting the liquid treatment media 121 from a liquid phase media to a non-liquid vapor phase media 122 with a heat of vaporization in the range of 60° C. to 200° C., or 80° C. to 120° C. A vaporization system using Rf energy and opposing polarity electrodes is disclosed in co-pending U.S. patent application Ser. No. 11/329,381 which is incorporated herein by reference. Another embodiment of vapor generation system is described in below in the Section titled “INDUCTIVE VAPOR GENERATION SYSTEMS”. In any system embodiment, for example in the system of FIG. 2, a controller 150 is provided that comprises a computer control system configured for controlling the operating parameters of inflows of liquid treatment media source 120 and energy applied to the liquid media by an energy source to cause the liquid-to-vapor conversion. The vapor generation systems described herein can consistently produce a high quality vapor having a temperature of at least 80° C., 100° C. 120° C., 140° C. and 160° C.
As can be seen in FIG. 2, the medical system 100 can further include a negative pressure or aspiration source indicated at 155 that is in fluid communication with a flow channel in probe 102 and working end 110 for aspirating treatment vapor media 122, body fluids, ablation by-products, tissue debris and the like from a targeted treatment site, as will be further described below. In FIG. 2. the controller 150 also is capable of modulating the operating parameters of the negative pressure source 155 to extract vapor media 122 from the treatment site or from the interior of the working end 110 by means of a recirculation channel to control flows of vapor media 122 as will be described further below.
In another embodiment, still referring to FIG. 2, medical system 100 further includes secondary media source 160 for providing an inflow of a second media, for example a biocompatible gas such as CO2. In one method, a second media that includes at least one of depressurized CO2, N2, O2 or H2O can be introduced and combined with the vapor media 122. This second media 162 is introduced into the flow of non-ionized vapor media for lowering the mass average temperature of the combined flow for treating tissue. In another embodiment, the medical system 100 includes a source 170 of a therapeutic or pharmacological agent or a sealant composition indicated at 172 for providing an additional treatment effect in the target tissue. In FIG. 2, the controller indicated at 150 also is configured to modulate the operating parameters of source 160 and 170 to control inflows of a secondary vapor 162 and therapeutic agents, sealants or other compositions indicated at 172.
In FIG. 2, it is further illustrated that a sensor system 175 is carried within the probe 102 for monitoring a parameter of the vapor media 122 to thereby provide a feedback signal FS to the controller 150 by means of feedback circuitry to thereby allow the controller to modulate the output or operating parameters of treatment media source 120, energy source 140, negative pressure source 155, secondary media source 160 and therapeutic agent source 170. The sensor system 175 is further described below, and in one embodiment comprises a flow sensor to determine flows or the lack of a vapor flow. In another embodiment, the sensor system 175 includes a temperature sensor. In another embodiment, sensor system 175 includes a pressure sensor. In another embodiment, the sensor system 175 includes a sensor arrangement for determining the quality of the vapor media, e.g., in terms or vapor saturation or the like. The sensor systems will be described in more detail below.
Now turning to FIGS. 2 and 3, the controller 150 is capable of all operational parameters of system 100, including modulating the operational parameters in response to preset values or in response to feedback signals FS from sensor system(s) 175 within the system 100 and probe working end 110. In one embodiment, as depicted in the block diagram of FIG. 3, the system 100 and controller 150 are capable of providing or modulating an operational parameter comprising a flow rate of liquid phase treatment media 122 from pressurized source 120, wherein the flow rate is within a range from about 0.001 to 20 ml/min, 0.010 to 10 ml/min or 0.050 to 5 ml/min. The system 100 and controller 150 are further capable of providing or modulating another operational parameter comprising the inflow pressure of liquid phase treatment media 121 in a range from 0.5 to 1000 psi, 5 to 500 psi, or 25 to 200 psi. The system 100 and controller 150 are further capable of providing or modulating another operational parameter comprising a selected level of energy capable of converting the liquid phase media into a non-liquid, non-ionized gas phase media, wherein the energy level is within a range of about 5 to 2,500 watts; 10 to 1,000 watts or 25 to 500 watts. The system 100 and controller 150 are capable of applying the selected level of energy to provide the phase conversion in the treatment media over an interval ranging from 0.1 second to 10 minutes; 0.5 seconds to 5 minutes, and 1 second to 60 seconds. The system 100 and controller 150 are further capable of controlling parameters of the vapor phase media including the flow rate of non-ionized vapor media proximate an outlet 125, the pressure of vapor media 122 at the outlet, the temperature or mass average temperature of the vapor media, and the quality of vapor media as will be described further below.
FIGS. 4A and 4B illustrate a working end 110 of the system 100 of FIG. 2 and a method of use. As can be seen in FIG. 4A, a working end 110 is singular and configured as a needle-like device for penetrating into and/or through a targeted tissue T such as a tumor in a tissue volume 176. The tumor can be benign, malignant, hyperplastic or hypertrophic tissue, for example, in a patient's breast, uterus, lung, liver, kidney, gall bladder, stomach, pancreas, colon, GI tract, bladder, prostate, bone, vertebra, eye, brain or other tissue. In one variation, the extension portion 104 is made of a metal, for example, stainless steel. Alternatively or additionally, at least some portions of the extension portion can be fabricated of a polymer material such as PEEK, PTFE, Nylon or polypropylene. Also optionally, one or more components of the extension portion are formed of coated metal, for example, a coating with Teflon® to reduce friction upon insertion and to prevent tissue sticking following use. In one embodiment at in FIG. 4A, the working end 110 includes a plurality of outlets 125 that allow vapor media to be ejected in all radial directions over a selected treatment length of the working end. In another embodiment, the plurality of outlets can be symmetric or asymmetric axially or angularly about the working end 110.
In one embodiment, the outer diameter of extension portion 105 or working end 110 is, for example, 0.2 mm, 0.5 mm, 1 mm, 2 mm, 5 mm or an intermediate, smaller or larger diameter. Optionally, the outlets can comprise microporosities 177 in a porous material as illustrated in FIG. 5 for diffusion and distribution of vapor media flows about the surface of the working end. In one such embodiment, such porosities provide a greater restriction to vapor media outflows than adjacent targeted tissue, which can vary greatly in vapor permeability. In this case, such microporosities insure that vapor media outflows will occur substantially uniformly over the surface of the working end. Optionally, the wall thickness of the working end 110 is from 0.05 to 0.5 mm. Optionally, the wall thickness decreases or increases towards the distal sharp tip 130 (FIG. 5). In one embodiment, the dimensions and orientations of outlets 125 are selected to diffuse and/or direct vapor media propagation into targeted tissue T and more particularly to direct vapor media into all targeted tissue to cause extracellular vapor propagation and thus convective heating of the target tissue as indicated in FIG. 4B. As shown in FIGS. 4A-4B, the shape of the outlets 125 can vary, for example, round, ellipsoid, rectangular, radially and/or axially symmetric or asymmetric. As shown in FIG. 5, a sleeve 178 can be advanced or retracted relative to the outlets 125 to provide a selected exposure of such outlets to provide vapor injection over a selected length of the working end 110. Optionally, the outlets can be oriented in various ways, for example so that vapor media 122 is ejected perpendicular to a surface of working end 110, or ejected is at an angle relative to the axis 115 or angled relative to a plane perpendicular to the axis. Optionally, the outlets can be disposed on a selected side or within a selected axial portion of working end, wherein rotation or axial movement of the working end will direct vapor propagation and energy delivery in a selected direction. In another embodiment, the working end 110 can be disposed in a secondary outer sleeve that has apertures in a particular side thereof for angular/axial movement in targeted tissue for directing vapor flows into the tissue.
FIG. 4B illustrates the working end 110 of system 100 ejecting vapor media from the working end under selected operating parameters, for example a selected pressure, vapor temperature, vapor quantity, vapor quality and duration of flow. The duration of flow can be a selected pre-set or the hyperechoic aspect of the vapor flow can be imaged by means of ultrasound to allow the termination of vapor flows by observation of the vapor plume relative to targeted tissue T. As depicted schematically in FIG. 4B, the vapor can propagate extracellularly in soft tissue to provide intense convective heating as the vapor collapses into water droplets which results in effective tissue ablation and cell death. As further depicted in FIG. 4B, the tissue is treated to provide an effective treatment margin 179 around a targeted tumorous volume. The vapor delivery step is continuous or can be repeated at a high repetition rate to cause a pulsed form of convective heating and thermal energy delivery to the targeted tissue. The repetition rate vapor flows can vary, for example with flow durations intervals from 0.01 to 20 seconds and intermediate off intervals from 0.01 to 5 seconds or intermediate, larger or smaller intervals.
In an exemplary embodiment as shown in FIGS. 4A-4B, the extension portion 105 can be a unitary member such as a needle. In another embodiment, the extension portion 105 or working end 110 can be a detachable flexible body or rigid body, for example of any type selected by a user with outlet sizes and orientations for a particular procedure with the working end attached by threads or Luer fitting to a more proximal portion of probe 102.
In other embodiments, the working end 110 can comprise needles with terminal outlets or side outlets as shown in FIGS. 6A-6B. The needle of FIGS. 6A and 6B can comprise a retractable needle as shown in FIG. 6C capable of retraction into probe or sheath 180 for navigation of the probe through a body passageway or for blocking a portion of the vapor outlets 125 to control the geometry of the vapor-tissue interface. In another embodiment shown in FIG. 6D, the working end 110 can have multiple retractable needles that are of a shape memory material. In another embodiment as depicted in FIG. 6E, the working end 110 can have at least one deflectable and retractable needle that deflects relative to an axis of the probe 180 when advanced from the probe. In another embodiment, the working end 110 as shown in FIGS. 6F-6G can comprise a dual sleeve assembly wherein vapor-carrying inner sleeve 181 rotates within outer sleeve 182 and wherein outlets in the inner sleeve 181 only register with outlets 125 in outer sleeve 182 at selected angles of relative rotation to allow vapor to exit the outlets. This assembly thus provides for a method of pulsed vapor application from outlets in the working end. The rotation can be from about 1 rpm to 1000 rpm.
In another embodiment of FIG. 6H, the working end 110 has a heat applicator surface with at least one vapor outlet 125 and at least one expandable member 183 such as a balloon for positioning the heat applicator surface against targeted tissue. In another embodiment as shown in FIG. 6I, the working end can be a flexible material that is deflectable, for example, by a pull-wire. The embodiments of FIGS. 6H and 6I have configurations for use in treating various other medical indications, such as atrial fibrillation, for example in pulmonary vein ablation.
In another embodiment of FIG. 6J, the working end 110 includes additional optional heat applicator means which can comprise a mono-polar electrode cooperating with a ground pad or bi-polar electrodes 184a and 184b for applying energy to tissue. In FIG. 6K, the working end 110 includes resistive heating element 187 for applying energy to tissue. FIG. 6L depicts a snare for capturing tissue to be treated with vapor and FIG. 6M illustrates a clamp or jaw structure. The working end 110 of FIG. 6M includes means actuatable from the handle for operating the jaws.
Sensors for Vapor Flows, Temperature, Pressure, Quality
Referring to FIG. 7, one embodiment of sensor system 175 is shown that is carried by working end 110 of the probe 102 depicted in FIG. 2 for determining a first vapor media flow parameter, which can consist of determining whether the vapor flow is in an “on” or “off” operating mode. The working end 110 of FIG. 7 comprises a sharp-tipped needle suited for needle ablation of any neoplasia or tumor tissue, such as a benign or malignant tumor as described previously, but can also be any other form of vapor delivery tool. The needle can be any suitable gauge and in one embodiment has a plurality of vapor outlets 125. In a typical treatment of targeted tissue, it is important to provide a sensor and feedback signal indicating whether there is a flow, or leakage, of vapor media 122 following treatment or in advance of treatment when the system is in “off” mode. Similarly, it is important to provide a feedback signal indicating a flow of vapor media 122 when the system is in “on” mode. In the embodiment of FIG. 7, the sensor comprises at least one thermocouple or other temperature sensor indicated at 185a, 185b and 185c that are coupled to leads (indicated schematically at 186a, 186b and 186c) for sending feedback signals to controller 150. The temperature sensor can be a singular component or can be plurality of components spaced apart over any selected portion of the probe and working end. In one embodiment, a feedback signal of any selected temperature from any thermocouple in the range of the heat of vaporization of treatment media 122 would indicate that flow of vapor media, or the lack of such a signal would indicate the lack of a flow of vapor media. The sensors can be spaced apart by at least 0.05 mm, 1 mm, 5 mm, 10 mm and 50 mm. In other embodiments, multiple temperature sensing event can be averaged over time, averaged between spaced apart sensors, the rate of change of temperatures can be measured and the like. In one embodiment, the leads 186a, 186b and 186c are carried in an insulative layer of wall 188 of the extension member 105. The insulative layer of wall 188 can include any suitable polymer or ceramic for providing thermal insulation. In one embodiment, the exterior of the working end also is also provided with a lubricious material such as Teflon™ which further insures against any tissue sticking to the working end 110.
Still referring to FIG. 7, a sensor system 175 can provide a different type of feedback signal FS to indicate a flow rate or vapor media based on a plurality of temperature sensors spaced apart within flow channel 124. In one embodiment, the controller 150 includes algorithms capable of receiving feedback signals FS from at least first and second thermocouples (e.g., 185a and 185c) at very high data acquisition speeds and compare the difference in temperatures at the spaced apart locations. The measured temperature difference, when further combined with the time interval following the initiation of vapor media flows, can be compared against a library to thereby indicate the flow rate.
Another embodiment of sensor system 175 in a similar working end 110 is depicted in FIG. 8, wherein the sensor is configured for indicating vapor quality—in this case based on a plurality of spaced apart electrodes 190a and 190b coupled to controller 150 and an electrical source (not shown). In this embodiment, a current flow is provided within a circuit to the spaced apart electrodes 190a and 190b and during vapor flows within channel 124 the impedance will vary depending on the vapor quality or saturation, which can be processed by algorithms in controller 150 and can be compared to a library of impedance levels, flow rates and the like to thereby determine vapor quality. It is important to have a sensor to provide feedback of vapor quality, which determines how much energy is being carried by a vapor flow. The term “vapor quality” is herein used to describe the percentage of the flow that is actually water vapor as opposed to water droplets that is not phase-changed. In another embodiment (not shown) an optical sensor can be used to determine vapor quality wherein a light emitter and receiver can determine vapor quality based on transmissibility or reflectance of a vapor flow.
FIG. 8 further depicts a pressure sensor 192 in the working end 110 for providing a signal as to vapor pressure. In operation, the controller can receive the feedback signals FS relating to temperature, pressure and vapor quality to thereby modulate all other operating parameters described above to optimize flow parameters for a particular treatment of a target tissue, as depicted in FIG. 1. In one embodiment, a MEMS pressure transducer is used, which are known in the art. In another embodiment, a MEMS accelerometer coupled to a slightly translatable coating can be utilized to generate a signal of changes in flow rate, or a MEMS microphone can be used to compare against a library of acoustic vibrations to generate a signal of flow rates.
Inductive Vapor Generation Systems
FIGS. 9 and 10 depict a vapor generation component that utilizes and an inductive heating system within a handle portion 400 of the probe or vapor delivery tool 405. In FIG. 9, it can be seen that a pressurized source of liquid media 120 (e.g., water or saline) is coupled by conduit 406 to a quick-connect fitting 408 to deliver liquid into a flow channel 410 extending through an inductive heater 420 in probe handle 400 to at least one outlet 425 in the working end 426. In one embodiment shown in FIG. 9, the flow channel 410 has a bypass or recirculation channel portion 430 in the handle or working end 426 that can direct vapor flows to a collection reservoir 432. In operation, a valve 435 in the flow channel 410 thus can direct vapor generated by inductive heater 420 to either flow channel portion 410′ or the recirculation channel portion 430. In the embodiment of FIG. 10, the recirculation channel portion 430 also is a part of the quick-connect fitting 408.
In FIG. 9, it can be seen that the system includes a computer controller 150 that controls (i) the electromagnetic energy source 440 coupled to inductive heater 420, (ii) the valve 435 which can be an electrically-operated solenoid, (iii) an optional valve 445 in the recirculation channel 430 that can operate in unison with valve 435, and (iv) optional negative pressure source 448 operatively coupled to the e recirculation channel 430.
In general, one variation of a system can provide a small handheld device including an assembly that utilized electromagnetic induction to turn a sterile water flow into superheated or dry vapor which can is propagated from at least one outlet in a vapor delivery tool to interface with tissue and thus ablate tissue. In one aspect, an electrically-conducting microchannel structure or other flow-permeable structure is provided and an inductive coil causes electric current flows in the structure. Eddies within the current create magnetic fields, and the magnetic fields oppose the change of the main field thus raising electrical resistance and resulting in instant heating of the microchannel or other flow-permeable structure. In another aspect, it has been found that corrosion-resistant microtubes of low magnetic 316 SS are suited for the application, or a sintered microchannel structure of similar material. While magnetic materials can improve the induction heating of a metal because of ferromagnetic hysteresis, such magnetic materials (e.g. carbon steel) are susceptible to corrosion and are not optimal for generating vapor used to ablate tissue. In certain embodiments, the electromagnetic energy source 440 is adapted for inductive heating of a microchannel structure with a frequency in the range of 50 kHz to 2 Mhz, and more preferably in the range of 400 kHz to 500 kHz. While a microchannel structure is described in more detail below, it should be appreciated that variations of the devices or methods can include flow-permeable conductive structures selected from the group of woven filaments structures, braided filament structures, knit filaments structures, metal wool structures, porous structures, honeycomb structure and an open cell structures.
In general, a method of treating tissue as described herein can include utilizing an inductive heater 420 of FIGS. 9-10 to instantly vaporize a treatment media such as deionized water that is injected into the heater at a flow rate of ranging from 0.001 to 20 ml/min, 0.010 to 10 ml/min, 0.050 to 5 ml/min., and to eject the resulting vapor into body structure to ablate tissue. The method further comprises providing an inductive heater 420 configured for a disposable had-held device (see FIG. 9) that is capable of generating a minimum water vapor that is at least 70% water vapor, 80% water vapor and 90% water vapor.
FIG. 10 is an enlarged schematic view of inductive heater 420 which includes at least one winding of inductive coil 450 wound about an insulative sleeve 452. The coil 450 is typically wound about a rigid insulative member, but also can comprise a plurality of rigid coil portions about a flexible insulator or a flexible coil about a flexible insulative sleeve. The coil can be in handle portion of a probe or in a working end of a probe such as a catheter. The inductive coil can extends in length at least 5 mm, 10 mm, 25 mm, 50 mm or 100 m.
In one embodiment shown schematically in FIG. 10, the inductive heater 420 has a flow channel 410 in the center of insulative sleeve 452 wherein the flows passes through an inductively heatable microchannel structure indicated at 455. The microchannel structure 455 comprises an assembly of metal hypotubes 458, for example consisting of thin-wall biocompatible stainless steel tube tightly packed in bore 460 of the assembly. The coil 450 can thereby inductively heat the metal walls of the microchannel structure 455 and the very large surface area of structure 455 in contact with the flow can instantly vaporize the flowable media pushed into the flow channel 410. In one embodiment, a ceramic insulative sleeve 452 has a length of 1.5″ and outer diameter of 0.25″ with a 0.104″ diameter bore 460 therein. A total of thirty-two 316 stainless steel tubes 458 with 0.016″ O.D., 0.010″ I.D., and 0.003″ wall are disposed in bore 460. The coil 450 has a length of 1.0″ and comprises a single winding of 0.026″ diameter tin-coated copper strand wire (optionally with ceramic or Teflon™ insulation) and can be wound in a machined helical groove in the insulative sleeve 452. A 200 W RF power source 440 is used operating at 400 kHz with a pure sine wave. A pressurized sterile water source 120 comprises a computer controlled syringe that provides fluid flows of deionized water at a rate of 3 ml/min which can be instantly vaporized by the inductive heater 420. At the vapor exit outlet or outlets 125 in a working end, it has been found that various pressures are needed for various tissues and body cavities for optimal ablations, ranging from about 0.1 to 20 psi for ablating body cavities or lumens and about 1 psi to 100 psi for interstitial ablations.
FIGS. 11A-11D schematically depict a catheter system 600 and method of use wherein the catheter is adapted for treating structure in the wall of body lumen, such as treating electrical disorders in various body tissue. For example such treatments can take place in a patient's heart or in or near nerves carried within or about the wall of a blood vessel. In one example, referring to FIG. 11A, the catheter system 600 can be configured for the treatment of chronic hypertension. Hypertension or high blood pressure can be a persistent condition in which a patient's systemic arterial blood pressure is abnormally high. Hypertension can be classified as either primary or secondary. About 90%-95% of cases are termed primary hypertension, which refers to an abnormally high blood pressure for which no medical cause can be found. The remaining 5% to 10% of secondary hypertension can be cause by a variety of other conditions that affect the kidneys, arteries, heart or endocrine system. Persistent hypertension is a major risk factor for stroke, heart attack and kidney failure. In the progression to later stage persistent hypertension, there is a noted excess activity of the renal nerves. The principal therapies for hypertension comprise oral and intravenous drugs that act directly or indirectly on the kidney, such as diuretics and angiotensin converting enzyme (ACE) inhibitors. Such drug therapies are most effective in the early stages of hypertension. In mid- to later stages of chronic hypertension, the drug treatments are not truly effective. Studies have shown that renal denervation can be used to control persistent hypertension which thus may slow the progression to later- or end-stage disease.
The renal arteries normally extend from the side of the abdominal aorta 602 and carry a large portion of total blood flow to the kidneys (FIG. 11A). In FIG. 11A, it can be seen that renal artery 605 extends from aorta 602 to the kidney 608. Up to one third of total cardiac output can pass through the renal arteries for filtration by the kidneys. The arterial supply of the kidneys is somewhat variable. There may be one or more renal arteries supplying each kidney. Supernumerary renal arteries (two or more arteries to a single kidney) are the most common anomaly, with such occurrences ranging from 25% to 40%. The mean diameter of a renal artery is in the 5 mm range.
FIGS. 11A-11B depict a process of modifying the electrical signal transmission characteristics in nerve fibers in an arterial wall wherein an elongated catheter shaft 610 with a working end 615 has been navigated into the lumen 616 of renal artery 605. A femoral artery access can be used as is known in the art. The catheter working end 615 carries an elongated expandable portion that can comprise a balloon 620. The balloon 620 in a collapsed position is configured for insertion and navigation through lumen 616 and can carry radiopaque markings 622, or that catheter shaft can have similar markings. The balloon can have a length ranging from about 1 cm to 40 cm with a diameter suited for engaging the wall 624 of the artery. The balloon can be compliant (distensible), non-compliant (non-distensible) or comprise a balloon that is slightly compliant under high inflation pressures as is known in the art. One type of balloon can have a wall of Nylon that is complaint at pressures ranging from 2 to 12 bar or more.
Now turning to FIG. 11B, an enlarged sectional view of renal artery 605 is shown, wherein the artery wall 624 is comprised of three layers: the internal intima 626, the muscular media 628 and the external fibrous adventitia 630. FIG. 11B further shows nerves 632 that extend along the length of the renal artery generally in and about the adventitia and the interface between the media 628 and adventitia 630 of the vessel wall. FIG. 11B illustrates the catheter working end 615 with the balloon 620 in a collapsed position.
FIG. 11C illustrates the working end 615 following actuation of the inflation source 635 and expansion of balloon 620 which is expanded to a diameter that engaged the arterial wall. As can be seen in FIG. 11C, a source of flow media 640 is operatively coupled to a handle end of the catheter (not shown) and flow channel 644 in the catheter shaft to provide a high pressure flow of flow media through a jet or microchannel flow outlet 645 in a radial outward portion of the expandable structure or balloon 620. In one embodiment shown in FIGS. 11B-11C, the microchannel outlet 645 can have a diameter ranging from about 0.0005″ to 0.015″ and can be carried in a projecting feature indicated at 648. The projecting feature 648 can comprise an element formed of plastic or metal and is configured for pressing into tissue of the vessel wall, with a radial or height dimension H of from 0.005″ to 0.100″. FIGS. 12A-12B depict the apex or surface 650 of exemplary projecting features 648 and 648′ wherein the apex 650 can be flattened or relatively sharp about the flow outlet 645. FIG. 12C illustrates another embodiment with a plurality of microchannel outlets 645 in the projecting feature 648″. FIG. 12D further depicts that microchannels 645 can be oriented with axes that converge so that flows 662 can converge with one another at a predetermined depth in tissue to further focus the delivery of mechanical energy on the targeted tissue site 665 in the vessel wall. In another working end embodiment schematically depicted in FIG. 12E, one or a more hollow micro-needles 680 can be extended from the catheter to deliver the jetted flow media to the targeted tissue. A micro-needle with an angled tip can be rotated to jet flow media in slightly different orientations to expand the region of damaged tissue. In another embodiment, a solid wire microneedle can be penetrated into tissue and the flow media can then follow the path dissected by the needle penetration. Such a needle can also be rotated and a feature at the needle tip can be configured to damage or cut nerve tissue. The source of flow media 640 can use any type of high pressure pump known in the art of water jet systems, such as piston pumps, peristaltic pumps and the like.
FIG. 11C further illustrates the method of using the working end 615 to damage alter electrical conduction in structure in the vessel wall, wherein the source of flow media 640 and controller 660 are actuated to cause a high pressure flow of flow media indicated at 662 into the vessel wall. In one embodiment, the flow media is saline or sterile water and the flow 662 can comprise one or more pulses at a pressure sufficient to mechanically cut tissue of the vessel wall and further cut and/or damage nerve fibers 632 in treatment region 665 of the vessel wall to thereby alter electrical signal transmission or transduction.
FIG. 11D illustrates a subsequent step of the method wherein the balloon 620 is collapsed and further depicts the treatment region 665 wherein signal transduction or transmission is altered, diminished or terminated. In the method illustrated in FIGS. 11A-11D, the flow media can have an ambient temperature, or can be a cryofluid or a heated liquid. The pressure require for tissue cutting can range from 100 psi to 20,000 psi. In one embodiment, such high pressure pulses can be provided by a circulating flow that is interrupted by a flow control valve as will be described further below in FIGS. 15A-15B. The volume of the pulse of flow media can be controlled by this means, as well as the pressure, to provide a flow that delivers mechanical energy to a predetermined depth in tissue before the mechanical energy is dissipated, wherein the predetermined depth of targeted site 665 can range from 0.1 mm to 2.0. The volume of flow media per pulse of the flow 662 can range from 10 to 100 microliters, and a treatment can consist of 1 to 20 pulses as depicted in FIGS. 11C and 12A-12D.
In another method, similar to that of FIG. 11C, the flow media can comprise or include a water vapor component which can undergo a phase change in or about the targeted site 665 to thereby apply thermal energy to the targeted site as well as mechanical energy to alter the electrical signaling capability of nerve fibers 632 in the vessel wall. In general, such vapor media can be generated and delivered as described in previous embodiments above.
Still referring to FIG. 11C, it can be understood that the working end 615 can be re-positioned in the lumen 616 in an artery 605 to apply energy in a plurality of treatment sites. For example, FIGS. 13A-13C illustrate various patterns of treatment sites that can be discrete and spaced apart or can be overlapping to provide elongated linear, annular, or spiraling regions in which electrical transmission or transduction in nerve fibers is altered. Clearly, any variation or combination of patterns is within the scope of this disclosure.
FIG. 13A depicts two partly annular treatment regions 665a and 665b that can be created by a plurality of closely spaced jetting outlets 645 in the catheter to provide each continuous treatment region (see FIG. 14B). FIG. 13B shows a continuous treatment zone 665c which spirals about the vessel. FIG. 13C illustrates four discrete, spaced apart treatment regions 665d-665g that in one method are radially spaced apart at 90°. The scope of the method thus can comprise any annular, partly annular, spiraling, partly spiraling, localized or spaced apart regions or any combination thereof. In one method, a plurality of treatment regions are spaced apart and non-continuous yet extend from 180° to 360° around the vessel within the length of the renal artery.
In the methods described above, as practiced with the working end 615 of FIGS. 11A-11D, the intima 626 is substantially protected from mechanical or thermal damage by providing the high pressure jetted flow 662 of flow media through the intima to thus provide energy delivery to the interior portions of the vessel wall. This is advantageous over other thermal ablation systems that heat substantial regions of the intima 626 in order to cause passive heat conduction to the nerve fibers or to cause ohmic heating of the nerve fibers. In any embodiment that utilizes a balloon or balloons for engaging the wall of the lumen, the expansion media for the balloon can comprise a cooled gas or liquid, either static or recirculating to cool the vessel wall.
In another embodiment, the flow media can comprise or carry pharmacological agents or ablating fluids, such as BOTOX, alcohol, sclerosing agents, anesthetics and the like, for causing damage to the nerve fibers 632 in the vessel wall.
In FIGS. 11A-11D, the catheter shaft 605 is shown without a guidewire lumen but it should be appreciated that the catheter can have at least one other lumen for a guidewire or for blood perfusion, all of which are not shown for convenience only.
Now turning to FIGS. 14A-14B, another embodiment of catheter system 700 is shown with a catheter body 705 extending to working end 715. In one embodiment, the catheter body 705 is configured to spiral about an expansion balloon 720. In the expanded condition as depicted in FIG. 14B, it can be seen that the expanded balloon 720 will press the catheter body wall into contact with the vessel wall 624. In the embodiment of FIGS. 14A-14B, the high pressure source of flow media again is coupled to lumen 722 in the catheter body 705 that communicates with a plurality of jets or outlets 725 in the working end 715. The plurality of outlets 725 can have optionally can have projecting features 648 about each outlet 725 as described in the embodiment of FIGS. 11A-11D. The outlets 725 can be spaced apart from about 0.020″ to 0.2″. Thus, it can be understood that using the working end 715 as depicted in FIG. 14B will create a plurality of treatment region 665 as described previously in a spiral around the vessel, wherein the spiral pattern can comprise spaced apart treatment regions 665, close adjacent treatment regions or overlapping treatment regions to thus provide non-continuous or continuous damage to the nerve fibers around the circumference of the vessel. The method can further consist of delivering high pressure jets of flow media to cause mechanical damage in the targeted tissue or thermal energy provided by a vapor media, or a combination of both mechanical energy and thermal effects.
FIGS. 15A-15B schematically depict another aspect of the catheter system 700 of FIGS. 14A-14B that is adapted to deliver high pressure pulses of a flow media, and is based on providing continuous circulating flow of a flow media (liquid or vapor) through the system. Related flow media circulation systems are disclosed in Application No. 61/126,647 filed on May 6, 2008; Application No. 61/126,651 filed on May 6, 2008; Application No. 61/126,612 Filed on May 6, 2008; Application No. 61/126,636 filed on May 6, 2008; Application No. 61/130,345 filed on May 31, 2008 and Application No. 61/191,459 filed on Sep. 9, 2008 each incorporated by reference. As can be seen in FIGS. 14B and 15A, the flow media source 640 can be actuated to provide a continuous flow of flow media through a lumen 722 in the portion of catheter body 705 that engages the vessel wall (not shown) upon expansion of a balloon or other expandable member. FIGS. 15A-15B show only a small portion of catheter body 705 that is configured with outlets 725. The flow media within inflow channel 722 flows through the working end 715 and then reverses flow outwardly (proximally) in return lumen 732. The return lumen 732 is within the catheter shaft 705 and is only shown schematically in FIGS. 15A-15B and can be understood to be in shaft 705 in FIGS. 14A-14B. The plurality of lumens can be parallel in the catheter body or concentric. The flow in the return lumen 732 optionally can be assisted by a negative pressure source 735 fluidly coupled to the return lumen and a collection reservoir (not shown). The negative pressure source also can be operated by controller 660. A solenoid valve 736 in the return line 732 is provided and can be left in the open position as depicted in FIG. 15A to thus provide a continuous flow of flow media thru the system. The cross section of microchannel outlets 725 is substantially small which thus prevents any significant flow through the outlets when the return lumen is open. FIG. 15B depicts the actuation of valve 736 to a closed position for an interval that may range from 0.01 second to 5 seconds or more which terminates the return flow and causes a pulse of treatment flows 750 from the outlets 725. The controller 660 can control the flow rate through the system, and then control the closing of valve 736 to generate the desired depth of mechanical damage caused by a liquid flow media. The same flow system can be used for delivering a vapor media to cause thermal effects in tissue, or combination of mechanical and thermal effects.
FIG. 16 is an illustration of another embodiment of catheter system 755 which includes a catheter body 756 that diverges into a plurality of body portions 758a and 758b that can spiral about expansion balloon 760 or the body portions can be longitudinal relative to the balloon 760. A balloon inflation lumen is provided in catheter body portion 764. In this embodiment, the flow media outlets 765 are again disposed about the radially-outward surfaces of the catheter body portions 758a and 758b and can function as described in the embodiment of FIGS. 14A-14B. Again, the method of use consists of delivering high pressure jets of flow media to cause mechanical damage in the targeted tissue or thermal energy provided by a heated liquid or vapor media, or a combination of both mechanical energy and thermal effects. It should be appreciated that the catheter body portions 758a and 758b also could be moved to the expanded positions by a central pull-wire that would articulate the catheter body portions outwardly. Further, in any embodiment, the catheter body portion can range from two to six or more.
FIG. 17 illustrates another embodiment of catheter system 800 which includes a catheter body 802 that extends to an articulating working end 810 that is configure to engage the vessel wall without a balloon as in several previous embodiments. The working end 810 can be articulated by an interior pull wire 812. In this embodiment, the flow media outlets 815 again disposed in the radially-outward surface of the catheter working end when in the expanded position. As described previously, the method of use consists of delivering high pressure jets of flow media 825 to cause mechanical damage in the targeted tissue or thermal effects from vapor media, or a combination of both mechanical energy and thermal effects. It should be appreciated that the embodiment of FIG. 17 can include articulating the working end 810 to provide a substantially annular treatment region (or pattern) or a spiral treatment region of any suitable geometry.
FIG. 18 illustrates another embodiment of catheter system 850, and more particularly a portion of catheter working end 855 that includes first and second media inflow channels 860A and 860B that are coupled to independent pressurized sources of flow media. A first source 865A comprises a water jet liquid media source, for example that is configured to jet saline or another liquid at high pressure to cut tissue and thereby cause mechanical damage to tissue. The second flow source 865B comprises a source of water vapor that is adapted for causing thermal effects in tissue. A first return flow channel 866A is distally coupled to the first inflow channel 860A to allow a recirculating flow as described previously with valve 888a configured to provide high pressure liquid media jets 890 being ejected from a plurality of outlets 892. A second return flow channel 886B is distally coupled to second inflow channel 860B to again allow a recirculating flow which is controlled by valve 888b in the manner described above. FIG. 18 shows high pressure vapor jets 895 being propagated from outlets 896 to cause thermal effects the targeted. In one embodiment, the liquid cutting jets 890 and vapor jets 895 can be pulsed alternatively or pulsed contemporaneously to delivery vapor the targeted region of the adventitia to damage nerve fibers therein. In one aspect of the method, the liquid cutting jet provides a dissected path to thereby permit vapor to propagate more effectively to the region of the nerve fibers and to allow greater vapor condensation and energy delivery in the targeted region. The controller 660 and negative pressure source 735 can operate as described previously. It should be appreciated that the first and second media inflow channels 860A and 860B can intersect proximal to a single outlet to thus provide a single outlet and pathway for intermittent pulses of liquid and vapor jets. In this embodiment, a single outflow channel could be optionally be used along with a valve system to control the first and second media flows in the catheter. Such single or multiple inflow channels that intersect also can be used to mix flowable media to control the temperature of the ejected flow with a cooled gas or liquid, to add substances such as pharmacological agents or abrasives to the flow or the like.
In general, another variation of a method for modifying structure in a targeted wall of a lumen comprises engaging the targeted wall with at least one engagement surface of an instrument working end and propagating a flowable media at a substantial velocity from at least one outlet in the engagement surface into the targeted tissue, wherein the flowable media modifies the structure in the targeted wall to modify electrical signal transmission therein. The method includes flowable media causing at least one of mechanical and thermal effects to modify the nerve fibers in the targeted wall. The method includes using flowable media that comprises water vapor and/or water droplets. In one method, the targeted tissue is in the renal arteries.
In another embodiment and method, the vapor can be generated from at least one of water, saline and alcohol. Further, the method can include introducing at least one pharmacologically active agent with the vapor. The pharmacologically active agent can be at least on one of an anesthetic, an antibiotic, a toxin and a sclerosing agent. Further, the method can included introducing an imaging enhancement media with the vapor.
The method of generating the flow of vapor can be by at least one of resistive heating means, inductive heating means, radiofrequency (Rf) energy means, microwave energy means, photonic energy means, magnetic induction energy means, compression and decompression means together with heating means, and ultrasonic energy means.
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 and the above description of the invention is not exhaustive. 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. A number of variations and alternatives will be apparent to one having ordinary skills in the art. Such alternatives and variations are intended to be included within the scope of the claims. Particular features that are presented in dependent claims can be combined and fall within the scope of the invention. The invention also encompasses embodiments as if dependent claims were alternatively written in a multiple dependent claim format with reference to other independent claims.
Patent Application
20130116683
