Patent Publication Number: US-2011077628-A1

Title: Medical system and method of use

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a non-provisional of U.S. Patent Application No. 61/274,162 filed on Aug. 13, 2009, the content of which is incorporated herein by reference in its entirety 
    
    
     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, sealing, welding, coagulating, shrinking or creating lesions in tissue by means of contacting a targeted in a patient with a vapor phase media wherein a subsequent vapor-to-liquid phase change of the media applies thermal energy to the tissue to cause an intended therapeutic effect. Variations of the invention include devices and methods for generating a flow of high quality vapor and monitoring the vapor flow for various parameters with one or more sensors. In yet additional variations, the invention includes devices and methods for modulating parameters of the system in response to the observed parameters. 
     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 soft 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 thermal energy in a controlled and localized manner without the lack of control often associated when Rf, laser and microwave energy are applied directly to tissue. 
     This application is related to the following U.S. Non-provisional and Provisional applications: Application No. 61/126,647 Filed on May 6, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T004.20-US); Application No. 61/126,651 Filed on May 6, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T004.40-US); TSMT-P-T004.50-U.S. Application No. 61/126,612 Filed on May 6, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T004.40-US); Application No. 61/126,636 Filed on May 6, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T004.60-US; Application No. 61/130,345 Filed on May 31, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T004.70-US); Application No. 61/191,459 Filed on Sep. 9, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T005.50-US); Application No. 61/066,396 Filed on Feb. 20, 2008 TISSUE ABLATION SYSTEM AND METHOD OF USE (TSMT-P-T005.60-US); Application No. 61/123,416 Filed on Apr. 8, 2008 MEDICAL SYSTEM AND METHOD OF USE (TSMT-P-T005.70-US); Application No. 61/068,049 Filed on Mar. 4, 2008 MEDICAL SYSTEM AND METHOD OF USE (TSMT-P-T005.80-US); Application No. 61/123,384 Filed on Apr. 8, 2008 MEDICAL SYSTEM AND METHOD OF USE (TSMT-P-T005.90-US); Application No. 61/068,130 Filed on Mar. 4, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T006.00-US); Application No. 61/123,417 Filed on Apr. 8, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T006.10-US); Application No. 61/123,412 Filed on Apr. 8, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T006.20-US); Application No. 61/126,830 Filed on May 7, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T006.40-US); and Application No. 61/126,620 Filed on May 6, 2008 MEDICAL SYSTEM AND METHOD OF USE (docket TSMT-P-T006.50-US). 
     The systems and methods described herein are also related to U.S. patent application Ser. No. 10/681,625 filed Oct. 7, 2003 titled “Medical Instruments and Techniques for Thermally-Mediated Therapies”; Ser. No. 11/158,930 filed Jun. 22, 2005 titled “Medical Instruments and Techniques for Treating Pulmonary Disorders”; Ser. No. 11/244,329 (Docket No. S-TT-00200A) filed Oct. 5, 2005 titled “Medical Instruments and Methods of Use” and Ser. No. 11/329,381 (Docket No. S-TT-00300A) filed Jan. 10, 2006 titled “Medical Instrument and Method of Use”. 
     All of the above applications are incorporated herein by this reference and made a part of this specification, together with the specifications of all other commonly-invented applications cited in the above applications. 
     SUMMARY OF THE INVENTION 
     The present invention is adapted to provide improved methods of controlled thermal energy delivery to localized tissue volumes, for example for ablating, sealing, coagulating or otherwise damaging targeted tissue, for example to ablate a tissue volume interstitially or to ablate the lining of a body cavity. Of particular interest, the method causes thermal effects in targeted tissue without the use of Rf current flow through the patient&#39;s body and without the potential of carbonizing tissue. 
     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 of the invention exploits 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 of the invention provides 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 (PAD) 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 invention. The system 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 method of the invention comprises 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 of 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 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 flow 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 thermal conductivity; 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. 
     Variations of such systems include systems where the maximum thermal conductivity ranges from 0.05 W/mK, 0.01 W/mK and 0.005 W/mK. 
     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 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 
     The method of claim  1  where introducing the flow of liquid media comprises introducing the flow of liquid media in less than 10 minutes. However, the rate can be reduced as described below. 
     In another variation, the methods described herein include inductively heating the portion of 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. Optionally, 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 energy ranging from 5 joules to 100,000 joules to cause a therapeutic effect, wherein the vapor media is converted from a liquid media within the probe by inductive heating means. 
     Methods described herein also include methods of treating tissue by providing 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 ranging from 5 joules to 100,000 joules to cause a therapeutic effect. 
     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 instrument and method of the invention can cause an energy-tissue interaction that is imageable with intra-operative ultrasound or MRI. 
     The instrument and method of the invention cause thermal effects in tissue that do not rely applying an electrical field across the tissue to be treated. 
     Additional advantages of the invention will be 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 invention. 
         FIG. 3  is a block diagram of a control method of the invention. 
         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 an partly disassembled view of a handle and inductive vapor generator system of the invention. 
         FIG. 10  is an enlarged schematic view of the inductive vapor generator of  FIG. 9 . 
         FIG. 11  is an illustration of a method of using a first embodiment of vapor delivery tool for treating an intervertebral disc. 
         FIG. 12A  is a sectional view of the disc of  FIG. 11  and an initial step of the method of introducing the vapor delivery tool of  FIG. 11  into the disc. 
         FIG. 12B  is a sectional view of the disc as in  FIG. 11  depicting the vapor delivery tool deployed and showing the step of delivering vapor into the disc tissue. 
         FIG. 13  is an enlarged perspective view of the working end of the vapor delivery tool of  FIGS. 12A-12B  showing the configuration of vapor outlets. 
         FIG. 14  is an illustration of a method of using another embodiment of vapor delivery tool for treating an intervertebral disc similar to that of  FIGS. 12A-12B , which includes the step of applying aspiration forces to the interior of the disc. 
         FIG. 15  is an enlarged perspective view of the working end of the vapor delivery tool of  FIG. 14  showing the configuration of an aspiration channel. 
         FIG. 16  is an enlarged sectional view of the working end of another vapor delivery tool showing the configuration of an air-gap and gas flow channel for thermal insulation. 
         FIG. 17A  is an illustration of a method of using another embodiment of vapor delivery tool for treating an intervertebral disc similar to that of  FIG. 14 , which includes first and second penetrating members for introducing vapor and applying aspiration forces, respectively. 
         FIG. 17B  is a sectional view of the method of  FIG. 17A  depicting the first and second penetrating members introducing vapor and applying aspiration forces, respectively. 
         FIG. 18A  is a view of an alternative working end of a vapor delivery tool that carries an elastomeric sleeve for preventing retrograde vapor flows in tissue. 
         FIG. 18B  is a view of the working end of  FIG. 18A  in operation depicting the flexing of the elastomeric sleeve to capture and prevent retrograde vapor flows. 
       the disc as in  FIG. 11  depicting the vapor delivery tool deployed and showing the step of delivering vapor into the disc tissue. 
         FIG. 19  is a view of an alternative vapor delivery tool configured for hammering into bone, such as a vertebra, for use in treating and ablating a basivertebral nerve. 
         FIG. 20  depicts a method corresponding to the invention utilizing the vapor delivery tool of  FIG. 19 , wherein vapor is directed to a central region of the vertebral body to ablate the basivertebral nerve. 
         FIG. 21  is a view of an alternative vapor delivery tool similar to that of  FIG. 19  configured for hammering into bone. 
         FIG. 22  is a view of another vapor delivery tool similar to that of  FIGS. 19 and 21  configured for hammering into bone. 
         FIG. 23  is a sectional view of the shaft of a vapor delivery tool of  FIGS. 19 ,  21  and  22  with an insulative air gap. 
         FIG. 24  is a view of an alternative deflectable vapor delivery tool hammered into a vertebral body and a method of delivering vapor to ablate the basivertebral nerve. 
         FIG. 25A  is a disassembled view of components of the deflectable vapor delivery tool of  FIG. 24  which includes concentric rotatable shape memory sleeves. 
         FIG. 25B  is an assembled view of the components of  FIG. 25A  showing the deflectable vapor delivery tool in a straight configuration. 
         FIG. 26  is a view of another vapor delivery tool hammered into a vertebral body and a method of delivering vapor to ablate the basivertebral nerve. 
         FIG. 27  is a view of another vapor delivery tool and method that includes independently deployable temperature sensing elements. 
     
    
    
     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 medical system  100  of the present invention is shown that 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  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 the scope of the invention encompasses 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&#39;s cornea or a somewhat longer length for treating a patient&#39;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  144   a ,  144   b ) 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 CO 2 . In one method, a second media that includes at least one of depressurized CO 2 , N 2 , O 2  or H 2 O 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 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&#39;s breast, uterus, lung, liver, kidney, gall bladder, stomach, pancreas, colon, GI tract, bladder, prostate, bone, vertebra, eye, brain or other tissue. In one embodiment of the invention, 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 of  FIG. 6I , the working end can be a flexible material that is deflectable by a pull-wire as is known in the art. The embodiments of  FIGS. 6H and 6I  have configurations for use in treating 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  184   a  and  184   b  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  185   a ,  185   b  and  185   c  that are coupled to leads (indicated schematically at  186   a ,  186   b  and  186   c ) 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  186   a ,  186   b  and  186   c  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.,  185   a  and  185   c ) 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  190   a  and  190   b  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  190   a  and  190   b  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, the system of the invention provides 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 of the invention, 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 of the invention, it has been found that corrosion-resistant microtubes of low magnetic  316  SS are best 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 the scope of the invention includes 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 the invention comprises 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 hand-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 0.1 psi to 100 psi for interstitial ablations. 
     FIGS.  11  and  12 A- 12 B schematically depict another system  500 , vapor delivery tool with an elongated introducer  505  with bore  508  therein carrying an extendable vapor delivery needle or extension member  510 , and method of use configured for treating a back pain, and more particularly in one embodiment for treating a patient&#39;s disc to alleviate discogenic pain. 
     It has been reported that 80% of U.S. adults suffer from lower back pain at some point in their lives. In many cases, the pain is related to a disc disorder such as an internal disc disruption, a bulging disc or a herniated disc. While many people are asymptomatic people with a disc bulging or internal disc disruption, about 40% of chronic back pain patients will have tears or disruptions within their discs that are often can be invisible on MRI. 
       FIG. 12A  is a schematic view of an intervertebral disc  512  with internal disc disruption consisting of concentric tears  514  within the lamellae  516  of the annulus fibrosus  520 . It is believed that such internal disc disruptions are a major cause of discogenic pain. 
     The annulus fibrosis  520  is the tough circular exterior of the intervertebral disc  512  that surrounds the nucleus pulposus  522 . The annulus is a layered structure, in that it contains 15 to 25 sheets of collagen called lamellae  516 . The annulus is predominantly formed of collagen fibers which have a much lower water content than the nucleus  522 . The annulus  520  securely connects the vertebral bodies above and below the disc, and further provides containment of the highly pressurized nucleus  522  and protects the nerve-laden outer one-third of the annulus and posterior epidural neural structures, e.g., the delicate nerve roots  530  and thecal sac  532 . 
     The nucleus pulposus  522  is a gelatinous-like material in the core of the vertebral disc. In a young, healthy patient, the nucleus  522  has a gelatinous material with high water content, comprising mostly proteoglycans produced by the cells of the nucleus. The elastic inner structure allows the vertebral disc  512  to withstand forces of compression and torsion. With age, the body&#39;s discs dehydrate and become stiffer, causing the disc to be less able to adjust to compression. 
     Referring to  FIG. 12A , due to the higher pressure within the nucleus pulposus  522 , irritating nuclear material can migrate from the nucleus through the tear  514  outwardly to contact the sinuvertebral nerves SVN that lie within the outer one-third of the annulus  520 . Such leakage of nuclear material can cause in many patients an inflammatory reaction within the outer disc portion that causes chronic and debilitating back and/or leg pain. Nerves  536  in the disc that branch from the sympathetic nervous system or grey ramus communicans GRC also can be irritated by leaking nuclear material ( FIG. 12A ). 
     Referring to  FIG. 11 , the system  500  includes a tool with a handle as shown in  FIG. 2  with a liquid media source  120 , energy source  140  and controller  150  that are adapted to produce and deliver a high temperature vapor media through an elongated vapor delivery tool or extension member  510 . The system embodiment  500  of  FIG. 11  is similar to that of FIG.  6 C, wherein the vapor delivery needle or extension member is extendable from bore  508  in introducer sleeve  505 . 
     Referring to  FIGS. 11 and 12A , the physician advances the introducer  505  through a skin incision to a targeted location on the disc  512 . The distal end  540  of the elongated sleeve-type introducer  505  has a dull tip, with optional radiopaque markings (not shown) for viewing under fluoroscopy, which is pressed against the wall of disc  512  in the selected location. As further can be seen in be  FIG. 12A , the vapor-delivery needle  510  then can be advanced from the introducer  505  into the annulus  520 . The angle and orientation of the introducer  505  can be determined by the location of targeted treatment in disc, as well as by selection of the vapor delivery needle  510 . 
     Now turning to  FIG. 12B , one embodiment of vapor delivery tool or needle  510  comprises a metal needle of a shape memory material such as Nitinol that has a predetermined curved portion  544  that permits a plurality of vapor outlets  545  to be positioned to face posteriorly for treating a disc defect in a posterior portion of the disc  512 . In the embodiment of  FIG. 12B , it can be understood that the curved vapor delivery needle  510  is rotationally keyed with handle (not shown) and/or introducer  505  and a visual marking  548  indicates to the physician the direction that the needle will curve when in the interior of the disc  512 . The curved portion  544  or working end further is configured with radiopaque markers  550 A and  550 B for positioning the working end under fluoroscopy. In  FIG. 12B , the needle  510  is advanced to a suitable location to deliver vapor adjacent the target tissue which in this case is the posterior disc region, wherein vapor delivery is indicated by arrows. In the embodiment of  FIG. 12B , the vapor is delivered from a plurality of vapor outlets  545  that all face either the same direction or are configured to emit vapor within a radial arc A of less than 90° as shown in  FIG. 13 , or optionally less than 45°. 
     In use, one method comprises delivering a high quality water vapor, for example at least 70% water vapor, at least 80% water vapor or at least 90% water vapor for between 1 second and 30 seconds at a pressure ranging from 0.01 psi to 20 psi in the interior bore  555  of the needle  510 . A method of the invention comprises permitting condensation of the water vapor in the targeted site, wherein the applied energy can range from 10 J to 1,000 J or more. Of particular interest, the vapor can find a path through the tear  514  in annulus  520  and ablate nerve receptors of the sinuvertebral nerves SVN as shown in  FIG. 12B . This modality of energy application via convective heating (non-desiccating and entirely without the potential of tissue carbonization) is far different from IDET and laser discectoiny modalities—which must rely on thermal diffusion from an electrode or optic fiber to ablate nerve receptors and may not apply energy rapidly enough to damage nerve receptors without diffusing heat too far outwardly into the disc periphery, the vertebral endplates and adjacent tissues. 
       FIG. 14  depicts another embodiment  600  of vapor delivery system that includes additional subsystems as described in text accompanying the embodiment of  FIG. 2 . The system again includes a liquid media source  120 , energy source  140  and controller  150  for generating and expelling a therapeutic heated vapor media from the vapor delivery needle  610 . This system embodiment  600  of  FIG. 14  further includes a negative pressure source  155  and an optional second gas source  160  for mixing with the heated vapor, as will be described below. In the method depicted in  FIG. 14 , the defect in the disc  512  consists of a radially annular tear  612  and disc nucleus protrusion. 
     In the embodiment of  FIG. 14 , it can be seen that the vapor delivery needle  610  is extendable from lumen  614  in sleeve  615 . The sleeve  615  is coupled to negative pressure source  155  and thus comprises an aspiration sleeve to allow negative pressures to subtract pressure, vapor and liquid media from the interior of the disc  512 . The assembly of vapor-delivery needle  610  and sleeve  615  is extendable and retractable relative to introducer sleeve  620  and bore  622  therein. 
     In  FIG. 14 , it can be understood that the assembly of needle  610 , sleeve  615  and introducer  620  can be advanced through a skin incision into the disc  512 . Thereafter, the needle  610  and sleeve  615  can be advanced through a small incision in the disc so that the distal end  624  of sleeve  615  is within the treatment region in the nucleus  522 . The handle of the device (not shown) is configured with handle portions to allow axial and/or rotational movement of the needle  610  and sleeve  615 . The distal end  624  of sleeve  615  is shown with radiopaque marking  630  to allow the physician to insure the location at which aspiration forces are applied, that is, at the open termination  640  of lumen  614  in sleeve  615 . 
       FIG. 15  is an enlarged view of the distal end  624  of sleeve  615  showing the extendable-retractable vapor delivery needle  610 . It can be seen that bore  614  in sleeve  615  is larger than the outer diameter of needle  610  to provide an annular space that can function as an aspiration lumen. Thus, negative pressure or aspiration forces can provided at the annular open termination  640  of lumen  614 . In one embodiment as shown in  FIG. 15 , the sleeve  615  is configured with radially spaced apart protrusions  644  at least at the distal end of lumen  614  to maintain the annular lumen  614  in an open configuration. Further, the free space between the vapor needle  610  and the wall of sleeve  615  provides a thermally insulative gap that reduces heating of the sleeve  615  and prevents unwanted condensation of vapor in the vapor delivery needle  610  before the vapor is expelled from ports  545 . 
     In use, the method of vapor delivery is the same as described above to allow vapor propagation and condensation to apply energy to the annular defect  612  while activation of the negative pressure source reduces intradiscal pressure during treatment and further can extract vapor and liquids. 
     In another method of the invention, still referring to  FIG. 14 , the second gas source  160  can be actuated contemporaneous with vapor delivery for one or more purposes. In one method, a biocompatible gas such as CO, can be introduced to reduce the mass average temperature of the vapor media. For example, in one embodiment, the combined vapor media can be reduced from the water vapor&#39;s temperature of at least 100° C. to a lower mass average temperature of approximately 60° C., or approximately 70° C., or approximately 80° C. In treating disc defects, it is believed that lower temperatures of the mass of the vapor media, such as a maximum of 60° C., 70° C. or 80° C. can ablate nerve receptors and migrate within annular tears to thus eliminate pain, with lesser risk of unwanted thermal diffusion. 
     In another related method, the second gas source  160  can comprise a source of oxygen and/or ozone. In recent years, it has been found that that oxygen and/or ozone (O 2 O 3 ) injections can be used to treat lower back pain. See, e.g., M. Paoloni, et al., “Intramuscular Oxygen-Ozone Therapy in the Treatment of Acute Back Pain With Lumbar Disc Herniation,” SPINE Vol. 34, No. 13, pp. 1337-1344. Such treatments have used intradiscal or intraforaminal injections, as well a paravertebral intramuscular injections. Such O 2 O 3  therapies are known in medicine and are based on the exploitation of the chemical properties of ozone, which is an unstable form of oxygen. In the treatment of disc defects, the O 2 O 3  injection is believed to have an effect on proteoglycans within the disc&#39;s nucleus pulposus which ultimately reduces nucleus volume and hence reduces intradiscal pressure, and further has and analgesic and anti-inflammatory effect. By combining a thermal vapor with an O 2 O 3  component, the resulting vapor can have a lower mass average temperature as well as providing the chemical or pharmacologic effects described above. 
       FIG. 16  illustrates another embodiment of the invention, which comprises a sleeve  700  that houses an extendable-retractable vapor delivery needle  610  in phantom view, and for example can comprise the intermediate sleeve of  FIG. 14 . As can be seen in  FIG. 16 , the sleeve  700  has lumen  705  with dual-lead helical elements  708 A and  708 B that have a small edge or surface area  712  that contacts the vapor delivery needle  610 . The helical elements  708 A and  708 B thus form dual, adjacent helical channels  715 A and  715 B that wind helically around the slidable vapor delivery needle  610 . Thus, the space or air gap provided by the channels  715 A and  715 B provides a thermally insulative gap which can assist in preventing unwanted heating of the sleeve  700 . In the embodiment of  FIG. 16 , the distal termination of channels  715 A and  715 B have a notch or gap indicated at  720  that allows air or gas flow between the channels when a vapor delivery needle  610  is disposed therein. Further, one of the channels  715 A is connected to a negative pressure source  155  at a proximal handle end which thus allow for air or gas flow in a distal direction from the handle (see arrows) and then reverse to flow back toward the negative handle and negative pressure source  155  in the proximal direction. Such a circulating gas flow thus can help in maintaining the sleeve at a low temperature. Further, the negative pressure source and an inlet restrictor or pressure relief valve can provide a negative pressure in channels  715 A and  715 B to provide further insulative value to the space around the vapor delivery needle. In another embodiment (not shown), the distal end  722  of the sleeve can have an opening to apply negative pressure to the channel  715 A to aspirate gas from the treatment site, as well to draw gas through the cooperating channel  715 B. It should be appreciated that a gas inflow source connected to channel  715 B to cooperate with a negative pressure source  155  coupled to channel  715 A. It should be appreciated that the gas flow in channels  715 A and  715 B can be a cooled gas or cryogenic fluid for providing any desired cooling effect. 
       FIG. 17A-17B  illustrate another embodiment in which introducer sleeve  805  houses first and second passageways  808 A and  808 B that carry extendable-retractable extension members or needles  810 A and  801 B. The cross-section of sleeve  805  can be round, oval or rectangular to accommodate the needles and provide a small cross-sectional dimension for allowing a minimally invasive approach. The distal tip  812  of sleeve  805  is configured to allow both needles to penetrate the disc proximate the engagement of the distal tip  812  with the disc  512 . The tip  812  can be angled or beveled to interface with the disc  512  at any anticipated angle of approach to thus allow the needles  810 A and  810 B to enter the disc, wherein the needles&#39; relationship can be (i) above and below each other, or (ii) side to side with one another. In this embodiment, referring to  FIG. 17B , needle  810 A is coupled to the vapor source  150  and needle  810 B is operatively coupled to the negative pressure source  160 . The method of use is similar to that describe above, wherein vapor is introduced to thermally treat the disc tissue and the negative pressure source  160  is used to reduce pressure in the disc nucleus  522  and/or extract fluids. The needles can have a straight shape or any curved memory shape. 
     It should be appreciated that the method of the invention includes actuating independent vapor injection and aspiration needles that are introduced from a single sleeve or multiple sleeves introduces on one side of a disc or bi-laterally. 
       FIGS. 18A-18B  depict another embodiment of a working end  900  the invention that comprises means for preventing vapor propagation in an unwanted direction retrograde along the shaft of the vapor needle  910 . As can be seen in  FIG. 18A , the vapor delivery needle  910  can be in introduced into any tissue  912 , such as disc tissue in  FIGS. 12A-12B , and the tissue may not have characteristics suitable for sealably pressing against the shaft of needle  910 . In the embodiment of  FIG. 18A , the needle  910  is provided with a thin-wall, elastomeric sleeve  915  that is bonded in its proximal aspect  916  to the needle shaft along bond line  918 . The distal end  920  of the elastomeric sleeve  915  is free and not bonded to the needle shaft. In a method of use, the needle  910  together with outer protective sleeve  925  are inserted into tissue  912  and then the protective sleeve is retracted to expose the elastomeric sleeve  915 . 
       FIG. 18B  illustrates the needle  910  in use with vapor (see arrows) being expelled from vapor outlets  945  wherein the vapor propagates outwardly into tissue but also tends to flow retrograde along the needle shaft. As can be seen in  FIG. 18B , any tendency of vapor to flow retrograde will be immediately captured by outward expansion and ballooning of the distal end  902  of the elastomeric sleeve  915 —thus preventing any further retrograde flow of the vapor. 
       FIGS. 19-20  illustrate another ablation system  1000  and method corresponding to the invention which includes a vapor delivery needle of probe  1005  having an extension portion or shaft  1010  extending along axis  1015  that is configured for driving into bone for ablation of intraosseal nerves, and in one example, a basivertebral nerve BVN in the interior of vertebral body  1016  as shown in  FIG. 20 . It is believed that certain types of back pain, which differ from types of discogenic pain and vertebral fracture pain, can be alleviated by ablation of nerves within the center of a vertebral body.  FIG. 19  illustrates a probe  1005  with a proximal handle  1016  that is configured with hammering surface  1020  to allow driving the sharp-tipped needle shaft  1010  through cortical hone  1022  and cancellous bone  1024  to the location of the targeted nerve. The shaft  1010  can be of a medical grade stainless steel suited for hammering into bone, similar to probes used in vertebroplasty procedures. In one embodiment, the working end  1025  of the needle has radiopaque markings  1030  proximate vapor outlets  1035  that can be oriented on one side of the working end  1025  to orient vapor flow and the ablation in the desired direction, for example toward the center of the vertebral body as shown in  FIG. 20 . In the embodiment of  FIG. 19 , the handle  1016  has a fitting  1040  coupling for connecting a flexible vapor delivery tube  1042  to the handle to communicate with vapor delivery lumen  1044  in the probe. The probe of  FIG. 19  provides the vapor connection fitting  1040  non-aligned with the needle shaft  1010  or its axis to allow the use of a hammer against hammering surface  1020  after the vapor delivery tube  1042  has been connected the device. In another embodiment of  FIG. 21 , the proximal handle  1016  can have a fitting  1040  in line with axis  1015  and aligned with shaft  1010  of the device with a removeable or moveable hammering surface  1020  that can cover and protect the fitting  1040 . In the embodiment of  FIG. 21 , a removable cap  1045  carries the hammering surface  1020 , and the cap  1045  can have screw-fit, snap fit or the like. The cap also can have a living hinge to allow the hammering surface  1020  to be pivoted away from the fitting. In another embodiment shown in  FIG. 22 , the fitting  1040  can be recessed from the hammering surface  1020  within a notch or recess  1048  to allow hammering without contacting the recessed fitting  1040 . 
       FIG. 23  is a sectional view of the extension portion  1010  of probe  1005  showing an insulative air space  1050  between outer sleeve  1052  and inner sleeve  1055  that carries the vapor delivery lumen  1044 . The outer sleeve  1052  can be any metal tube suitable for driving into bone, such as a 10 ga. to 14 ga, stainless steel tube. The inner sleeve  1055  can be a high-temperature resistant biocompatible plastic such as PEEK with longitudinal or helical fins  1056  that support the sleeve  1055  centrally in the bore  1058  of outer sleeve  1052  to maintain the insulative air space. The air space  1050  can also comprise a sealed partial vacuum or can be configured with a pump mechanism to provide a partial vacuum at the time of use. The insulative space  1050  can also be provided by an aerogel filler instead of the fins  1056  on the inner sleeve  1055 . 
     In a method of use, the probe shaft  1010  of  FIGS. 19-20  is hammered into a vertebral body in a transpedicular approach as shown in  FIG. 20 . In another method, the shaft may be advanced parapedicularly. The physician can utilize bi-planar fluoroscopy to optimize the position of working end  1025 . Thereafter, the physician can actuate the system to deliver vapor for a predetermined interval to ablate the basivertebral nerve, for example, 5 seconds or less; 10 seconds or less; 30 seconds or less; or 60 seconds or less. The working end can be configured to deliver vapor from vapor outlets that number from 1 to about 20 over a length of from 1 mm to 20 mm. The vapor can be expelled in pulses or in a continuous mode. 
       FIG. 24  illustrates another embodiment of system  1000  that is similar to that of  FIGS. 19-20  except that the vapor delivery probe  1005 ′ has an extension member  1010  that carries a working end  1025  that is deflectable to allow its navigation to a posterior portion of the interior of a vertebral body. Such a deflectable working end can be configured with vapor outlets  1035  facing outwardly from the radius or curved axis of the working end to expel vapor anteriorly to ablate the basivertebral nerve BVN. Such an approach may be safer that expelling vapor in a posterior direction toward the spinal canal. This approach also may be safer in used in a method that does not include an aspiration component as described above.  FIGS. 25A-25B  show one system with a deflectable working end  1025  in which first and second sleeves,  1060 A and  1060 B, are fabricated of a shape memory alloy (e.g., Nitinol) and have cooperating curved memory shapes as indicated in  FIG. 25A . The sleeves are designed so that 180° relative rotation of the sleeves can move the working end from the straight configuration of  FIG. 25B  in which both sleeves are stressed to a deflected position in which both sleeves are unstressed as in  FIG. 25A . The inner sleeve  1060 B can carry the vapor delivery lumen  1044 , which can communicate with vapor outlets  1035  in both sleeves that align in a selected deflected configuration. The deflecting working end  1025  can be provided by other mechanisms known in the art, such as slotted tubes with pull-cables, concentric slotted tubes, hinged and segmented tubes and the like. 
     In another embodiment shown in  FIG. 26 , the probe extension member  1070  and working end  1025  can be configured for accessing any tissue in a straight or deflecting working end, and further can include vapor delivery lumen  1044  and outlets  1035  for delivering vapor as described previously. In addition, the extension portion carries a second lumen  1080  that communicates with second flow outlet(s)  1085  in the working end for expelling a second fluid from the working end. The at least one second outlet  1085  is spaced apart from the vapor outlets  1035  and is adapted for delivery of another functional fluid (gas, liquid, gel) to the region targeted for treatment, either prior to vapor delivery or contemporaneous with vapor delivery. In the method depicted in  FIG. 26 , the physician can inject a protective cooling fluid, cooling gas, or cryogenic gas to indicated at  1088  to protectively cool a region of tissue on one side of the working end before or concurrently with vapor delivery. In another embodiment, the second channel can be used for delivering a protective gel, or polymerizable liquid that turns into a gel or solid, to provide a convective barrier to vapor flow in the tissue.  FIG. 26  shows the protective flow media  1088  on the opposite side of the vapor outlets. In another embodiment (not shown), the working end can carry vapor outlets  1035  on a shaft that are intermediate first and second sets of second outlets  1085  that are configured for injection of a protective flow media that serves as a convective barrier or cooling media. 
     In another embodiment shown in  FIG. 27 , a system and probe  1100  with extension member  1110  and working end  1125  functions as described above with additional features comprising at least one temperature-sensing extendable member  1128  that extends from the working end into tissue a predetermined distance in soft tissue. In one embodiment, as shown in  FIG. 27 , there are two, three or four extendable members  1128  spaced around the shaft and configured for extension into soft tissue, with a thermocouple  1130  disposed on a distal end  1132  of each member. The thermocouples  1130  are operatively connected to the controller  150 , and software can be provided to terminate or modulate vapor delivery when one or more thermocouples reach a peak temperature or a rate or acceleration of temperature increase. The extendable members further can have radiopaque marking for imaging to confirm or determine location. The objective would be to position the temperature sensors at the periphery of the tissue volume targeted for ablation. The extendable members can have a rectangular or flat cross-section or otherwise keyed to guide channels  1140  and apertures  1142  from which they extend to control the direction of deployment. 
     Referring to  FIG. 27 , a method of invention comprises the steps of (i) introducing an elongated probe into a patient body such that a working end with at least one vapor delivery outlet within or adjacent to the targeted tissue, (ii) deploying at least one extension member with temperature sensor in region proximate a periphery of the targeted tissue and monitoring temperature; (iii) delivering vapor through the working end and outlet(s) configured to apply ablative energy to the tissue, and (iv) controlling the applied energy in response to the monitored temperature. Thus, the temperature sensor, such as a thermocouple, has feedback circuitry coupled to the controller  150  for modulating, pulsing, or terminating energy delivery or vapor parameters. In another embodiment, the temperature sensors can be fiber optic probes configured for temperature measurement. 
     Referring back to  FIG. 26 , another method of invention comprises utilizing a vapor delivery tool or needle to access a zygapophyseal joint or paravertebral region and delivering vapor to ablate such tissue and nerves therein to treat spinal pain. Needle  1150  is shown schematically in  FIG. 26  delivering vapor and ablative energy to the zygapophyseal joint. 
     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.