Patent Publication Number: US-2022233228-A1

Title: Systems and methods for prostate treatment

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of pending application Ser. No. 12/768,544, filed Apr. 27, 2010, titled “Systems and Methods for Prostate Treatment”, which application claims the benefit under 35 U.S.C. 119 of U.S. Provisional Patent Application No. 61/173,108, filed Apr. 27, 2009, titled “Medical Systems and Methods”. These applications are herein incorporated by reference in their entirety. 
    
    
     INCORPORATION BY REFERENCE 
     All publications, including patents and patent applications, mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to devices and related methods for treatment of benign prostatic hyperplasia using a minimally invasive approach. 
     BACKGROUND OF THE INVENTION 
     Benign prostatic hyperplasia (BPH) is a common disorder in middle-aged and older men, with prevalence increasing with age. At age 70, more than one-half of men have symptomatic BPH, and nearly 90% of men have microscopic evidence of an enlarged prostate. The severity of symptoms also increase with age with 27% of patients in the 60-70 age bracket having moderate-to-severe symptoms, and 37% of patients in their 70&#39;s suffering from moderate-to-severe symptoms. 
     The prostate gland early in life is the size and shape of a walnut and weighs about 20 grams. Prostate enlargement appears to be a normal process. With age, the prostate gradually increases in size to twice or more its normal size. The fibromuscular tissue of the outer prostatic capsule restricts expansion after the gland reaches a certain size. Because of such restriction on expansion, the intracapsular tissue will compress against and constrict the prostatic urethra thus causing resistance to urine flow. 
       FIG. 1  is a sectional schematic view the male urogenital anatomy, with the walnut-sized prostate gland  50  located below the bladder  55  and bladder neck indicated at  56 . The walls  58  of bladder  55  can expand and contract to cause urine flow through the urethra  60 , which extends from the bladder  55 , through the prostate  50  and penis  62 . The portion of urethra  60  that is surrounded by the prostate gland  50  is referred to as the prostatic urethra  70 . The prostate  50  also surrounds the ejaculatory ducts  72  which have an open termination in the prostatic urethra  70 . During sexual arousal, sperm is transported from the testes  74  by the ductus deferens  76  to the prostate  50  which provides fluids that combine with sperm to form semen during ejaculation. On each side of the prostate, the ductus deferens  76  and seminal vesicles  77  join to form a single tube called an ejaculatory duct  72 . Thus, each ejaculatory duct  72  carries the seminal vesicle secretions and sperm into the prostatic urethra  70 . 
     Referring to  FIGS. 2A-2B and 3 , the prostate glandular structure can be classified into three zones: the peripheral zone PZ, transition zone TZ, and central zone CZ.  FIGS. 2A and 2B  illustrate a normal prostate gland, and  FIG. 3  schematically depicts an enlarged prostate resulting from benign prostatic hyperplasia.  FIGS. 2A-2B and 3  include reference to other male anatomy as previously described with respect to  FIG. 1 . In a normal prostate as depicted in  FIGS. 2A-2B , the peripheral zone PZ, which is the region forming the postero-inferior aspect of the gland, contains 70% of the prostate glandular elements. A majority of prostate cancers (up to 80%) arise in the peripheral zone tissue PZ. The central zone CZ surrounds the ejaculatory ducts  72  and contains about 20-25% of the prostate volume in a normal prostate. The central zone is often the site of inflammatory processes. The transition zone TZ is the site in which benign prostatic hyperplasia develops, and contains about 5-10% of the volume of glandular elements in a normal prostate ( FIGS. 2A, 2B ). Referring to  FIG. 3 , the peripheral zone tissue PZ can constitute up to 80% of prostate such volume in a case of BPH. The transition zone TZ consists of two lateral prostate lobes  78   a ,  78   b  and the periurethral region indicated at  79 . As can be understood from  FIGS. 2B-3 , there are natural barriers around the transition zone tissue TZ, namely, the prostatic urethra  70 , the anterior fibromuscular stroma FS, and a fibrous plane  80  between the transition zone TZ and peripheral zone PZ. Another fibrous plane  82  lies between the lobes  78   a  and  78   b . In  FIGS. 2A-3 , the anterior fibromuscular stroma FS or fibromuscular zone can be seen which is predominantly fibromuscular tissue. 
     BPH is typically diagnosed when the patient seeks medical treatment complaining of bothersome urinary difficulties. The predominant symptoms of BPH are an increase in frequency and urgency of urination. BPH can also cause urinary retention in the bladder which in turn can lead to lower urinary tract infection (LUTI). In many cases, the LUTI then can ascend into the kidneys and cause chronic pyelonephritis, and can eventually lead to renal insufficiency. BPH also may lead to sexual dysfunction related to sleep disturbance or psychological anxiety caused by severe urinary difficulties. Thus, BPH can significantly alter the quality of life with aging of the male population. 
     BPH is the result of an imbalance between the continuous production and natural death (apoptosis) of the glandular cells of the prostate. The overproduction of such cells leads to increased prostate size, most significantly in the transition zone TZ which traverses the prostatic urethra ( FIG. 3 ). 
     In early stage cases of BPH, drug treatments can alleviate the symptoms. For example, alpha-blockers treat BPH by relaxing smooth muscle tissue found in the prostate and the bladder neck, which may allow urine to flow out of the bladder more easily. Such drugs can prove effective until the glandular elements cause overwhelming cell growth in the prostate. 
     More advanced stages of BPH, however, can only be treated by surgical interventions. A number of methods have been developed using electrosurgical or mechanical extraction of tissue, and thermal ablation or cryoablation of intracapsular prostatic tissue. In many cases, such interventions provide only transient relief, and there often is significant peri-operative discomfort and morbidity. 
     In one prior art ablation method for treating BPH, an RF needle in inserted into the prostate and RF energy is delivered to prostate tissue. In a first aspect of the prior art system and method, the elongated RF needle can be extended from an introducer member into the prostate lobes from the urethra. Some prior art systems further utilize an insulator sleeve extended over the RF needle through the urethral wall to prevent thermal damage to the urethra. The resulting RF treatment thus ablates tissue regions away from the prostatic urethra and purposefully does not target tissue close to and parallel to, the prostatic urethra. The prior art systems and method leave an untreated tissue region around the urethra in which smooth muscle cells and alpha adrenergic receptors are not ablated. Thus, the untreated tissue can continue to compress the urethra and subsequent growth of such undamaged tissue can expand into the outwardly ablated regions. 
     In another aspect of some prior art RF methods, the application of RF energy typically extends for 2 to 3 minutes or longer which can allow thermal diffusion of the ablation to reach the capsule periphery of the prostate. In some instances, the application of RF energy for such a long duration can cause lesions that extend beyond the prostate and into the urethra. Such prior art RF energy delivery methods may not create a durable effect, since smooth muscle tissue and are not uniformly ablated around the prostatic urethra. Due to the size of lesions created with RF ablation, these prior art systems typically ablate at a suboptimal location within the prostate (e.g., at a distance of 2 cm or greater from the prostatic urethra) to prevent damage to this tissue. The result can be leaving non-ablated tissue adjacent the urethra that may once again be subject to hyperplasia. As a result, the hyperplasia in the lobes can continue resulting in tissue impinging on the urethra thus limiting long term effectiveness of the RF ablation treatment. 
     SUMMARY OF THE INVENTION 
     A method for treating benign prostatic hyperplasia (BPH) is provided, comprising introducing a vapor delivery member into a transition zone tissue of a prostate, and injecting a condensable vapor media from the vapor delivery member into the transition zone tissue, wherein the condensable vapor media propagates interstitially in the transition zone tissue and is confined in the transition zone tissue by a boundary tissue adjacent the transition zone tissue. 
     In some embodiments, the boundary tissue comprises a prostatic urethra. In other embodiments, the boundary tissue comprises a fibrous plane between lateral lobes of the prostate. In other embodiments, the boundary tissue comprises a central zone tissue. In yet additional embodiments, the boundary tissue comprises a fibrous plane between transition zone tissue and a peripheral zone tissue. In one embodiment, the boundary tissue comprises an anterior fibromuscular stromal tissue. 
     In some embodiments, the condensable vapor media is injected for an interval of 20 second or less. In another embodiment, the condensable vapor media is injected at a pressure at the tissue interface ranging from about 20 mm Hg to 200 mm Hg. 
     In some embodiments, the vapor deliver member is introduced transversely relative to a urethra. In another embodiment, the vapor deliver member is introduced substantially aligned with a urethra. 
     In some embodiments, the condensable vapor media is injected in a plurality of selected locations in the transition zone tissue. 
     In one embodiment, the vapor delivery member is introduced into the transition zone tissue through a wall of a urethra from a trans-urethral probe. In another embodiment, the vapor delivery member is introduced into the transition zone tissue from a trans-rectal probe. 
     In some embodiments, a pressure of the vapor media introduction is controlled by a computer controller. 
     A method for treating benign prostatic hyperplasia (BPH) is provided, comprising introducing a probe into a prostatic urethra, extending a vapor delivery member from the probe into a transition zone tissue of a prostate at a depth of less than 12 mm outward from the prostatic urethra, and delivering a condensable vapor media from the vapor delivery member to the transition zone tissue. 
     In some embodiments, the condensable vapor media is delivered into the transition zone tissue for a delivery interval of less than 20 seconds. In other embodiments, the condensable vapor media is delivered into the transition zone tissue for a delivery interval of less than 10 seconds. 
     In some embodiments, the condensable vapor media is delivered into the transition zone tissue at a delivery pressure ranging from approximately 20 mm Hg to 200 mm Hg. In other embodiments, the condensable vapor media is configured to provide energy ranging from 1 to 40 cal/sec into the transition zone tissue. 
     A method for treating benign prostatic hyperplasia (BPH) is provided, comprising introducing a vapor delivery member into at least one selected location in transition zone tissue of a prostate, and injecting a condensable vapor media from the vapor delivery member into the transition zone tissue so as to ablate transition zone tissue adjacent a urethra without ablating transition zone tissue adjacent a fibromuscular stroma. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional schematic view the male urogenital anatomy. 
         FIG. 2A  is a perspective view of a patient&#39;s normal prostate showing zones of prostate tissue. 
         FIG. 2B  is transverse sectional view of the normal prostate of  FIG. 2A  showing tissue zones, including the central zone, the transition zone, the peripheral zone and the fibromuscular stroma. 
         FIG. 3  is another sectional view of a patient prostate later in life with BPH greatly increasing the dimensions of the transition zone. 
         FIG. 4  is a perspective view of a probe corresponding to the invention. 
         FIG. 5  is a view of components within a handle portion of the probe of  FIG. 4 . 
         FIG. 6  is another view of components within a handle portion of the probe of  FIG. 4 . 
         FIG. 7  is a sectional view of the extension portion of the probe of  FIG. 4  taken along line  7 - 7  of  FIGS. 4 and 6 . 
         FIG. 8  is a side elevation view of the working end of the probe of  FIG. 4  showing a flexible microcatheter or needle in an extended position extending laterally relative to the axis of the extension portion. 
         FIG. 9  is a perspective view of the working end of the probe of  FIG. 4  showing the openings therein for viewing and the flexible microcatheter or needle in an extended position. 
         FIG. 10  is a side elevation view of the microcatheter or needle of the probe of  FIG. 4  showing its dimensions and vapor outlets. 
         FIG. 11  is another view of a distal portion of the microcatheter of  FIG. 10 . 
         FIG. 12  is a sectional view of the microcatheter of  FIG. 10  taken along line  11 - 11  of  FIG. 10 . 
         FIG. 13A  is a longitudinal sectional schematic view of a prostate showing a method of the invention in treating transition zone tissue adjacent the prostatic urethra. 
         FIG. 13B  is a transverse sectional view of the prostate of  FIG. 13A  taken along line  13 B- 13 B of  FIG. 13A  illustrating the containment of the ablation in transition zone tissue adjacent the prostatic urethra. 
         FIG. 14  is a transverse sectional view of a prostate showing the range or radial angles in which the microcatheter of the invention in introduced into transition zone tissue. 
         FIG. 15  is an MRI of a BPH patient 1 week after a treatment as indicated schematically in  FIGS. 13A-13B . 
         FIG. 16  is a block diagram of a method corresponding to the invention. 
         FIG. 17  is a longitudinal sectional schematic view of a prostate showing a method of treating transition zone tissue with an elongated needle introduced parallel to the prostatic urethra. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 4, 5 and 6  depict one embodiment of a probe  100  configured for trans-urethral access to the prostate which provides a viewing mechanism to view the urethra as the probe is navigated to a site in the interior of the patient&#39;s prostate. The probe  100  further carries an extendable and retractable microcatheter member  105  ( FIG. 5 ) having a distal tip portion  108  ( FIG. 4 ) configured to penetrate into precise targeted locations in transition zone tissue in prostate lobes to ablate targeted tissue volumes. 
     Handle and Introducer Portion 
     In  FIG. 4 , it can be seen that probe  100  has an elongate introducer portion  110  configured for insertion into the urethra and a handle portion  111  for gripping with a human hand. The key structural component of introducer portion  110  comprises a rigid introducer sleeve or extension sleeve  112  extending along longitudinal axis  113  with proximal end  114   a  and distal end  114   b . A bore  115  ( FIG. 5 ) in the rigid extension sleeve  112  extends along longitudinal axis  113 . In one embodiment, referring to  FIGS. 4 and 5 , the extension sleeve  112  comprises a thin-wall stainless steel tube with bore  115  dimensioned to receive a commercially available viewing scope or endoscope  118 . The schematic cut-away view of  FIG. 5  shows structural bulkhead  120  coupled to a medial portion  122  of extension sleeve  112 . The structure or bulkhead  120  comprises the structural member to which the molded handle having pistol grip  124 , and more particularly the right- and left-side mating handle parts,  125   a  and  125   b , are coupled ( FIG. 4 ). The bulkhead can be a plastic molded part that can be fixed to sleeve  112  or rotationally coupled to sleeve  112 . 
     Referring to  FIGS. 5-6 , in which the molded handle left and right sides,  125   a ,  125   b , are not shown, it can be seen that bore  115  in sleeve  112  has a proximal open end  130  into which the endoscope  118  can be inserted. The proximal end portion  114   a  of extension sleeve  112  can be coupled to an adapter mechanism  132  that releasably engages the endoscope  118  and rotationally aligns the endoscope  118  with the introducer portion  110 . The endoscope  118  has a proximal viewing end  135  and light connector  136  extending outward from the viewing end  136  for coupling a light source  140  to the endoscope.  FIG. 7  illustrates that bore  115  in sleeve  112  has a diameter ranging from about 2 to 5 mm for accommodating various endoscopes  118 , while at the same time providing an annular space  138  for allowing an irrigation fluid to flow through bore  115  and outwardly from the introducer portion. 
     In one embodiment of probe  100 , referring to  FIGS. 5-8 , the extendable-retractable microcatheter  105  comprises a thin-wall flexible polymer tube with a sharp tip that is axially slidable in a passageway  148  in the introducer portion  110 .  FIGS. 4, 7 and 9  show that the introducer portion  110  comprises an elongate introducer body  144  of plastic or another suitable material that surrounds extension sleeve  112 . The introducer body  144  extends to a distal working end portion  145  having a blunt nose or tip  146  for advancing through the urethra. The elongate introducer body  144  is further configured with passageway  148  that accommodates the microcatheter member  105  as will be described below. 
     Referring to  FIGS. 8-9 , the distal end portion  145  of the introducer body  144  is configured with openings  160  that open to central open region  162  that is distal to the distal lens  164  of endoscope  118  that allows for viewing of the urethra through the lens  164  of the endoscope during navigation. The endoscope  118  can have a lens with a 30°, 12.5° or other angle for viewing through openings  160 . As can be seen in  FIGS. 8-9 , the openings  160  have bridge elements  165  therebetween that function to prevent tissue from falling into central open region  162  of the introducer body  144 . In  FIG. 8 , it can be seen that the working end portion  105  of the flexible microcatheter shaft  105  is disposed adjacent to open region  162  and thus can be viewed through the endoscope lens  164 . 
     Microcatheter and Spring-Actuator 
       FIGS. 10-11  show the flexible microcatheter member or needle  105  de-mated from the probe  100  to indicate its repose shape. In one embodiment, the microcatheter  105  has a first (proximal) larger cross-section portion  170  that necks down to second (distal) cross-section portion  175  wherein the smaller second cross-section portion  175  has a curved repose shape with the curve configured to conform without significant resistance to the contour of the curved axis  177  of the path followed by the working end  108  of the microcatheter  105  as it is moved from its non-extended position to its extended position as shown in  FIGS. 1, 8 and 9 . In one embodiment, referring to  FIGS. 10-12 , the microcatheter&#39;s first cross section portion  170  comprises a thin wall outer sleeve  180  that is concentrically outward from inner microcatheter tube  185  that extends the length of the microcatheter member  105 . As can be seen in  FIG. 12 , the outer sleeve  180  provides a thermally insulative air gap  188  around inner tubular member  185 . In one embodiment shown depicted in  FIG. 12 , the outer sleeve  180  is configured with intermittent protrusions  190  that maintain the air gap  188  between the inner surface  192  of outer sleeve  180  and outer surface  193  of inner microcatheter tube. Referring back to  FIG. 12 , both the outer sleeve  180  and inner tubular member can comprise a high-temperature resistant polymer such as Ultem® that is suited for delivering a high temperature vapor as will be described below. In one embodiment, the microcatheter tube  185  has an outside diameter of 0.050″ with an interior lumen  195  of approximately 0.030″. Referring to  FIG. 11 , one embodiment of working end portion  108  for delivering vapor media to tissue has a thin wall  198  with a plurality of outlet ports  200  therein that are configured for emitting a condensable vapor media into tissue as will be described below. The outlet ports can range in number from about 2 to 100, and in one embodiment comprise of 12 outlets each having a diameter of 0.008″ in six rows of two outlets with the rows staggered around the working end  108  as shown in  FIGS. 10-11 . In one embodiment shown in  FIGS. 10-11 , the distal-most tip  202  of the microcatheter  105  has a sharpened conical configuration that can be formed of a plastic material. As will be described below, it has been found that a polymeric needle and needle tip  202  is useful for its thermal characteristics in that its heat capacity will not impinge on vapor quality during vapor delivery. 
       FIGS. 10-11  further illustrate that the distal tip portion  108  of microcatheter  105  can have at least one marking  204  that contrasts with the color of the microcatheter  105  that is configured to be viewed through the endoscope (not shown). In one embodiment, the marking  204  can comprise annular marks of a first color that contrast with a second color of the microcatheter, wherein the marks are not visible through the endoscope when the microcatheter is in a retracted position. After the microcatheter is extended into tissue, the marks can be visible through the endoscope, which indicates that the microcatheter  105  has been extended into tissue. 
     Returning now to  FIGS. 5 and 6 , the cut-away view of the handle portion  111  shows the microcatheter member  105  and associated assemblies in the non-extended or retracted position.  FIG. 5  shows flanges  208   a  and  208   b  of cocking actuator  210  are disposed on either side of actuator collar  212  that is coupled to proximal end  114   a  of the slidable microcatheter member  105 . As can be understood from  FIG. 5 , the downward-extending cocking actuator  210  is adapted to cock the flanges  208   a ,  208   b  and microcatheter  105  to a cocked position which corresponds to the non-extended or retracted position of the microcatheter  105 . In  FIG. 5 , the actuator  210  is shown in a first position B (phantom view) and second position B′ following actuation with an index finger to thus cock the microcatheter member  105  to the second releasable non-extended position (or cocked position) B′ from its extended position B. The flange  208   a  and actuator  210  is further shown in phantom view in the released position indicated at  208   a ′. In  FIG. 5 , the flanges  208   a ,  208   b  and associated assemblies are configured for an axial travel range indicated at A that can range from about 8 mm to 15 mm which corresponds to the travel of the microcatheter  105  and generally to the tissue-penetration depth. In the embodiment of  FIG. 5 , the flanges  208   a ,  208   b  and microcatheter member  105  are spring-actuatable to move from the non-extended position to the extended position by means of helical spring  215  disposed around sleeve  112 . As can be seen in  FIG. 5 , the spring  215  is disposed between the slidable flange  208   b  and trigger block  218  that comprises a superior portion of the release trigger  220  which is configured to release the microcatheter  105  from its cocked position. In some embodiments, the release trigger  220  is configured to release the microcatheter  105  from its cocked or non-extended position into its extended position. 
       FIG. 5  further illustrates the release trigger  220  releasably maintaining the flange  205   a  and microcatheter  105  in its cocked position wherein tooth portion  222  of the trigger  220  engages the lower edge of flange  208   a . It can be understood from  FIG. 5  that the release trigger  220  is configured to flex or pivot around living hinge portion  224  when trigger  220  is depressed in the proximal direction by the physician&#39;s finger actuation. After actuation of trigger  220  and release of the microcatheter  105  to move distally, the axial travel of the assembly is configured to terminate softly rather than abruptly as flange  208   a  contacts at least one bumper element  230  as depicted in  FIG. 6 . The bumper elements  230  can comprise any spring or elastomeric element, and in  FIG. 6  are shown as an elastomer element housed in a helical spring, which serve to cushion and dampen the end of the travel of the spring-driven microcatheter assembly. The bumper elements  230  are coupled to flange  235  which in turn is configured to be fixed between right- and left-side handle parts  125   a  and  125   b  ( FIG. 4 ). 
     Now turning to the energy-delivery aspect of the system, a vapor source  250  is provided for delivering a vapor media through the microcatheter member  105  to ablate tissue. The vapor source can be a vapor generator that can deliver a vapor media, such as water vapor, that has a precisely controlled quality to provide a precise amount of thermal energy delivery, for example measured in calories per second. Descriptions of suitable vapor generators can be found in the following U.S. application Ser. Nos. 11/329,381; 12/167,155; 12/389,808; 61/068,049; 61/068,130; 61/123,384; 61/123,412; 61/126,651; 61/126,612; 61/126,636; 61/126,620 all of which are incorporated herein by reference in their entirety. The vapor generation system also can comprise an inductive heating system similar to that described in U.S. Application Nos. 61/123,416, 61/123,417, and 61/126,647. The system further includes a controller  255  that can be set to control the various parameters of vapor delivery, for example, the controller can be set to deliver vapor media for a selected treatment interval, a selected pressure, or selected vapor quality. 
     Referring to  FIGS. 4-5 , in one embodiment, the vapor source  250  can be remote from the handle  124  and vapor media is carried to the handle by a flexible conduit  262  that couples handle and check valve  264  therein. In one embodiment, vapor can be re-circulated in conduit  262  until a solenoid in the vapor source is actuated to cause the vapor flow to thus provide an increased fluid pressure which opens the check valve  264  and allows the vapor media to flow through flexible tube  268  to valve  270  that can be finger-actuated by trigger  275 . In one embodiment depicted in  FIG. 5 , the trigger  275  is urged toward a non-depressed position by spring  277  which corresponds to a closed position of valve  270 . The trigger  275  also can be coupled by an electrical lead (not shown) to controller  255 . Thus, actuating the trigger  275  can cause the controller to actuate a solenoid valve in the vapor generator to cause vapor flow through the relief valve. As a safety mechanism, the valve  270  in the handle is opened only by its actuation to thus permit the flow of vapor media through flexible tube  278  which communicates with inflow port portion  280  of collar  212  which in turn communicates with the lumen  195  ( FIG. 12 ) in the microcatheter  105 . Thus,  FIG. 5  illustrates the flow path and actuation mechanisms that provide vapor flow on demand from the vapor source  250  to the vapor outlets  200  in working end  108  of the microcatheter  105 . 
     As can be seen in  FIG. 5 , the handle can also provide an interlock mechanism that prevents the actuation of vapor flow if the microcatheter release trigger is in the cocked position, wherein edge portion  290  coupled to release trigger  220  can engage notch  292  in trigger  275  to prevent depression of said trigger  275 . 
     Still referring to  FIG. 5 , one embodiment of the system includes a fluid irrigation source  300  that is operatively couple to the bore  115  in extension member  112  to deliver a fluid outward from the bore  115  to the open region  162  of the probe working end  145  (see  FIG. 8 ). As can be seen in  FIG. 7 , the bore  115  is dimensioned to provide a space  138  for fluid irrigation flow around the endoscope  118 . In  FIG. 5 , it can be seen that fluid source  300 , which can be a drip bag or controlled pressure source of saline or another fluid, is detachably coupled to tubing  302  in the handle which extends to a valve  305  that can be thumb-operated from actuators  308  on either side of the handle. The thumb actuator  308  can also control the rate of flow of the irrigation fluid by moving the actuator  308  progressively forward, for example, to open the valve more widely open. The fluid flows from valve  305  through tube  306  to a port or opening  315  in the extension sleeve  112  to thus enter the bore  115  of the sleeve. 
       FIG. 5  further depicts an aspiration source  320  operatively coupled to tubing  322  in the handle  124  which also can be actuated by valve  305  wherein the thumb actuator  308  can be rocked backwardly to allow suction forces to be applied through the valve  305  to tubing  306  that extends to port  315  in the extension member—which is the same pathway of irrigation flows. Thus, suction or aspiration forces can withdraw fluid from the working end of the device during a treatment. 
     In another aspect of the invention, referring to  FIGS. 10-11 , the microcatheter  105  carries a temperature sensor or thermocouple  405  at a distal location therein, for example as indicated in  FIG. 10 . The thermocouple is operatively connected to controller  255  to control vapor delivery. In one embodiment, an algorithm reads an output signal from the thermocouple  405  after initiation of vapor delivery by actuation of trigger  275 , and in normal operation the thermocouple will indicate an instant rise in temperature due to the flow of vapor. In the event, the algorithm and thermocouple  405  do not indicate a typical rise in temperature upon actuation of trigger  275 , then the algorithm can terminate energy delivery as it reflects a system fault that has prevented energy delivery. 
     In another embodiment, referring again to  FIGS. 10-11 , the microcatheter  105  can carry another temperature sensor or thermocouple  410  in a portion of microcatheter  105  that resides in passageway  148  of the introducer body  144 . This thermocouple  410  is also operatively connected to controller  255  and vapor source  250 . In one embodiment, an algorithm reads an output signal from thermocouple  410  after initiation of vapor delivery and actuation of actuator  308  that delivers an irrigation fluid from source  300  to the working end  145  of the probe. The delivery of irrigation fluid will maintain the temperature in the region of the thermocouple at a predetermined peak level which will not ablate tissue over a treatment interval, for example below 55° C., below 50° C. or below 45° C. If the temperature exceeds the predetermined peak level, the algorithm and controller can terminate vapor energy delivery. In another embodiment, a controller algorithm and modulate the rate of cooling fluid inflows based on the sensed temperature, and/or modulate the vapor flow in response to the sensed temperature. In an alternative embodiment, the thermocouple  410  can be in carried in a portion of introducer body  144  exposed to passageway  148  in which the microcatheter resides. 
     Method of Use 
     Referring to  FIGS. 13A and 13B , the device and method of this invention provide a precise, controlled thermal ablative treatment of tissue in first and second lateral prostate lobes,  78   a  and  78   b . Additionally, the device of the invention can be used to treat an affected median lobe in patients with an enlarged median lobe. In particular, the ablative treatment is configured to ablate smooth muscle tissue, to ablate alpha adrenergic (muscle constriction) receptors, and to ablate sympathetic nerve structures. More in particular, the method of ablative treatment is configured to target such smooth muscle tissue, alpha adrenergic receptors, and sympathetic nerve structures parallel to the prostatic urethra in transition zone tissue TZ between the bladder neck region  420  and the verumontanum region  422  as depicted in  FIGS. 13A-13B . The targeted ablation regions  425  can have a depth indicated at D in  FIGS. 13A-13B  that is less than 2 cm outward from the prostatic urethra  70 , or less than 1.5 cm outward from the urethra. In another embodiment, the targeted ablation regions can have a depth D that is less than 12 mm outward from the prostatic urethra  70 . In one embodiment, the targeted ablation region has a depth D between 10 mm-12 mm from the prostatic urethra. Depending on the length of the patient&#39;s prostatic urethra  70 , the number of energy deliveries and ablated regions  425  can range from 2 to 4 and typically is 2 or 3. 
     In a method of use, the physician can first prepare the patient for trans-urethral insertion of the extension portion  110  of probe  100 . In one example, the patient can be administered orally or sublingually a mild sedative such as Valium, Lorazepam or the like from 15 to 60 minutes before the procedure. Of particular interest, it has been found that prostate blocks (injections) or other forms of anesthesia are not required due to lack of pain associated with an injection of a condensable vapor. The physician then can actuate the needle-retraction actuator  210 , for example with an index finger, to retract and cock the microcatheter  105  by axial movement of the actuator (see  FIGS. 4-6 ). By viewing the handle  124 , the physician can observe that the microcatheter  105  is cocked by the axial location of trigger  210 . A safety lock mechanism (not shown) can be provided to lock the microcatheter  105  in the cocked position. 
     Next, the physician can advance the extension portion  110  of the probe  100  trans-urethrally while viewing the probe insertion on a viewing monitor coupled to endoscope  118 . After navigating beyond the verumontanum  422  to the bladder neck  420  ( FIG. 13A ), the physician will be oriented to the anatomical landmarks. The landmarks and length of the prostatic urethra can be considered relative to a pre-operative plan based on earlier diagnostic ultrasound images or other images, such as MRI images. 
     As can be seen in  FIG. 14 , the physician can rotate the handle of the probe relative to the horizontal plane H from 0° to about 60° upwardly, to insure that the microcatheter  105  penetrates into a central region of the transition zone tissue TZ (see  FIGS. 13B and 14 ). After the physician rotates the microcatheter-carrying probe about its axis to orient the microcatheter within the range of angles depicted in  FIG. 14 , the release trigger  220  can be actuated to thereby penetrate the microcatheter  105  into the prostate lobe. Thereafter, the vapor actuation trigger  275  can be actuated to deliver vapor media into the prostate tissue for a treatment interval of approximately 30 seconds or less, or 20 seconds or less. In one embodiment, the vapor delivery interval is 10 seconds. 
       FIG. 13A  depicts a complete treatment which includes cocking the microcatheter  105 , re-positioning the microcatheter, and releasing the microcatheter followed by vapor delivery in a plurality of locations in each lobe, for example for a total of three vapor injections in each lobe (i.e., for a total of six “sticks” of the microcatheter into the prostate). The schematic view of  FIG. 13A  thus illustrates a method the invention wherein three penetrations of microcatheter  105  are made sequentially in a prostate lobe and the treatment interval, the vapor pressure and calories/sec provided by vapor energy are selected to produce slightly overlapping ablations or lesions to ablate the smooth muscle tissue, alpha adrenergic receptors, and sympathetic nerve structures in a region parallel to the prostatic urethra. The pressure of the vapor media exiting the vapor outlets  200  can be between 40 mmHg and 50 mmHg. The system can deliver a vapor media configured to provide energy in the range of 1 to 40 cal/sec at pressures at the tissue interface ranging from about 20 mmHg to 200 mmHg. The system can utilize a source of vapor media that provides a vapor having a temperature of at least 60° C., 80° C., 100° C., 120° C., or 140° C. The method of the invention, when compared to the prior art, can reduce the total volume burden of ablated tissue and thus can lessen the overall inflammatory response. This aspect of the method can lead to more rapid tissue resorption, more rapid clinical improvement and can eliminate the need for post-treatment catheterization. 
     In another embodiment, the urethra can be irrigated with a cooling fluid from source  300  (see  FIGS. 5-6 ) throughout the selected interval of energy delivery. It has been found that such a flow of cooling fluid may be useful, and most important the flow of cooling fluid can be continuous for the duration of the treatment interval since such times are short, for example 10 to 30 seconds at each treatment location. Such a continuous flow method cannot be used in prior art methods, such as RF ablation methods, since the cooling fluid volume accumulates in the patient&#39;s bladder and the lengthy RF treatment intervals would result in the bladder being filled rapidly, resulting in further time-consuming steps to withdraw the RF probe, removing the excess irrigation fluid volume and then re-starting the treatment. 
       FIG. 15  is a sagittal MRI image of an exemplary treatment of a BPH patient 1 week following the procedure, in which the treatment included the following steps and energy delivery parameters. The patient&#39;s prostate weighed 44.3 gms based on ultrasound diagnosis. Amparax (Lorazepam) was administered to the patient 30 minutes before the procedure. In the treatment of the patient in  FIG. 15 , each treatment interval comprised of 10 seconds of vapor delivery at each of six locations in transition zone TZ tissue (3 injections in each lobe). Thus, the total duration of actual energy delivery was 60 seconds in the right and left prostate lobes. The energy delivered was 5 cal/sec, or 50 calories per treatment location  425  ( FIG. 13A ) and a total of 300 total calories delivered to create the targeted ablation parallel to the prostatic urethra  70 , which can be seen in the MRI of  FIG. 15 . The vapor media comprised water vapor having a temperature of approximately 100° C. 
     By comparing the method of the present invention of  FIGS. 13A-13B  with prior art methods, it can be understood the present invention is substantially different than the prior art. Prior art RF needles typically are elongated, which ablates tissue away from the prostatic urethra and does not target tissue close to and parallel to the prostatic urethra. Second, many prior art RF energy delivery methods apply RF energy for 1 to 3 minutes or longer which allows thermal diffusion to reach the capsule periphery, unlike the very short treatment intervals of the method of the present invention which greatly limit thermal diffusion. Third, most prior art RF energy delivery methods do not create a uniform ablation of tissue adjacent and parallel to the prostatic urethra to ablate smooth muscle tissue, alpha adrenergic receptors, and sympathetic nerve structures in a region parallel to the prostatic urethra. 
     In another embodiment of the method of the invention, referring again to  FIG. 13B , the vapor delivery member or microcatheter  105  is introduced into selected locations in the transition zones tissue TZ as described above. The transition zone tissue TZ comprises the region in which substantially all benign hyperplastic growth occurs, and therefore this tissue impinges on the urethra resulting in symptoms of BPH. In a method of the invention, the selected radial angle of the microcatheter as show in  FIG. 14  thus provides injection of the vapor media into a central portion of such transition zone tissue TZ which allows for ablation of transition zone tissue without ablating non-transition zone tissue. This aspect of the method is enabled by the use of vapor media, a form of convective heating, and wherein such convective heating does not propagate beyond denser tissue or fibrous layers that surround the transition zone tissue TZ. Thus, energy delivered from condensation of the vapor media will be confined to the treated region of the transition zone tissue TZ, since vapor propagation is impeded by tissue density.  FIG. 13B  depicts that the propagation of vapor media is reflected from tissues that interface with transition zone tissue TZ, which tissue includes the prostatic urethra  70 , central zone tissue, a fibrous layer or plane  92  between the lobes  78   a ,  72   b , a fibrous layer  80  adjacent peripheral zone tissue PZ, and the fibromuscular stroma FS. The method of ablation is advantageous in that only the tissue causally related to BPH is ablated and thereafter resorbed. In prior art methods that utilize RF energy, the applied energy can cross natural boundaries between tissue zones since RF current flow and resultant Joule heating is only influenced by electrical impedance, and not by tissue density. The additional advantage is that the ablated tissue burden can be significantly reduced, when compared to other modalities of energy delivery, such as RF. The reduced burden of ablated tissue in turn lessens the overall inflammatory response, and will lead to more rapid patient recovery. 
     In another aspect of the invention, referring to  FIG. 13A , the vapor media propagation and convective heating can extend adjacent a selected length of the prostatic urethra  70  from the bladder neck  420  to verumontanum  422  within the transition zone tissue TZ, while leaving prostatic urethra undamaged which in turn can eliminate the need for post-treatment catheterization. In another aspect of the invention, the vapor propagation, when confined to transitional zone tissue TZ, further ensures that no unwanted tissue heating or ablation will occur outward of the prostatic capsule  96  where nerves and nerve bundles are located. The treated tissue geometry within transition zone tissue TZ can be limited to region adjacent the prostatic urethra  70  without damage to prostate tissue outward from the urethra greater than 1.5 cm or greater that 2.0 cm. 
     One method corresponding to the invention is shown in the block diagram of  FIG. 16 , which includes the steps of advancing a probe trans-urethrally to the patient&#39;s prostate, introducing a vapor delivery member into at least one selected location in transition zone TZ tissue of a prostate, and injecting a condensable vapor media from the vapor delivery member wherein the selected location causes the vapor media to reflect from boundary tissue adjacent the transition zone tissue to thereby confine vapor condensation and heating to the transition zone tissue. In general, a method for treating BPH comprises introducing a vapor delivery member into prostatic transition zone tissue, and injecting vapor media into a selected location that is at least partly surrounded by another outward tissue with a higher density, wherein the outward tissue either reflects propagation of the vapor media or has a build-up of interstitial pressure therein (due to vapor media injection) which impeded the flow of vapor outwardly to thereby confine the vapor-induced thermal treatment to the targeted transition zone tissue. 
     In another aspect of the invention, referring to  FIG. 17 , a similar method for treating BPH comprises introducing a vapor delivery needle  105 ′ into transition zone tissue TZ from a location near the apex  430  of the prostate, advancing the working end of needle  105 ′ end substantially parallel to the prostatic urethra  70 , and introducing vapor from the working end to ablate a region of the transition zone tissue adjacent the urethra similar to the treatment of  FIGS. 13A-13B . An apparatus and method utilizing such an elongate needle was disclosed in co-pending U.S. patent application Ser. No. 12/614,218. It should be appreciated that a vapor delivery needle also can be introduced into the targeted transition zone tissue from a trans-rectal approach and viewed under ultrasound as disclosed in U.S. patent application Ser. No. 12/687,734. 
     In another embodiment, the system include a vapor delivery mechanism that delivers controlled and substantially predetermined amount of energy, and thus controlled amount of energy, over a variable time interval wherein injection pressure varies in response to tissue characteristics. 
     As for additional details pertinent to the present invention, materials and manufacturing techniques may be employed as within the level of those with skill in the relevant art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts commonly or logically employed. Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Likewise, reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “and,” “said,” and “the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. Unless defined otherwise herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The breadth of the present invention is not to be limited by the subject specification, but rather only by the plain meaning of the claim terms employed.