Abstract:
The invention provides an apparatus and system for ablation of body structures or tissue in the region of the rectum. A catheter is inserted into the rectum, and an electrode is disposed thereon for emitting energy. The environment for an ablation region is isolated or otherwise controlled by blocking gas or fluid using a pair of inflatable balloons at upstream and downstream locations. Inflatable balloons also serve to anchor the catheter in place. A plurality of electrodes are disposed on the catheter and at least one such electrode is selected and advanced out of the catheter to penetrate and ablate selected tissue inside the body in the region of the rectum. The electrodes are coupled to sensors to determine control parameters of the body structure or tissue, and which are used by feedback technique to control delivery of energy for ablation or fluids for cooling or hydration. The catheter includes an optical path disposed for coupling to an external view piece, so as to allow medical personnel to view or control positioning of the catheter and operation of the electrodes. The catheter is disposed to deliver flowable substances for aiding in ablation, or for aiding in repair of tissue, such as collagen or another substance for covering lesions or for filling fissures. The flowable substances are delivered using at least one lumen in the catheter, either from at least one hole in the catheter, from an area of the catheter covered by a microporous membrane, or from microporous balloons.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation of U.S. application Ser. No. 09/557,993, filed Apr. 25, 2000 (Attorney Docket No. STUA0012C). 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    This invention relates to ablation of rectal and other internal body structures.  
           [0004]    2. Description of Related Art  
           [0005]    Human beings are subject to a number of disorders in the area of the rectum and colon, including hemorrhoids (external and internal), prolapse of the rectal muscles, rectal muscle spasms, anal fissures, polyps, diverticulosus and diverticulitus, and pilonital cysts. Other internal disorders in nearby regions of the body include (in men) prostate cancer, (in women) incontinence, vaginal bleeding, vaginal cysts, vaginal fibroids, prolapse of the uterus, and related tumors or cancerous tissue.  
           [0006]    Although there are treatments available for these disorders, such as surgery, systemic or topical medication, these treatments suffer from various drawbacks, including (for surgery) their relative invasiveness and expense, and (for medicinal approaches) their relative ineffectiveness and the causation of serious side-effects. Accordingly, it would be advantageous to provide methods and apparatus for treatment which are not subject to the drawbacks of surgery and medicinal approaches.  
           [0007]    Although it is known to use RF energy to ablate tissue in the body (such as heart muscle tissue) to treat disorders, one problem which has arisen in the art is accounting for the flow of bodily fluids and gases while ablating tissue. Bodily fluids can dissipate, and can detrimentally absorb, energy to be applied to tissue.  
           [0008]    Accordingly, it would be advantageous to provide improved techniques for treatment of disorders in the area of the rectum and colon. This advantage is achieved by a method and system according to the present invention in which a catheter is inserted into the rectum, and at least one electrode is disposed thereon for emitting energy to ablate body structures or other tissue in an ablation region in or near the rectum, such as the sphincter, rectum, colon, or prostate.  
         SUMMARY OF THE INVENTION  
         [0009]    The invention provides a method and system for ablation of body structures or tissue in an ablation region in or near the rectum (such as the sphincter, rectum, colon, or prostate). A catheter is inserted into the rectum, and at least one electrode is disposed thereon for emitting energy to ablate body structures or other tissue, such as by cell death, dehydration, or denaturation. The environment for the ablation region is isolated or otherwise controlled, such as by blocking gas or fluid using a pair of inflatable balloons at upstream and downstream locations from the ablation region. In a preferred embodiment, inflatable balloons also serve to anchor the catheter in place and prevent the catheter from being expelled from the body.  
           [0010]    In preferred embodiments, the catheter is flexible for reaching a selected internal organ or region, a plurality of electrodes are disposed on the catheter and at least one such electrode is selected and advanced out of the catheter to penetrate and ablate selected tissue inside the body in ablation region in or near the rectum, such as an individual cyst, hemorrhoid, polyp, tumor, or other selected lesion or tissue. The electrodes are coupled to sensors to determine control parameters of the body structure or tissue, such as impedance or temperature, and which are used by feedback technique to control delivery of energy for ablation or fluids for cooling or hydration. In a preferred embodiment, the catheter includes an optical path disposed for coupling to an external view piece, so as to allow medical personnel to view or control positioning of the catheter and operation of the electrodes.  
           [0011]    In further preferred embodiments, the catheter is disposed to deliver flowable substances for aiding in ablation, such as saline or antibiotics, or for aiding in repair of tissue (either before or after ablation), such as collagen or another substance for covering lesions or for filling fissures in or near the ablation region, or for other medicinal effects, such as anesthetic, anti-inflammatory, or antispasmodic substances. The flowable substances are delivered using at least one lumen in the catheter, either from at least one hole in the catheter, from an area of the catheter covered by a microporous membrane, or from microporous balloons (either the same as or in addition to balloons used to anchor the catheter in place or to block gas or fluid). 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIGS. 1 and 1 a  show a side view of a catheter and electrode assembly.  
         [0013]    [0013]FIGS. 2 and 2 a  show a cut-away view of a catheter and electrode, taken along a line  2 -- 2  in FIG. 1.  
         [0014]    [0014]FIG. 3 shows a method of treatment of a hemorrhoid.  
         [0015]    [0015]FIG. 4 shows a method of treatment of a prolapsed or spasmodic muscle.  
         [0016]    [0016]FIG. 5 shows a method of treatment of an anal fissure.  
         [0017]    [0017]FIG. 6 shows a method of treatment of a tumor in the prostate.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    Catheter and Electrode Assembly  
         [0019]    [0019]FIG. 1 shows a side view of a catheter and electrode assembly.  
         [0020]    An assembly  100  for ablating rectal and other internal body structures includes a catheter  110 , a control and delivery linkage  120 , and a control element  130 .  
         [0021]    The catheter  110  is coupled to the control and delivery linkage  120  using a gearing element  121 , which allows the catheter  110  to be rotated with respect to the control and delivery linkage  120  by an operator using the control element  130 .  
         [0022]    The catheter  110  includes a base  111 , having a substantially cylindrical shape, coupled at a proximal end to the gearing element  121 , and having a distal end. The catheter  110  is preferably disposed for insertion into the rectum at an angle to the control and delivery linkage  120 , preferably an angle between about 30° and about 45° less than a right angle. The catheter  110  is between about 1 inch (2.54 cm) and about 2 inches (5.08 cm) in diameter, and between about 6 inches (15.24 cm) and about 8 inches (20.32 cm) in length.  
         [0023]    The catheter  110  includes a plurality of holes  112 , and a plurality of electrodes  113  which may be extended from at least some of the holes  112 . The holes  112  are spaced regularly around the circumference and along the length of the catheter  110 , having a spacing of about 0.25 inches (0.64 cm) between adjacent holes  112 . The electrodes  113  are spaced regularly to occupy about one-half of the holes  112 , and are between about 0.5 cm and about 1.0 cm in length.  
         [0024]    The electrodes  113  each include a metallic tube  114  defining a hollow lumen  115 , shaped similarly to an injection needle, so as to be disposed to deliver at least one flowable substance to a region  140  near the catheter  110 . In a preferred embodiment, the deliverable flowable substance includes saline with a concentration of less than about 10% NaCl, which aids in both hydration of body structures and other tissue, and in delivery of RF energy to the region  140 . However, in alternative embodiments, the deliverable flowable substance includes other substances, including saline with other concentrations, systemic or topical antibiotics, collagen or another hardenable substance, or other bioactive, chemoactive, or radioactive substances (including anesthetic, anti-inflammatory, or antispasmodic substances, or tracer materials).  
         [0025]    The catheter  110  includes at least one balloon  116 , disposed for inflation so as to block gas or fluid from the body from entering the region  140 . In a preferred embodiment, there is a distal balloon  116  disposed at the distal end of the catheter  110  and there is a proximal balloon  116  disposed at the proximal end of the catheter  110 . The distal balloon  116  and the proximal balloon  116  preferably each comprise ring-shaped balloons, disposed so that when inflated each surrounds the catheter  110  and makes a gas-tight or fluid-tight seal, both with the catheter  110  and with a wall  141  of the rectum or other body structure into which the catheter  110  is inserted. However, in alternative embodiments, the distal balloon  116  may comprise a spherical or ellipsoidal balloon disposed at the distal end of the catheter  110  in such manner that when inflated it surrounds the catheter  110  and makes a gas-tight or fluid-tight seal with the wall  141 .  
         [0026]    The catheter  110  also includes at least one balloon  116  disposed to anchor the catheter  110  at a selected location within the rectum or other body structure into which the catheter  110  is inserted. In a preferred embodiment, the balloon  116  used to anchor the catheter  110  is the proximal balloon  116 , which when inflated prevents the catheter  110  from being expelled from the body in like manner as the operation of a Foley catheter. However, in alternative embodiments, the balloon  116  used to anchor the catheter  110  may comprise an additional or alternative balloon which is disposed solely or primarily for the purpose of anchoring the catheter  110  into its selected place, again in like manner as the operation of a Foley catheter.  
         [0027]    The catheter  110  includes a fluid circulation system  117 , including at least one fluid outlet port and at least one fluid inlet port. The fluid circulation system  117  is disposed for providing fluid in the region near the catheter  110 , such as for delivering fluid for cooling the region  140  and for removing other fluid for aspirating the region  140 .  
         [0028]    The catheter  110  includes an optical view port  118 , possibly including a lens or other transparent or translucent covering, disposed to allow inflow of light (visible or infrared) for transmission to an operator for viewing and control of the operation of the catheter  110 .  
         [0029]    The catheter  110  includes at least one sensor  119 , such as a sensor  119  for impedance or temperature. In a preferred embodiment, the temperature sensor  119  includes a thermocouple, but in alternative embodiments, the temperature sensor  119  may include a thermistor or other device for sensing temperature and providing signals responsive to temperature near the catheter  110 .  
         [0030]    The control and delivery linkage  120  includes a metallic tube  223  defining a hollow lumen  224 , and is further described with reference to FIG. 2.  
         [0031]    In a preferred embodiment, the control and delivery linkage  120  is between about ½ inch (1.27 cm) and about ⅝ inches (1.59 cm) in diameter, and between about 6 inches (15.24 cm) and about 8 inches (20.32 cm) in length.  
         [0032]    The control element  130  includes an electrode actuation element  131  for advancing the electrodes  113  out from the catheter  110 , a electrode retraction element  132  for retracting the electrodes  113  into from the catheter  110 , and an operation element  133  for controlling operation of the catheter  110 , including delivery of flowable substances using the holes  112  and delivery of energy using the electrodes  113 .  
         [0033]    Advancing and Retracting Electrodes  
         [0034]    [0034]FIG. 2 shows a cut-away view of a catheter, taken along a line  2 -- 2  in FIG. 1.  
         [0035]    The catheter  110  comprises a rotatable element  210  which is disposed for rotation in a first direction  211  to advance the electrodes  113  out of the catheter  110  and in a second direction  212  opposite the first direction  211  to retract the electrodes  113  back into the catheter  110 .  
         [0036]    In a preferred embodiment, the rotatable element  210  is coupled to a spring (not shown) or other device which holds the rotatable element  210  in a steady state with the electrodes  113  retracted into the catheter  110 .  
         [0037]    The rotatable element  210  is coupled to the electrode actuation element  131 , which forces the rotatable element  210  to rotate in the first direction  211  so as to advance the electrodes  113  out of the catheter  110 . When the actuator element is not actuated, the spring causes the rotatable element  210  to rotate in the second direction  212  so as to retract the electrodes  113  back into the catheter  110 .  
         [0038]    Each electrode  113  is coupled to an electrode carrier  220 . In a preferred embodiment, each electrode carrier  220  is substantially bar-shaped (but is shown end-on in the figure) and is coupled to a plurality of electrodes  113 , such as about between about three and about six electrodes  113 , so as to substantially simultaneously advance that plurality of electrodes  113  out of the catheter  110  and retract that plurality of electrodes  113  back into the catheter. A plurality of electrode carriers  220  are each disposed in a set of lines corresponding to lines of electrodes  113  disposed for advancement out of the catheter  110  and retraction back into the catheter  110 .  
         [0039]    In a preferred embodiment, the electrodes  113  may be disposed so that when advanced, the electrodes  113  extend to selected depths within the body structure to be ablated. These selected depths may be the same depth for all electrodes  113  which are advanced, or may include a first depth for a first set of electrodes  113  and a second depth for a second set of electrodes  113 .  
         [0040]    In a preferred embodiment, the electrode carriers  220  are coupled to a set of controls (not shown) in the control element  130  for selecting one or more electrode carriers  220  independently using one or more actuation levers  221 , so as to be able to independently advance one or more sets of electrodes  113  coupled thereto out of the catheter  110  and to independently retract one or more sets of electrodes  113  back into the catheter  110 .  
         [0041]    Each electrode carrier  220  is coupled to the rotatable element  210  using a bearing  222 , in such manner so as to translate rotation of the rotatable element  210  into linear radial movement of the electrodes  113 . When the rotatable element  210  is rotated in the first direction  211 , the electrodes are advanced in a first linear movement  223 , while when the rotatable element  210  is rotated in the second direction  212 , the electrodes are retracted in a second linear movement  224 .  
         [0042]    An interior  230  of the rotatable element  210  includes a lumen  225  through which fluids and other flowable substances are provided, and in which conductors providing control signals and sensor signals are disposed.  
         [0043]    Operation of the Catheter and Electrode Assembly  
         [0044]    Operation of the catheter and electrode assembly  100  includes at least the following steps:  
         [0045]    The catheter  110  is inserted into the body at an opening, such as the rectum.  
         [0046]    In a preferred embodiment, the opening is the rectum. A region of the rectum is first infused with a lubricant, such as K-Y jelly, and with an anesthetic, such as lidocaine. An anti-inflammatory, antispasmodic, or other condign medication would also be applied as appropriate. Thereafter, the catheter  110  is inserted into the lubricated region of the rectum. Due to the potential pain induced by the presence of the catheter  110  or electrodes  113 , during operation the catheter  110  infuses a mixture of saline and lidocaine into the region  140  to be ablated.  
         [0047]    In alternative embodiments, the opening may be another opening into the body, such as a natural orifice such as the vagina or the urethra, or an opening which has been made surgically, such as an incision which allows the catheter  110  to be inserted into a blood vessel.  
         [0048]    The preferred size of the catheter  110  will of course be responsive to the size of the opening if other than the rectum. The choice of medicinal elements to be infused prior to or coeval with the catheter  110  will of course be responsive to judgments by medical personnel, and may include lubricants, anesthetics, antispasmodics, antiinflammatories, antibiotics, or other materials with bioactive, chemoactive, or radio-active effect.  
         [0049]    The catheter  110  is positioned within the body at a selected orientation and location, such as a position near a hemorrhoid.  
         [0050]    In one preferred embodiment, the catheter  110  is positioned in the rectum near an eternal or internal hemorrhoid, in a manner as shown in FIG. 3. In this preferred embodiment, the electrodes  113  are ultimately advanced into the hemorrhoid to ablate the hemorrhoid.  
         [0051]    In another preferred embodiment, the catheter  110  is positioned in the rectum near a prolapsed or spasmodic muscle, in a manner as shown in FIG. 4. In this preferred embodiment, the electrodes  113  are ultimately advanced into the prolapsed or spasmodic muscle to ablate selected portions of the prolapsed or spasmodic muscle.  
         [0052]    In another preferred embodiment, the catheter  110  is positioned in the rectum near an anal fissure, in a manner as shown in FIG. 5. In this preferred embodiment, collagen is deposited into the fissure and the electrodes  113  are ultimately advanced into a region near the collagen to harden the collagen for filling the fissure.  
         [0053]    In another preferred embodiment, the catheter  110  is positioned in the colon near a polyp, in a manner similar to that shown in FIG. 3. In this preferred embodiment, the electrodes  113  are ultimately advanced into the polyp to ablate the polyp.  
         [0054]    In another preferred embodiment, the catheter  110  is positioned in the rectum near a pilonital cyst, in a manner similar to that shown in FIG. 3. In this preferred embodiment, the electrodes  113  are ultimately advanced into the cyst to ablate the cyst.  
         [0055]    In another preferred embodiment, the catheter  110  is positioned in the rectum, colon, large intestine, or small intestine, near a cyst or tumor, in a manner similar to that shown in FIG. 3. In this preferred embodiment, the electrodes  113  are ultimately advanced into the cyst or tumor to ablate the cyst or tumor.  
         [0056]    In another preferred embodiment, the catheter  110  is positioned in a male patient, in the rectum near the prostate, in a manner as shown in FIG. 6. In this preferred embodiment, the electrodes  113  are ultimately advanced into a tumor in the prostate to ablate the tumor.  
         [0057]    In another preferred embodiment, the catheter  110  is positioned in a female patient, in the vagina, near a cyst or fibroid, in a manner similar to that shown in FIG. 3. In this preferred embodiment, the electrodes  113  are ultimately advanced into the cyst or fibroid to ablate the cyst or fibroid.  
         [0058]    In another preferred embodiment, the catheter  110  is positioned in a female patient, in the vagina, near a prolapsed uterus, in a manner similar to that shown in FIG. 4.  
         [0059]    In this preferred embodiment, the electrodes  113  are ultimately advanced into the prolapsed uterus selected portions of the prolapsed uterus.  
         [0060]    The catheter  110  is anchored into place at the selected orientation and location by inflating a balloon  116 , such as the distal balloon  116  and the proximal balloon  116 .  
         [0061]    In embodiments where the catheter  110  is positioned in the rectum, the catheter  110  is anchored into place using the proximal balloon  116  and the proximal balloon  116  operates in similar manner as a Foley catheter.  
         [0062]    In alternative embodiments, the catheter  110  includes a stop balloon  116 , such as a ring balloon (as shown in FIG. 3), disposed outside the body so as to prevent the catheter  110  from being inserted “too far”, i.e., beyond its selected location.  
         [0063]    The region  140  near the catheter  110  is isolated from the rest of the body by inflating the distal balloon  116  and the proximal balloon  116 . In a preferred embodiment, this step uses the same distal balloon  116  and the proximal balloon  116  as the step of anchoring the catheter  110  into place.  
         [0064]    Isolation of the region  140  near the catheter  110  from the rest of the body need not be absolute. In a preferred embodiment, the distal balloon  116  and the proximal balloon  116  are microporous, are inflated using saline or water, and thus are disposed to provide saline or water into the region  140  near the catheter  110 . However, in such an embodiment, gas and fluids from the rest of the body are allowed to leak into one or more of the balloons  116  and from there are allowed to leak into the region  140  near the catheter  110 .  
         [0065]    Moreover, while in a preferred embodiment the seal made with the wall  141  of the region  140  by the balloon  116  is gas-tight, in alternative embodiments, that seal is allowed to be simply fluid-tight, and might allow gas to leak from the rest of the body into the region  140  near the catheter  110 .  
         [0066]    One or more sets of electrodes  113  are selected for advancement into a selected mass of tissue in the region  140 . The rotatable element  210  is rotated in the first direction  211 , causing the selected sets of electrodes  113  to advance out of the catheter  110  and into the selected mass of tissue.  
         [0067]    The selected set of electrodes  113  are just those electrodes  113  which are needed to penetrate the selected mass of tissue for ablation.  
         [0068]    In a preferred embodiment where the selected mass of tissue for ablation is a hemorrhoid, the selected set of electrodes  113  are just those electrodes  113  which are needed to penetrate the hemorrhoid. If a plurality of hemorrhoids are selected for ablation, either (1) electrodes  113  needed to penetrate the plurality of hemorrhoids are selected, or (2) electrodes  113  needed to penetrate one of the hemorrhoids are selected, and the operation is repeated for each individual one of the hemorrhoids.  
         [0069]    Similarly, in preferred embodiments where the selected body structure for ablation is an individual cyst, fibroid, polyp, or tumor, the selected set of electrodes  113  are just those electrodes  113  which are needed to penetrate the selected body structure. If there is more than one such selected body structure, either (1) more than one set of electrodes  113  may be selected, or (2) just one set of electrodes  113  may be selected and the operation is repeated for each individual such body structure.  
         [0070]    Similarly, in preferred embodiments where the selected body structure for ablation is muscle tissue or other tissue which is part of a larger body structure, such as a prolapsed or spasmodic muscle, the selected set of electrodes  113  are just those one or more sets of electrodes  113  which are needed to penetrate the portion of the body structure which has been selected for ablation.  
         [0071]    Flowable substances are provided using the holes  112 , and energy is provided to the electrodes  113 , so as to ablate the mass of tissue in the region  140 .  
         [0072]    In a preferred embodiment, the flowable substances are provided using the holes  112  to the region  140  near the catheter  110 .  
         [0073]    In alternative embodiments, the flowable substances may be provided, in addition or instead, (1) from an area of the catheter covered by a microporous membrane, or (2) from one or more microporous balloons. The microporous balloons may either be the same as or in addition to the balloons  116  used to anchor the catheter in place or to block gas or fluid.  
         [0074]    In preferred embodiments, the flowable substances have one of the following functions: (1) to aid in ablation, such as by transmitting RF energy from the electrodes  113  to the body structure to be ablated, as is done by saline or other electrolytic solutions, (2) to rehydrate tissue, as in done by saline or water, or (3) to repair tissue, such as by flowing into cysts or fissures or voids, or by covering lesions, as is done by collagen in a soft form which can be hardened by RF energy.  
         [0075]    In a preferred embodiment, the electrodes  113  deliver RF energy having a frequency between about 435 megahertz and about 485 megahertz, for a period between about 5 minutes and about 10 minutes. The RF energy is received by and heats tissue and other body structures near the electrodes  113 , causing ablation by means of cell death, dehydration, or denaturation.  
         [0076]    In alternative embodiments, the electrodes  113  may deliver other forms of energy, such as heat, microwaves, or infrared or visible laser energy.  
         [0077]    The electrodes  113  are controlled by a feedback technique, using the at least one sensor  119 . In embodiments where there is more than one sensor  119 , the feedback technique may be responsive to each sensor  119 .  
         [0078]    In one preferred embodiment, the at least one sensor  119  includes a temperature sensor  119  and the feedback technique includes a microprocessor (not shown) disposed in or coupled to the control element  130  and operating under control of application software for maintaining the temperature of the body structure to be ablated at a selected temperature, such as a temperature exceeding between about 90° Celsius and about 120° Celsius. In this preferred embodiment, the microprocessor also controls delivery of fluids for cooling or hydration, so as to maintain the temperature of surrounding tissue (i.e., other than the tissue selected for ablation) at temperatures less than between about 90° Celsius and about 120° Celsius.  
         [0079]    In another preferred embodiment, the at least one sensor  119  also includes an impedance sensor  119  and the feedback technique includes a microprocessor operating to terminate delivery of RF energy when a measured impedance of the body structure to be ablated undergoes a substantial change indicative of dehydration or denaturation.  
         [0080]    One or more sets of electrodes  113  are selected for retraction back from the selected mass of tissue in the region  140 . The rotatable element  210  is rotated in the second direction  211 , causing the selected sets of electrodes  113  to retract out of the selected mass of tissue and back into the catheter  110 .  
         [0081]    The same electrodes  113  which were advanced out of the catheter  110  are retracted back into the catheter  110 .  
         [0082]    The catheter  110  is withdrawn from the body at the opening through which it was inserted.  
         [0083]    Before removal, the balloons  116  are deflated so the catheter  110  is no longer anchored in place, all electrodes  113  are retracted back into the catheter  110 , and the catheter  113  is configured to no longer provide flowable substances or energy for ablation.  
         [0084]    Particular Methods and Apparatus for Treatments  
         [0085]    In preferred embodiments, the catheter and electrode assembly  100  may also be used for treatments in addition to, or instead of, ablation of body structures or tissue.  
         [0086]    In one preferred embodiment, operation of the catheter and electrode assembly  100  includes at least the following steps:  
         [0087]    The catheter  110  is inserted into a natural body lumen, such as the urethra.  
         [0088]    In a preferred embodiment, the natural body lumen comprises a normally tubular body structure which has prolapsed, is spasmodic, or is otherwise subject to blockage (partial or complete) or damage (such as to a wall of the natural body lumen).  
         [0089]    The catheter  110  infuses a hardenable substance into the natural body lumen, so as to coat at least one selected section of the wall of the natural body lumen.  
         [0090]    In a preferred embodiment, the hardenable substance includes a collagen which is capable of being flowed onto the wall of the natural body lumen and which is capable of being hardened by application of RF energy, heat, or another agent to be provided by the catheter and electrode assembly  100 .  
         [0091]    The electrodes  113  are advanced and deliver energy to the hardenable substance to harden it.  
         [0092]    In a preferred embodiment, the holes  112  provide saline and the electrodes  113  deliver RF energy to the collagen to harden it, so as to form a hard covering to the wall of the natural body lumen. If appropriate, more than one layer of collagen is applied, so as to provide a hard covering having a thickness exceeding a selected threshold, such as 0.1 inch (0.25 cm). The particular selected threshold will of course depend on the preferred diameter of the natural body lumen.  
         [0093]    In a preferred embodiment for treatment of a prolapsed or spasmodic muscle, (1) the catheter  110  is inserted and pushed through a region where the muscle has prolapsed or blocked the rectum, colon, large intestine, or small intestine, (2) the prolapsed or spasmodic muscle is partially ablated, and (3) collagen is infused and hardened to strengthen the muscle wall. In alternative embodiments, the collagen may be infused before ablation in one or more boluses deposited within the muscle (or on the muscle or near the muscle), so that the steps of muscle ablation and collagen hardening will occur substantially simultaneously.  
         [0094]    In a preferred embodiment for treatment of an anal fissure, (1) the catheter  110  is inserted into a region where the fissure has occurred, (2) a suspension of collagen and saline is infused and fills the fissure, and (3) the collagen is hardened while the saline is removed from the suspension. In this preferred embodiment, the isolated region between the distal balloon  116  and the proximal balloon  116  is maintained at a positive differential pressure with respect to the rest of the rectum, so that the collagen infuses into the fissure; this procedure or a similar procedure is also followed for treatment of diverticulosus and diverticulitus.  
         [0095]    In a preferred embodiment for treatment, in a female patient, of a prolapsed uterus, (1) the catheter  110  is inserted into a region where the uterus has prolapsed, (2) the prolapsed uterus is partially ablated, and (3) collagen is infused and hardened to strengthen, the muscle wall. Similarly to treatment of a prolapsed muscle, in alternative embodiments, the collagen may be infused before ablation, so that the steps of muscle ablation and collagen hardening will occur substantially simultaneously.  
         [0096]    Although preferred embodiments are disclosed herein, many variations are possible which remain within the concept, scope, and spirit of the invention, and these variations would become clear to those skilled in the art after perusal of this application.