Abstract:
A method for treating a sphincter provides a polymer material having a liquid state. The method also provides a catheter having a distal end, a tissue piercing device carried by the distal end, and an energy delivery device coupled to the tissue piercing device. The tissue piercing device has a lumen. The method introduces the catheter into an esophagus and pierces an exterior sphincter tissue surface within with the tissue piercing device. The method advances the tissue piercing device into an interior sphincter tissue site and conveys the polymer material while in a liquid state through the lumen into the interior sphincter tissue site. The method delivers energy to the tissue piercing device to transform the polymer material into a less liquid state within the interior sphincter tissue site, to thereby remodel the sphincter.

Description:
RELATED APPLICATIONS  
       [0001]     This application is a divisional of co-pending U.S. patent application Ser. No. 10/254,471, filed 25 Sep. 2002, which is a continuation of U.S. patent application Ser. No. 09/090,794, filed Jun. 4, 1998 (now abandoned), which is a continuation-in-part of U.S. patent application Ser. No. 09/032,367, filed Feb. 27, 1998 (now U.S. Pat. No. 6,044,846), and a continuation-in-part of U.S. patent application Ser. No. 09/921,356, filed Aug. 2, 2001 (now U.S. Pat. No. 6,613,047), which is a continuation of U.S. patent application Ser. No. 09/032,366, filed Feb. 27, 1998 (now abandoned). 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates generally to an apparatus to treat sphincters, and more particularly to an apparatus to treat esophageal sphincters.  
       DESCRIPTION OF RELATED ART  
       [0003]     Gastroesophageal reflux disease (GERD) is a common gastroesophageal disorder in which the stomach contents are ejected into the lower esophagus due to a dysfunction of the lower esophageal sphincter (LES). These contents are highly acidic and potentially injurious to the esophagus resulting in a number of possible complications of varying medical severity. The reported incidence of GERD in the U.S. is as high as 10% of the population (Castell D O; Johnston B T: Gastroesophageal Reflux Disease: Current Strategies For Patient Management. Arch Fam Med, 5(4): 221-7; (1996 April)).  
         [0004]     Acute symptoms of GERD include heartburn, pulmonary disorders and chest pain. On a chronic basis, GERD subjects the esophagus to ulcer formation, or esophagitis and may result in more severe complications including esophageal obstruction, significant blood loss and perforation of the esophagus. Severe esophageal ulcerations occur in 20-30% of patients over age  65 . Moreover, GERD causes adenocarcinoma, or cancer of the esophagus, which is increasing in incidence faster than any other cancer (Reynolds J C: Influence Of Pathophysiology, Severity, And Cost On The Medical Management Of Gastroesophageal Reflux Disease. Am J Health Syst Pharm, 53(22 Suppl 3):S5-12 (1996 Nov. 15)).  
         [0005]     Current drug therapy for GERD includes histamine receptor blockers which reduce stomach acid secretion and other drugs which may completely block stomach acid. However, while pharmacologic agents may provide short term relief, they do not address the underlying cause of LES dysfunction.  
         [0006]     Invasive procedures requiring percutaneous introduction of instrumentation into the abdomen exist for the surgical correction of GERD. One such procedure, Nissen fundoplication, involves constructing a new “valve” to support the LES by wrapping the gastric fundus around the lower esophagus. Although the operation has a high rate of success, it is an open abdominal procedure with the usual risks of abdominal surgery including: postoperative infection, herniation at the operative site, internal hemorrhage and perforation of the esophagus or of the cardia. In fact, a recent 10 year,  344  patient study reported the morbidity rate for this procedure to be 17% and mortality 1% (Urschel, JD: Complications Of Antireflux Surgery, Am J Surg 166(1): 68-70; (1993 July)). This rate of complication drives up both the medical cost and convalescence period for the procedure and may exclude portions of certain patient populations (e.g., the elderly and immuno-compromised).  
         [0007]     Efforts to perform Nissen fundoplication by less invasive techniques have resulted in the development of laparoscopic Nissen fundoplication. Laparoscopic Nissen fundoplication, reported by Dallemagne et al. Surgical Laparoscopy and Endoscopy, Vol. 1, No. 3, (1991), pp. 138-43 and by Hindler et al. Surgical Laparoscopy and Endoscopy, Vol. 2, No. 3, (1992), pp. 265-272, involves essentially the same steps as Nissen fundoplication with the exception that surgical manipulation is performed through a plurality of surgical cannula introduced using trocars inserted at various positions in the abdomen.  
         [0008]     Another attempt to perform fundoplication by a less invasive technique is reported in U.S. Pat. No. 5,088,979. In this procedure, an invagination device containing a plurality of needles is inserted transorally into the esophagus with the needles in a retracted position. The needles are extended to engage the esophagus and fold the attached esophagus beyond the gastroesophageal junction. A remotely operated stapling device, introduced percutaneously through an operating channel in the stomach wall, is actuated to fasten the invaginated gastroesophageal junction to the surrounding involuted stomach wall.  
         [0009]     Yet another attempt to perform fundoplication by a less invasive technique is reported in U.S. Pat. No. 5,676,674. In this procedure, invagination is done by a jaw-like device and fastening of the invaginated gastroesophageal junction to the fundus of the stomach is done via a transoral approach using a remotely operated fastening device, eliminating the need for an abdominal incision. However, this procedure is still traumatic to the LES and presents the postoperative risks of gastroesophageal leaks, infection and foreign body reaction, the latter two sequela resulting when foreign materials such as surgical staples are implanted in the body.  
         [0010]     While the methods reported above are less invasive than an open Nissen fundoplication, some still involve making an incision into the abdomen and hence the increased morbidity and mortality risks and convalescence period associated with abdominal surgery. Others incur the increased risk of infection associated with placing foreign materials into the body. All involve trauma to the LES and the risk of leaks developing at the newly created gastroesophageal junction.  
         [0011]     Besides the LES, there are other sphincters in the body which if not functioning properly can cause disease states or otherwise adversely affect the lifestyle of the patient. Reduced muscle tone or otherwise aberrant relaxation of sphincters can result in a laxity of tightness disease states including but not limited to urinary incontinence.  
         [0012]     There is a need to provide an apparatus to remodel a sphincter. Another need exists for an apparatus to deliver a polymer material into a sphincter wall and deliver sufficient energy to the polymer material to increase a wall thickness of the sphincter. There is a further need for an apparatus to controllably reduce a diameter of a sphincter without creating a permanent impairment of the sphincter&#39;s ability to achieve a physiologically normal state of closure. Still a further need exists for an apparatus to deliver energy to a sphincter wall and create a tightening of a sphincter without permanently damaging anatomical structures near the sphincter. There is still another need for an apparatus to reduce the diameter of a lower esophageal sphincter to reduce a frequency of reflux of stomach contents into an esophagus.  
       SUMMARY OF THE INVENTION  
       [0013]     One aspect of the invention provides a method for treating a sphincter. The method provides a polymer material having a liquid state. The method also provides a catheter having a distal end, a tissue piercing device carried by the distal end, and an energy delivery device coupled to the tissue piercing device. The tissue piercing device has a lumen. The method introduces the catheter into an esophagus and pierces an exterior sphincter tissue surface within with the tissue piercing device. The method advances the tissue piercing device into an interior sphincter tissue site and conveys the polymer material while in a liquid state through the lumen into the interior sphincter tissue site. The method delivers energy to the tissue piercing device to transform the polymer material into a less liquid state within the interior sphincter tissue site, to thereby remodel the sphincter.  
         [0014]     In one embodiment, the method delivers energy to the tissue piercing device to create controlled cell necrosis in the sphincter.  
         [0015]     In one embodiment, the method provides a cooling medium and conveys the cooling medium into contact with the exterior sphincter tissue surface pierced by the tissue piercing device.  
         [0016]     The polymer material can comprise, e.g., collagen or silicone. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1A  is an illustrated lateral view of the upper GI tract illustrating the positioning of the sphincter treatment apparatus of the present invention in the lower esophageal sphincter.  
         [0018]      FIG. 1B  is an illustrated lateral view of the upper GI tract illustrating the delivery of a polymer material into a treatment site in the sphincter wall.  
         [0019]      FIG. 2  is a lateral view of the present invention illustrating the catheter lumen, catheter end energy delivery device, cable and power supply.  
         [0020]      FIG. 3  depicts a cross sectional view of sphincter anatomy illustrating the layers of the sphincter wall.  
         [0021]      FIG. 4A  is a lateral view of the RF electrode and sphincter wall, illustrating insulated and exposed electrode segments and the creation of a protected site.  
         [0022]      FIG. 4B  is a lateral view of the RF electrode and sphincter wall, illustrating apertures in the catheter which are used to control the penetration angle of the tissue piercing device in a sphincter wall.  
         [0023]      FIG. 5  is an enlarged lateral view illustrating the placement of sensors on/adjacent the energy delivery device/RF electrode.  
         [0024]      FIG. 6  is a cross sectional view illustrating the use of a fluid introduction lumen and aperture in the energy delivery device/RF electrode for delivery of a cooling medium.  
         [0025]      FIG. 7  is a cross sectional view illustrating a visualization device coupled to an embodiment of the invention.  
         [0026]      FIG. 8  is a lateral view of the sphincter wall illustrating the use of cooling medium to create cooled zones at the electrode-tissue interface.  
         [0027]      FIG. 9  depicts the flow path and fluid connections employed to deliver cooling medium to the energy delivery device/RF electrode and/or electrode-tissue interface.  
         [0028]      FIG. 10  is a flow chart illustrating a sphincter treatment method.  
         [0029]      FIG. 11  is a lateral view of sphincter smooth muscle tissue illustrating electrical foci and electrically conductive pathways for the origination and conduction of aberrant electrical signals in the smooth muscle of the lower esophageal sphincter or other tissue.  
         [0030]      FIG. 12  is a lateral view of a sphincter wall illustrating the infiltration of tissue healing cells into a lesion in the smooth tissue of a sphincter following treatment with the sphincter treatment apparatus of the present invention.  
         [0031]      FIG. 13  is a view similar to that of  FIG. 12  illustrating shrinkage of the lesion site caused by cell infiltration.  
         [0032]      FIG. 14  is a lateral view of the esophageal wall illustrating the preferred placement of lesions in the smooth muscle layer of an esophageal sphincter.  
         [0033]      FIG. 15  is a lateral view illustrating a radial distribution of cured polymer particles used to increase sphincter wall thickness and decrease sphincter inner diameter.  
         [0034]      FIG. 16  is a lateral view illustrating the use of a band of shrunk collagen surrounding and mechanically supporting a radial distribution of cured polymer particles.  
         [0035]      FIG. 17  depicts a block diagram of the feed back control system that can be used with the sphincter treatment apparatus.  
         [0036]      FIG. 18  depicts a block diagram of an analog amplifier, analog multiplexer and microprocessor used with the feedback control system of  FIG. 17 .  
         [0037]      FIG. 19  depicts a block diagram of the operations performed in the feedback control system depicted in  FIG. 17 . 
     
    
     DETAILED DESCRIPTION  
       [0038]     Referring now to  FIGS. 1A, 1B  and  2 , one embodiment of a sphincter treatment apparatus  10  delivers energy to a target tissue site  12 , also called treatment site  12 , to produce cell necrosis  14  in a sphincter  16 , such as the lower esophageal sphincter (LES). In this embodiment, sphincter treatment apparatus  10  comprises a flexible elongate shaft  18 , also called introducer  18 , or catheter  18 , with a distal extremity  20 , also called catheter end  20 , in turn coupled with one or more energy delivery devices  22 . Energy delivery devices  22  are coupled to a guide wire  24  also called cable  24  and are also configured to be coupled to a power source. Energy delivery device  22  is coupled to a tissue piercing device  26 , which can also be the distal end  26  of energy delivery device  22 . Energy delivery device  22  and tissue piercing device  26  may both have a continuous internal lumen  23  that is fluidically coupled to a fluid lumen  24 ′ in guide wire  24 . Energy delivery device  22  and tissue piercing device  26  are configured to penetrate a fixed depth into a sphincter wall  28  and deliver energy to a portion thereof. In one embodiment tissue piercing device  26  is a hollow hypodermic needle  26  well known to those skilled in the art.  
         [0039]     In one embodiment illustrated in  FIG. 1B , tissue piercing device  26  is configured to penetrate a fixed depth into a sphincter wall  28  and deliver a polymer material  15  (also called polymer  15 ) via lumen  23  to a treatment site  12 . Delivery of polymer  15  can be accomplished using an infusion pump or syringe (neither shown but both well known to those skilled in the art) fluidically coupled to tissue piercing device  26 . Upon delivery of sufficient thermal energy from energy delivery device  22  to treatment site  12 , the delivered polymer material  15 ′, undergoes a curing and/or polymerization reaction well known to those skilled in the art whereby one or more of the following occurs: (i) crosslinks form between adjacent molecular chains of polymer  15 , (ii) the molecular chains of polymer  15  contract along their linear/longitudinal axis resulting in a shortening or shrinkage of polymer  15  in one or more axises, (iii) the molecular chains of polymer  15  increase in length (iv) a viscoelastic property of delivered polymer  15  is altered (v) the viscosity of delivered polymer  15 ′ is increased, and (vi) the stiffness of delivered polymer  15  is increased. As a result of one or more of these changes, all or a portion of delivered polymer  15 ′ may undergo a transformation from a liquid or emulsion state to a less liquid or semisolid state. The portion of delivered polymer  15 ′ that undergoes this reaction is called cured polymer  15 ″ also called polymer particle  15 ″. Suitable materials for polymer  15  include polysiloxanes (e.g. silicones), polyurethanes and collagen, all well known to those skilled in the art. Suitable geometries for polymer particle  15 ″ include, but are not limited to, the following shapes: spherical, semispherical, oval and cylindrical. Suitable diameters for polymer particles  15 ″ include a range from 0.01 to 0.5 inches.  
         [0040]     Referring to  FIG. 2 , catheter end  20  is configured to be positionable in a sphincter  16  such as the LES or adjacent anatomical structure, such as the cardia of the stomach. Catheter  18  has sufficient length to position catheter end  20  in the LES and/or stomach using a trans-oral approach. Typical lengths for catheter  18  include, but are not limited to, a range of 40-180 cms. Suitable materials for catheter  18  include, but are not limited to, polyethylenes, polyurethanes, silicones other biocompatible polymers known to those skilled in the art. Energy delivery devices  22  can be in the form of needle electrodes, both solid or hollow, as is well known to those skilled in the art. In other embodiments, energy delivery device  22  can be conical, cylindrical, rectangular or any polyhedron; each of said shapes having a flat, rounded, beveled, or pointed tip. Suitable materials for energy delivery device  22  include a combination of one or more of the following: i) stainless and other steels suitable for electrode applications known to those skilled in the art, ii) alloys of gold, silver and platinum, iii) nickel-titanium alloys, or iv) other conductors known to those skilled in the art.  
         [0041]     Catheter  18  may have one or more lumens  30 , that extend the frill length of catheter  18 , or only a portion thereof. Lumens  30  may be used as paths for cables, catheters, guide wires, pull wires, insulated wires, fluid and optical fibers. Lumens  30  may have one or more apertures  30 ′ at or near distal catheter end  20 . In one embodiment, lumens  30  (along with aperture  30 ′) in catheter  18  are used as a guiding pathway for guidewire  24  to facilitate the positioning of tissue piercing device  26  at treatment site  12 .  
         [0042]     Guide wire  24  is configured to facilitate the positioning of energy delivery device  22  a selectable distance (1-4 mms) into the sphincter wall  28 . Suitable materials and components for guide wire  24  include an insulated wire, an insulated guide wire, a plastic-coated stainless steel hypotube with internal wiring, or a catheter with internal wiring, all of which are known to those skilled in the art. Guide wire  24  may also have one or more lumens  24 ′ which can be used to deliver fluid or gas. Also guide wire  24  may have one or more proximal fittings  24 ″ (such as a luer fitting or lemo connector) for facilitating connection to fluid lines and electronic cabling.  
         [0043]     Turning now to a discussion of energy-tissue interactions, energy flowing through sphincter or other tissue causes heating of the tissue due to absorption of the energy by the tissue. This heating can cause injury to the affected cells and can be substantial enough to cause cell death, a phenomenon also known as cell necrosis. The controlled delivery of energy by energy delivery device  22  results in controlled cell necrosis  14 , also called lesions  14 , at target tissue site  12 .  
         [0044]     Suitable energy devices and power sources for energy delivery device  22  include the following: (i) a radio-frequency (RF) source coupled to an RF electrode, (ii) a coherent source of light coupled to an optical fiber, (iii) an incoherent light source coupled to an optical fiber, (iv) a heated fluid coupled to a catheter with a closed channel configured to receive the heated fluid, (v) a heated fluid coupled to a catheter with an open channel configured to receive the heated fluid, (vi) a cooled fluid coupled to a catheter with a closed channel configured to receive the cooled fluid, (vii) a cooled fluid coupled to a catheter with an open channel configured to receive the cooled fluid, (viii) a cryogenic fluid, (ix) a resistive heating source, (x) a microwave source providing energy from 915 MHz to 2.45 GHz and coupled to a microwave antenna, (xi) an ultrasound power source coupled to an ultrasound emitter, wherein the ultrasound power source produces energy in the range of 300 KHZ to 3 GHz, or (xii) combinations of any of the above. For ease of discussion for the remainder of this application, the power source utilized is an RF source and energy delivery device  22  is one or more RF electrodes  22 , also described as electrodes  22 . However, all of the other herein mentioned power sources and energy delivery devices are equally applicable to sphincter treatment apparatus  10 .  
         [0045]     Turning now to a discussion of sphincter anatomy (depicted in  FIG. 3 ), the first several layers of sphincter  16  consist of a mucosal layer  32 , a submucosal layer  33  and an underlying smooth muscle collagen tissue layer  34 . RF electrode  22  is configured to produce controlled cell necrosis or lesions  14  in smooth muscle collagen tissue layer  34  underlying mucosal and submucosal layers  32  and  33 . More specifically, RF electrode  22  is configured to produce controlled cell necrosis  14  in the portion of smooth muscle collagen tissue  34 ′ that lies approximately 1-4 nuns from the surface of mucosal layer  32 .  
         [0046]     Referring now to  FIG. 4A , RF electrode  22  has an insulator  36 , covering the exterior of an insulated segment  38  except for an exposed segment  40 . For purposes of this disclosure, an insulator is a barrier to either thermal or electromagnetic energy flow. As shown in  FIG. 4A , insulated segment  38  is of sufficient length to extend into sphincter wall  28  and minimize the transmission of energy and subsequent injury to a protected site  42  near or adjacent to insulated segment  38 . Typical lengths for insulated segment  38  include, but are not limited to, 1-4 mms. Suitable materials for insulator  36  include, but are not limited to, polytetrafluoroethylene (Teflon®, polyimides, polyamides and other insulating polymers known to those skilled in the art.  
         [0047]     Referring now to  FIG. 4B , in one embodiment lumens  30  and apertures  30 ′ are of sufficient diameter to allow the free movement of guidewire  24  in catheter  18  so as to be able to controllably position tissue piercing device  26  to a selected depth into sphincter wall  28 . Apertures  30 ′ can be configured so as to control the angle of penetration  48  (also called penetration angle  48  emergence angle  48 ) that tissue piercing device  26  makes with sphincter wall  28 . Apertures  30 ′ can be further configured so as to maintain penetration angle  48  constant (or near constant) during the insertion of tissue piercing device  26  into sphincter wall  28  so as to minimize tearing or unnecessary trauma to sphincter wall tissue. In various embodiments, the emergence angle  48  of apertures  30 ′ which can vary from 1 to 90°.  
         [0048]     Referring now to  FIG. 5 , one or more sensors  44  can be coupled to RF electrode  22  for sensing the temperature of sphincter tissue at target tissue site  12 . More specifically, sensors  44  permit accurate determination of the surface temperature of sphincter wall  28  at an electrode tissue interface  46 . This information can be used to regulate both the delivery of energy and cooling medium to the interior surface of sphincter wall  28  as will be discussed herein. Sensors  44  can be positioned on or adjacent to RF electrode  22 . Suitable sensors that may be used for sensor  44  include: thermocouples, fiber optics, resistive wires, thermocouple IR detectors, and the like. Suitable thermocouples for sensor  44  include: T type with copper constantene, J type, E type and K types as are well known those skilled in the art.  
         [0049]     Referring now to  FIG. 6 , RF electrode  22  includes a fluid introduction lumen  23 , that may be coupled with catheter lumen  30 . These coupled lumens provide a path for the delivery of a fluid, such as a cooling or electrolytic fluid (which will be discussed herein), to electrode tissue interface  46  or another site. As shown in  FIG. 6 , fluid introduction lumen  23  may include an aperture  50  on the distal portion of RF electrode  22 .  
         [0050]     Referring now to  FIG. 7 , another embodiment of sphincter treatment apparatus  10  includes a visualization device  52  which can include a combination of one or more of the following: a viewing scope, an expanded eyepiece, fiber optics (both imaging and illuminating fibers), video imaging and the like.  
         [0051]     It may be desirable to employ a cooling system  54  coupled to energy delivery device  22  to cool all or a portion of energy-delivery device  22  and the area near electrode tissue interface  46  before, during or after the delivery of energy in order to reduce the degree and area of cell injury in the tissue adjacent electrode tissue interface  46 . As shown in  FIG. 8 , the use of cooling protects against, or otherwise reduces the degree of, cell damage to cooled zone  56  in the vicinity of aperture  50  and/or electrode tissue interface  46  which will preferably include mucosal and submucosal layers  32  and  33 . In one embodiment shown in  FIG. 9 , cooling system  54  can include one or more of the following: i) a cooling medium  55  (which can be a liquid or a gas) that is delivered to RF electrode  22  via aperture  50  and flow-controlled via a feedback control system  60  discussed herein, ii) a cooling medium reservoir  58  coupled to aperture  50 , and iii) a cooling device  59  (which may be integral to fluid reservoir  58 ) coupled to cooling medium  55  and controlled via a feedback control system  60  discussed herein. In another embodiment, cooling medium  55  can be introduced via apertures  50  or semipermeable membranes located in one or more locations on sphincter treatment apparatus  10  in communication with reservoir  58  and thermal communication with cooling device  59 . In yet another embodiment, cooling medium  55  can be introduced externally to RF electrode  22 . In still another embodiment, cooling medium  55  is thermally coupled to RF electrode  22  and/or electrode tissue interface  46 . In yet another embodiment, cooling device  59  (such as a Peltier effect device or heat pipe) is thermally coupled to RF electrode  22  and/or electrode tissue interface  46 .  
         [0052]      FIG. 10  is a flow chart illustrating a method for using sphincter treatment apparatus  10 . In this embodiment, sphincter treatment apparatus  10  is first introduced into the esophagus under local anesthesia and positioned at target tissue site  12 . Sphincter treatment apparatus  10  can be introduced into the esophagus by itself or through a lumen in an endoscope (not shown), such as disclosed in U.S. Pat. Nos. 5,448,990 and 5,275,608, incorporated herein by reference, or a similar esophageal access device known to those skilled in the art.  
         [0053]     The diagnostic phase of the procedure then begins and can be performed using a variety of diagnostic methods, including, but not limited to, the following: (i) visualization of the interior surface of the esophagus via an endoscope or other viewing apparatus inserted into the esophagus, (ii) visualization of the interior morphology of the esophageal wall using ultrasonography to establish a baseline for the tissue to be treated, (iii) impedance measurement to determine the electrical conductivity between the esophageal mucosal layers and sphincter treatment apparatus  10 , and (iv) measurement and surface mapping of the electropotential of the LES during varying time periods which may include such events as depolarization, contraction and repolarization of LES smooth muscle tissue. This latter technique is done to determine target tissue sites  12  in the LES or adjoining anatomical structures that are acting as electrical foci  107  or electrically conductive pathways  109  for abnormal or inappropriate polarization and relaxation of the smooth muscle of the LES (Refer to  FIG. 11 ).  
         [0054]     After diagnosis, the treatment phase of the procedure then begins. In this phase of the procedure the delivery of energy to target tissue site  12  can be conducted under feedback control (described herein), manually or by a combination of both. Feedback control enables sphincter treatment apparatus  10  to be positioned and retained in the esophagus during treatment with minimal attention by the physician. Feedback can be included and is achieved by the use of one or more of the following methods: (i) visualization, (ii) impedance measurement, (iii) ultrasonography, (iv) temperature measurement and, (v) sphincter contractile force measurement via manometry. A second diagnostic phase may be included after the treatment is completed. This provides an indication of LES tightening treatment success, and whether or not a second phase of treatment, to all or only a portion of the esophagus, now or at some later time, should be conducted. The second diagnostic phase is accomplished through, (i) visualization, (ii) measuring impedance, (iii) ultrasonography, (iv) temperature measurement, or (v) measurement of LES tension and contractile force via manometry. It will be appreciated that the above procedure is applicable in whole or part to the treatment of other sphincters in the body.  
         [0055]     The area and magnitude of cell injury in the LES or sphincter  16  can vary. However, it is desirable to deliver sufficient energy to the targeted tissue site  12  to be able to achieve tissue temperatures in the range of 55-95° C. and produce lesions  14  at depths ranging from 1-4 mms from the interior surface of the LES or sphincter wall  28 . It is also desirable to deliver sufficient energy such that the resulting lesions  14  have a sufficient magnitude and area of cell injury to cause an infiltration and/or proliferation of lesion  14  by fibroblasts  110 , myofibroblasts  112 , macrophages  114  and other cells involved in the tissue healing process (refer to  FIG. 12 ). As shown in  FIG. 13 , these cells cause a contraction of tissue around lesion  14 , decreasing its volume and/or altering the biomechanical properties at lesion  14  so as to result in a tightening of LES or sphincter  16 . These changes are reflected in transformed lesion  14 ′ shown in  FIG. 13 .  
         [0056]     It is desirable that lesions  14  are predominantly located in the smooth muscle collagen layer of selected sphincter  16  at the depths ranging from 1 to 4 mms from the interior surface of sphincter wall  28 .  
         [0057]     Accordingly, the diameter of lesions  14  can vary between 0.1 to 4 mms. It is preferable that lesions  14  are less than 4 mms in diameter in order to reduce the risk of thermal damage to the mucosal layer. In one embodiment, a 2 mm diameter lesion  14  centered in the wall of the smooth muscle collagen layer provides a 1 mm buffer zone to prevent damage to the mucosa, submucosa and adventitia, while still allowing for cell infiltration and subsequent sphincter tightening on approximately 50% of the thickness of the wall of the smooth muscle collagen layer (refer to  FIG. 14 ). Also, lesions  14  can vary both in number and position within sphincter wall  28 . Once treatment is completed, sphincter treatment apparatus  10  is withdrawn from the esophagus or other sphincter  16 . This results in the LES or other sphincter returning to approximately its pretreatment state and diameter.  
         [0058]     Referring now to  FIG. 15 , in one embodiment polymer particles  15 ″ can be distributed in a variety of patterns in sphincter wall  28  including a radial distribution at even depths along a radial axis of sphincter  16 . Other distributions not shown include: (i) a wavy or folded circle of polymer particles  15 ″ at varying depths in sphincter wall  28  evenly spaced along the radial axis of sphincter  16 , (ii) polymer particles  15 ″ randomly distributed at varying depths, but evenly spaced in a radial direction; and, (iii) an eccentric pattern of polymer particles  15 ″ in one or more radial locations in sphincter wall  28 . The pattern of and diameter of polymer particles  15 ″ can be selected to controllably increase the thickness  28 ′ of sphincter wall  28  and/or decrease the inner diameter  16 ′ of sphincter  16 .  
         [0059]     Referring now to  FIG. 16 , RF energy can be delivered to sphincter wall  28  to shrink native collagen  51  within the smooth muscle collagen tissue layer  34  of sphincter wall  28  so as to create a supporting band  57  of tightened collagen in contact with one or more of polymer particles  15 ″ distributed along a radial axis of sphincter  16 . Band  57  serves to both mechanically link and mechanically support polymer particles  15 ″. This serves one or more of the following functions: (i) distribution of the stresses within sphincter wall  28 , (ii) retention of the desired placement of polymer particles  15 ″ within sphincter wall  28 ; and, (iii) maintenance of improvements in the tension and inner diameter of sphincter wall  28 . Also band  57  can be selectively shrunk so as to selectively tighten sphincter  16  and decrease inner sphincter diameter  16 ′. In another embodiment, band  57  can be composed of fibroblasts  110 , myofibroblasts  112  and other tissue healing cells.  
         [0060]     In one embodiment, elements of sphincter treatment apparatus  10  are coupled to an open or closed loop feedback control system  60 . Referring now to  FIG. 17 , an open or closed loop feedback system  60  couples sensor  346  to energy source  392 . In this embodiment, electrode  314  is one or more RF electrodes  314 . The temperature of the tissue, or of RF electrode  314 , is monitored, and the output power of energy source  392  adjusted accordingly. The physician can, if desired, override the closed or open loop system  60 . A microprocessor  394  can be included and incorporated in the closed or open loop system to switch power on and off, as well as modulate the power. The closed loop system  60  utilizes microprocessor  394  to serve as a controller, monitor the temperature, adjust the RF power, analyze the result, refeed the result, and then modulate the power.  
         [0061]     With the use of sensor  346  and feedback control system  60 , tissue adjacent to RF electrode  314  can be maintained at a desired temperature for a selected period of time without causing a shut down of the power circuit to electrode  314  due to the development of excessive electrical impedance at electrode  314  or adjacent tissue as is discussed herein. Each RF electrode  314  is connected to resources which generate an independent output. The output maintains a selected energy at RF electrode  314  for a selected length of time.  
         [0062]     Current delivered through RF electrode  314  is measured by current sensor  396 . Voltage is measured by voltage sensor  398 . Impedance and power are then calculated at power and impedance calculation device  400 . These values can then be displayed at user interface and display  402 . Signals representative of power and impedance values are received by a controller  404 .  
         [0063]     A control signal is generated by controller  404  that is proportional to the difference between an actual measured value, and a desired value. The control signal is used by power circuits  406  to adjust the power output an appropriate amount in order to maintain the desired power delivered at respective RF electrodes  314 .  
         [0064]     In a similar manner, temperatures detected at sensor  346  provide feedback for maintaining a selected power. Temperature at sensor  346  is used as a safety means to interrupt the delivery of power when maximum pre-set temperatures are exceeded. The actual temperatures are measured at temperature measurement device  408 , and the temperatures are displayed at user interface and display  402 . A control signal is generated by controller  404  that is proportional to the difference between an actual measured temperature and a desired temperature. The control signal is used by power circuits  406  to adjust the power output an appropriate amount in order to maintain the desired temperature delivered at the sensor  346 . A multiplexer can be included to measure current, voltage and temperature, at the sensor  346 , and energy can be delivered to RF electrode  314  in monopolar or bipolar fashion.  
         [0065]     Controller  404  can be a digital or analog controller, or a computer with software. When controller  404  is a computer it can include a CPU coupled through a system bus. This system can include a keyboard, a disk drive, or other non-volatile memory systems, a display, and other peripherals, as are known in the art. Also coupled to the bus is a program memory and a data memory.  
         [0066]     User interface and display  402  includes operator controls and a display. Controller  404  can be coupled to imaging systems including, but not limited to, ultrasound, CT scanners, X-ray, MRI, mammographic X-ray and the like. Further, direct visualization and tactile imaging can be utilized. The output of current sensor  396  and voltage sensor  398  are used by controller  404  to maintain a selected power level at RF electrode  314 . The amount of RF energy delivered controls the amount of power. A profile of the power delivered to electrode  314  can be incorporated in controller  404  and a preset amount of energy to be delivered may also be profiled.  
         [0067]     Circuitry, software and feedback to controller  404  result in process control, the maintenance of the selected power setting which is independent of changes in voltage or current, and is used to change the following process variables: (i) the selected power setting, (ii) the duty cycle (e.g., on-off time), (iii) bipolar or monopolar energy delivery; and, (iv) fluid delivery, including flow rate and pressure. These process variables are controlled and varied, while maintaining the desired delivery of power independent of changes in voltage or current, based on temperatures monitored at sensor  346 .  
         [0068]     Referring now to  FIG. 18 , current sensor  396  and voltage sensor  398  are connected to the input of an analog amplifier  410 . Analog amplifier  410  can be a conventional differential amplifier circuit for use with sensor  346 . The output of analog amplifier  410  is sequentially connected by an analog multiplexer  412  to the input of A/D converter  414 . The output of analog amplifier  410  is a voltage which represents the respective sensed temperatures. Digitized amplifier output voltages are supplied by A/D converter  414  to microprocessor  394 . Microprocessor  394  may be a type 68HCII available from Motorola. However, it will be appreciated that any suitable microprocessor or general purpose digital or analog computer can be used to calculate impedance or temperature.  
         [0069]     Microprocessor  394  sequentially receives and stores digital representations of impedance and temperature. Each digital value received by microprocessor  394  corresponds to different temperatures and impedances.  
         [0070]     Calculated power and impedance values can be indicated on user interface and display  402 . Alternatively, or in addition to the numerical indication of power or impedance, calculated impedance and power values can be compared by microprocessor  394  to power and impedance limits. When the values exceed predetermined power or impedance values, a warning can be given on user interface and display  402 , and additionally, the delivery of RF energy can be reduced, modified or interrupted. A control signal from microprocessor  394  can modify the power level supplied by energy source  392 .  
         [0071]      FIG. 19  illustrates a block diagram of a temperature and impedance feedback system that can be used to control the delivery of energy to tissue site  416  by energy source  392  and the delivery of cooling medium  55  to electrode  314  and/or tissue site  416  by flow regulator  418 . Energy is delivered to RF electrode  314  by energy source  392 , and applied to tissue site  416 . A monitor  420  ascertains tissue impedance, based on the energy delivered to tissue, and compares the measured impedance value to a set value. If measured impedance is within acceptable limits, energy continues to be applied to the tissue. However if the measured impedance exceeds the set value, a disabling signal  422  is transmitted to energy source  392 , ceasing further delivery of energy to RF electrode  314 .  
         [0072]     The control of cooling medium  55  to electrode  314  and/or tissue site  416  is done in the following manner. During the application of energy, temperature measurement device  408  measures the temperature of tissue site  416  and/or RF electrode  314 . A comparator  424  receives a signal representative of the measured temperature and compares this value to a pre-set signal representative of the desired temperature. If the measured temperature has not exceeded the desired temperature, comparator  424  sends a signal to flow regulator  418  to maintain the cooling solution flow rate at its existing level. However if the tissue temperature is too high, comparator  424  sends a signal to a flow regulator  418  (connected to an electronically controlled micropump, not shown) representing a need for an increased cooling solution flow rate.  
         [0073]     The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. It is intended that the scope of the invention be defined by the following claims and their equivalents.