Abstract:
The present invention is embodied in a medical device which is comprised of a thermal energy delivery component, for example, including an elongate optical fiber terminating in a lateral laser energy emitter, and an outer coolant component, which includes a cannula for receiving the thermal energy delivery component, which terminates in an energy-transmissive balloon for surrounding the thermal energy emitter and providing a tissue-contacting coolant chamber. The cannula portion of the coolant component is moveably sealed around the laser energy delivery component. In one embodiment, a retaining means prevents the thermal energy delivery component from being detached from the coolant component. In an alternate embodiment, there is no retaining means, allowing the more costly thermal energy delivery component to be removed, sterilized and later reused, whereas the less costly outer coolant component, which contacts tissue, blood and body liquids, can be discarded after use.

Description:
FIELD OF INVENTION 
       [0001]    This invention relates to thermal energy delivery devices which are used to denature, shrink, coagulate, scar, desiccate or vaporize internal body tissues surrounding or underlying a duct, blood vessel, hollow-organ or body cavity, while concomitantly cooling the interior surface of the duct, blood vessel, hollow organ or body cavity to prevent damage to its endothelial lining, in an economical, minimally invasive procedure. 
       BACKGROUND OF THE INVENTION 
       [0002]    Thermal energy delivery devices include those emitting coherent light or laser energy, incoherent high intensity white light, incoherent high intensity light of a particular wavelength, microwave and focused ultra-sound energy. Of these, optical fibers for conveying laser energy, sometimes referred to as wave guides, enjoy certain advantages. 
         [0003]    Fiber-optic based devices for delivering laser energy have many uses in medicine, as optical fibers are small in diameter, can reach areas of the body difficult to access by other means and can be made to emit laser energy straight ahead, sideways or at a desired angle. However, fiber-optic based devices are relatively expensive, particularly those which are able to emit laser energy laterally from the axis of the optical fiber at an angle of about 70° to 90°, generally referred to as side-firing laser devices. 
         [0004]    For example, side-firing laser devices manufactured by Trimedyne, Inc., the owner of this application, which are used in minimally invasive, outpatient procedures, sell for $600 or more each. Such devices are sold as “single-use,” disposable devices, as they contact body tissue and blood and cannot be safely sterilized and re-used. 
         [0005]    In the United States, where Medicare, insurance companies and health plans pay about $2,000 to $4,000 for a minimally invasive, outpatient medical procedure, the price of such devices and the cost of amortizing the equipment used in such procedures can be afforded. The same is true in Japan, where payments for medical procedures are also relatively high. However, in the developed countries of Europe, where only about $1,000 to $2,000 is paid for such procedures, such devices cannot presently be afforded, as the cost of such devices, operating room and nursing time and other supplies, as well as amortization of the equipment used in such procedures, cost more in aggregate than the amount paid. In underdeveloped countries, where the patients can pay only about $500 to $1,500 for a medical procedure, open surgery, using stainless steel scalpels and other utensils, is presently the only available choice for many patients. 
         [0006]    There are many conditions which could be treated if laser energy could be applied to internal tissues underlying a duct, blood vessel, hollow organ or body cavity without damaging their endothelial lining, much as laser energy is used with concomitant cooling of the skin to shrink the underlying tissues, for example, to remove facial wrinkles, coagulate blood vessels or damage hair follicles. Common methods to cool the skin during the emission of laser energy in cosmetic procedures include the concomitant emission of a cryogenic gas, a water spray, cooled air, room temperature air or a cold gel, which is transparent to the wavelength of laser energy used. However, there presently exists no means to economically provide cooling to the endothelial lining of internal ducts, blood vessels, hollow-organs or body cavities, while laser energy passes through and creates the desired effect on underlying tissues. 
         [0007]    Some of the conditions that may be so treated are gastro-esophageal reflux disease or GERD, female stress urinary incontinence or FSUI, fecal (anal) incontinence, mitral valve prolapse, benign prostatic hyperplasia or BPH, commonly referred to as an enlarged prostate, or an abdominal aortic aneurysm, where denaturing, shrinking, scarring, coagulating, desiccating or vaporizing the tissue underlying the endothelial lining could treat the condition, but where damage to the sensitive endothelial lining could cause pain and the risk of infection. 
         [0008]    It would be desirable to be able to provide the benefit of thermal energy delivering devices to treat such conditions, without damaging the sensitive endothelial linings of internal body structures, as a device with two, non-detachable, components, one for delivery of thermal energy and one for cooling the lining, which is intended to be used once and discarded. Such a device could be sold for up to $850 or more in the United States and Japan, where reimbursement by third party payors for medical procedures is relatively high. Alternatively, the device could consist of two detachable components, of which the more expensive, thermal energy delivery component is not in contact with tissue and can be sterilized and reused, and only the less expensive cooling component, which contacts tissue or body fluids, must be discarded after a single use. Re-using the thermal energy delivery component several times can reduce the cost of the combined components to about $300 per use, making such devices affordable in countries where reimbursement for medical procedures is less than in the United States and Japan. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    The present invention is embodied in a medical device and related method for creating a transforming effect upon tissue underlying an endothelial surface. The device and method provide for radiant energy treatment of tissue underlying an endothelial lining, avoiding damage to untargeted tissue areas, including the lining layer. The two, non-detachable component apparatus is sterile and easy to use and discard. The modular, two, detachable component apparatus allows for the sterility required for an invasive treatment at reduced cost, because the costly energy delivery component can be removed and reused, and a coacting, comparably less expensive cooling component, which contacts bodily fluids, blood and tissue, can be discarded after one use. 
         [0010]    The apparatus aspect of this invention contemplates a thermal energy component and a separate cooling component having a cannula for receiving the thermal energy component that terminates in an energy-transmissive balloon for surrounding the thermal energy emitter. The energy-transmissive balloon provides a tissue-contacting coolant chamber. The cannula defines a coolant passageway in communication with the balloon-defined chamber. The balloon is secured to the distal end of the cannula. If laser energy is the desired thermal energy source, it is transmitted through an optical fiber or wave guide. The optical fiber or wave guide has a proximal end portion adapted to be coupled to a laser source. The cannula portion of the coolant retainer is moveably sealed around a protective sheath disposed over the optical fiber. 
         [0011]    The laser energy device also preferably includes a handpiece secured to and located toward the proximal end of the optical fiber to facilitate handling and placement of the energy conduit in the internal duct, blood vessel, hollow organ or body cavity. 
         [0012]    The invention relates generally to devices for applying laser and other forms of electromagnetic energy, such as incoherent white light, incoherent light of a desirable wavelength, microwave or focused ultrasound energy, through an energy transmissive, expandable balloon to transform (by, for example, mechanically cross linking collagen, denaturing, coagulating or scarring) tissue underlying endothelial linings of ducts, hollow organs or body cavities in contact with the balloon. Concomitant damage to the endothelial lining is substantially reduced by pre-cooling and/or simultaneous tissue cooling by supplying coolant to the balloon during thermal or radiant energy delivery. 
         [0013]    A method aspect of this invention contemplates making a transforming effect upon tissue underlying an endothelial surface by providing a laser energy delivery component, including an elongate optical fiber terminating in a lateral laser emitter, providing a coolant component having a cannula for receiving the laser energy delivering component and terminating in an energy-transmissive balloon, positioning the energy-transmissive balloon adjacent tissue to be treated, supplying coolant to expand the balloon and contact the tissue, cooling the tissue for a predetermined time period, and supplying laser energy from a laser energy source through the optical fiber to the tissue through the coolant balloon for a period of time and at a laser energy intensity sufficient to transform the tissue. 
         [0014]    While in use for radiating tissue, the energy-transmissive balloon at least partially surrounds the emitter and provides a tissue-contacting coolant chamber. The cannula defines a coolant passageway in communication with the balloon, which is secured to the distal end of the cannula. The optical fiber or wave guide has a proximal end portion with a connection to a laser source. 
         [0015]    An apparatus to enable thermal energy to shrink tissues underlying an internal duct, blood vessel, hollow organ or body cavity is comprised of two components, one of which is movably disposed within the other component. The outer component comprises a tube or cannula to whose distal end a balloon is attached. The thermal energy delivery component is movably disposed within the outer cooling component, which can be appropriately positioned to treat the tissue at desired points through the balloon. In one embodiment of this invention, the inner component cannot be fully detached from the outer component. In another embodiment of this invention, the inner component is fully detachable from the outer component. 
         [0016]    The thermal energy delivery component can be an optical fiber equipped to emit laser energy or high intensity incoherent light laterally or a device equipped to emit focused ultrasound or microwave energy. The balloon is filled with a cold fluid, which cools the endothelial surface of the duct, blood vessel, hollow organ or body cavity and protects it against damage while the energy passes through and produces its desired tissue effect. Such a two component apparatus would be a single use, disposable, non-detachable device, which may sell for $850, which could be afforded in the United States and Japan. 
         [0017]    However, to reduce the cost per case of such an apparatus, and to make it affordable in less developed countries, it can be comprised of the same two components, one of which is a relatively inexpensive, outer, tissue cooling component, which is discarded after a single use, because it contacts body fluids and tissue and cannot be safely sterilized and re-used, and the other, inner, thermal energy delivery component can be a more expensive, laser energy-emitting, detachable component, which can be sterilized and reused, as it does not contact bodily tissue or fluid. 
         [0018]    The disposable component comprises a hollow plastic or metal tube, called a cannula, on whose distal end a balloon is mounted. The balloon can be made of a flexible material, transmissive to the energy being used to create the desired tissue effect. The cannula has one or more ports, enabling fluid to be infused into or circulated through the balloon. The cannula preferably has a gasket (or elastomeric layer) and manual compression device at its proximal end, the function of which is to movably and sealingly fix the detachable, reusable, thermal energy delivery component in place within the cannula and the balloon, as known in the art. The balloon is filled with gas or liquid which is also transmissive to the wavelength of laser energy being used. 
         [0019]    Since the thermal energy-emitting component does not contact body fluids or tissue, it can be removed from the cannula after use by loosening the compression device, safely sterilized and then re-used with another such disposable component. In an alternate embodiment of this invention, the inner, thermal energy-emitting component, while movably and sealingly fixed in place within the outer, tissue cooling component, it is prevented from being fully removed from the outer, tissue cooling component by a retaining ring, stop or other means. As a result, the entire apparatus will be disposed of after a single use. 
         [0020]    While coherent light (laser energy), incoherent, high intensity white light, incoherent high intensity light of a desired wavelength, microwave, focused ultrasound and other forms of energy can be utilized, this invention can best be illustrated by the use of laser energy. Consequently, whenever laser energy is referred to herein, it shall apply to these other forms of thermal energy. 
         [0021]    A fiber optic, laser energy emitting device can utilize a commercially available optical fiber that fires straight ahead, or a commercial optical fiber inside a metal tube bent at an angle up to 40 degrees or larger. However, in the treatment of many conditions, it would be desirable to emit laser energy laterally at an angle of 70° to 90° from the axis of the optical fiber. 
         [0022]    To achieve this effect, the distal end of a commercially available optical fiber may be beveled at an angle of about 35° to 45°, preferably about 38° to 40°, and enclosed by a capillary tube to provide an air interface at the beveled surface of the optical fiber, which is necessary for total internal reflection of the laser energy laterally from the axis of the optical fiber. 
         [0023]    Filling the balloon with air is not practical, since it could be released if the balloon ruptures, potentially creating a blood clot. If Holmium laser energy is used and the balloon is inflated, for example, with carbon dioxide (CO 2 ) gas, which is biocompatible in small amounts, the distal end of the optical fiber may be beveled as described above, and the need for the capillary tube may be avoided, as the laser energy will be totally internally reflected due to the refractive index of gas interface at the beveled surface of the optical fiber being significantly different from the refractive index of the optical fiber. 
         [0024]    Alternatively, a reflective metal surface, consisting of platinum, gold, silver, copper or the like, inclined at an angle of about 40° to 50°, preferably about 44° to 46°, is positioned opposite the distal end of an ordinary, flat-ended, commercially available optical fiber to reflect the laser energy emitted from the distal end of the optical fiber at an angle of about 80° to 90°, laterally from the axis of the optical fiber. 
         [0025]    In a preferred embodiment, the balloon is expanded with a cold gas or liquid, which cools the sensitive endothelial lining of, for example, a duct, hollow organ or body cavity prior to and during the emission of laser energy. This cools the endothelial lining of the duct, blood vessel, hollow organ or body cavity and prevents it from being thermally damaged by the laser energy, while allowing the laser energy to penetrate the tissue underlying the endothelial lining to produce its desired effect. The tissue effects of laser energy include shrinkage by photomechanical cross linkage of collagen, protein denaturization, coagulation, scarring, desiccation or vaporization. 
         [0026]    The disposable, balloon tipped cooling component of the apparatus, which can be made of relatively inexpensive materials, may sell for about $200 and can be discarded after its use, to avoid cross-contamination and infection. The more expensive, reusable, fiber-optic component, which does not contact body fluids or tissue, may sell for about $600 and could be used, for example, ten or more times, for a cost of $60 or less per procedure. Thus, the total cost of the apparatus would be $260 or less per use, which would be affordable in countries outside the United States and Japan. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    In the accompanying drawings that form part of the specification, 
           [0028]      FIG. 1  is a cross-sectional view of an embodiment of a balloon-tipped cooling component of the apparatus according to an embodiment of the invention; 
           [0029]      FIG. 2  is an external view of a side-firing laser energy delivery component of the apparatus according to an embodiment of the invention; 
           [0030]      FIG. 3  is an enlarged, partial cross-sectional view of the laser energy delivery component shown in  FIG. 2 ; 
           [0031]      FIG. 4  is an enlarged, partial cross-sectional view of a laser energy delivery component according to an alternate embodiment of the invention; 
           [0032]      FIG. 5  is an enlarged, partial cross-sectional view of the laser energy delivery component shown in  FIG. 3  removably deployed within the cooling component shown in  FIG. 1 ; 
           [0033]      FIG. 6  is a transverse cross-sectional view of the laser energy delivery component disposed within the cooling component according to an embodiment of the present invention; 
           [0034]      FIG. 7  is an enlarged, partial cross-sectional view of a the laser energy emitting portion of the laser energy delivery component removably deployed within the cooling component according to an alternate embodiment of the invention; 
           [0035]      FIG. 8  is a partial, schematic view of the distal end portion of the medical device of the present invention positioned in a female urethra; 
           [0036]      FIG. 9  is a partial, schematic view of the distal end portion of the medical device according to the present invention positioned within the annulus of the mitral valve of the heart; 
           [0037]      FIG. 10  is a partial, schematic view of the distal end portion of the medical device according to the present invention positioned within the left ventricle of the heart; 
           [0038]      FIG. 11  is a partial, schematic view of the distal end portion of the medical device according to the present invention removably disposed within the esophagus at the level of the esophageal sphincter; 
           [0039]      FIG. 12  is a partial, schematic view of the distal end portion of the medical device according to the present invention removably disposed in the anus; 
           [0040]      FIG. 13  is a partial, schematic view of the distal end portion of the medical device according to the present invention removably disposed within a bronchus of the lung; 
           [0041]      FIG. 14  is a partial, schematic view of the distal end portion of the medical device according to the present invention removably disposed within the male urethra between the lobes of the prostate gland; 
           [0042]      FIG. 15  is a partial, cross-sectional side view of the medical device of the present invention disposed within a movable, protective cover. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0043]    While this invention is susceptible to embodiment in many different forms, this specification and the accompanying drawings disclose only preferred forms as examples of the invention. The invention is not intended to be limited to the embodiments so described, however. The scope of the invention is identified in the appended claims. 
         [0044]    While the references above and hereafter in this application refer to laser energy, other sources of radiant energy may be used, such as incoherent, high intensity white light or incoherent, high intensity light of a desired wavelength. Also, other forms of energy, such as microwave or focused ultrasound energy may be transmitted through balloon  12 , directly ahead, at an angle or laterally from the axis of cannula  11 . It is understood that wherever laser energy is mentioned herein, other sources of energy shall also apply. 
         [0045]    Referring to  FIGS. 1 and 2 , disposable includes a hollow plastic or metal tube or cannula  11  to whose distal end balloon  12  is affixed by thermal fusion, an adhesive or the like. Balloon  12  is transparent or transmissive to the wavelength of laser energy to be used to create a desired tissue effect. 
         [0046]    Cooling component  10  has a compression coupling in the form of an externally threaded fitting  15  and a compression nut  13  for sealingly and movably grasping sheath  26  of laser energy delivery component  20  ( FIG. 2 ). When compression cap or nut  13  is turned clockwise, a beveled inner surface  14  of nut  13  compresses threaded flanges  15  around elastomeric layer or gasket  16  to create a fluid-tight seal between cannula  11  and sheath  26  of laser energy delivery component  20 . 
         [0047]    Other compression means, as known in the art, may be used to movably or removably fix sheath  26  of laser energy delivery component  20  within cannula  11  of cooling component  10 . For example, one type of compression device is illustrated in FIGS. 3 and 4 of U.S. Published Application No. 2005-0113814 by Loeb, the disclosure of which is expressly incorporated herein by reference to the extent not inconsistent with the present teachings. 
         [0048]    Cannula  11  preferably has one port for infusion of a fluid into cannula  11  to expand (or inflate) balloon  12 . Alternatively, cannula  11  can have two ports (not separately shown), one of which allows fluid to be infused into and expand balloon  12 , while the other port allows the fluid to exit cannula  11 . In the embodiment shown in  FIG. 1 , a single infusion port includes a male, luer-type fitting  17  attached to tube  18 , which is in fluid communication with the hollow interior of cannula  11  and balloon  12 . 
         [0049]    Preferably, the fluid infused into cannula  11  to inflate and press balloon  12  against the tissue to be treated is a gas or liquid transmissive to the wavelength of laser energy being used. In many applications, the fluid will be sterile water or saline, or a gas such as carbon dioxide (CO 2 ) or nitrogen. In a most preferred embodiment, the fluid is cooled and in turn cools the tissue which balloon  12  contacts, allowing the laser energy to penetrate the cooled endothelial lining of the tissue in contact with balloon  12 , reducing or substantially preventing thermal damage to the sensitive endothelial lining, while the laser energy passes through and produces its desired effect on the tissue underlying the endothelial lining. If the endothelial lining of a duct, blood vessel, hollow organ or body cavity is damaged, it can cause post-operative pain and increase the risk of infection. 
         [0050]    Laser energy penetrates the cooled endothelial lining without raising its temperature to more than about 50° C., and penetrates the underlying tissue and raises its temperature to about 500 to 60° C. to achieve its desired shrinkage or denaturing effect. For example, the area to be treated may be the urethra below the female bladder, the anus, the prostate gland below the male bladder, the esophagus in the area of the sphincter, the annulus or chordae tendonae of the mitral valve or the aorta, all of which are illustrative of shrinkage applications for the apparatus of the present invention. 
         [0051]    Coagulation applications, where the underlying tissue is heated to about 65° C. or more while the endothelial lining is kept to a temperature of less than about 50° C., include coagulation of a lung tumor affixed to the exterior of a bronchus of the lung or the prostate to treat BPH. To create a scarring effect can require higher temperatures. 
         [0052]    Laser energy sources which may be used with the apparatus of the present invention include, for example, diode lasers emitting at 650 to 980 nm, Nd:YAG lasers emitting at 1,064 nm, argon or KTP lasers emitting at about 438 nm or Holmium lasers emitting at about 2,100 nm. Sterile water or saline (coolant) can be used with all of the lasers cited above, except Holmium lasers, whose energy is highly absorbed by aqueous fluids. More generally, if the laser energy or source used is diode, KTP or Nd:YAG, balloon  12  is filled with a chilled liquid coolant such as saline. If the laser energy or source used is a Holmium laser is used, balloon  12  is filled with a cryogenic gas such as expanded CO 2  or expanded nitrogen. 
         [0053]    Balloon  12  may be made of a substantially compliant or substantially non-compliant, flexible material which is of a desirable thickness, tensile strength and substantially transmissive to the radiant energy being emitted, including materials such as natural rubber, a polyurethane, a polyethylene, a polyethylene terephthalate, a polyester, a co-polyester, a polyvinyl chloride, a copolymer of vinyl chloride and vinylidene chloride and composites thereof. 
         [0054]      FIG. 2  illustrates laser energy delivery component  20  of the apparatus of the present invention, the distal end of which is constructed to emit light energy laterally from the axis of optical fiber  21 . Optical fiber  21  extends from connector  22 , which is in optical communication with laser  23 . Optical fiber  21  extends through and is fixed within handpiece  24  by an adhesive or the like. Button  25  on handpiece  24  indicates the direction in which the laser energy will be emitted. In the embodiment shown, laser energy will be emitted from the same side of cannula  26  indicated by button  25 . In an alternate embodiment, laser energy can be emitted in the opposite direction from the orientation of button  25  on handpiece  24 . When the operator puts his/her index finger on button  25 , the index finger will be pointing in the direction of the laser energy emission. 
         [0055]    optical fiber  21  also extends through protective plastic or metal sheath  26 , the purpose of which is to protect optical fiber  21  while it is advanced into place in the body. Sheath  26  is fixedly attached to handpiece  24  by an adhesive or the like and extends distally from handpiece  24 . In the embodiment shown, distal end  27  of sheath  26  has a blunt ended shape to prevent damage to the duct, blood vessel, hollow organ or body cavity. Alternatively, distal end  27  of sheath  26  may be pointed, may be a sharp, syringe needle-like shape or be of any other shape. Offset from and proximal to distal end  27  of cannula  26  is an opening or port  28  in sheath  26  for emission of laser energy in the direction shown by lines  29 , by a means described in detail with reference to  FIG. 3 . Sheath  26  may be made of medical grade stainless steel or any flexible or semi-rigid biocompatible plastic. 
         [0056]      FIG. 3  illustrates a preferred embodiment of the thermal energy delivery component  30  of the apparatus of the present invention. In this embodiment, optical fiber  31  extends through handpiece  34  and is fixed therein by adhesive  32 . The proximal end of metal or plastic sheath  36  is also fixed within the distal end of handpiece  34  by adhesive  32 . Optical fiber  31  also extends through sheath  36 , and the distal end surface  33  of optical fiber  31 , the distal end portion buffer coating  35  having earlier been removed, has been beveled at an angle of about 35° to 45°, preferably about 38° to 40°. Distal end surface  33  is encased in a closed ended capillary tube  37 , the proximal end of which is sealed about bare optical fiber  31  by thermal fusion or an adhesive, as known in the art, and whose distal end has been closed by thermal fusing. Capillary tube  37  provides an air interface opposite the beveled distal end surface  33  of optical fiber  31 , which is necessary for substantially total internal reflection of light energy laterally from the axis of optical fiber  31 . 
         [0057]    Preferably, sheath  36  is coextensive with optical fiber  31  (i.e., extends from the distal end of handpiece  34  fully over optical fiber  31 ), to provide superior stability and a smooth, contiguous outer surface. As can be seen, opening or port  38  in sheath  36  allows laser energy to be emitted laterally, as indicated by arrows  39 . 
         [0058]      FIG. 4  illustrates an alternate embodiment of the laser energy delivery component  40  of the apparatus of the present invention. As shown, the distal end of optical fiber  41  extends partially through tip  42  and presents a substantially flat end shape  43 , such that laser energy will be emitted directly ahead (i.e., in an axial direction). Tip  42  has been attached to recess  48  in the distal end portion of a plastic or metal sheath  46  by an adhesive, crimping or both (not separately shown). While tip  42  may be attached directly to optical fiber  41 , attaching tip  42  to a recess  48  in sheath  46  provides a substantially smooth outer surface of energy emitting component  40 . However, tip  42  can be attached to optical fiber  41  by any other means known in the art. 
         [0059]    Tip  42  has a beveled surface  47  opposite the flat distal end face  43  of optical fiber  41 , as described in co-owned U.S. Pat. No. 5,649,924 to Everett et al, which is expressly incorporated herein by reference. Beveled surface  47  is inclined at an angle of about 40° to 50°, preferably about 44° to 46°, to reflect the laser energy as shown at an angle of about 80° to 90°. Tip  42  is may be made of stainless steel, whose exterior has been plated with gold, silver or copper with a thickness of at least 5 thousandths of an inch. Silver provides almost the same reflectivity of gold but is less expensive, and silver has higher reflectivity than copper. 
         [0060]    Preferably, beveled surface  47  of tip  42  can have a recess into which an insert of copper, silver or gold (not separately shown), with a thickness of at least 10 thousandths of an inch may be fixed, by an adhesive, force fit or other means known in the art. In a most preferred embodiment, tip  42  is made entirely of copper, silver or gold for enhanced resistance to degradation by prolonged exposure to laser energy. Since silver is more reflective than copper and is less expensive than gold, silver is preferred. 
         [0061]    Alternatively, tip  42  can be made of a heat resistant plastic, the exterior of which is similarly plated with gold, silver or copper. Alternatively, plastic tip  42  can have a recess  48 , into which a gold, silver or copper insert, as described above, may be fixed in place by an adhesive, force fitting or both, forming beveled surface  47 , which is inclined at an angle of about 40° to 50° C., preferably of about 44° to 46° C. 
         [0062]    Markings  49  on the exterior of sheath  46  or, if sheath  46  is eliminated, on optical fiber  41 , indicate to the user the position of the distal end of tip  42  within balloon  12  of coolant retainer component  10  ( FIG. 1 ). 
         [0063]      FIGS. 5 and 6  illustrate the distal end portion of the two component medical device  50  according to the present invention. The distal end portion of laser energy delivery component  40  is disposed within the distal end portion of the balloon-tipped cannula component  10 . However, in this embodiment, plastic cannula  11  has been extruded with a central channel for optical fiber  41  and-sheath  46 , and two kidney-shaped channels  61  and  62  for infusing fluid in and out of cannula  11  and balloon  12 , as shown in  FIG. 6 . Fluid is infused in and out of cannula  11  and balloon  12  by input and output ports (not separately shown) in cannula  11 , which are in fluid communication with channels  61  and  62 , respectively. Alternatively, channels  61  and  62  can be round, crescent or of any other cross-sectional shape. Means for circulating fluid through cannula  11  and balloon  12  at a constant rate, pressure and/or temperature are known in the art and are not described herein. 
         [0064]    In one embodiment, energy delivery component  20  and coolant component  10  have complementary dimensions to prevent detachment. Delivery component  20  preferably includes a protrusion small enough to allow insertion into coolant component  10  but large enough to prevent complete withdrawal. For example, ring  58 , which is fixedly attached by an adhesive or the tube on the exterior surface of sheath  46  prevents laser energy delivery component  40  of  FIG. 4  from being removed from cannula  11 , of cooling component  10  of  FIG. 1 , as ring  58  has a larger outside diameter than channel  19  of cooling component  10  ( FIG. 1 ), making laser energy delivery component  40  ( FIG. 4 ) non-detachable from cannula/balloon cooling component  10  of  FIG. 1 . Other means may be used instead of ring  58  to prevent the removal of laser energy delivery component  40  from cannula  11 . If it is desired that fiber-optic component  40  of  FIG. 4  be completely detachable from cannula component  11  of  FIG. 1 , as provided in the two component, detachable embodiment of the present invention, ring  58  or other retaining are not provided. 
         [0065]      FIG. 6  illustrates an alternative embodiment of cannula  11  of  FIG. 1 . In this embodiment, cannula  11  is extruded with central channel  19  through which optical fiber  21  movably extends. Fluid is infused through channel  61 , circulates through balloon  12  (not separately shown) and exits through channel  62 . 
         [0066]      FIG. 7  illustrates an alternate embodiment  70  of a laser energy delivery component  30  of  FIG. 3  according to the present invention. In this embodiment, there is no sheath over optical fiber  71 . Instead of the distal end of optical fiber  31  being beveled into a single, prism-like surface  33  as shown in  FIG. 3 , the distal end of optical fiber  71  is instead beveled into a conical shape  72 , as described in co-owned U.S. Pat. No. 5,242,438 to Saadatmanesh, which is expressly incorporated herein by reference. The distal end portion of optical fiber  71  is encased by distal close-ended capillary tube  73  to create an air interface opposite the surface of conical shape  72 . Laser energy is emitted in a 360-degree arc, laterally from the axis of optical fiber  71 , as indicated by arrows  74 . Arrow  75  indicates the path of coolant fluid into balloon  76 , and arrow  77  indicates the path of coolant fluid circulating through balloon  76  and out of cannula  78 . If Holmium laser energy is to be used, balloon  76  is filled with CO 2  gas, and capillary tube  73  may be eliminated. However, to prevent the sharp point  72  of optical fiber  71  from inadvertently puncturing balloon  76 , capillary tube  73  is best retained. 
         [0067]    In this embodiment, the fluid optionally comprises saline in which light reflecting particles are suspended, as described in U.S. Pat. No. 4,612,938 to Dietrich, which is hereby expressly incorporated by reference. Preferred light reflecting particles are microscopic, inert quartz particles, known as fumed silica, such as Cab-O-Sil made by Cabot Corporation of Boston, Mass., a suspension of albumen microspheres with a diameter of less than 10 microns at a concentration of less than 25%, or a commercially available high fat intravenous fluid suspension. The light reflecting particles reflect the laser energy, creating a more uniform emission pattern. Such light reflecting particles can be incorporated into the liquid used to inflate the balloon of any of the embodiments of the invention, and the liquid may be cooled to cool and protect the endothelial surface of the duct, hollow organ or body cavity. 
         [0068]    In  FIG. 8 , the distal end portion  80  of the apparatus of the present invention is disposed within female urethra  83  at the level of sphincter  84  below bladder  85 , with a cold fluid infused through cannula  81  having expanded balloon  82 . Pubic bone  86  is shown to the left. Dotted lines a-a and b-b indicate the desired positions for emission of laser energy. In this embodiment, two markings  49 , as shown in  FIG. 4 , are made on sheath  26 ,  36  or  46  of reusable laser energy delivery components  20 ,  30  or  40  shown in  FIG. 2 ,  3  or  4 , respectively. When the markings reach the proximal end of compression nut  13  at the proximal end of cannula  11  ( FIG. 1 ), these marking each indicate that the laser emission port  28 ,  38  or  48  of reusable fiber-optic component  20 , or  40  ( FIG. 2 ,  3  or  4 , respectively) has reached dotted line positions a-a or b-b within balloon  12  of  FIG. 1 . Any number of positions for the emission of laser energy may be employed, depending on the size of the area to be treated, with the number and position of markings on sheath  26 ,  36  and  46  of  FIGS. 20 ,  30  and  40  corresponding thereto. 
         [0069]    Balloon  82  is inflated with a cold fluid during or, preferably, for at least about five seconds prior to and during the emission of laser energy, to cool the endothelial lining  87  of urethra  83  in contact with balloon  82 . Laser energy may be emitted at about 2 to 25 watts, preferably at about 5 to 15 watts, for about 5 to 60 seconds, preferably for about 10 to 30 seconds, by rotating handpiece  24  and using button  25  on the handpiece  24  of the device of  FIG. 2  to direct the laser energy to, for example, each of 12, 3, 6 and 9 o&#39;clock at position a-a to shrink urethral sphincter  84 , repeating the above procedure at each of 12, 3, 6 and 9 o&#39;clock at position b-b, to treat female stress urinary incontinence. 
         [0070]    If the laser energy emitter is the 360° lateral laser energy emitting device  70  shown in  FIG. 7 , button  25  is eliminated, and laser energy is emitted in a 360° arc at about 2 to 15 watts, preferably about 5 to 15 watts, without rotating handpiece  24 , for about 20 to 240 seconds, preferably for about 40 to 120 seconds, at each of positions a-a and b-b, using markings  49  of  FIG. 4 , as described above. Only one lasing position or more than two may also be used. 
         [0071]      FIG. 9  illustrates the distal end portion of apparatus  90  disposed within the annulus  93  and leaflets  94  of mitral valve  95 , with a cold fluid infused through cannula  91  having inflated balloon  92 . Laser energy is emitted at positions a-a, b-b and c-c at the power levels and for the time periods described above in  FIG. 8 , with the cold fluid cooling endothelial lining  97  of mitral valve  95  and leaflets  94  during and, preferably, for at least about 5 seconds before and during the emission of laser energy to shrink annulus  93  and, if desired, leaflets  94  to improve the closure of mitral valve  95 . Any other selection of lasing positions may be also used. 
         [0072]      FIG. 10  illustrates the distal end portion of apparatus  100  disposed within the left ventricle  107  of the heart. If prolapse of mitral valve  104  is caused or contributed to by stretching of chordae tendonae  106 , the distal end portion of apparatus  100  may be positioned in left ventricle  107  of the heart by inserting guiding catheter  108  through aortic valve  109 , as known in the art. Cannula  101  may have been thermally preformed into the curved shape shown, may be articulated by wires, as known in the art, or may be positioned by any other means. Fluid is infused into balloon  102 , pressing balloon  102  against chordae tendonae  106 . Laser energy is emitted as described above at positions d-d and e-e to shrink and tighten chordae tendonae  106 , which in turn cause leaflets  105  of mitral valve  103  to close tighter. 
         [0073]    Preferably, for at least about 5 seconds before and during the emission of laser energy, a cold fluid is infused into cannula  101  and balloon  102 , or circulated through cannula  101  and balloon  102 , to cool chordae tendonae  106  while the shrinkage is created. After deflating balloon  102 , cannula  101  and balloon  102  may be withdrawn into catheter  109 , and catheter  109  may then be withdrawn from the body. 
         [0074]    If the emission of laser energy in pulses, with a duration of about 0.2 to 0.4 seconds, is synchronized with the patient&#39;s ECG to occur during systole, when chordae tendonae  106  are relaxed, up to 30% shrinkage of charade tendonae  106  has been shown to occur, whereas the same amount of laser energy emission occurs during diastole, when chordae tendonae  106  are tightly stretched to close leaflets  105 . 
         [0075]    In  FIG. 11 , the distal end portion apparatus  110  is shown positioned in the esophagus  113  in the area of the esophageal sphincter  114 . Apparatus  110  is inserted, with balloon  112  deflated, through a delivery catheter or a channel of endoscope  115 . Cold fluid is infused through cannula  111  to inflate balloon  112 , or circulated through balloon  112 , during or, preferably, for at least about 5 seconds before and during the emission of laser energy at positions a-a, b-b and c-c, or a greater or lesser number of positions, at the energy levels and for the time periods described above, to shrink the esophageal sphincter to treat gastroesophageal reflux disease or GERD. Cold fluid infused through cannula  111  inflates balloon  112  cools and prevents thermal damage to endothelial lining  117  of sphincter  114 . 
         [0076]      FIG. 12  illustrates the distal end portion of apparatus  120  with cannula  121  and balloon  122  positioned in anus  123 . Cold fluid infused into or circulated through balloon  122  during or, preferably, for at least about 5 seconds before and during the emission of laser energy at position a-a, at the energy levels and for the time period described above, cools and prevents thermal damage to endothelial lining  124  of anus  123 , while the laser energy shrinks the tissue of anus  123  to treat fecal incontinence. More than one lasing position may be used, if desired. 
         [0077]      FIG. 13  shows the distal end portion of apparatus  130  with cannula  131  and balloon  132  positioned in the bronchus  133  of the lung  135  of a person with a tumor  134  surrounding bronchus  133 . A cold fluid is infused into or circulated through cannula  131  to inflate balloon  132  and cool endothelial lining  135  of bronchus  133 , preferably, for at least about 5 seconds before and during the emission of laser energy at the powers and for the time periods described above at position a-a or additional positions, depending on the size of tumor  134 . The laser energy lethally coagulates or denatures the proteins of tumor  134  to treat lung cancer. 
         [0078]      FIG. 14  illustrates the distal end portion of apparatus  140  with cannula  141  and balloon  142  extending distally from a catheter or a channel of endoscope  143  and positioned in the male urethra  144  within prostate gland  145 . A cold fluid may be infused into cannula  141  to inflate balloon  142  and cool the endothelial lining  146  of urethra  144 , while laser energy passes through the shrink, denature proteins or coagulate prostate  145  to treat benign prostatic hyperplasic or BPH. Balloon  142  is advanced to its position proximal to bladder neck  147 , having passed over veru montaneum  148 . Lines a-a, b-b and c-c illustrate some of the positions at which laser energy may be emitted at the energy levels and for the time periods described above to shrink or denature the proteins of the prostate or, at higher energy levels for longer time periods, to coagulate the prostate to treat BPH. 
         [0079]      FIG. 15  illustrates the distal end portion of apparatus  150 , with cannula  151  and balloon  152  movably disposed within retractable cover  153 . Optionally, as shown in  FIG. 15 , distal end  154  of retractable cover  153  may be slightly curved inwardly to form a less traumatic distal end. Alternatively, the distal end of cannula  151  may not be curved inwardly (not separately shown). Cover  153  prevents damage to balloon  152  when apparatus  150  is inserted through a channel of an endoscope (not shown) or directly into a duct, blood vessel, hollow organ or body cavity. When cover  153  is retracted, narrowed distal end cannot pass beyond ring  155 , at which point the operator knows, balloon  152  is fully exposed and can be inflated with a cold fluid and laser energy emitted as described above. Flanges and other means known in the art can be employed to prevent cover  153  from being retracted further than necessary to fully expose balloon  152 . 
         [0080]    Alternatively, markings (not separately shown) outside the body on cannula  151  can indicate to the operator when cover  153  has been extended fully over balloon  152  and when cover  153  has been retracted and balloon  142  is fully exposed. 
       EXAMPLE 
       [0081]    A group of medical devices were constructed according to embodiments shown in  FIGS. 1 and 3 . Specifications for selected features are presented below in Table I. 
         [0000]    
       
         
               
               
               
             
               
             
               
               
               
             
               
             
               
               
               
             
           
               
                   
                 TABLE I 
               
               
                   
                   
               
               
                   
                 Device 
                 Specification 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Laser Energy Emitting Component: 
               
             
          
           
               
                   
                 fiber optic 
                 365 to 550 micron case diameter 
               
               
                   
                   
                 3 meters in length 
               
               
                   
                 sheath material 
                 medical grade stainless steel or 
               
               
                   
                   
                 PEEK 
               
               
                   
                 sheath outside diameter 
                 1.5 to 2.33 mm 
               
               
                   
                 emitter configuration 
                 Beveled, prism-like optical fiber 
               
               
                   
                 capillary tube 
                 Fused silica 
               
               
                   
                 preferred laser type 
                 Diode 
               
             
          
           
               
                 Coolant Retainer/Balloon: 
               
             
          
           
               
                   
                 cannula length 
                 10 to 75 cm 
               
               
                   
                 (handpiece to balloon) 
               
               
                   
                 cannula outside diameter 
                 2 to 3 mm 
               
               
                   
                 balloon material 
                 silicone 
               
               
                   
                 balloon diameter (inflated) 
                 5 to 80 mm 
               
               
                   
                 port(s) 
                 Luer configuration 
               
               
                   
                   
               
             
          
         
       
     
         [0082]    The meetings and sizes of the example devices vary by the particular medical application. The example devices provide a reusable higher-cost thermal energy delivery component and a relatively lower cost, disposable coolant component. These devices can be made non-detachable as a single use, disposable device, or detachable to enable the more costly laser energy delivery component to be reused and the lower cost, outer, cooling component to be discarded after one use. Such devices enable the treatment of tissues underlying internal ducts, blood vessels, hollow organs and body cavities. with protective cooling for their endothelial linings. 
         [0083]    Numerous variations and modifications of the embodiments described above can be effected without departing from the spirit and scope of the novel features of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims, all such modifications as fall within the scope of the claims.