Abstract:
A fiber optic device includes an optical fiber passing through a handpiece that defines an internal passageway with an apertured endwall at a distal end of the passageway. A portion of the optical fiber is disposed within the passageway, and a stop member, such as a rigid sheath, within the passageway is attached to the optical fiber. An indexing member releasably engages the rigid sheath to maintain the rigid sheath at a predetermined position within the passageway. The rigid sheath preferably contains a series of index positions for incrementally adjusting the position of the sheath within the passageway. The rigid sheath is slidably mounted in the passageway and is configured to interfere with the endwall when the rigid sheath is released for movement within the internal cavity to its final position within the passageway.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to fiber optic devices, whose frequency of use can be controlled, and especially to such devices suitable for use in a medical procedure. 
       BACKGROUND OF THE INVENTION 
       [0002]    Optical fibers, sometimes called fiber-optics, are used to transmit laser energy in a wide variety of medical and surgical procedures to vaporize, cut, coagulate, shrink and denature tissue. The ability to create a variety of tissue effects by varying the amount or wavelength of the laser energy being delivered makes optical fibers a desirable means for delivering laser energy through body orifices or tiny punctures, instead of larger incisions, which are necessary for the use of laser energy not transmittable through optical fibers or other surgical tools. 
         [0003]    Optical fibers typically consist of a fused silica or quartz core, which is covered by a thin glass cladding, which is further encased by a relatively thicker buffer coating of a fluorocarbon or a similar plastic to prevent mechanical damage to the optical fiber. 
         [0004]    Laser energy reflected from the tissue can vaporize the protective buffer coating of the optical fiber, however, leaving the optical fiber subject to fracture. Also, the distal end portion of the optical fiber can be deformed or melted by laser energy reflected from the target tissue, causing laser energy to be emitted in an undesired direction, perhaps affecting an unintended tissue, nerve or blood vessel. 
         [0005]    One solution is to periodically clip-off a portion of buffer coating from the distal end of the optical fiber. For example, about 4 to 12 mm of the distal end of the buffer coating of the optical fiber, preferably about 8 mm, is clipped off with a clipping tool, leaving 8 mm of bared optical fiber exposed. Then about 2 to 6 mm of the exposed bared distal end of the optical fiber, preferably about 4 mm, is cleaved-off with a clipping tool. This process is called “clipping and cleaving,” after which the fiber-optic device can be cleaned and sterilized for another use. Clipping and cleaving tools are often provided or sold to users of lasers by the optical fiber manufacturer. 
         [0006]    Since fiber-optic devices are usually supplied in lengths of about 2.5 to 3 meters, they can be clipped and cleaved up to 100 or more times before the laser source, which cannot enter the sterile field in the operating room, can no longer be moved closer and the optical fiber cannot be easily handled during use. 
         [0007]    Excessive reuse of fiber-optic devices is not always desirable. In some instances, as known in the art, a microchip-bearing or bar-coded card is supplied with each optical fiber. Alternatively, as known in the art, a microchip may be embedded in the connector of the optical fiber device. In either case, when the microchip-bearing or bar-coded card is inserted into a card reader or the connector is inserted into the optical coupler of the laser, it is recognized by the computer&#39;s microprocessor. If the card or connector has been recognized before, the microprocessor will not allow the laser to be turned-on. 
         [0008]    The laser&#39;s microprocessor can be programmed to permit, for example, the optical fiber to be used one, five, ten or any number of times. However, if a hospital, surgery center or physician already owns a laser without such a microprocessor, the laser cannot be refitted with such a microprocessor without the customer&#39;s consent, which is unlikely to be given. Since thousands of lasers without such microprocessors have been sold to hospitals, surgery centers and physicians, there is no way to limit the number of reuses of conventional optical fibers with these lasers. 
         [0009]    Customers sometimes leave a laser unit with such a microprocessor on “standby” between medical procedures or surgeries, during which it is operating at a very low level and its energy delivery port is closed. Initially, an unused fiber-optic device can be connected, recognized and the laser “enabled”. When the medical procedure or surgery is completed, the laser remains on standby, the optical fiber remains connected to the laser, and the distal end portion of the optical fiber can be cleaned, sterilized and reused. However, if left on standby all day or through one or more nights, the laser&#39;s lifetime may be shortened. 
         [0010]    It would be desirable to satisfy the manufacturer&#39;s desire to prevent excessive reuse of fiber-optic devices by the operators of existing lasers in hospitals, surgery centers or physicians&#39; offices, while satisfying the customer&#39;s desire to amortize the cost of the fiber-optic device over a sufficient number of medical procedures or surgeries, to reduce the cost per case. This is particularly important in countries where governmental organizations or insurance plans do not pay hospitals, surgery centers or physicians for medical procedures as handsomely as Medicare and insurance plans in the United States. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention provides a novel and improved fiber optic device in which an elongated handpiece for an optical fiber defines an internal, elongated, confined flow passageway with an apertured endwall at a distal end portion of the passageway, and controls the length of optical fiber that can pass through the handpiece. An optical fiber having a distal working end is dispensed through the handpiece and is disposed within the passageway. A stop member, such as a rigid sheath and the like, within the passageway surrounds and is attached to the optical fiber. The stop member limits the length of optical fiber that can pass through the handpiece. The stop member preferably contains a series of index positions for incrementally adjusting the position of the stop member within the passageway and thus the position of the optical fiber working end. The stop member is configured to abut the endwall when the stop member is moved within the internal passageway to a final position. 
         [0012]    Preferably, a tube or cannula extends from the distal end of the elongated handpiece and defines an extension of the passageway through which the optical fiber passes. The working end of the optical fiber extends beyond the free end of the cannula in such a case. After an initial use, the stop member and the optical fiber are advanced a predetermined distance, and the portion of the free end of the optical fiber, damaged during the prior lasing procedure, is removed so as to expose a new working end. Spaced markings may be provided on the optical fiber to indicate the amount of optical fiber advanced within the internal passageway and available for use. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    In the drawings, 
           [0014]      FIG. 1  is a diagrammatic representation of a system employing a first embodiment of a fiber optic device illustrating certain aspects of the present invention; 
           [0015]      FIG. 2  is a fragmentary cross-sectional view of the fiber optic device, taken along the plane  2 - 2  of  FIG. 1 ; 
           [0016]      FIG. 3  is a fragmentary cross-sectional view of a second embodiment of a fiber optic device illustrating certain aspects of the present invention; 
           [0017]      FIG. 4  is a fragmentary cross-sectional view of the fiber optic device of  FIG. 3 , shown ready for last use; 
           [0018]      FIG. 5  is a fragmentary cross-sectional view of the fiber optic device of  FIG. 4 , shown after its last use; 
           [0019]      FIG. 6  is a fragmentary top plan view of a third embodiment of a fiber optic device illustrating certain aspects of the present invention; 
           [0020]      FIG. 7  is a fragmentary cross-sectional view of a fourth embodiment of a fiber optic device illustrating certain aspects of the present invention; 
           [0021]      FIG. 8  is a fragmentary cross-sectional view of a fifth embodiment of a fiber optic device illustrating certain aspects of the present invention; 
           [0022]      FIG. 9  is a fragmentary cross-sectional view of a sixth embodiment of a fiber optic device illustrating certain aspects of the present invention; 
           [0023]      FIG. 10  is a fragmentary cross-sectional view of a seventh embodiment of a fiber optic device illustrating certain aspects of the present invention; 
           [0024]      FIG. 11  is a fragmentary cross-sectional view of components employed in the embodiment of  FIG. 10 ; 
           [0025]      FIG. 12  is a fragmentary cross-sectional view of an eighth embodiment of a fiber optic device illustrating certain aspects of the present invention; and 
           [0026]      FIG. 13  is a fragmentary cross-sectional view of a ninth embodiment of a fiber optic device illustrating certain aspects of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    For ease of description, fiber optic devices embodying the present invention are described herein below in their usual assembled position as shown in the accompanying drawings and terms such as front, rear, upper, lower, horizontal, longitudinal, distal, proximal, etc., may be used herein with reference to this usual position. However, the fiber optic devices may be manufactured, transported, sold, or used in orientations other than that described and shown herein. 
         [0028]    Referring now to the drawings and initially to  FIGS. 1 and 2 , a first embodiment is shown in relation to system  8  for delivering laser energy. As seen in  FIG. 1 , system  8  is comprised of a fiber optic device  10  and a source of laser energy  11 . Fiber optic device  10  comprises optical fiber  13 , handpiece  14 , and a connector  12  that optically couples optical fiber  13  to the source of laser energy  11 . Optical fiber  13  has core  18  surrounded by a buffer coating  52 , and extends through an optional rubber or plastic strain relief, as known in the art, and through an enclosing body or handpiece  14 . A fiber advancement mechanism is associated therewith. Handpiece  14  is preferably made of a sturdy metal, such as medical grade stainless steel, or a rigid, durable plastic, such as acetal homopolymer resin, available from Interstate Plastics, Sacramento, Calif. Handpiece  14  is comprised of two halves, which can be joined together with a locking mechanism, screws and/or an adhesive. 
         [0029]    Optical fiber  13  extends through an elongated hollow passageway  21  ( FIG. 2 ) defined by handpiece  14  and a tubular extension thereof which can be unitary with the handpiece  14  or a tube segment extending therefrom, such as cannula  17 . If it is desired to infuse a fluid into the passageway in handpiece  14 , optionally, a “luer” fitting  15 , as known in the art, may extend into and provide a fluid infusion port in confined flow fluid communication with the passageway through handpiece  14 . 
         [0030]    A portion of optical fiber  13  is encased in a sturdy, rigid sheath  20  ( FIG. 2 ) which is moveably disposed within the passageway  21  in handpiece  14 . Sheath  20  serves as a stop member for the optical fiber, and may be made of metal, such as medical grade stainless steel. Sheath  20  may also be made of a biocompatible, rigid plastic, such as polyetheretherketone (PEEK) tubing, or a biocompatible, semi-rigid plastic, such as fluorocarbon, nylon or polyether block amide (PEBA) tubing, all of which are commercially available from Zeus Industrial Products, Orangeburg, S.C. Sheath  20  may have a round, square or rectangular cross-section or any other shape, preferably a square or rectangular cross-section. Passageway  21  in the handpiece  14  has a slightly larger cross-section, but of the same cross-sectional shape as sheath  20 , to enable sheath  20  to move along the passageway. 
         [0031]    With reference to  FIG. 2 , an indexing member such as threaded set screw  16  terminating in a tip that can be screwed down to removably fix the above mentioned sheath  20  encasing optical fiber  13  in place, at a fixed position within passageway  21  in handpiece  14 . If handpiece  14  is made of a plastic, a metal insert with a matching threaded bore hole may optionally be incorporated in handpiece  14  at the time of its manufacture, to provide a stronger anchorage for set screw  16 . Sheath  20  has sufficient density and thickness to prevent damage to the optical fiber from the set screw and its tip. 
         [0032]    Distal end portion of optical fiber  13  extends through cannula  17 , whose proximal end is mounted to the handpiece  14  and preferably fixed within the apertured endwall of handpiece  14  by an adhesive or other means, as known in the art, so as to form a portion of the fiber optic device  10 . Cannula  17  preferably is a hollow and rigid tube, but may be flexible, semi-rigid or malleable, especially if the intended use is in conjunction with an instrument channel of a flexible endoscope. Cannula  17  may be made of a metal material, such as medical grade stainless steel, a biocompatible, rigid plastic, such as PEEK tubing, a biocompatible, semi-rigid or flexible plastic, such as fluorocarbon, nylon or polyether block amide tubing, and the like. Cannula  17  is in fluid communication with handpiece  14  and defines a continuation of passageway  21 . While cannula  17  may be straight, a portion of its distal end may optionally be bent at an angle as shown in  FIG. 2  to facilitate directing laser energy to a target tissue site. Cannula  17  typically is provided as part of fiber optic device  10 , but it may be provided separately, as an accessory, if desired. 
         [0033]    Optical fiber  13  has a working distal end that extends beyond the distal end of cannula  17 . As illustrated, a portion of the plastic buffer coating  52  has been removed from the distal or working end of optical fiber  13 , exposing the bared, glass clad core  18  of optical fiber  13 . By way of an example of its use, fiber optic device  10  of the present invention may be typically supplied by the manufacturer with, for example, about 4 mm of buffer coating  52  extending distally from the distal end of the cannula and about 4 mm of the bare, glass cladding covered core  18 , optical fiber  12  extending from the distal end of buffer coating  52 . During its first use, the exposed core  18  of optical fiber  13  may be deformed and the distal end of protective buffer coating  52  may be degraded, from both laser energy reflected from the target tissue and the hot gasses created by the vaporization of tissue. Accordingly, ongoing maintenance procedures must be performed on the optical fiber device if it is to be reused. To that end, an additional portion of buffer coating  52  and core  18  of optical fiber are advanced or dispensed through handpiece  14 , providing a new working end. 
         [0034]    Referring to  FIG. 2 , optical fiber  13  extends through snugly fitting gasket  19  mounted in the proximal end of handpiece  14  to prevent leakage of fluid from the proximal end of handpiece  14 , as known in the art. Optical fiber  13  extends through and is affixed by an adhesive or the like within sturdy, rigid metal or plastic sheath  20 . Sheath  20  may have a round, square, rectangular or other shaped cross-section, preferably square or rectangular. Passageway  21  within handpiece  14  has slightly larger cross-sectional dimensions compared to those of sheath  20 , and preferably has the same cross-sectional shape. 
         [0035]    Set screw  16  may have a rounded, pointed, flat or other shaped distal end or tip, preferably pointed, as shown. When set screw  16  is screwed into handpiece  14  and tightened-down upon sheath  20 , set screw  16  removably fixes sheath  20  and attached optical fiber  13  in place within handpiece  14 . 
         [0036]    Cannula  17  is preferably made of metal, such as medical grade stainless steel, but may also be made of a biocompatible, rigid plastic, such as PEEK tubing, a biocompatible semi-rigid plastic, a flexible plastic, and the like. If cannula  17  is made of a rigid metal or rigid plastic, the distal end portion of cannula  17  may be bent downward from its axis, as shown, at an angle of about 10° or more to better address the target tissue. A bend greater than about 10° to 15° of a rigid metal or plastic, although desirable, may not be feasible, as the bend may be too great to enable cannula  17  to pass through the instrument channel of a conventional endoscope or cystoscope. If cannula  17  is made of a semi-rigid plastic, its distal end portion may be bent at a substantially greater angle. 
         [0037]    Spaced markings  22  may be provided on optical fiber  13 , either adjacent the proximal end of handpiece  14  and/or distally from the distal end of cannula  17  (as shown for example, at the left hand and/or right hand end of  FIG. 2 ). Markings  22  are preferably cylindrical or arcuate, and preferably are spaced apart from each other by the distance that optical fiber  13  is intended to be advanced after each use. Markings  22  may partially surround optical fiber  13 , and indicia such as numbers (not separately shown) may appear between markings  22  to indicate to the operator the number of the present use or the number of uses remaining. Accordingly, when a new marking  22  is made to appear at the proximal end of handpiece  14  and/or the distal end of cannula  17 , optical fiber  13  has been advanced the proper distance for another reuse, and set screw  16  can be tightened down to removably fix sheath  20  and attached optical fiber  13  in place, at the new use position. 
         [0038]    As illustrated in  FIGS. 3-5 , in a second embodiment of the present invention, sheath  20  has indexing capability in the form of an array of adjacent indentations  23  on its upper surface, opposite set screw  16 . Set screw  16  may be provided with a rounded tip that enters one of indentations  23  to removably fix the optic fiber  13  in place within handpiece  14 . Preferably the tip of set screw  16  and the indentations  23  are complementary. The number of indentations  23  in the array preferably corresponds to the number of intended uses of device  10 , as described heretofore. The spaces between the centers of indentations  23  are preferably equal to the amount of intended protrusion of optical fiber  13  from the free end of cannula  17 , i.e., length of advance of buffer coating  52  and core  18  of optical fiber  13  after each use. The spacing of indentations provides a convenient indexing of the optical fiber as it is readied for shortening of its free end, prior to a subsequent use. As shown in  FIG. 3 , the distal end of set screw  16  has been advanced to engage the initial, or most distal indentation  23  for the first use of device  10 , with optical fiber  13  extended a preferable distance distally from cannula  17 . A desired length of buffer coating  52  has been removed from the distal, working end of optical fiber  13 , exposing a desired length of core  18 . 
         [0039]    In the illustrated embodiment of  FIG. 3 , cannula  17  is made of a semi-rigid plastic tubing, and its distal end portion may be bent downwardly from its central longitudinal axis during a molding, heat treating or other conventional process, to form an angle of about 20° to 40°, but preferably about 30°. Cannula  17  is temporarily straightened out by its insertion into the instrument channel of an endoscope and returns approximately to its original bent configuration upon emerging from the distal end of the endoscope to address the target tissue. 
         [0040]    In  FIG. 4 , set screw  16  is shown inserted into the last indentation  23  from the distal end of sheath  20 , prior to the last use of optical fiber  13 . As with the other, prior uses of optical fiber  13 , its free end is extended out of the distal end of cannula  17  by a suitable distance for its clipping and cleaving, to remove the prior, now damaged buffer coat  54  and core tip  56  working end of optical fiber  13 , thereby exposing a sufficient length of new working end or tip of optical fiber  13  having buffer coating end portion  60  and core tip  58 . As shown in  FIG. 4 , tip  56  of core  18  as well as distal end portion  54  of the buffer coating  52  of optical fiber  13  have been damaged during their prior use by the back scatter of laser energy from the target tissue and hot gases generated at the treatment site. 
         [0041]      FIG. 5  illustrates device  10  ready for its final use cycle, after the damaged buffer coating end portion  54  and the tip  56  of core  18  shown in  FIG. 4  have been clipped off exposing new tip  58  and buffer coating end portion  60 . 
         [0042]      FIG. 6  illustrates a third embodiment of the present invention. In this embodiment, handpiece  14  has two viewing slots for the stop member on its top surface, one distal to expose sheath  20  that receives set screw  16 , and a second, proximal slot  24 . In the preferred embodiment, these slots are covered by a transparent glass or clear plastic insert and sealed with a gasket material, as known in the art, to provide a window so that sheath  20  and indentations  23  can be viewed by a user, while preventing leakage of fluid. 
         [0043]    Optionally, slot  24  may be provided in one or both sides of handpiece  14 , extending throughout most of the length of handpiece  14 , to provide the functionality of the two slots shown in  FIG. 6 . When thus constructed, the single slot formed in handpiece  14  is filled by a glass or clear plastic insert and sealed with a gasket material as described above, to enable the operator to fully view sheath  20  and indentations  23 . 
         [0044]    In the embodiment shown in  FIG. 6 , sheath  20  with indentations  23  functions as an indexing device controlling advancement of fiber optic  13  beyond the distal end of cannula  17 . It is generally preferred that sheath  20  be dimensioned to interfere with or abut a stop such as apertured endwall  9  at the end of the passageway within handpiece  14 . 
         [0045]      FIG. 7  illustrates a fourth embodiment of device  10 . In this embodiment, gear  25  is mounted on gear shaft  26  within housing  27  of handpiece  14 . Gear teeth  28  of gear  25  engage rack gear  29  preferably provided as features formed in sheath  20 . Gear shaft  26  extends into a recess (not separately shown) in the bottom of housing  27  and extends through a retaining ring (not separately shown) to prevent its exiting the top of housing  27 . 
         [0046]    Shaft  26  further extends through the top of housing  27 , through a snugly fitting gasket (not separately shown) that prevents leakage of fluid from the junction of shaft  26  with the top of housing  27 . A knob by which gear  25  can be turned, is fixedly attached by welding or other means, as known in the art, to the end of gear shaft  26  that extends through the top of housing  27 , if desired. When the gear  25  is turned clockwise, for example, gear  25  advances sheath  20  and attached optical fiber  13 . 
         [0047]    A tactile or audible mechanism (not separately shown), as known in the art, may be attached to gear  25 , to advise the operator that gear  25  has advanced sheath  20  and attached optical fiber  13  to the next operating position. The sheath may then be fixed in place by set screw  16  in preparation for clipping and cleaving of optical fiber  13  prior to its next use. The diameter of gear  25  and the spacing of gear teeth  28  may be based upon the distance sheath  20  and attached optical fiber  13  are to be advanced by one or more clicks to its next clipping and cleaving portion. 
         [0048]      FIG. 8  illustrates a fifth embodiment of device  10  wherein an adjustable curvable tip for supporting the free end of optical fiber  13  is provided. In this embodiment, flexible, biocompatible plastic tube  30  extends distally from the distal end of cannula  17 . The proximal end of flexible plastic tube  30  may be attached to the distal end of cannula  17  by an adhesive, an adhesively attached collar over the junction of cannula  17  and plastic tube  30 , or other means, with the distal end portion of cannula  17  optionally overlapping the proximal end portion of flexible tube  30  or vice versa, as known in the art. 
         [0049]    Wire  32  is anchored to the distal end of flexible tube  30  and is manipulated by wheel  31  in housing  67 . The proximal end of wire  32  is force-fit into and/or fixed by welding, solder or other means, as known in the art, in a pocket or depression  33  in wheel  31 . Shaft  66  of wheel  31  extends into a recess in the bottom of housing  67  and extends through a retaining ring (not separately shown) for the same purpose as described in  FIG. 7 , and through the top of housing  67 , through a snugly fitting gasket (not separately shown) to prevent leakage of fluid from housing  67 . 
         [0050]    A knob (not separately shown), can be fixedly attached by welding or other means to the end of shaft  66  extending through the top of housing  67 , to turn wheel  31 , causing wire  32  to be tightened and flexible plastic tube  30  to be bent at a desired angle to better address the target tissue. 
         [0051]      FIG. 9  shows a sixth embodiment of fiber optic device  10 . This embodiment preferably comprises a variation of the embodiment of  FIG. 8 , in which the proximal ends of wire  32  is fixedly attached to lever  34 , whose distal end portion is made in the shape of a trigger (as shown). The distal end portion of lever  34  can also be made in the shape of a hollow ring or any other desired shape. Wire  32  passes around rod  35  and its distal end is fixedly attached to the distal end of flexible tube  30 , as described in  FIGS. 7 and 8 . When handle  36  is gripped and lever  34  is moved toward handle  36 , wire  32  causes flexible tube  30  to be bent at a desired angle. One or any number of wires  32  may be used. Other variations for tensioning the wires so as to bend flexible tube  30 , as are known in the art, may also be used. If desired, a geared rack can be employed in place of lever  34 . 
         [0052]    Optionally, hollow tube  30  can be made of a flexible memory metal, such as nitinol, a composition of 45% nickel and 55% titanium, made by Memry, Inc. of Bethel, Conn., and can be attached to metal or plastic cannula  17  by an adhesive and/or crimping or other means, as known in the art. The distal end portion of hollow tube  30  can be bent at a desired angle, preferably about 10 to 40 degrees or more, and made to conform to its bent shape by thermal treating. After being straightened-out, while confined, for example, in the instrument channel of an endoscope, hollow tube  30  returns to its original bent shape when it emerges from the endoscope. 
         [0053]    Alternatively, hollow tube  30  may be made of a memory metal or plastic which has been heat treated and forced to assume a bent shape at a temperature of, for example, greater than abut 30° C. and a straight shape when cooled to a temperature less than about a 30° C. transition temperature. For example, tube  30  may be cooled in a bath of sterile, cold water and inserted into an endoscope, body orifice or surgical pathway. When it reaches body temperature, it resumes its bent shape to better address the target tissue. After use, when cooled by the infusion of sterile, cold water through cannula  17 , hollow tube  30  resumes its straight shape for removal from the endoscope, body orifice or surgically created passageway. 
         [0054]    Referring again to  FIG. 9 , metal cannula  17  may optionally be covered by plastic sleeve  37 , preferably a lubricious plastic such as a fluorocarbon, e.g., Teflon® PTFE tubing, available from Zeus Industrial Products, Inc., Orangeburg, S.C., to ease its insertion into and through the instrument channel of an endoscope, body orifice or surgically created passageway. Sleeve  37  can be attached to cannula  17  by heat-shrinking, an adhesive or other means known in the art. 
         [0055]    If flexible tube  30  is made of a flexible memory metal, as described above, it is also preferably covered by a lubricious plastic sleeve  37  to both ease its insertion into and through the instrument channel of an endoscope and to prevent damage to the instrument channel&#39;s surface during its advancement and withdrawal. 
         [0056]    A seventh embodiment is illustrated in  FIG. 10 , with a hollow sheath  20 , of cylindrical, square, triangular, rectangular or other cross-sectional shape affixed to optical fiber  13 . The outside dimensions of sheath  20  are somewhat smaller than the inside dimensions of hollow passageway  21  in handpiece  14 . 
         [0057]    Sheath  20  may be attached to optical fiber  13  by an adhesive, crimping or other means, as known in the art. For simplicity and low manufacturing cost, the exterior of sheath  20  and the interior passageway  21  of handpiece  14  both preferably have a cylindrical cross-sectional shape. 
         [0058]    Sheath  20  can be made of metal such as medical grade stainless steel, or a rigid plastic, such as PEEK tubing. In this embodiment, there is no set screw as described above, and the length of sheath  20  can be made relatively short, but with a sufficient inner surface area to enable sheath  20  to be fixedly attached to optical fiber  13  with an adhesive, as known in the art. For example, sheath  20  can be about 5 to 15 mm in length. 
         [0059]    Sheath  20  can also be very short, to resemble a retaining ring, with a length of only about 2 to 4 mm. To assure that ring-like sheath  20  is not dislodged from optical fiber  13 , sheath  20  can be crimped to optical fiber  13 . However, crimping sheath  20  to optical fiber  13  may fracture the core  18  of optical fiber  13 , causing device  20  to fail to function as desired and, possibly, overheating handpiece  14 . The length of passageway  21  in handpiece  14 , may be sized, for example, to allow the device to be used 10 times. If optical fiber  13  is to be extended for each use is 8 mm, the length of sheath  20  is 6 mm, is 10 times 8 mm plus 6 mm or 86 mm in length. 
         [0060]    Shoulders  38  at the proximal and distal ends of channel or passageway  21  are sized so as to prevent sheath  20  from exiting passageway  21 . As described heretofore, markings  22  on optical fiber  13  (located proximal to the proximal end of handpiece  14  and/or distal to the distal end of cannula  17 ), provide a next marking that enables the operator to position optical fiber  13  at the proper position for the next clipping and cleaving procedure of optical fiber  13 , prior to the next intended use of device  10 . In this embodiment, the operator tightens compression nut  41  so as to cause optical fiber  13  to be removably and sealingly fixed within handpiece  14  With this arrangement, set screw  16  of  FIGS. 1-9 , indentations  23  of  FIGS. 3-6  and  8 - 9  and gear  25  and ridges  28  of  FIG. 7  can be eliminated. 
         [0061]    Referring again to  FIG. 10 , threaded compression assembly  39  is incorporated in the proximal end of handpiece  14  to mechanically grip optical fiber  13  and/or compress gasket  19  to removably and sealingly fix optical fiber  13  in place within handpiece  14 . The benefit of this embodiment is its simplicity of construction and lower manufacturing cost, enabling device  10  to be sold at a lower price in underdeveloped countries, where the patient has to pay the cost of the medical procedure or where governmental or insurance health care programs are not readily available to pay for such devices. However, while not shown separately in this embodiment, wheel  25  and wires  31  of  FIG. 8  and handle  36 , trigger  34 , rod  35  and wires  31  of  FIG. 9  may be added to bend flexible plastic tube  30  of  FIGS. 8 and 9  at a desired angle to better address the target tissue. Also, cannula  17  and/or tube  30  in this embodiment may be covered with lubricious plastic sleeve  37 , as described with respect to  FIG. 9 . 
         [0062]      FIG. 11  illustrates components used in the construction of compression assembly  39  of  FIG. 10 . Nut  40  has a threaded, cylindrical nose portion  41 , with threads  42  about its exterior surface. Channel  43 , extending through nut  40  and nose portion  41  have an inside diameter just slightly larger than the outside diameter of optical fiber  13  (not separately shown). Optionally, gasket  19 , may be incorporated in nose portion  41 , as shown. Gasket  19  is sized to snugly and sealingly encase optical fiber  13  to prevent the leakage of fluid from the proximal end of handpiece  14 . 
         [0063]    Tapered opening  44  in the distal end of handpiece  14  is sized to receive nose portion  41  and progressively decreases as opening  44  extends into handpiece  14 . Opening  44  in handpiece  14  has matching cylindrical threads  45  about its inner surface to engage external threads  42  of nose portion  41 . When nut  40  and its nose portion  41  are threaded into opening  44  provided in handpiece  14 , the progressively decreasing diameter of opening  44  forces fingers  46  in the distal end portion of nose portion  41  to removably and sealingly fix optical fiber  13  in place within handpiece  14 . Compression assembly  39  can be composed of any other means, as known in the art. 
         [0064]      FIG. 12  illustrates an eighth embodiment of the device of the present invention. To prevent the user from positioning set screw  16  down upon the shoulder between indentations  23  (shown, for example, in  FIGS. 3-5 ,  8  and  9 ), the array of contiguous indentations  23  in  FIGS. 12 and 13  have a relatively wide top diameter and/or center, the distance between consecutive adjacent centers being about equal to the distance optical fiber  13  is advanced out of cannula  17  after each use for clipping and cleaving, with no shoulders between indentations  23 . In this embodiment, set screw  16  has a threaded shaft with a diameter up to about equal to the distance optical fiber  13  is to be advanced after each use for clipping and cleaving. The tip of set screw  16  is conical, and indentations  23  are conical of matching size and shape dimensions as the conical tip of set screw  16 . Alternatively, the threaded shaft of set screw can be relatively small, about 2 to 6 mm in diameter, and a conical distal end portion, having a diameter substantially the same as that of indentations  23 , may be machined as a single piece and attached to the shaft of set screw  16  by welding, matching threads and the like. 
         [0065]      FIG. 13  illustrates a ninth embodiment, preferably constructed as a variation of the device of  FIG. 12 . In this embodiment, contiguous indentations  23  are hemispherical, with a top diameter and center each about equal to the distance optical fiber  13  is advanced after each use for clipping and cleaving, with no shoulders or lands therebetween. Instead of the set screw described in the preceding  FIGS. 2-6  and  8 - 9 , spring-biased lifter  47  is employed. Shaft  48  of lifter  47  has a semi-circular distal end or tip, which fits into matchingly sized and shaped, i.e., complementary, semi-circular indentations  23 , with no shoulders between indentations  23 . Spring  49  is biased between shoulder  50  and ring  51  of shaft  47 . Ring  51  may be attached to shaft  48  of lifter  47 , just proximal to the bottom of spring  49  when spring  49  is not compressed, preferably by welding or by force fitting into a semi-circular, circumferential channel (not separately shown) in shaft  48 . 
         [0066]    Shaft  48  may be attached to lifter  47 , with lifter  47  and shaft  48  having matching screw threads. Alternatively, lifter  47  and shaft  48  can be machined as one part. Shaft  48  may have a diameter up to about the distance optical fiber  13  is to be advanced after each use for clipping and cleaving. Alternatively, shaft  48  can have a diameter of about 2 to 6 mm and a hemispherically shaped distal portion, whose outside diameter is substantially the same as that of indentations  23 , may be formed as a part of shaft  48  or attached to shaft  48  as described above. 
         [0067]    The distal end of shaft  48  is raised out of matching, hemispherical indentation  23  by pulling lifter  47  upwardly, against the pressure of spring  48 . Optical fiber  13  is then advanced and, when lifter  47  is released, the distal semi-circular distal end of shaft  48  seats itself in the next matchingly shaped, hemispherical indentation  23 . 
         [0068]    If desired, the distal end of shaft  48  of lifter  47  can be conical and indentations  23  of this embodiment can be of a complementary conical shape, as shown in  FIG. 12 , or both can be of any other matching shape, as known in the art. 
         [0069]    Instead of lifter  47 , a ball and plate mechanism (not separately shown) may enable optical fiber  13  to be advanced and the distal end of shaft  48  advanced into the next matchingly shaped indentation  23 . 
         [0070]    In any of the embodiments herein, cannula  17  can be made of a rigid metal, such as medical grade stainless steel, with its distal end optionally bent downward at an angle of about 10 degrees and, optionally, covered by lubricious plastic sleeve  37 . Cannula  17  can likewise be made of a biocompatible semi-rigid plastic, such as PEEK tubing, with its distal end bent downwardly at an angle of 10 to 40 degrees or more, or cannula  17  may have a rigid proximal portion to which a flexible distal end portion of a flexible plastic or flexible memory metal is attached, the latter optionally covered by a lubricious plastic sleeve. 
         [0071]    A device embodying the present invention provides a compromise of the desires of the manufacturer and customer. The device of the present invention is comprised of an optical fiber and a handpiece with a hollow cavity or passageway through its body, through which the optical fiber moveably extends. A gasket in the proximal end of the handpiece, through which the optical fiber snugly passes, prevents a fluid injected through a port into the passageway in the handpiece from escaping from the proximal end of the handpiece. Optionally, a threaded compression device can be used to compress the optical fiber or the gasket to removably fix the optical fiber within the handpiece. 
         [0072]    In one example the fiber optic device according to principles of the present invention is adapted for medical use through a channel of an endoscope. The length of the cannula is determined by the length of the instrument or “working channel” of the endoscope being used and the distance the cannula is to be inserted into a body for the treatment of a particular medical condition. The length of the optical fiber extending through the cannula is also determined by the length of the cannula. 
         [0073]    In yet another embodiment of the present invention, the fiber optic device is adapted for incorporation in an endoscope designed for limited use. The stop member, such as a rigid sheath is movably disposed within a passageway defined by the endoscope handpiece and provided with a luer fitting for fluid introduction. The optical fiber extends through a fluid-tight gasket or compression fitting in the distal end of the endoscope handpiece. The stop member, such as a sheath, is secured to the optical fiber and is sized for the number of intended uses and so that the stop member abuts an internal endoscope wall at the distal end of the passageway for the last use. The limited use endoscope and the optical fiber associated therewith are discarded after the last use. 
         [0074]    Another example of possible use of reusable fiber optic devices according to principles of the present invention will now be given. After its first use, following cleaning and sterilization of the device, for example, the optical fiber is advanced about 8 mm and the set screw is tightened-down to fix the sheath and the attached optical fiber in place. Then, about 8 mm of the buffer coating may be clipped-off by the operator from the distal end of the optical fiber, leaving about 4 mm of the buffer coating extending distally from the distal end of the cannula and about 12 mm of bared optical fiber exposed. Finally, about 8 mm of the bared optical fiber is cleaved-off, leaving about 4 mm of bared optical fiber exposed, ready for the device&#39;s next use. In this particular embodiment, the distance between the center points of the indentations is about 8 mm. 
         [0075]    For example, if the manufacturer determines that ten uses of the device will enable the customer to obtain an acceptable “cost per case,” while preventing the optical fiber from being excessively reused, and if an average of about 8 mm of the plastic buffer coating on the distal end of the optical fiber is clipped-off after each use, the sheath should be 10 times 8 mm or 80 mm long, plus about 4 mm (allowing for about an extra 4 mm of play at the sheath&#39;s distal end) for a total length of about 84 mm. This extra length of the sheath is provided inasmuch as the distal end of the clipping device may extend up to 3 mm or more beyond the clipping location. If five uses are contemplated, for example, and the same 8 mm of the buffer coating is clipped-off after each use, the sheath should be about 5 times 8 mm, plus about 4 mm long, for a total length of about 44 mm. This assumes the nose of the clipping device extending beyond the clipping point is about 3 mm long. Any other length of the buffer coating and optical fiber may be clipped and cleaved-off, and a clipping device with a nose longer than about 3 mm may be used, with the length of the sheath adjusted accordingly. 
         [0076]    Markings at, for example, 8 mm or other desired intervals can be made circumferentially around or on the top surface of the buffer coating of distal end portion of the optical fiber extending distally from the distal end of the cannula. When the set screw is loosened, the optical fiber is advanced for its next use and the next marking appears at the distal end of the cannula, the operator knows the set screw may then be screwed down on the sheath to hold the optical fiber in place. Also, the buffer coating can have a number within each interval to alert the operator as to the number of uses remaining available. 
         [0077]    The sheath optionally may have indentations in its upper surface, into which the distal end of the set screw may be inserted to better removably fix the sheath and attached optical fiber in place. The number of indentations in the sheath may be equal to the number of intended uses of the optical fiber permitted by the manufacturer. In the example cited above, the centers of the indentations should be about 8 mm apart. 
         [0078]    To avoid the likelihood that the set screw is positioned on a land or shoulder between adjacent indentations, the open end of the indentations preferably is complementary to the dimensions of the distal end of the set screw to be received therewithin, and successive indentations are contiguous to one another so that there is no land or shoulder between the indentations. 
         [0079]    In a lengthy procedure involving the vaporization of a large volume of tissue, it may become necessary to refurbish the working tip of the device during the procedure. For example, when two or more tip refurbishments are needed to complete the procedure, the optical fiber is advanced after each such refurbishment, and the set screw reset into the next indentation after the optical fiber has been advanced. 
         [0080]    For its first use, with the proximal end of the sheath close to the proximal end of the hollow passageway in the handpiece, the set screw is tightened-down into the first indentation from the distal end of the sheath encasing the optical fiber. After use, the device is cleaned and sterilized, the sheath and optical fiber are advanced and clipped and cleaved for its next use, as described above. This process is repeated until the device is ready for its last use. 
         [0081]    When the last intended use of the optical fiber is reached (e.g., when the distal end of the metal sheath contacts the shoulder at the distal end of the passageway in the handpiece) the distance the optical fiber extends distally from the distal end of the cannula should be about 12 mm, based upon the above cited example, and the clipping and cleaving procedure is repeated. After its last use, the sheath and optical fiber cannot be advanced, and the device must be discarded. 
         [0082]    As explained herein, various arrangements of fiber optic devices are contemplated by the present invention. For example, optional slots are provided in one embodiment, in the top surface or one or both side surfaces of the handpiece may be filled with a glass or clear plastic insert and sealingly fixed in place to prevent leakage of fluid. This enables the operator to see the indentations on the handpiece. Optionally, numbers on the metal sheath opposite each indentation may alert the operator as to the number of uses consumed or the number of uses remaining. 
         [0083]    In another embodiment described herein, one side of the sheath is provided with vertical ribs or ridges and a matching ribbed gear, rotatably fixed within the handpiece, with appropriate gaskets about its shaft to prevent leakage of fluid, enables the operator to advance the sheath and optical fiber the desired distance. Preferably one notch on the ribbed wheel or gear, with a tactile feel or sound or both, advances the sheath the proper distance to enable the set screw to be screwed into the next indentation in the sheath. 
         [0084]    In another embodiment of the present invention, the proximal portion of the delivery cannula is made of a metal, such as medical grade stainless steel, or a rigid biocompatible plastic, such as PEEK tubing, to whose distal end a section of flexible, biocompatible plastic tubing may be attached by an adhesive, covered by an adhesively attached collar or other means known in the art. One distal end portion of the cannula may overlap the proximal end portion of the flexible tubing, or vice versa. 
         [0085]    One or more wires, affixed to the distal end of the flexible plastic tube, extend through the delivery cannula and are attached to a lever or other mechanism, preferably attached within or to the bottom surface of the handpiece. When the wire or wires are tightened, they cause the flexible tubing to bend at a desired angle to better direct the laser energy to the desired tissue. 
         [0086]    The handpiece may have a port or luer lock, as known in the art, into the hollow passageway in the handpiece, which is in fluid communication with the delivery cannula, to enable a fluid (gas or liquid) to be infused into the passageway, pass through the cannula and exit from the distal end of the cannula to irrigate and cool the target tissue or to displace blood or other aqueous liquid from the space between the distal end of the optical fiber and the target tissue. 
         [0087]    Displacing blood or an aqueous irrigation liquid from the space between the optical fiber and the target tissue would enable, for example, Holmium:YAG laser energy, at a wavelength of 2100 nm, which is highly absorbed by water, or any other wavelength of laser energy, which is highly absorbed by water, to be emitted during the infusion of the fluid. 
         [0088]    For example, a small amount of carbon dioxide gas may be infused through the port to displace blood or other aqueous liquid from the space between the distal end of the optical fiber and the target tissue. If blood or aqueous liquid exists between the distal end of the optical fiber and the tissue, it would absorb a substantial amount of the laser energy and prevent the target tissue from receiving all or most of the laser energy, as described in co-owned U.S. Pat. No. 6,953,458 B2. 
         [0089]    While this invention is susceptible of embodiment in many different forms, there are shown in the drawings and described in detail herein specific embodiments thereof, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not to be limited to the specific embodiment illustrated. 
         [0090]    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.