Abstract:
An elastic band for ligating tissue within a living body comprises an inner tissue engaging surface which, when in an operative position within the body, surrounds and directly contacts the tissue. At least a portion of the inner tissue engaging surface defines a plurality of discontinuities formed by one of projections and depressions. A method of ligating tissue within a living body using such a ligating band comprises the steps of positioning the elastic band, which has been stretched to increase the size of a central opening extending therethrough, adjacent to a portion of tissue to be ligated. The tissue to be ligated is then drawn through the central opening of the elastic band and the elastic band is released so that the size of the central opening decreases to grip the tissue received therein.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates generally to the field of tissue ligation, and more particularly to an improved ligating band and a method of use of the ligating band to ligate tissue.  
         BACKGROUND OF THE INVENTION  
         [0002]    Physicians have used elastic ligating bands to treat lesions, including internal hemorrhoids and mucositis and for performing mechanical hemostasis.  
           [0003]    The object of ligation is to position a ligating band over the targeted lesion or blood vessel section by stretching the band beyond its undeformed diameter drawing the tissue to be ligated within the band and then releasing the band so that it contracts, applying inward pressure on the section of tissue caught within the band. The effect of the inward pressure applied by the band is to stop all circulation through the targeted tissue, thereby causing the tissue to die. The body then sloughs off the dead tissue or the dead tissue may be aspirated into an endoscope or a similar device.  
           [0004]    U.S. Pat. No. 5,356,416 to Chu et al. and U.S. Pat. No. 5,398,844 to Zaslavsky et al., both of which are incorporated herein by reference, describe ligating band dispensing devices including cylindrical support surfaces over which elastic ligating bands are stretched. The cylindrical support surfaces are typically attached to the distal end of an endoscope which is advanced into the body to a target area. A user then applies suction through the endoscope to draw the tissue to be ligated into the cylindrical support surface and then releases a ligating band to contract around the tissue.  
           [0005]    There are two problems inherent with the type of ligating bands typically used with the above-described devices. The first is that the bands have a tendency to slip off the targeted tissue before the tissue is completely ligated. One reason why a ligating band may slip off targeted tissue is because tissue contained within a ligating band is effectively “pinched” by the ligating band, creating an outward pressure on the band. Specifically, the bulb-shaped projection of tissue which has been drawn under suction into the lumen of a cylindrical support surface is pulled away from the surrounding tissue creating tension within the projection which draws the tissue of the projection back toward the its natural position. Thus, the tissue is urged to slip out of the ligating band as the band contracts. In addition, blood and fluid within the body can make the surface of the targeted tissue slick, thereby decreasing the coefficient of friction between the ligating band and the targeted tissue. Also, if the targeted tissue is an active blood vessel the “pulsing” effect of blood moving through the vessel can cause the ligating band to slip off of the targeted tissue.  
           [0006]    A second problem with current ligating bands is that the bands are not adjustable once they have been dispensed from the ligating band dispenser. Therefore, if a band is improperly placed around a section of tissue, or if the physician placing the ligating band should wish to draw more tissue within the band, there is no effective way to adjust the band.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention is directed to an elastic band for ligating tissue within a living body comprising an inner tissue engaging surface which, when in an operative position within the body, surrounds and directly contacts the tissue. At least a portion of the inner tissue engaging surface defines a plurality of discontinuities formed by one of projections and depressions. A method of ligating tissue within a living body using such a ligating band comprises the steps of positioning the elastic band, which has been stretched to increase the size of a central opening extending therethrough, adjacent to a portion of tissue to be ligated. The tissue to be ligated is then drawn through the central opening of the elastic band and the elastic band is released so that the size of the central opening decreases to grip the tissue received therein. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The invention will be more readily understood through the following detailed description, with reference to the accompanying drawings, in which:  
         [0009]    [0009]FIG. 1 is a perspective view of a first ligating band according to a embodiment of the present invention;  
         [0010]    [0010]FIG. 2 is a perspective view of a ligating band according to a second embodiment of the present invention;  
         [0011]    [0011]FIG. 3 is a perspective view of a ligating band according to a third embodiment of the present invention;  
         [0012]    [0012]FIG. 4 is a perspective view of a ligating band according to the second embodiment of the present invention, wherein the texturing is perpendicular to the band&#39;s centerline axis;  
         [0013]    [0013]FIG. 5 is a perspective view of a ligating band according to the third embodiment of the present invention, wherein the texturing is perpendicular to the band&#39;s centerline axis;  
         [0014]    [0014]FIG. 6 is a perspective view of a ligating band according to the second embodiment of the present invention, wherein the texturing is angled to the band&#39;s centerline axis;  
         [0015]    [0015]FIG. 7 is a perspective view of a ligating band according to the third embodiment of the ligating band depicted in FIG. 3, wherein the texturing is angled to the band&#39;s centerline axis;  
         [0016]    [0016]FIG. 8 is a perspective view of an alternate embodiment of the ligating band depicted in FIG. 2, wherein the texturing is parallel to the band&#39;s centerline axis, and showing manipulation apertures;  
         [0017]    [0017]FIG. 9 is a perspective view of an alternate embodiment of the ligating band depicted in FIG. 3, wherein the texturing is comprised of securing prongs, and showing manipulating apertures;  
         [0018]    [0018]FIG. 10 is a perspective view of an alternate embodiment of the ligating band depicted in FIG. 9, wherein the securing prongs are configured as injection prongs;  
         [0019]    [0019]FIG. 11 shows a side view of a blood vessel drawn into a device for applying ligating bands;  
         [0020]    [0020]FIG. 12 shows a side view of a blood vessel with an elastic ligating band received thereon;  
         [0021]    [0021]FIG. 13 shows a side view of a blood vessel received within a device for applying ligating bands wherein the elastic ligating band has been reopened on the blood vessel to adjust its position;  
         [0022]    [0022]FIG. 14 shows a side view of the blood vessel of FIG. 13, wherein the elastic ligating band has been released;  
         [0023]    [0023]FIG. 15 shows a side view of a ligating band of FIG. 9, wherein a ligating band spreading device is being used to stretch the ligating band while a mechanical gripping device is used to draw tissue through the central opening in the ligating band;  
         [0024]    [0024]FIG. 16 shows a side view of the ligating band of FIG. 9 wherein the ligating band spreading device has been inserted through a central channel formed through an endoscope or other insertion device;  
         [0025]    [0025]FIG. 17 shows a side view of a distal end of an alternate ligating band dispensing device specifically adapted for use with textured ligating bands. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]    As illustrated in FIG. 1, a ligating band  1  is preferably formed as a ring with an inner surface  2 , an outer surface  4 , a first side surface  6 , and a second side surface  8 . Of course, those skilled in the art will understand that during manipulation, the ligating band  1  may be intentionally or accidentally twisted so that any of the surfaces  4 ,  6  and  8  becomes the inner surface  2 . Thus, in the ligating band  1  according to the first embodiment of the invention includes texturing  10  which covers all surfaces of the ligating band  1 .  
         [0027]    The ligating band  1  according to the first embodiment has a cross-section which is substantially rectangular. That is, the ligating band  1  is formed as a portion of a cylinder. Those skilled in the art will recognize that one or more of surfaces  2 ,  4 ,  6 , or  8  may be rounded reducing the distinction between the various surfaces. However, this distinction between the various surfaces is unimportant so long as the surface of the ligating band  1  which is in contact with the tissue to be ligated includes texturing as described herein.  
         [0028]    As shown in FIG. 1, the texturing  10  is comprised of a pattern of raised bumps which are formed as cylindrical stems  12  and hemispherical caps  14 . Alternate forms of texturing  10  can employ one or more of a variety of different shapes, including raised elongated members  16  as shown in FIG. 4, securing prongs  24  as shown in FIG. 9, or indentations (not shown) in the inner surface  2  of the ligating band  1 . On any surface  2 ,  4 ,  6  or  8  to which the texturing  10  is applied, the texturing  10  is preferably evenly distributed.  
         [0029]    The texturing  10  may preferably be applied to the ligating band  1  via a molding process, thereby making the texturing  10  an integral part of the structure of the ligating band  1 . Preferably, the texturing  10  and the ligating band  1  are formed from latex or a synthetic equivalent thereof, such as polyisoprene. The ID (inner diameter) of the ligating bands  1  may preferably be between 0.06 and 0.10 inches and is more preferably approximately 0.07 inches. The OD (outer diameter) of the ligating bands is preferably between 0.20 and 0.24 inches, while the bands may preferably be approximately 0.08 inches thick in a direction substantially parallel to a central axis of the ligating bands  1 . Of course, those skilled in the art will recognize that such a ligating band may easily be twisted so that the ID surface becomes the OD surface, etc. and that it may therefore be preferable to make the thickness of the band in each direction between 0.06 to 0.18 inches.  
         [0030]    The texturing  10  is applied to the ligating band  1  so that the raised bumps on a first side  18  of the inner surface  2  and the raised bumps on a second side  20  thereof combine to form an interlocking pattern. By interlocking those skilled in the art will understand that the raised bumps on both the first side  18  and the second side  20  hold the tissue to be ligated by the ligating band  1  more securely in place when the ligating band  1  applies inward pressure on said tissue with the bumps from one side forcing the tissue into a gap between the bumps on the other side. Thus, as shown in FIG. 4, raised elongated members  16  on the first side  18  of the inner surface  2  may also form an interlocking pattern with respect to the second side  20  of the inner surface  2 .  
         [0031]    As shown in FIG. 8, an ligating band  1  according to the present invention may also include one or more manipulating apertures  22 . If manipulating apertures  22  are used in conjunction with an ligating band  1 , it is preferable to have at least three manipulating apertures  22  but, may have four or more. The purpose of the manipulating apertures  22  is to allow the physician placing the ligating band of the present invention to control the proper placement of the ligating band on the tissue to be ligated by inserting tines  42  of a ligating band spreader  38  into the apertures  22  and, by spreading the tines  42  apart, increasing the interior diameter d of the ligating band  1  so that the position of the ligating band  1  on the tissue to be ligated may be adjusted to allow an additional amount of tissue to be drawn up through the interior diameter d of the ligating band  1 . Alternatively, the physician may use such a manipulating instrument  38  with an ligating band  1  including apertures  22  to originally place ligating bands on tissue to be ligated. That is, the physician may place an ligating band  1  including apertures  22  on the manipulating device, spread the tines  42  to increase the diameter d and manually draw tissue through the central opening in the ligating band  1 . The physician may then release the ligating band  1  to ligate the tissue.  
         [0032]    With reference to FIG. 1, although it is preferable to have texturing  10  on all surfaces  2 ,  4 ,  6  and  8  of the ligating band  1 , it is not necessarily required so long as the user ensures that the surface including the texturing  10  remains, through the placement procedure, positioned so that it contacts the surface to be ligated. In use, the tissue to be ligated is drawn up within the interior diameter d of the ligating band  1 . Thus, only texturing  10  placed on the surface positioned at inner surface  2  is designed to come in contact with the tissue to be ligated. FIG. 2 depicts an ligating band  1  according to the present invention wherein texturing  10  is provided only on the inner surface  2  and the outer surface  4 , while FIG. 3 depicts an ligating band  1  according to the present invention wherein texturing  10  is provided only on the inner surface  2 .  
         [0033]    However, it is preferred that texturing  10  be provided on each of surfaces  4 ,  6  and  8  in addition to inner surface  2  as the ligating band  1  may “roll” after during the dispensing procedure or after being dispensed onto the tissue to be ligated. Thus, a physician cannot be certain that the ligating band  1  will not ultimately be turned “inside out” on the tissue to be ligated such that outer surface  4 , for example, comes in contact with the tissue to be ligated rather than the inner surface  2 .  
         [0034]    With references to FIGS. 4 and 5, the texturing  10  may be comprised of raised elongated members  16  and placed in such a manner that the raised elongated members  16  are aligned perpendicular to the longitudinal centerline Cl of the ligating band  1 . Alternately, the raised elongated members  16  may be placed at an angle, preferably between 30° and 60°, to the longitudinal centerline Cl of the ligating band  1 , as shown in FIGS. 6 and 7. Alternatively, the raised elongated members  16  may be placed perpendicular to the longitudinal centerline Cl of the ligating band  1 , as shown in FIG. 8.  
         [0035]    In FIG. 9, securing prongs  24  are used to provide texturing  10  to the inner surface  2  of the ligating band  1 . The securing prongs  24  perform the same function as either the other types of texturing  10  previously described; that is, the securing prongs  24  increase the resistance of the ligating band  1  to any forces acting to dislodge it from the tissue to be ligated.  
         [0036]    The securing prongs  24  may alternately be configured as injection prongs  26 , as shown in FIG. 10. After tissue to be ligated has been drawn within the interior diameter d of the ligating band  1 , the ligating band  1  is allowed to return to its undeformed state, applying inward pressure on the tissue. By employing injection prongs  26 , not only does the ligating band  1  depicted in FIG. 10 securely hold the tissue to be ligated in place, but it also pierces the tissue with the injection prongs  26 , thereby injecting a fluid held in an interior reservoir  28  into the tissue. The fluid is injected as the return of the ligating band  1  to its undeformed state compresses the reservoir  28 . Those skilled in the art will recognize that this fluid may be a sclerotherapy agent, a healing agent or any other desired medicinal fluid. Alternatively, the fluid may be coated on an area F at the tips  30  of the injection prongs  26 , so that the fluid F would be injected into the tissue after the tissue to be ligated has been drawn within the interior diameter d of the ligating band  1  and the ligating band  1  has been allowed to return to its undeformed state.  
         [0037]    Alternately, injection prongs  26  may be used to transmit RF energy into the section of tissue directly beneath the tissue to be ligated. To achieve this, the structure illustrated as the reservoir  28 , is replaced by a similarly shaped and situated electrically conductive member which, after the ligating band  1  has been positioned on the tissue, may be coupled to a source of RF energy via apertures  22  to cauterize the surrounding tissue. Those skilled in the art will understand that the electrically conductive material may be in the form of a spring or other expandable shape to allow the structure to expand and contract when the ligating band is stretched or released.  
         [0038]    In use, as shown in FIGS.  11 - 16 , in use a physician first loads the ligating band  1  onto the distal end of a ligating band dispenser  32 , such as the ligating dispenser described in U.S. Pat. No. 5,356,416, so that the interior diameter d of the ligating band  1  is substantially greater that its natural, pre-deformed interior diameter d.  
         [0039]    Next the physician positions a distal aperture  34  of the ligating band dispenser  32  adjacent to a first section of tissue T 1 . The first section T 1  is then drawn into the distal aperture  34 , preferably under suction. Alternatively, the first section of tissue T 1  may be drawn within the distal aperture  34  by mechanical means, such as a forceps, jaws, clamp, or the like (not shown). The physician then triggers the ligating band dispenser  32  to release one or more ligating bands  1  over the targeted tissue T 1 .  
         [0040]    As seen in FIG. 12, when the ligating band  1  has been dispensed from the ligating band dispenser  32 , the interior diameter d of the ligating band  1  suddenly decreases as the ligating band  1  seeks to return to its predeformed state. As the interior diameter d decreases, the texturing  10  on the inner surface  2  of the ligating band  1  engages a portion  36  of the first section of tissue  33  and exerts inward pressure on the tissue  36 . The pressure on the tissue  39  stops all circulation through the targeted tissue T 1 , thereby causing the portion  36  to die. The body then sloughs off the dead tissue  36 . Alternatively, the dead tissue  36  may be removed by mechanical means and aspirated into an endoscope, the ligating band dispenser  32 , or a similar device.  
         [0041]    While the texturing  10  on the inner surface  2  of the ligating band  1  is exerting inward pressure on the tissue  36 , the texturing  10  restricts the movement of the ligating band  1  over the tissue  36 . Thus, the ligating band  1  of the present invention is less likely than prior art ligating bands to be displaced from the targeted tissue  36  in response to outward pressures caused by the “pinching” of the targeted tissue  33  or by the movement of blood or other fluid through the targeted tissue T 1 . In addition, when the texturing  10  on the inner surface  2  of the ligating band  1  is exerting inward pressure on the tissue  36 , it is preferable that the texturing  10  on the first side  18  of the inner surface  2  remotely engages the texturing  10  on the second side  20  of the inner surface  2  through the portion  36  of tissue to form an interlocking pattern. By forming such an interlocking pattern, the texturing  10  more effectively restricts the movement of the ligating band  1  relative to the tissue  36 .  
         [0042]    As discussed previously, the optional manipulation apertures  22  provide the physician with the ability to place the ligating band  1  directly over the targeted tissue  36  and then decrease the interior diameter d until the texturing  10  on the inner surface  2  of the ligating band  1  engages and exerts inward pressure against the tissue  36 . To position the ligating band  1 , the physician loads the ligating band  1  onto a ligating band spreader  38  by inserting each of the tines  42  into one of the manipulation apertures  22 . Next, the physician manipulates the ligating band spreader  38  to increase the interior diameter d of the ligating band  1 , and positions the ligating band  1  adjacent to the first section of tissue T 1 . A portion of the tissue is then drawn through the ligating band  1  (using a clamping device  40  for example), and the physician manipulates the ligating band spreader  38  to decrease the interior diameter d of the ligating band  1  until the texturing  10  engages the tissue  36 .  
         [0043]    By manipulating the ligating band spreader  38 , the physician may not only position the ligating band  1  over the tissue  36 , but may also subsequently wholly or partially disengage the ligating band  1  from the tissue  36  to allow the physician to reposition the ligating band  1  relative to the tissue  36 . The physician may use the ligating band spreader  38  whether the ligating band  1  was initially placed over the tissue  33  using a ligating band spreader  38  or using a ligating band dispenser  32 .  
         [0044]    Finally, FIG. 17 shows the distal end  50  of an alternate ligating band dispensing device including a ligating band supporting structure  52  which has a diameter which decreases from a maximum diameter at a proximal end  54  to a minimum diameter at a distal end  58 . Thus, the ligating band supporting structure  52  may be formed as a portion of a cone. As shown in FIG. 17, the proximal end  54  is received within a sleeve  60  which forms an abutting surface  62  adjacent to the outer surface of the proximal end  54  so that, when a plurality of ligating bands  4  are received on the ligating band supporting structure  52 , a proximal most ligating band  4  may not move proximally past the abutting surface  62 . The ligating band supporting structure  52  is coupled within the distal end  50  so that the ligating band supporting structure  52  may be moved proximally relative to the abutting surface  62 , for example by being screwed into the sleeve  60  by rotation about the central axis C in the direction of arrow A. Thus, as the ligating band supporting structure  52  is moved into the sleeve  60 , the proximal most ligating band  4  abuts the abutting surface  62  and pushes the more distal ligating bands  4  toward the distal end  58  until they are dispensed therefrom one-by-one. Eventually, when the distal end  58  is drawn proximally past the abutting surface  62 , the proximal-most ligating band  4  is dispensed from the ligating band supporting structure  52 . Thus, as the force urging the ligating bands  4  off the ligating band supporting structure  52  is applied around the entire circumference of the ligating bands  4 , the increased frictional forces associated with the textured ligating bands according to the present invention may more easily be overcome.  
         [0045]    Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the detailed description, wherein the preferred embodiment and several alternate embodiments of the invention have been shown and described. The description of the preferred embodiment is simply by way of illustration of the best mode contemplated for carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modification in various respects, all without departing from the invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive of the invention which is to be limited only by the claims appended hereto.