Abstract:
A compassion ring to grip and compress body structure such as diverticulum, hemorrhoids, and tissue adjacent a hole. A resilient ring-shaped body defines a compression channel, and as elongated axially rigid gripping member extends diametrically across the through-opening. The gripping member cm rest on a flange on the opposite side of the through-opening or engage with a second gripping member mat extends diametrically across the through-opening from the opposite side of fee ring. Or, a flexible cage structure can be disposed in the through-opening.

Description:
[0001]    This application claims priority to U.S. provisional patent application 61/492,289, filed Jun. 1, 2011 and incorporated herein by reference. This application is also a continuation in part of U.S. patent application Ser. No. 13/240,018, filed Sep. 22, 2011, which is a continuation of U.S. patent application Ser. No. 12/141,391, filed Jun. 18, 2008, now U.S. Pat. No. 8,062,308, which in turn claims priority from U.S. provisional patent applications Ser. Nos. 60/982,083, filed Oct. 23, 2007 and 61/012,124, filed Dec. 7, 2007. Priority is claimed to all of the above documents. U.S. Pat. No. 8,062,308 is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present application relates generally to devices and methods for securing tissue. 
       BACKGROUND 
       [0003]    Internal body tissue sometimes must be secured together for various reasons. As an example, diverticulosis is an unfortunately common condition in which an area of the intestine bulges out into the peritoneal cavity to form a sac referred to as a “diverticulum”. The above-referenced patent envisions a natural orifice method for resolving diverticulum by inverting them arid then securing opposed serosal surfaces together using a ring to thereby tightly and securely close off the affected tissue to alleviate the risk of peritonitis. 
         [0004]    While the patented approach is effective, present principles further understand that slippage of the ring can occur once it is placed on tissue. In the colon and bowel, for instance, significant peristalsis and pressure can stretch the tissue wall, which can force the ring off the tissue, losing the therapeutic effect of the ring. 
       SUMMARY OF THE INVENTION 
       [0005]    A ring for engaging tissue has a round resilient body defining an axial through-opening configured to receive the tissue. At least one elongated axially rigid gripping member extends diametrically across the through-opening. The gripping member has a first end embedded in the ring and a second end distanced from the first end and not embedded in the ring. The gripping member extends substantially entirely across the through-opening. 
         [0006]    In one implementation, the gripping member rests on a flange attached to a portion of the through-opening opposite to where the gripping member is embedded in the ring. In another example, the gripping member is first gripping member and the ring includes a second gripping member that extends diametrically across the through-opening from a portion of the ring opposite to where the gripping member is embedded in the ring. Each gripping member may he barbed in that each gripping member may be formed with a respective barb extending away from the other gripping member. Or, the first gripping member can be flat and can include a hook segment forming a bight, while the second gripping member can define a long axis and can be twisted about the long axis. The second gripping member likewise includes a hook forming a bight, and the bights of the gripping members face each other. 
         [0007]    Yet again, in another embodiment the first gripping member is urgable by tissue through an eye formed in the second gripping member. Or, the first gripping member can be wider than the second gripping member, with the gripping members being flushly disposed with each other throughout their length. In this last embodiment, first and second stabilizing elements can be formed on the ring in an. orthogonal relationship to the gripping members, extending into the through-opening. 
         [0008]    In another aspect, a ring for engaging tissue includes a round resilient body defining an axial through-opening configured to receive the tissue, and a flexible cage structure disposed in the through-opening. 
         [0009]    In another aspect, a method for making a tissue gripping ring includes forming at least one spike on a circular support, with the spike extending inward relative to the circular support. The method includes overmolding a toroidal resilient ring onto the spike, removing the spike and ring from the circular support, and removing excess ring material from the spike. 
         [0010]    In another aspect, a method for configuring a resilient ring tor placement in a patient to cause the ring to surroundingly grip tissue in the patient includes engaging the ring with a first end of an expander. The expander tapers radially outwardly from the first end to a cylindrical segment, with a diameter of the first end substantially equaling a diameter of the ring when the ring is in a relaxed state. The method contemplates pushing the ring along the expander to radially stretch fee ring until the ring surrounds the cylindrical segment. The cylindrical segment is juxtaposed with a carrying portion of a delivery device having substantially the same diameter as the cylindrical segment, and then the ring is pushed from the cylindrical segment onto the carrying portion to load the ring in a stretched state for delivery to the tissue. 
         [0011]    The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a top plan view of a first embodiment of the present tissue ring; 
           [0013]      FIG. 2  is a perspective view of a second embodiment of the present tissue ring; 
           [0014]      FIG. 3A  is a perspective view of a third embodiment of the present tissue ring; 
           [0015]      FIG. 3B  is a top plan view of the third embodiment of the present tissue ring showing an intermediate configuration of the gripping members during manufacture; 
           [0016]      FIGS. 4-9  are various views of a fourth embodiment of the ring and stages of installing it in a patient; 
           [0017]      FIGS. 10A and 10B  are a perspective and cross-sectional view, respectively, of a fifth embodiment of the ring; 
           [0018]      FIGS. 11-13D  are views of a sixth embodiment of the ring; 
           [0019]      FIGS. 14A-C  show three alternate spike configurations prior to manufacture; 
           [0020]      FIGS. 15A-D  show a series of ring configurations during manufacturing to illustrate an example method for making a ring according to present principles; 
           [0021]      FIGS. 16-19  show various stages of loading the ring onto a delivery device; and 
           [0022]      FIG. 20  is a cross-sectional view showing an example mold with an example ring therein to further illustrate methods for making the ring, 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Referring initially to  FIG. 1 , a ring is shown, generally designated  10 , which includes a disk-shaped or more preferably toroidal body  12  made of resilient material such as silicone or other biocompatible resilient material. Note that in general, the body is round with a central opening, although non-limiting examples below disclose toroidal bodies. In the relaxed state shown, the ring  10  assumes a radially smaller configuration, and is resilient so that it can he stretched to a radially enlarged state to fit onto a delivery device as explained further below. The ring is slid off the delivery device to engage tissue such as but not limited to a diverticulum to surround and compress the tissue. In the case of an inverted diverticulum as disclosed in the above-referenced patent, it is compressed by the ring  10  in its inverted state, and so is closed off serosa to serosa. 
         [0024]    As shown in  FIG. 1 , the ring  10  also includes a spike design having a barb element to prevent backing out of the tissue once it has been installed. With more specificity, the body  12  defines an axial through-opening  14  configured to receive the tissue, and one or more (in the embodiment shown, two) elongated axially rigid gripping members  16  which may be configured as spikes as shown in the example extend diametrically across the through-opening, parallel to each other and side by side, i.e., are offset from each other in the radial dimension defined by the body. In one example embodiment, the gripping members are made of stainless steel. 
         [0025]    As shown, each gripping member  16  has a respective first end  18  embedded in the ring and a second end  20  distanced from the first end and not embedded in the ring. In the example shown, the second end  20 , which is a free end, is pointed, and extends almost to the body  12  but does not quite reach the body  12 , thus extending substantially entirely across the through-opening  14 . In some examples, each gripping member  16  extends at least past the longitudinal axis defined by the body  12 , and preferably extends to eighty percent (80%) of the way across the diameter of the through-opening  14 . More preferably still, each gripping member  16  extends to at least ninety percent (90%) of the way across the diameter of the through-opening  14 . 
         [0026]    In the example of  FIG. 1 , each gripping member  16  is barbed, in that each gripping member is formed with a respective barb  22  extending away from the other gripping member. Specifically describing an example barb, each gripping member  16  may have a straight inside edge  24  and an opposed outside edge  26 , and the barb  22  is established by an extension at the second end  20  of the gripping member  16  that has two opposed barb surfaces  28 ,  30  extending outwardly away from the outside edge  26  at an acute angle thereto and tapering to a barb point  32 . The inside edges  24  of the gripping members face each other as shown. 
         [0027]    Turning to  FIG. 2 , barbed spikes are shown wherein the barb structures engage with each other and lock together. With greater specificity, a ring  34  with a toroidal ring body  36  defines a through-opening  38 , and first and second gripping members  40 ,  42  extend diametrically across the opening  38  side by side. i.e., are offset from each other in the radial dimension defined by the body. The gripping members  40 ,  42  are formed at their respective free ends with respective hook segments  44 ,  46 , each forming, in concert with the rest of the gripping member, a respective bight  48 ,  50 . The first gripping member  40  is flat as shown, whereas the second gripping member defines a long axis and is twisted about the long axis. The bights  48 ,  50  of the gripping members  40 ,  42  face each other so that as tissue forces the gripping members  40 ,  42  together, the hook segments engage with each other and under the force of the tissue lock together. 
         [0028]    Now considering  FIGS. 3A and 3B , a spike design is shown with a nesting configuration. As will be explained shortly in further detail, one gripping member establishes a prong like structure and the opposite gripping member has a receptacle structure designed for receiving the opposing member. When the ring is applied to tissue, the ring is first stretched and the spikes rotated out parallel to the central axis of the ring. When released onto the tissue, the spikes spontaneously rotate inwards to the resting position of the molded elastomeric material. The ring eventually compresses to the tightest diameter possible and while doing so, the spikes engage and interlock with themselves. Once interlocked, there is not adequate expansion force from the tissue to enlarge the ring that would allow the spikes to release and slip off of the tissue. These spike designs take advantage of the ring having to be stretched open prior to applying to the tissue. Once released, the spikes become locked together and the only way to unlock them is to reexpand the ring, which is not feasible once implanted into the body. 
         [0029]    In greater detail, a ring  52  with a toroidal ring body  54  defines a through-opening  56 , and first and second gripping members  58 ,  60  extend diametrically across the opening  56  side by side, i.e., are offset from each other in the radial dimension defined by the body. The first gripping member  58  terminates in a distal point  62  as shown, and the first gripping member can be urged by tissue through an eye  64  formal in the second gripping member  60 . As shown, in  FIG. 3 , the first gripping member  58  is formed offset from the diameter of the ring and is straightened after molding the body  54  onto the gripping members to a configuration in which the first gripping member extends diametrically across the through-opening  56  so that it can slide into the eye  64  when so urged by tissue. 
         [0030]      FIGS. 4-9  illustrate various facets of yet another embodiment in which a spike design is shown with an overlapping configuration. The two overlapping spikes discussed further below prevent each other from rotating outwards. For the outer spike to rotate inwards, the inner spike must fully rotate inwards to clear the tip of the outer spike in a sequential manner, and since this is not how tissue entrapped on the spikes will cause the spikes to react since the outer spike tip does not have enough force acting on the inner spike to rotate it out of the way, the outer spike remains anchored across the diameter. If the outer spike cannot move, then the inner cannot move and dear first, thereby establishing an interlocking feature in which each spike lying across the diameter effectively fights each other from movement and slippage. 
         [0031]    With more specificity and referring first to  FIGS. 4 ,  5 , and  7 , a ring  70  with a toroidal ring body  72  defines a through-opening  74 , and first and second axially rigid gripping members  76 ,  78  extend diametrically across the opening  56  one over the other, i.e., are offset from each other in the axial dimension defined by the body. That is, instead of being at the same location along the axis of the ring as in the previous embodiments, in  FIGS. 4 and 5  the gripping members are at different locations along the axis. As was the case in the examples above, the gripping members  76 ,  78  shown in  FIGS. 4 ,  5 , and  7  each have a fixed end embedded in the body  72  and a free end that is disposed substantially diametrically across the through-opening  74  from the fixed end. 
         [0032]    As perhaps best shown in  FIG. 7 , the first gripping member  76  is wider than the second gripping member  78 , and the second gripping member  78  can lay flush against the first gripping member  76 . In some examples, opposed short triangular stabilizing spikes  80  can have respective fixed ends embedded in the body  72  and respective pointed free ends closely juxtaposed with the gripping members  76 ,  78  near the center of the through-hole  74 . The stabilizing spikes  80  are formed on the ring  70  in an orthogonal relationship to the gripping members  76 ,  78 , extending into the through-opening  74 . 
         [0033]      FIGS. 6-9  are now addressed to illustrate a specialized loading device  82  for loading the ring  70  for installation in a patient. Due to the overlapping gripping members  76 ,  78  interfering with each other in the resting condition shown in  FIG. 7 , the first member  76  is wider (or has some other distinguishing feature) than the second member  78  to facilitate a loading sequence. Specifically, note in cross-reference to  FIGS. 8 and 9  that the loading device  82  is configured to engage and rotate the wider gripping member  76  out of the way first ( FIG. 8 , showing the first member  76  rotated out of the plane defined by the ring body  72 ), then the second, thinner gripping member  78  can be rotated ( FIG. 9 ) outwardly from the plane of the body  72 . The ring  70  is also expanded at the same time to be fitted on the delivery system as it rides up against a tapered portion  84  of the loading device  82 , with the gripping members now rotated out of the plane of the ring such that they can ride against the device  82  until the body  72  is positioned on a larger cylindrical part  86  of the device  82  in an expanded (stretched) configuration. 
         [0034]    In one example, the device  82  may be formed with offset ramp portions arranged to engage the wider member  76  first and then engage the narrower member  78 . In another example best illustrated in  FIG. 6 , the device  82  is formed with plural axially-oriented slots  88  that are wider than the second member  78  but narrower than the wider member  76 . It will readily be appreciated that the distal end  90  of the device  82  will thus abut and push the wider member  76  as the ring  70  is slid proximally relative to the device  82  onto the device  82 , while the narrower member  78  remains in the position shown in  FIG. 8 , riding through one of the slots  88 . As the ring  70  is pushed further onto the device  82 , eventually the narrower member  78  abuts a slot end  92 . Continued relative motion from there causes the slot end  92  to push the narrower member  78  outwardly as shown in  FIG. 9 . 
         [0035]    Turning now to  FIGS. 10A and 10B , a spike and tab configuration is shown. A ring  100  has a toroidal ring body  102  defining a through-opening  104 , and a single axially rigid gripping member  106  extends diametrically across the opening  104 . As shown, the gripping member  106  is long enough to reach across the diameter of the ring. The member  106  is also biased at an acute angle relative to the plane defined by the ring body  102  as shown in  FIG. 11 , and/or is curved so as it penetrates through the tissue, it always ends up on an outer side of a locking tab  108  which is embedded in the body  102  opposite to the fixed end of the member  106 . Subsequently, any tissue movement trying to force the ring off will cause the free end of the elongated gripping member  106  to contact the tab  108  and thereby prevent any slippage of the ring off of the tissue. 
         [0036]      FIGS. 11-13  illustrate a toroidal ring  120  with a ring body  122  defining a through-opening in the manner of the devices disclosed above, except that in  FIGS. 11-13  the through-opening is diametrically spanned by a flexible expandable cage structure  124  that is disposed in the through-opening as shown with opposed ends  126  embedded in the body  122 . The cage structure  124  defines plural openings  128  into which tissue can extend and preferably has a central through-opening which can expand around the below-described delivery device. The webbed cage structure may be made similar to a stent using a laser to cut out portions of a tube such as but not limited to a nitinol tube, or it may be formed by arranging a wire into a cone-shaped structure.  FIG. 13B  shows the cage  131 , which is tapered toward an apex and thus can be regarded as frusto-conical and in some cases completely conical, may also be formed by laser cutting or photoetching flat stock nitinol or steel and subsequently rolled to form the desired generally conical shape  133  shown in  FIG. 13C .  FIG. 13D  shows silicone rubber is then overmolded onto the cage to form the body  122 . The cage places the triangular spikes at a biased angle against the tissue. Stated differently, the spikes of the cage are oriented toward the long axis defined by the cage. Expulsion forces of the tissue causes these spikes to further engage the tissue and become tighter to prevent slippage of the ring. 
         [0037]      FIGS. 12 and 13A  illustrate operational delivery of the ring  120  to constrict tissue  130 . The ring  120  is stretched over a delivery device  132  in an expanded configuration shown in  FIG. 12 . The delivery device  132  is then removed while the ring  120  is held or remains in place to collapse around the tissue  130  as shown in  FIG. 13A , constricting the tissue. The cage structure  124  grips and/or digs into the tissue  130  to prevent slippage of the ring  120  off of the tissue  130 . 
         [0038]      FIGS. 14A-C  and  15 A-D show manufacturing steps tor making a ring such as any of the rings described above. As shown in  FIGS. 14A-C  various gripping member configurations may be used in addition to those described above. For example, as shown at  140  three gripping members may extend radially inwardly to almost meet each other, being radially spaced apart by 120°.Or, as shown at  142  and  144 , four gripping members may be arranged at 90° intervals and can extend toward each other at a central point, with the ends of two opposed members slightly overlapping each other ( 142 ) or with the ends of ail four members almost meeting each other at a central point ( 144 ). 
         [0039]    Regardless of the particular gripping member configuration used, it will readily be appreciated in reference to  FIGS. 14A-C  that all gripping members have respective fixed ends arranged on a circular support  146 ., with the gripping members extending radially inward relative to the circular support  146 . The circular support and gripping members are made of a unitary piece of material e.g., stainless steel, by, e.g., employing laser cutting or photoetching principles. 
         [0040]    Next, as shown in the illustration of  FIG. 15B , a toroidal resilient ring  148  is overmolded onto the support/gripping member assembly. Thus, the support/gripping member assembly may be disposed in a mold having a toroidal cavity formed therein and then fluidic silicone rubber or other appropriate ring material injected into the cavity and heat cured to form the body  148 . Then, as shown in  FIGS. 15C and 15D , the gripping members and ring are removed from the circular support  146  to establish one of the present tissue gripping rings. Excess ring material may then be removed from the gripping members. 
         [0041]    Referring briefly to  FIG. 20 , in one embodiment the overmolding step is executed in a mold  150  having first and second parts  152 ,  154  that when facing each other define a toroidal void into which material establishing the ring  148  is directed. The mold also is formed with spike channels into which the spikes or gripping members  156  are disposed prior to overmolding, with the circular support being sandwiched between the parts  152 ,  154 . After molding, the first part  152  is distanced from the second part  154  to expose the ring  148  and spike  156 . 
         [0042]    In the example shown in  FIG. 20 , if desired ejector pins  160  may be provided in one of the parts of the mold. Alter distancing the first part  152  from the second part  154 , the ring may he removed from the second part  154  by reciprocating the ejector pins  160  against the ring to push it out of the mold. 
         [0043]      FIGS. 16-19  illustrate an assembly including a delivery device  170  onto which a ring  172  is to be disposed by pushing the ring  172  onto an expander tool  174  and then onto the delivery device  170 , in some eases using an elongated axially rigid pusher tool  176 . When disposed on the delivery device  170 , the ring is stretched to a radially enlarged configuration such that when it is pushed off of the delivery device  170  onto tissue, the ring collapses to a relaxed, radially smaller configuration around the tissue. 
         [0044]    As best shown in  FIG. 17 , the expander  174  tapers radially outwardly from a first end  176  of the expander to a radially enlarged cylindrical segment  178 , which has substantially the same diameter as the end segment  180  of the delivery device  170  onto which the ring  172  is to be disposed, In contrast, the diameter of the end  176  substantially equals the diameter of the ring  172  when the ring is in a relaxed state. As the ring  172  is pushed from the first end  176  toward the cylindrical segment  178 , it expands, with the spikes being rotated out of the plane defined by the ring body as they ride against the tapered part of the expander  174 . 
         [0045]    The cylindrical segment  178  of the expander  174  is juxtaposed with the carrying portion  180  of the delivery device  170  as shown, and then the ring  172  is pushed from the cylindrical segment  178  onto the carrying portion  180  ( FIG. 18 ) to load die ring  172  in a stretched state for delivery to the tissue. The expander  174  is removed and the ring  172  is now loaded onto the delivery device  170  ( FIG. 19 ). Subsequently, to push the ring  172  off of the delivery device, a collar  182  is moved against the ring to urge it off of the delivery device, either by pushing the collar  182  toward the ring or by retracting the carrying portion  180  toward the collar. 
         [0046]      FIG. 17  perhaps best shows that when it is desired to push the ring onto the expander and delivery device using the pusher tool  176 , the pusher tool  176  may be formed with an end segment  184  that in turn is formed with longitudinal slots  186 . The slots  186  enable the end segment  184  to radially expand as the end segment  184  rides over the expander  174  from the first end  176  of the expander toward the cylindrical portion  178  of the expander. 
         [0047]    While the particular DEVICES AND METHODS FOR SECURING TISSUE are herein shown and described in detail, it is to be understood that the subject matter which is encompassed by the present invention is limited only by the claims.