Abstract:
Provided is a device for extracting from a body tissue surgical fasteners having a crown, a baseplate and prongs extending from the crown to the baseplate. The device includes a shaft having a lumen with a cross-sectional shape and dimensions to allow the crown to enter the lumen while preventing the baseplate from entering the lumen. Also provided is a method for extracting from a body tissue a fastener having a crown, a baseplate and prongs extending from the crown to the baseplate. According to the method of the invention, the crown of a fastener is introduced into the hollow portion of the device of the invention while preventing the advancement of the baseplate by the distal part of the hollow shaft.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to surgical devices, and more particularly to devices related to surgical fastening. 
       BACKGROUND OF THE INVENTION 
       [0002]    Surgical anchors are used instead of surgical suturing, which is often both time consuming and inconvenient, in order to join two tissue locations. A surgeon can often use a stapling apparatus to implant an anchor into a body tissue and thus accomplish in a few seconds, what would take a much longer time to suture. A surgical anchor is used, for example in inguinal hernia surgery to fasten polypropylene mesh to the abdominal wall in order to reinforce the abdominal wall. 
         [0003]    Surgical fasteners are known in the form of a staple in which a pair of prongs extends from a crown. In some applications, the body tissue is accessible from two opposite direction so that a deployment device may be used having an anvil that is used to bend the prongs towards each other after the prongs have penetrated through the tissue. In applications where access to the tissue is from one direction only, deployment device is used that delivers a force to the crown that deforms the crown and thus causes the prongs to project towards and grasp the tissue. 
         [0004]    Applicant&#39;s co-pending application PCT/IL2006/000783 filed on Jul. 6, 2006, the contents of which are included herein in their entirety by reference, discloses surgical fasteners having two or more prongs, each of which is connected to a crown by hinge. In an undeployed configuration of the fastener, the tips of the prongs are inserted into slots in a base plate. The crown is thus separated from the baseplate in the undeployed configuration of the fastener by the length of the prongs. This configuration is stabilized by an engagement between the prongs and the baseplate, for example, by friction between the prongs and slot edges or by filling the slots with adhesive, glue or by a plug of softer material such as a biodegradable material. Deployment of such a fastener involves positioning the fastener at the site of a tissue surface where it is to be deployed and urging the crown towards the baseplate. As the prongs pass through the slots, they enter the tissue while the force applied to the prongs by the slot edges causes them to rotate at the hinges and splay radially outward from the crown so as to become embedded in the tissue. Only the prongs penetrate into the tissue, while the crown and baseplate become attach to the tissue surface without penetrating into it. The fastener may be used to attach a graft or a mesh to a body tissue. 
         [0005]    As further disclosed in PCT/IL2006/000783, the above described fastener may become locked in its deployed configuration. Locking of the fastener in its deployed configuration allows the fastener to better withstand forces acting on it within the tissue and thus prevents inadvertent release of the fastener from the body tissue. The locking is accomplished by means of an engagement between components of the fastener that increases the force necessary to bend the extended prongs of the deployed fastener closer to the longitudinal axis of the fastener compared to situation in which locking means are not provided. The locking may be due to an engagement between the prongs and the crown, the prongs and the baseplate, or the crown and the baseplate. For example, the locking may result from increased friction between the prongs and slots due to a region along the length of the prongs of increased width or thickness that enters the slot during deployment, so that the prong becomes jammed in the slot. The prongs may be locked in the deployed configuration by engagement of a tongue extending from each slot of the second element into an opening in the prong. Alternatively, a tongue in the prong may engage an opening in the second element. 
       SUMMARY OF THE INVENTION 
       [0006]    In its first aspect, the present invention provides an extracting device for extracting a deployed surgical fastener from a body tissue. The extracting device of the invention is used to extract surgical fasteners having a crown and a baseplate, for example, surgical fasteners as disclosed in PCT/IL2006/000783. The extracting device may be used for surgical fasteners that become locked in the deployed configuration. 
         [0007]    The extraction device of the invention has a slender shaft. At least a distal portion of the shaft is hollow. In accordance with the invention, the hollow distal portion has a lumen having a cross-sectional shape and dimensions that allow the crown to enter lumen while preventing the baseplate from entering the lumen. As the crown is pulled into the distal portion, the baseplate becomes immobilized at the distal end of the shaft causing the crown and baseplate to be pulled apart. 
         [0008]    In one preferred embodiment, the extracting device of the invention has a slender shaft that may be stiff or flexible, as required in any application. The shaft comprises an internal rod that terminates at its distal end in a hook. The rod is slidable inside a hollow sheath between a retracted position in which the hook is contained within the distal end of the sheath and an extended position in which the hook extends beyond the distal end of the sheath. 
         [0009]    To extract a deployed surgical fastener the rod is brought to its extended configuration with the hook extending beyond the distal end of the sheath. The hook is then inserted between the crown and baseplate of the deployed fastener and the rod is made to move towards its retracted position pulling the fastener towards the distal end of the sheath. The sheath has an interior lumen that has a cross-sectional shape and dimensions that allow the crown to enter the lumen, while the baseplate is prevented from entering the lumen. Thus, as the hook enters the interior of the sheath, the crown is pulled by the hook into the interior of the sheath while movement of the baseplate is arrested with the baseplate in contact with the distal end of the sheath. As the crown moves away from the baseplate, the prongs slide through the slots until the tips of the prongs are at or near the tissue surface. The extraction device can then be removed from the body together with the un-deployed fastener. 
         [0010]    In another preferred embodiment, the extracting device has a shaft having at its distal end a hollow tubular unit. The tubularunit includes a hollow cylindrical element having a longitudinal groove along its length. The cylindrical element has a lumen having a cross-sectional shape and dimensions that allow the crown to enter the lumen, while the baseplate is prevented from entering the lumen. This embodiment is used when a filament has been inserted between the crown and the baseplate of the deployed fastener. The filament is inserted into the longitudinal groove and grasped in the groove. The filament is then pulled away from the tissue surface in which the fastener is deployed. As the filament is pulled away, the crown of the fastener enters into the lumen of the cylindrical element, while movement of the baseplate is arrested when the baseplate contacts the distal end of the cylindrical element. As the crown moves away from the baseplate, the prongs slide through the slots until the tips of the prongs are at or near the tissue surface. The extraction device, with the fastener is then removed from the body. 
         [0011]    In its second aspect, the invention provides a method for removing a deployed surgical fastener having a crown and baseplate. In accordance with this aspect of the invention, a surgical extraction device of the invention is used to extract the fastener by bringing the rod to its extended position and inserting the hook between the crown and baseplate of the deployed fastener. The rod is then brought to its retracted position to pull the fastener towards the distal end of the sheath. As the crown moves away from the baseplate, the prongs slide through the slots until the tips of the prongs are at or near the tissue surface. The extraction device can then be removed from the body together with the undeployed fastener. 
         [0012]    Thus, in its first aspect, the invention provides a device for extracting a surgical fastener, the surgical fastener having a crown, a baseplate and prongs extending from the crown, the surgical fastener having an undeployed configuration in which the crown is separated from the baseplate by a first distance and a deployed configuration in which the crown is separated from the baseplate by a second distance that is less than the first distance, the device comprising:
       (a) a shaft having a proximal end and a distal end, at least a distal portion of the shaft having a lumen with a cross-sectional shape and dimensions to allow the crown to enter the lumen while preventing the baseplate from entering the lumen.       
 
         [0014]    In its second aspect, the invention provides a method for extracting a deployed surgical fastener from a body tissue, the surgical fastener having a crown, a baseplate and prongs extending from the crown, the surgical fastener having an undeployed configuration in which the crown is separated from the baseplate by a first distance and a deployed configuration in which the crown is separated from the baseplate by a second distance that is less than the first distance; 
         [0015]    the method comprising:
       (a) providing an extracting device, the extracting device comprising:
           i) a shaft having a proximal end and a distal end, at least a distal portion of the shaft having a lumen with a cross-sectional shape and dimensions to allow the crown to enter the lumen while preventing the baseplate from entering the lumen.; and   
           (b) Introducing the crown into the hollow portion while preventing the advancement of the baseplate by the distal part of the hollow shaft.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
           [0020]      FIG. 1  shows a device for extracting a surgical fastener in accordance with one embodiment of the invention, in a side view ( FIG. 1   a ), a longitudinal section with the hook retracted ( FIG. 1   b ), and a longitudinal section with the hook extended ( FIG. 1   c ); 
           [0021]      FIG. 2  shows a surgical fastener having a crown and a baseplate in an undeployed configuration; 
           [0022]      FIG. 3  shows the fastener of  FIG. 2  at a tissue surface in an undeployed configuration ( FIG. 3   a ) and in a deployed configuration ( FIG. 3   b ); 
           [0023]      FIGS. 4   a  to  FIGS. 4   d  show use of the device of  FIG. 1  for removing a surgical fastener having a baseplate and crown; 
           [0024]      FIG. 5  shows a device for extracting a surgical fastener in accordance with another embodiment of the invention, with the ring element in register with the longitudinal groove ( FIG. 5   a ) and with the ring element out of register with the longitudinal groove ( FIG. 5   b ); 
           [0025]      FIG. 6  shows a surgical fastener having a crown and a baseplate in an undeployed configuration ( FIG. 6   a ) and in a deployed configuration ( FIG. 6   b ) with a filament passing between the crown and the baseplate; and 
           [0026]      FIGS. 7   a  to  7   e  show use of the device of  FIG. 5  for removing a surgical fastener having a crown and a baseplate and a filament passing between the crown and the baseplate. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0027]      FIG. 1  shows an extracting device  2  for extracting a surgical fastener in accordance with one embodiment of the invention. The extracting device  2  is shown in a side view in  FIGS. 1   a  and  1   c,  and in a longitudinal sectional view in  FIG. 1   b.  The extracting device  2  has a proximal end,  10  and a distal end  12 . The extracting device  2  has a slender shaft  4  that may be stiff or flexible, as required in any application. The shaft  4  comprises an internal rod  6  surrounded by an external sheath  8 . The rod  6  terminates at its distal end in a hook  14 . The rod  6  is slidable inside the sheath between a retracted position shown in  FIGS. 1   a  and  1   b  in which the hook  14  is contained within the distal end of the sheath  8  and an extended position shown in  FIG. 1   c  in which the hook extends beyond the distal end of the sheath  8 . The rod  6  is spring  17  biased in its extended position by means of a spring  17 . The rod  6  is brought to its retracted position by pulling a handle  18  in a proximal direction towards a knob  16 . The handle  18  is attached to the proximal end of the rod  6 , and as the handle is pulled, the spring  17  is compressed. The palm of a user&#39;s hand is applied to the knob  16  and the user&#39;s fingers are hooked on the handle  18 . The user then squeezes the handle towards the knob. When the handle is released, the rod reverts to its extended position under the influence of the spring  17 . 
         [0028]    As shown in  FIGS. 1   b  and  1   c  (enlarged views), the hook  14  has a flat top surface and a flat bottom surface, the top and bottom surfaces being substantially perpendicular to a direction of motion of the hook when the hook moves between the retracted position and the extended position. 
         [0029]      FIG. 2  shows an exemplary prior art surgical fastener  20  having a crown  22  and a baseplate  24  in its undeployed configuration. A number of prongs  26  extend from the crown. The prongs  26  are bent at hinge regions  30 . Each of the prongs  26  terminates in a tip  28  that is inserted into a slot  32  in the baseplate. 
         [0030]      FIG. 3  shows the fastener  20  after delivery to a body tissue site. As shown in  FIG. 3   a , the fastener  20  has been delivered to a surface  33  of a body tissue  34 , with the baseplate  24  and prong tips adjacent to the tissue surface  33 . The body tissue  34  is indicated in  FIG. 3  by broken lines. A surgical material  38  such as a sheet or mesh-like structure may first be applied to the tissue surface  33 . Using a deployment device (not shown), the crown  22  of the fastener  20  is displaced towards the base plate  24 . As the crown  22  approaches the baseplate  24 , the prongs  26  enter the tissue  34  and splay radially outward inside the tissue, as shown in  FIG. 3   b . The prongs  26  become embedded in the tissue  34 , so that the fastener  20  is immobilized at the tissue surface  33  with the crown  22  and the baseplate  24  on the tissue surface  33 . The surgical material  38 , if present has thus been grasped at the tissue surface. The fastener  20  may become locked in the deployed configuration. 
         [0031]      FIG. 4  shows use of the extracting device  2  to extract the surgical fastener  20  after its deployment as shown in  FIG. 3   b . This is by way of example only, and the extracting device of the invention may be used to extract any surgical fastener having a crown and baseplate.  FIG. 4   a  shows the extracting device  2  with the rod  6  in its extended configuration so that the hook  14  extends beyond the distal end of the sheath  8 . In  FIG. 4   b , the hook  14  has been inserted between the crown  22  and the baseplate  24 . As the handle  18  is pulled ( FIG. 4   c ), the hook  14  moves towards its retracted position, pulling the crown of the fastener  20  towards the distal end of the sheath  8 . The sheath  8  has an inner lumen having a cross-sectional shape and dimensions that allow the crown to enter the lumen, while the baseplate is prevented from entering the lumen. Thus, as the hook  14  enters the lumen of the sheath, the crown  22  is pulled by the hook  14  into the lumen of the sheath  8  while movement of the baseplate  24  is arrested when the baseplate  24  contacts the distal end of the sheath  8 , as shown in  FIG. 4   d . As the crown  22  moves away from the baseplate  24 , the prongs  26  slide through the slots  32  until the tips  28  of the prongs  26  are at or near the tissue surface  33 . With the handle  18  remaining pulled towards the knob  16  so that the fastener  20  is firmly held at the distal end of the sheath  8  by the hook  14 , the extraction device  2  is removed from the body. 
         [0032]      FIG. 5  shows an extracting device  42  for extracting a surgical fastener in accordance with another embodiment of the invention. The extracting device  42  has a proximal end  50  and a distal end  53 . The extracting device  42  has a shaft  44  that may be stiff or flexible, as required in any application. The shaft  44  may have a uniform diameter along its length, or may have a thinner portion  46  at its distal end as shown in  FIG. 5 . The shaft  44  has at its distal end a hollow tubular unit  48  The tubularunit  48  includes a hollow cylindrical element  58  having a longitudinal groove  49  along its length. The tubular unit  48  is rigidly fixed to the distal end of the shaft  44  and has a lumen having a cross-sectional shape and dimensions that allow the crown to enter the lumen, while the baseplate is prevented from entering the lumen. The tubular unit  48  also includes a ring element  52 . The ring element  52  incompletely surrounds the cylindrical element  58  and thus has a gap  60  between its ends. The ring element  52  is rotatable about the cylindrical element  58  from a position in which the gap  60  is in register with the longitudinal groove  49 , as shown in  FIG. 5   a , and a position in which the gap  60  is completely out of register with the groove  49 , as shown in  FIG. 5   b . The extraction device also includes a handle  62  for manipulating the device during extraction of a deployed surgical fastener, as explained below. 
         [0033]      FIG. 6  shows again the surgical fastener  20  in its undeployed configuration. In  FIG. 6   a , a filament  62  has been inserted between the crown  22  and the baseplate  24 . After deployment of the fastener  20 , at a body tissue site, as explained above, the filament becomes pinched and immobilized between the crown  22  and the baseplate  24 , as shown in  FIG. 6   b.    
         [0034]      FIG. 7  shows use of the extracting device  42  to extract the surgical fastener  20  after its deployment as shown in  FIG. 6   b . This is by way of example only, and the extracting device of the invention may be used to extract any surgical fastener having a crown and baseplate provided that a filament was inserted between the crown and baseplate prior to deployment in such a way that the filament becomes pinched and immobilized between the crown and baseplate after deployment. In  FIG. 7   a , a user  70  has grasped the extracting device  42  in one hand and has grasped the filament  62  with his or her other hand, with the gap  60  of the ring element  52  in register with the longitudinal groove  49  of the cylindrical element  58 . The filament  62  and the device  42  are then manipulated so as to insert the filament into the longitudinal groove  49  ( FIG. 7   b ). The ring element  52  is then rotated into its position in which the gap  60  is not in register with the groove  49  ( FIG. 7   c ). In this configuration, the filament  62  is prevented from escaping from the groove  49 . Then, as shown in  FIG. 7   d , the extraction device is moved towards the tissue and applied to the fastener. The filament  62  is then pulled away from the tissue surface  33  of the body tissue  34 . As the filament  62  is pulled away, the crown  22  of the fastener  20  enters into the interior of the cylindrical element  58 . The cylindrical element  58  has a lumen having a cross-sectional shape and dimensions that allow the crown to enter the lumen, while thebaseplate isprevented from entering the lumen. Thus, as the filament  62  continues to be pulled away from the tissue surface  33 , the crown  22  is pulled by the filament  62  into the interior of the cylindrical element  58  while movement of the baseplate  24  is arrested when the baseplate  24  contacts the distal end of the cylindrical element  58 , as shown in  FIG. 7   e . As the crown  22  moves away from the baseplate  24 , the prongs  26  slide through the slots  32  until the tips  28  of the prongs  26  are at or near the tissue surface  33 . The extraction device  42 , with the fastener  20  firmly held at the distal end of the cylindrical element by the pulled filament  62  is then removed from the body.