Abstract:
The present invention involves an automatic suture locking device useable with vascular closure device. The suture locking device includes a housing and a locking mechanism. The locking mechanism has locked and unlocked positions. In the locked position, a suture pathway through the mechanism is sufficiently tortuous to prevent free suture movement.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a vascular closure devices and, more particularly, to a vascular closure device having an automatic suture locking device. 
     BACKGROUND OF THE INVENTION 
     Many surgical procedures today require entry into an arterial vessel and placement of devices using catheters or insertion sheaths. After the procedure, the arterial puncture or opening must be closed. Vascular closure procedures and devices are generally known in the art, but a brief background will be provided herein.  FIG. 1  shows a conventional vascular closure device  100  useful in closing arterial punctures. Device  100  may include an anchor  102 , a bypass tube  104 , a hemostatic collagen sponge  106 , a suture  108 , a carrier tube  110 , a tamper tube  112 , a device sleeve  114 , a reference indicator  116 , and a device cap  118 . 
     To use device  100 , an insertion sheath  202  or catheter (see  FIG. 2 ) is placed such that a tip of the insertion sheath or catheter is just beyond the arterial puncture. Any tools or devices delivered via the insertion sheath, such as, guide wires, dilators, catheters, stents, or the like, are removed. Vascular closure device  100  is delivered to the puncture site by sliding device  100  through insertion sheath  202  until reference indicator  116  lines up with an insertion sheath reference indicator  204 . After lining up the reference indicators  116  and  204 , the doctor begins removing vascular closure device  100  by pulling device cap  118  until slight resistance to movement is felt. When resistance is felt, anchor  102  has deployed and is flush with a tip  302  of insertion sheath  202 . Of course, other deployment indications are possible. 
     Once the doctor has deployed anchor  102 , insertion sheath  202  and vascular closure device  100  are pulled away from the puncture location leaving anchor  102 , hemostatic collagen sponge  106 , and suture  108  in place closing the vascular puncture. Conventionally, a doctor ties anchor  102 , collagen  106 , and suture  108  using a slipknot (not specifically shown but generally know in the art.) Along with other problems, the slipknot can be difficult for the doctor to deploy and can be difficult to manufacture. Thus, it would be desirable to develop an automatic suture locking device useful with vascular closure devices. 
     SUMMARY OF THE INVENTION 
     To attain the advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, an automatic suture locking assembly is provided. The suture locking assembly generally comprises a housing and a locking mechanism. The locking mechanism has locked and non-locked positions. In the locked position, a suture pathway through the mechanism should be sufficiently tortuous to prevent free suture movement. 
     The foregoing and other features, utilities and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which: 
         FIG. 1  is a cross-sectional view of a conventional vascular closure device; 
         FIG. 2  is a perspective view of a conventional vascular closure device inserted in a conventional insertion sheath; 
         FIG. 3  is a view of a conventional vascular closure device with an anchor deployed in a patient; 
         FIG. 4  is a cross-sectional view of a vascular closure assembly consistent with the present invention; 
         FIGS. 5A-5J  are cross-sectional views of automatic locking devices illustrative of the present invention; 
         FIGS. 6A-6D  are cross-sectional views of automatic locking devices illustrative of the present invention; and 
         FIGS. 7A-C  are cross-sectional views of automatic locking devices illustrative of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described with reference to  FIGS. 4-7C . Referring to  FIG. 4 , an assembly  400  consistent with the present invention is shown. Assembly  400  includes an anchor  402 , a collagen  404 , a suture  406 , and an automatic locking device  408 . Assembly  400  is shown deployed to close a puncture  410  in a vessel  412  of a patient  414 . Largely, deployment of assembly  400  is similar to conventional vascular closure device  100  described above and will not be further explained here. While the present invention is described with reference to vascular closure devices, one of skill in the art will recognize on reading the disclosure that the present invention is useful for locking sutures in other surgical applications. 
     Once deployed and placed, instead of using a slip not to secure assembly  400 , automatic locking device  408  is used. Automatic locking device  408  can be any number of types that will be explained further below. One advantage of locking device  408  is that it may have sufficient seating surface area  410  to inhibit locking device  408  from pushing to far into collagen  404 . Further, while a doctor could manually move the locking device from a non-locked to a locked position, the locking could be accomplished automatically by, for example, using the pressures exhibited by the collagen when it expands, preloading the device, using a predefined tension on the suture, or the like. 
     Automatic locking device  408  can encompass many variations, some of which will be explained further below. These examples should be considered exemplary and in a non-limiting sense. Generally, the embodiments described below relate to rotating automatic locking devices  500  ( FIGS. 5A-5J ), sliding automatic locking devices  600  ( FIGS. 6 ), and snap-lock automatic locking devices  700  ( FIGS. 7 ). Automatic locking device, as well as other part, could be made from bio-resorbable polymers, such as, for example, PGA. 
     Rotating Automatic Locking Devices 
       FIGS. 5A to 5J  show several embodiments of rotating automatic locking device  500 .  FIGS. 5A and 5B  show a rotating automatic locking device  502 . Device  502  has a square housing  504 , a suture  506  running through housing  504 , and cantilevered locking posts  508 .  FIG. 5A  shows device  502  in a deployment state. In the deployment state, suture  506  runs through housing  504  and around locking posts  508  relatively easily. 
     Device  502  is rotated after deployment to locked status shown by  FIG. 5B . As seen, rotating device  502  causes suture  506  to be in contact with relatively more surface area on locking posts  508 . The increased friction due to the increased surface area locks suture  506  in place. Resistance could be further increased if at least one of the locking posts  508  have one or more ridges, grooves, notches, channels, or textured surfaces to increase frictional resistance. 
     Rotating device  502  from the deployment to locked status could be done manually by a practitioner or automatically by, for example, pressure from the expanding collagen  404 . In particular, during deployment, rotating device  502  would be subject to rotating pressure from the tamper tube (not specifically shown in  FIG. 4 ,  5 A, or  5 B, but generally known in the art) and equal but opposite rotating pressure from collagen  404 . After deployment, the tamper tube is removed and collagen  404  applies a rotating force. In  FIGS. 5A-5F , for example, device  502  is shown with a 90 degree rotation, but more or less rotation could be user as a matter of design choice. Generally, the rotation needs to be sufficient such that the suture locks after rotation is complete. In other words, as shown in  FIGS. 5A-5B , suture  506  must travel a sufficiently tortuous pathway around posts  508  such that the suture  506  does not move. 
       FIGS. 5C and 5D  show an alternative shaped rotational automatic locking devices  520 . Device  520  is similar to device  502  but has a triangular housing  522  instead of a square housing.  FIGS. 5E to 5H  show still other embodiments of rotational automatic locking devices  530  and  540 .  FIGS. 5E and 5F  show the deployed and locked position respectively of device  530 . Device  530  also has a triangular housing  532 , but it has a tube  534  or cylinder (which could be circular, square, rectangular, elliptical, triangular or the like) passing through the center instead of locking posts. A suture  536  can run through freely in the deployed position ( FIG. 5E ), but in the locked position ( FIG. 5F ) suture  536  is pinched and inhibited from movement, which locks it in place. Device  540  shows that a tube  542  can be curved. 
       FIGS. 5A to 5H  identify several embodiments of rotational automatic locking device consistent with the present invention, but should be deemed as exemplary and not limiting. In particular, rotational automatic locks could be of most shapes or configurations, such as, for example, rectangular, trapezoidal, triangular, square, circular, elliptical, spherical, conical, or the like. At least  FIGS. 5I and 5J  illustrate a generally wedge shaped locking device having at least one triangle shaped side  551  and multiple planar trapezoid faces  553 ,  555 ,  557 . Similarly, the lock is provided by an increase in friction that can be provided by many styles of design, such as wrapping the suture about locking posts or dragging the suture along the wall of a tube or cylinder. 
       FIG. 5I  shows another embodiment of a rotational automatic locking device  550 . Device  550  has a triangular housing  552 , a tube  554  running through housing  552 , and a suture  556 . In this case, tube  554  (or suture pathway) has a rounded side  558  and a notched side  560  forming a tear drop shape. As shown in  FIG. 5I , in the deployed state, suture  556  passes through rounded side  558  or tube  554 . As shown in the locked state, however, device  550  has rotated and suture  556  passes through the notched side  560  of tube  554 . Passing through notch side  560  locks suture  556  in place. To facilitate the locking of suture  556 , notch side  560  could be textured, grooved, ribbed, or the like to increase resistance. 
     While the tear drop shape of tube  554  is somewhat arbitrary, it highlights the wide pass through portion of tube  554  and the narrow lock portion of tube  554 . Other designs would work equally well, such as a triangular design, a circular design with a channel, or the like. 
     Sliding, Locking Device 
     Referring now to  FIGS. 6A to 6D , sliding locking devices are shown. Referring first to  FIG. 6A , a sliding, locking device  602  comprises an outer housing assembly  604 , an inner housing assembly  606 , at least one gap  608  between the outer housing assembly  604  and inner housing  606 , and a suture  610 . Suture  610  resides in the at least one gap  608 , but could also reside in a channel  612  (shown in phantom) in inner housing  606 . During device deployment, tamping forces and tension on suture  610  cause suture  610  to engage inner housing assembly  606  and lift inner housing. Once deployed, tamping forces are removed and tension on suture  610  is no longer sufficient to lift inner housing assembly  606 . Because inner housing assembly  606  is no longer being lifted, it drops and mates with housing assembly  604 , effectively clamping and locking suture  610 . A collagen  614  expands and provides additional seating force between outer housing assembly  604  and inner housing assembly  606 .  FIGS. 6B to 6D  show alternative embodiments of slide, locking assembly  620 ,  630 , and  640 . The inner housing assemblies  606  of the locking assemblies  602 ,  620 ,  630 ,  640  each include a wedge shaped portion  607  that is generally triangular shaped. The wedge shaped portion  607  includes a surface  609  that faces a surface  611  of the outer housing assembly  604 . These embodiments should be deemed exemplary of locking mechanisms that have bodies that slide into a fitted arrangement to lock a suture. 
     Snap Lock Device 
     A snap lock device will be explained with reference to  FIG. 7A  to  FIG. 7C .  FIG. 7A  shows a snap lock device  700  comprises an external housing  702  and a locking device  704 . External housing  702  has sidewalls  706 , deploying position holes  708 , which could be detents, and locking position holes  710 , which could be detents. Sidewalls  706  angle inwards between holes  708  and holes  710 . Locking device  704  comprises extension mount  712  and two extensions  714 , although more or less extensions are possible. Extensions  714  have a proximate end  716  connected to extension mount  712  and a distal end  718 . Distal end  718  comprises a tab  720  and a mating surface  722 . 
     When device  700  is in the deploy mode, tabs  720  are engaged with deploying position holes  708 . In the deploying position, a suture (not shown) would freely run through the device  700 . To lock the device  700 , locking device  704  would move towards external housing  702 . Tabs  720  would disengage from holes  708 . Extensions  714  would move inward toward each other closing a gap between opposed mating surfaces  722 . In the locked position, tabs  720  would engage locking position holes  710  and opposed mating surfaces would clamp the suture, locking it in place. Optionally, when locked, extension mount  712  could engage external housing  702 . 
     Because extensions  714  may be squeezed, as in this example, when in the locking position, they have a tendency to try and separate, which would tend to push locking device  704  away from housing  702 . Thus, tabs  720  engaging locking position holes  710  inhibit extensions  714  from opening device  700 . 
       FIG. 7B  shows an alternative snap-lock device  730 . Device  730  has a housing  732 . Housing  732  comprises a base  734  and flexible sidewalls  736 . Extending inward from flexible sidewalls  736  is at least one lock tab  738 . Flexible sidewalls  736  experience a compressive force tending to collapse sidewalls  736  inwardly. Flexible sidewalls  736  could be entirely made of a flexible material, such as a high density plastic, or only a portion need be flexible. 
     A junction  740  is formed by lock tab  738  and flexible sidewall  736 . In the deploying position, an end of tamper tube  112  fits in junction  740 . Tamper tube  112  resists the compressive force on flexible sidewall  736  such that lock tab  738  does not close off gap  742  through which a suture  744  runs. Once the assembly has been tampered, the lock is formed by removing tamper tube  112 . When tamper tube  112  is removed, the compressive force is no longer resisted and flexible sidewalls  736  collapse inward causing lock tab  738  to close the gap  742  and lock suture  744  in place.  FIG. 7C  shows a similar device  760 , but junction  740  is formed by outcrops from housing  732   
     While the invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those skilled in the art that various other changes in the form and details may be made without departing from the spirit and scope of the invention.