Patent Publication Number: US-2020297347-A1

Title: Clip retention for surgical clip applier

Description:
CROSS-REFERENCE 
     The present application is a continuation of U.S. patent application Ser. No. 15/674,075 filed on Aug. 18, 2017, entitled “Clip Retention for Surgical Clip Applier,” which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD 
     Surgical clip applier devices and methods are provided having features for facilitating with clip retention. 
     BACKGROUND 
     Surgical clip appliers are commonly used for ligating a blood vessel, a duct, shunt, or a portion of body tissue during surgery. Most clip appliers typically have a handle with an elongate shaft having a pair of movable opposed jaws formed on an end thereof for holding and forming a ligation clip therebetween. The jaws are positioned around the vessel or duct, and the clip is crushed or formed on the vessel by the closing of the jaws. 
     One challenge with current clip appliers is retention of a clip within the jaws prior to and during clip formation. Many clip appliers advance a clip into the jaws when the trigger is released and/or during an initial phase of squeezing the trigger, and the jaws are released to return to the open configuration. As a result, the clip is pre-loaded in the jaws. Any movement or manipulation of the jaws could cause the clip to become misaligned, which can lead to clip malformation, or to fall out. 
     Accordingly, there remains a need for improved techniques for retaining surgical clips within the jaws of a surgical clip applier. 
     SUMMARY 
     Devices and method are provided for retention of a surgical clip within the jaws of a surgical clip applier. In at least one aspect, a surgical clip applier is provided that in some embodiments can include an elongate shaft and a clip advancing assembly extending through the elongate shaft. The elongate shaft can have first and second jaws on a distal end thereof that are movable between open and closed positions for engaging tissue therebetween. The clip advancing assembly can be configured to advance a stack of clips through the elongate shaft and to advance a distal-most clip into the first and second jaws. The first and second jaws can have opposed inward facing surfaces, with each inward facing surface having a clip guide channel formed there along for receiving and guiding legs of a clip into the first and second jaws. The clip guide channel on at least one of the first and second jaws can include at least one deflectable clip retention member disposed therein and configured to apply a biasing force to a leg of a clip disposed within the first and second jaws to thereby retain the clip within the first and second jaws. 
     The surgical clip applier can vary in many ways. For example, the at least one deflectable clip retention member can apply the biasing force to a leg of a clip a direction substantially perpendicular to a plane extending through the first and second jaws. As another example, the at least one deflectable clip retention member can apply the biasing force to a leg of a clip a direction of a plane extending through the first and second jaws. 
     In some embodiments, the at least one deflectable clip retention member can extend along a longitudinal length of at least one of the first and second jaws and the biasing force applied by the at least one deflectable clip retention member can vary along the longitudinal length. In some embodiments, the at least one deflectable clip retention member can be elastically deformable. For example, the at least one deflectable clip retention member can be or can include a leaf spring. 
     The clip guide channel of the surgical clip applier can also vary in many ways. For example, the clip guide channel can include an upper surface, a lower surface, and a sidewall extending between the upper and lower surfaces. The at least one deflectable clip retention member can be disposed on the sidewall and can bias a leg of a clip toward the opposed jaw. As another example, the clip guide channel can include an upper surface, a lower surface, and a sidewall extending between the upper and lower surfaces, and the at least one deflectable clip retention member can include a first deflectable clip retention member disposed on the upper surface and a second deflectable clip retention member disposed on the lower surface such that the first and second deflectable clip retention members engage a leg of a clip therebetween. As another example, the clip guide channel can further include at least one deflectable tab configured to engage a proximal surface of a clip after the clip moves distally past the at least one deflectable tab. 
     The at least one deflectable clip retention member can be made from any suitable material(s). In some embodiments, at least a portion of the at least one deflectable clip retention member can be formed from a self-healing material. 
     In another aspect, a surgical clip applier is provided that in some embodiments can include an elongate shaft with first and second jaws on a distal end thereof, and a clip advancing assembly extending through the elongate shaft. The first and second jaws can be movable between open and closed positions for engaging tissue therebetween, and the first and second jaws can have inward facing surfaces defining a clip track for receiving and guiding a clip into the jaws. At least one compressible clip retention member can be disposed within the clip track in one of the first and second jaws. The clip advancing assembly can extend through the elongate shaft and it can be configured to distally advance a plurality of clips through the elongate shaft and to advance a distal-most clip of the plurality of clips into the clip track in the first and second jaws. The at least one clip retention member can be configured to move from a first, uncompressed configuration to a second, compressed configuration when the distal-most clip is advanced into the clip track. 
     The at least one clip retention member of the surgical clip applier can vary in many ways. For example, a distal portion of the at least one clip retention member can be more flexible than a proximal portion of the at least one clip retention member. As another example, the at least one clip retention member can be disposed on a sidewall of the clip track, with the sidewall extending between upper and lower walls of the clip track. As a further example, the at least one clip retention member can be disposed on at least one of an upper wall, a lower wall, and a sidewall of the clip track, with the sidewall extending between the upper and lower walls. 
     In some embodiments, the at least one clip retention member can include a first retention member disposed on an upper wall of the clip track and a second retention member disposed on a lower wall of the clip track such that the first and second retention member are configured to engage a leg of a clip therebetween. In some embodiments, the at least one clip retention member can be or can include a leaf spring extending longitudinally along at least one of the first and second jaws. 
     In some embodiments, the clip track can include at least one deflectable tab configured to engage a proximal surface of a clip after the clip moves distally past the at least one deflectable tab. 
     The clip retention members can be made from any suitable material(s). In some embodiments, a portion of at least one of the clip retention members be formed from a self-healing material, such as a poly(urea-urethane). 
     In another aspect, a method for applying a surgical clip to tissue is provided that in some embodiments can include manipulating first and second jaws on a clip applier to position tissue between the first and second jaws, and actuating the clip applier to move the first and second jaws from an open position to a closed position to deform a clip positioned within a clip track formed in each of the first and second jaws and thereby engage the tissue between legs of the clip. At least one resilient clip retention member disposed within the clip track in at least one of the first and second jaws can apply a biasing force to the clip to maintain the clip in alignment with the first and second jaws as the jaws are moved from the open position to the closed position. 
     The method can vary in many ways. For example, at least one deflectable tab in the clip track can prevent proximal movement of the clip within the clip track. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a side view of one exemplary embodiment of a surgical clip applier; 
         FIG. 2  is an exploded view of a distal portion of the surgical clip applier of  FIG. 1 ; 
         FIG. 3  is a perspective view of a distal portion of the surgical clip applier of  FIG. 1 ; 
         FIG. 4A  is a perspective, partially transparent view of a proximal portion of the surgical clip applier of  FIG. 1 ; 
         FIG. 4B  is another perspective view of the proximal portion of the surgical clip applier of  FIG. 1 ; 
         FIG. 5A  is another perspective view of a distal portion of the surgical clip applier of  FIG. 1 ; 
         FIG. 5B  is a perspective view of a clip that can be disposed between the jaws of the surgical clip applier of  FIG. 5A ; 
         FIG. 6  is a perspective, partial view of an embodiment of a jaw of a surgical clip applier having a deflectable clip retention member; 
         FIG. 7  is a top perspective, partial view of jaws of the surgical clip applier of  FIG. 6 , showing the deflectable clip retention member in an uncompressed configuration; 
         FIG. 8  is a top perspective, partial view of the jaws of the surgical clip applier of  FIG. 7 , showing the deflectable clip retention member in a compressed configuration when a clip is disposed between the jaws; 
         FIG. 9A  is a perspective, partial view of another embodiment of a jaw of a surgical clip applier showing the deflectable clip retention member disposed on the lower surface of the clip guide channels; 
         FIG. 9B  is a cross-sectional, partial view of the jaw of  FIG. 9A , showing the deflectable clip retention members disposed on the lower and upper surfaces of the clip guide channels, in a compressed configuration with a clip disposed within the jaws; 
         FIG. 10  is a perspective, partially transparent view of another embodiment of jaws of a surgical clip applier having clip retention members on sidewalls of a clip guide channel of each of the jaws; 
         FIG. 11  is a perspective, partially transparent view of jaws of a surgical clip applier according to another embodiment, having clip retention members on upper and lower surfaces of a clip guide channel of each of the jaws; 
         FIG. 12  is a perspective, partially transparent view of jaws of a surgical clip applier having another embodiment of clip retention members on upper and lower surfaces and a sidewall of a clip guide channel of each of the jaws; 
         FIG. 13  is a side perspective, partially transparent view of an embodiment of jaws of a surgical clip applier having clip retention members of varying height; 
         FIG. 14A  is a perspective, partially transparent view of an embodiment of first and second jaws of a surgical clip applier having clip retention members staggered along the longitudinal axis on upper and lower surfaces of a clip guide channel of each of the jaws; 
         FIG. 14B  is a side, partially transparent view of the first jaw  FIG. 14A ; 
         FIG. 14C  is a perspective, partially transparent view of an embodiment of jaws of a surgical clip applier having staggered clip retention members on upper and lower surfaces of a clip guide channel of each of the jaws, as well as clip retention members on a sidewall of the clip guide channel of each of the jaws; 
         FIG. 15  is a top schematic view of an embodiment of jaws of a surgical clip applier having deflectable tabs; 
         FIG. 16  is a perspective view of an embodiment of a jaw of a surgical clip applier having a separate clip track coupled thereto; 
         FIG. 17  is a perspective schematic view showing an embodiment of a separate clip track; 
         FIG. 18  is a top view of an embodiment of a jaw of a surgical clip applier having a clip track with a deformable tab; 
         FIG. 19A  is a perspective view of an embodiment of a clip track of a jaw of a surgical clip applier having a deformable tab; 
         FIG. 19B  is another perspective view of the clip track of  FIG. 19A ; 
         FIG. 20  is a top schematic view of an embodiment of a jaw of a surgical clip applier having a clip track with flexible extensions; 
         FIG. 21  is a top schematic view of another embodiment of a jaw of a surgical clip applier having a clip track with flexible extensions; 
         FIG. 22  is a top schematic view of yet another embodiment of a jaw of a surgical clip applier having a clip track with flexible extensions; 
         FIG. 23A  is a perspective view of a portion of jaws of a surgical clip applier having at least one mating feature configured to mate with a surgical clip, according to another embodiment; 
         FIG. 23B  is perspective view of an embodiment of a surgical clip; 
         FIG. 23C  is a cross-sectional top view of an embodiment of jaws of a surgical clip applier having recesses configured to mate with a surgical clip, showing the clip disposed between the jaws in an initial stage of clip formation; 
         FIG. 23D  is a cross-sectional top view of the jaws of  FIG. 23C , showing the clip disposed between the jaws and in a partially closed position; 
         FIG. 23E  is another cross-sectional top view of the jaws of  FIG. 23D , showing the clip disposed between the jaws and fully formed; 
         FIG. 24A  is a cross-sectional, partially transparent perspective view of an embodiment of a surgical clip applier having a male mating feature configured to mate with a corresponding female mating feature of a surgical clip; 
         FIG. 24B  is a perspective view of a portion of the jaw of  FIG. 24B  showing a surgical clip seated therein; 
         FIG. 24C  is a lateral cross-sectional view of an embodiment of jaws of a surgical clip applier each having a male mating feature configured to mate with a corresponding female mating feature of a surgical clip; 
         FIG. 24D  is a perspective view of an embodiment of jaws of a surgical clip applier each having a male mating feature configured to mate with a corresponding female mating feature of a surgical clip; 
         FIG. 24E  is a side view of an embodiment of a jaw of a surgical clip applier having a male mating feature configured to mate with a corresponding female mating feature of a surgical clip; 
         FIG. 25A  is a lateral cross-sectional view of an embodiment of jaws of a surgical clip applier each having a female mating feature configured to mate with a corresponding male mating feature of a surgical clip; 
         FIG. 25B  is a lateral cross-sectional view of an embodiment of jaws of a surgical clip applier each having a female mating feature configured to mate with a corresponding male mating feature of a surgical clip; 
         FIG. 26  is a cross-sectional view of an embodiment of a jaw a surgical clip applier having female mating features on upper and lower rails thereof that are configured to mate with corresponding male mating features of a surgical clip; 
         FIG. 27  is a lateral cross-sectional view of an embodiment of jaws of a surgical clip applier and a surgical clip having first and second legs, showing that the first and second legs of the clip each having small protrusions configured to facilitate retention of the clip by the jaws; 
         FIG. 28  is a lateral cross-sectional view of an embodiment of jaws of a surgical clip applier and a surgical clip having first and second legs, showing the first and second legs of the clip each having female mating features configured to mate with corresponding male mating features of the jaws; 
         FIG. 29A  is a lateral cross-sectional view of an embodiment of jaws of a surgical clip applier and a surgical clip having first and second legs, showing the first and second legs of the clip being reversibly deformable when the clip is advanced between the jaws; 
         FIG. 29B  is a lateral cross-sectional view of an embodiment of jaws of a surgical clip applier and a surgical clip having first and second legs, showing the jaws being reversibly deformable and shaped so as to deformably retain the first and second legs of the clip; 
         FIG. 29C  is a lateral cross-sectional view of an embodiment of a jaw of a surgical clip applier and a leg of a surgical clip, the jaw being reversibly deformable and shaped so as to deformably retain the leg of the clip, wherein the clip&#39;s leg is shown retain by the jaw when the clip unintentionally rotates during the clip formation; 
         FIG. 30A  is a longitudinal top view of one embodiment of first and second jaws of a surgical clip applier, where the first and second jaws are substantially parallel to one another, and where a surgical clip is shown disposed between the jaws, the clip having first and second legs that are disposed at an obtuse angle with respect to one another; 
         FIG. 30B  is a longitudinal top view of another embodiment of first and second jaws of a surgical clip applier, where the first and second jaws are disposed at an obtuse angle with respect to one another, and where a surgical clip is shown disposed between the jaws, the clip having first and second legs that are disposed at an obtuse angle with respect to one another; 
         FIG. 30C  is a longitudinal top view of another embodiment of first and second jaws of a surgical clip applier, where the first and second jaws are disposed at an acute angle with respect to one another, and where a surgical clip is shown disposed between the jaws, the clip having first and second legs that are substantially parallel to one another; 
         FIG. 30D  is a longitudinal top view of another embodiment of first and second jaws of a surgical clip applier, where the first and second jaws are proximally tapered, and where a surgical clip is shown disposed between the jaws, the clip having first and second legs that are also proximally tapered; 
         FIG. 31A  is a side perspective view of a distal portion of a surgical clip applier, showing jaws of the surgical clip applier positioned around tissue and in an open position during a surgical procedure; 
         FIG. 31B  is a side perspective view of the distal portion of the surgical clip applier of  FIG. 31A , showing the jaws of the surgical clip applier in the closed position and a clip formed by the jaws; 
         FIG. 32  is a schematic cross-sectional view of one embodiment of jaws of a surgical clip applier having a self-healing material; 
         FIG. 33  is another schematic cross-sectional view of the jaws of the surgical clip applier of  FIG. 32 , showing damage incurred to the jaws when the jaws apply a surgical clip over another clip previously formed on a tissue; and 
         FIG. 34  is another schematic cross-sectional view of the jaws of the surgical clip applier of  FIG. 32 , showing the jaw after damages are incurred and after self-healing. 
     
    
    
     DETAILED DESCRIPTION 
     Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices, systems, and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices, systems, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention. 
     Further, in the present disclosure, like-named components of the embodiments generally have similar features, and thus within a particular embodiment each feature of each like-named component is not necessarily fully elaborated upon. Additionally, to the extent that linear or circular dimensions are used in the description of the disclosed systems, devices, and methods, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such systems, devices, and methods. A person skilled in the art will recognize that an equivalent to such linear and circular dimensions can easily be determined for any geometric shape. Sizes and shapes of the systems and devices, and the components thereof, can depend at least on the anatomy of the subject in which the systems and devices will be used, the size and shape of components with which the systems and devices will be used, and the methods and procedures in which the systems and devices will be used. 
     Surgical clip appliers having first and second jaws, and methods for using a surgical clip applier apply surgical clips to a vessel, duct, shunt, etc., during a surgical procedure, are provided herein. At least one of the jaws of the surgical clip applier can include at least one clip retention member configured to retain a surgical clip between the jaws such that alignment of the clip with respect to the jaws is maintained. The at least one clip retention member can be formed on, within, or coupled to a clip track defined in an inward facing surface of the jaw, and the at least one clip retention member can apply a biasing force to a clip when a clip is disposed between the jaws. The clip retention member can have many different forms, and the jaw(s) can include multiple clip retention members on one or more surfaces thereof or coupled thereto. 
       FIGS. 1-4B  illustrate one embodiment of a surgical clip applier  100 . As shown, the surgical clip applier  100  generally includes a housing  102  having a stationary handle  104  and a movable handle or trigger  106  that is pivotally coupled to the housing  102 . An elongate shaft  108  extends distally from the housing  102  and includes a jaw assembly  110  formed on a distal end  108   d  thereof and including first and second jaws  112 ,  114  that are movable between open and closed positions. The first and second jaws  112 ,  114  include opposed inward facing surfaces and each inward facing surface has a clip track formed therealong for receiving and guiding legs of a clip into the first and second jaws  112 ,  114 . The elongate shaft  108  can be rotated with respect to the housing  102  via a rotation knob  103 . 
     As shown in  FIGS. 2 and 3 , the elongate shaft  108  can include an outer support tube  120 , an upper shroud  122  coupled distally to the outer support tube  120 , and a lower shroud  124 . The outer support tube  120  and the upper and lower shrouds  122 ,  124  form an outer casing of the shaft  108 . As shown in  FIGS. 2 and 3 , a clip stack  126  including multiple surgical clips is disposed within a clip track or holder  128  of the shaft  108  proximal to the first and second jaws  112 ,  114 , and is biased distally. A floor  130  extends beneath the clip stack  126  for maintaining the clip stack  126  in alignment within the shaft  108 , and for guiding a distal-most clip  126   d  into the jaws  112 ,  114 . A lifter spring  132  is positioned just proximal to the jaws  112 ,  114  and distal to the clip stack  126  for preventing distal movement of the clip stack  126 , with the distal-most clip  126   d  disposed around the lifter spring  132 . A feeder bar  134  extends through the elongate shaft  108  for feeding the distal-most clip  126   d  into the jaws. As shown in  FIG. 3  illustrating the clip applier  100  with the upper and lower shrouds  122 ,  124  removed, a former tube  136  extends around a proximal end of the jaws  112 ,  114  and is movable distally to cam the jaws  112 ,  114  to a closed position for forming a clip  127  disposed therebetween. 
     The surgical clip applier  100  has a clip forming assembly including various components that operate together to close the jaws  112 ,  114  when the trigger  106  is activated to thereby cause a clip (e.g., clip  127 ) disposed in the jaws to be applied (formed) to the tissue. The clip forming assembly encompasses the former tube  136  and other components that are coupled to the trigger  106  configured to be activated to move the former tube  136  distally to thereby close the jaws  112 ,  114 . A clip advancing assembly of the surgical clip applier  100  includes the feeder bar  134  that is also coupled to the trigger  106 , via a link  107  extending proximally from the trigger  106 , as shown in  FIGS. 4A and 4B . In this way, when the trigger  106  is activated, the feeder bar  134  is caused to move proximally, opposite to a distal direction in which the former tube  136  is moved upon activation of the trigger  106 . 
     The clip forming and clip advancing assemblies can have any suitable configurations. For example, in the illustrated embodiment, as shown in  FIGS. 4A and 4B , the former tube  136  of the clip forming assembly is coupled, via an inner coupling  138 , to a former plate  140  in the handle  104  that is, in turn, coupled to the trigger  106  via a pin  141 , and the feeder bar  134  of the clip advancing assembly is coupled to the trigger  106  via a feeder plate  142  that is also coupled to the trigger  106 , via the link  107 . As shown in  FIG. 4A , the feeder plate  142  has arms  144   a ,  144   b  at a distal end thereof that are disposed over and mate with a proximal end of an outer coupling  146  (shown partially transparent). A connecting pin  148  at a distal end of the outer coupling  146  attaches the feeder bar  134  to the outer coupling  146 .  FIGS. 4A and 4B  illustrate the handle  104  with part of an outer casing removed, and  FIG. 4B  shows the handle  104  without the feeder plate  142 , for illustration purposes only. It should be appreciated that the surgical clip applier  100  can include various other components and assemblies that are not described herein for the sake of simplicity. 
     In use, when the trigger  106  of the handle  104  is activated (e.g., moved towards the stationary handle  104 ), the former plate  140  of the clip forming assembly is advanced distally to cause the former tube  136  to advance distally over the jaws  112 ,  114 , thereby camming the jaws  112 ,  114  to the closed position. At the same time, the feeder plate  142  of the clip advancing assembly is moved proximally, thereby pulling the feeder bar  134  proximally to position the feeder bar  134  proximal of the distal-most clip  126   d  of the clip stack  126 . Once the clip  127 , disposed in the jaws  112 ,  114  such that clip&#39;s legs are received within the clip track of each of the jaws, is fully formed, the trigger  106  is released, which causes the clip forming assembly to move proximally while the clip advancing assembly moves distally.  FIG. 2  shows the clip  127  in an original, pre-formed configuration. The proximal movement of the clip forming assembly causes the former tube  136  to retract relative to the jaws, thus allowing the jaws  112 ,  114  to move to the original open position, thereby releasing the formed clip. The distal movement of the clip advancing assembly causes the feeder bar  134  to move distally, and the feeder bar  134  thereby pushes the distal-most clip  126   d  distally, overcoming the biasing force of the lifter spring  132  and causing the lifter spring  132  to deflect out of the way, thereby allowing the distal-most clip  126   d  to be advanced into the jaws  112 ,  114 . In this way, the distal-most clip becomes positioned in the jaws&#39; clip track, like the clip  127  in  FIG. 3 . The floor  130  helps guide the distal-most clip into the clip tracks of the jaws  112 ,  114 . 
     A person skilled in the art will appreciate that, while a trigger is shown and described, the clip appliers disclosed herein need not include a trigger, and can have a variety of other actuation mechanisms. For example, the clip applier can be powered and can include an actuation button for actuating a motor to control firing of the device. In other embodiments, the housing can be configured to couple to a robotic or tele-manipulator system, such that actuation of the device is controlled through the robotic or tele-manipulator system. 
     As mentioned above, each of the first and second opposed jaws  112 ,  114  of the surgical clip applier  100  include opposed inward facing surfaces  203 ,  205 , as shown in more detail in  FIG. 5A . The opposed inward facing surfaces  203 ,  205  can each define a clip track for receiving and guiding a clip into the jaws. The clip track, which can be in the form of a clip guide channel, receives the distal-most clip from the clip stack  126  disposed within a shaft  108 . As shown in  FIG. 5A , each inward facing surface  203 ,  205  has a clip guide channel formed there along for receiving and guiding legs  207   a ,  207   b  of a clip  207  (shown separately in  FIG. 5B ) into the first and second jaws  112 ,  114 . The clip  207  can be similar to the clip  127  in  FIGS. 2 and 3 , or it can have other configurations. The inward facing surface  203  of the first jaw  112  includes a clip guide channel  206 , while a clip guide channel of the inward facing surface  205  of the opposed jaw  114  is obscured. As further shown in  FIG. 5A , the clip guide channel  206  is defined by an upper rail  208   u , a lower rail  208   l , and a sidewall  210  extending between the upper and lower rails  208   u ,  208   l . When the clip  207  is advanced from the shaft  108  into the jaws  112 ,  114 , the clip  207  is positioned in the manner as shown in  FIG. 3 . 
     While the upper and lower rails  208   u ,  208   l  may help retain the clip within the clip track, proper retention of a clip by the jaws of a surgical clip applier may pose a challenge. In order to accommodate manufacturing variances in the clips, the clip track can be sized to provide a certain amount of clearance therein. This can result in inadequate grip of the clip by the jaws, and the clip can thus become tilted or otherwise improperly positioned with respect to the clip track. Such insufficient clip-to-jaw retention can lead to clip malformation (e.g., scissoring), premature clip ejection, or other undesirable consequences which can compromise a surgical procedure. 
     Accordingly, techniques are provided for ensuring proper retention of a clip with the jaws of a surgical clip applier. In particular, as mentioned above, in some embodiments, at least one of the jaws of a surgical clip applier can include at least one deflectable clip retention member disposed therein. The clip retention member can be configured to apply a biasing force to a leg of a clip disposed within the jaws to thereby retain the clip within the jaws. In this way, when a clip is advanced to be seated between the jaws, the retention member(s) can move from a first, uncompressed configuration to a second, compressed configuration. In at least some embodiments, the biasing force applied by the clip retention member(s) can compensate for differences in sizes between the clip and the jaws, thereby securely retaining the clip between the jaws. 
     The clip retention member(s) can have various configurations and can be positioned on a jaw of a surgical clip in various ways. For example, the clip retention member can be formed on or coupled to the jaw at one or more locations along the inward facing surfaces of the jaws. One or more clip retention members can be disposed on a sidewall of the clip guide channel, on one or both of the upper and lower rails of the clip guide channel, or in any other portions of the jaw. 
       FIG. 6  illustrates one embodiment of a deflectable clip retention member  302  positioned on an inward facing surface  303  of a first jaw  312  of a surgical clip applier  300 , with the opposed jaw  314  having a deflectable clip retention member  304  on it&#39;s inward facing surface  305 , as shown in  FIGS. 7 and 8 . The clip retention member  302  extending along the inward facing surface  303  can be disposed in a clip track or clip guide channel  306  formed in the inward facing surface  303 . It should be appreciated that, although not shown in  FIG. 6  for the sake of simplicity, the clip guide channel  306  can be configured similar to clip guide channel  206  ( FIG. 5A ), such that the clip guide channel  306  can have an upper rail, a lower rail, and a sidewall extending between the upper and lower rails. The clip retention member  302  can be formed on or disposed on the sidewall of the clip guide channel  306  such that the clip retention member  302  biases a leg of a clip toward the opposed jaw. The clip retention member  302  can extend along a longitudinal length of the jaw  312  and can be configured to move from a first, uncompressed configuration to a second, compressed configuration when a distal-most clip is advanced into the clip guide channel  306 . 
     The clip retention member  302  of  FIG. 6  can have various configurations, and it can be coupled to the inward facing surface  303  of the jaw  312  in various ways. In the illustrated embodiment, the clip retention member  302  is in the form of an elongate leaf spring coupled to the sidewall of the clip guide channel  306  on surface  303  in a suitable manner. A width W of the clip retention member  302  (shown in  FIG. 6 ) can be the same or substantially the same along its length. In at least some embodiments, the width can be less than a height of the clip guide channel  306 . Further, in this example, as shown in  FIG. 6 , the clip retention member  302  can be positioned such that its distal end  302   d  is offset proximally from a distal end  312   d  of the jaw  312 . As also shown, a proximal end  302   p  of the clip retention member  302  can be coupled to the inward facing surface  303  at a proximal end  312   p  of the jaw  312 . The proximal end  302   p  can include one, two, or more discrete attachment points, or the entire area of the proximal end  302   p  of the clip retention member  302  can be coupled to the jaw&#39;s inward facing surface  303 . In  FIG. 6 , a distal end  302   d  of the clip retention member  302  is not coupled to the jaw&#39;s facing surface  303 , and contacts and is biased against the surface  303 . As a result, the distal end  302   d  is freely movable and can slide distally when the clip retention member  302  deflects. It should be appreciated, however, that the clip retention member can be coupled to the inward facing surface of the jaw in more than one location. For example, in some embodiments, both the proximal and distal ends  302   p ,  302   d  ends of the clip retention member  302  can be coupled to the inward facing surface  303  in any suitable manner, or alternatively only the distal end  302   d  can be coupled to the inward facing surface  303 . 
     As shown in  FIGS. 6 and 7 , in an uncompressed configuration, the clip retention member  302  disposed on the jaw  312  is curved towards the opposed jaw, such that a middle portion  302   a  of the clip retention member  302  is positioned farthest away from the inward facing surface  303 . It should be appreciated that the clip retention member  302  can be configured to have one (as in this example) or more curves in the uncompressed configuration. 
       FIG. 7  illustrates both of the clip retention members  302 ,  304  on the opposed inward facing surfaces  303 ,  305  of the jaws  312 ,  314 , respectively. When a surgical clip  307  is advanced so as to be positioned between the jaws  312 ,  314 , the clip retention members  302 ,  304  apply a biasing force to legs  307   a ,  307   b  of the clip  307 , respectively. When the clip  307  is disposed between the jaws  312 ,  314  having the respective the clip retention members  302 ,  304 , the clip retention members  302 ,  304  move from the first, uncompressed configuration to a second, compressed configuration as shown in  FIG. 8 . In this configuration, the biasing force applied to the clip  307  by the clip retention members  302 ,  304  will help securely retain the clip within the jaws. Once positioned between the jaws  312 ,  314 , the clip  307  can be formed. As disused above in connection with  FIGS. 1-4B , as the jaws  312 ,  314  are approximated to clamp tissue therebetween and form the clip disposed therein, a subsequent clip of a clip stack (e.g., clip stack  126  in  FIGS. 2 and 3 ) can be advanced by a clip advancing assembly to be positioned between the jaws  312 ,  314 . 
     In the embodiment shown in  FIGS. 6, 7, and 8 , the clip retention member  302  on the first jaw  312 , as well as the clip retention member  304  on the opposed second jaw  314 , can be configured to apply the biasing force to a respective leg of the clip a direction (shown by arrow  309  in  FIG. 6 ) of a plane P ( FIG. 6 ) extending through the first and second jaws  312 ,  314 . The lateral loads applied by the clip retention members  302 ,  304  on the clip legs  307   a ,  307   b  improve clip retention by the jaws  312 ,  314 . 
     The clip retention member  302 , discussed as a representative of the clip retention members  302 ,  304 , can be configured to apply the biasing force in any desired manner. For example, the clip retention member  302  can be configured to apply the biasing force with the same or substantially the same strength along the length of the jaw. However, in some embodiments, the biasing force applied by the clip retention member  302  can vary along the longitudinal length of the jaw  312 . The biasing force can vary in a suitable manner along a longitudinal axis A of the jaw  312  shown in  FIG. 6 . For example, as schematically shown in  FIG. 6 , a distal portion  322   d  of the clip retention member  302  can be more flexible than a proximal portion  322   p  of the clip retention member  302 . This can help maintain legs of a clip at a desired distance from one another when the clip is formed and to decrease a possibility of deformation of the clip. 
     It should be appreciated that the distal and proximal portions  322   d ,  322   p  of the clip retention member  302  are shown by way of example, as the distal and proximal portions can have any suitable lengths, including the same or different lengths. In at least one embodiment, as in the example shown in  FIG. 6 , the distal portion  322   d  of the clip retention member  302  can be smaller than the proximal portion  322   p  of the clip retention member  302 . Furthermore, the distal and proximal portions  322   d ,  322   p  may not be discrete portions, as the strength of the biasing force applied by the clip retention member  302  can gradually change such that it increases from the distal end  302   d  of the clip retention member  302  towards the proximal end  302   p  of the clip retention member  302 . The distal portion  322   d  of the clip retention member  302  can be more flexible, softer, or otherwise configured to apply a biasing force with a lesser strength than the proximal portion  322   p  thereof. The biasing force can change depending on the properties of the clip retention member, such as the clip retention member&#39;s elasticity, stiffness, or any other properties. For example, in one embodiment, the clip retention member can have a distal end having a modulus that is less than a modulus of the remainder of the clip retention member. The rigidity or stiffness of the clip retention member can change (e.g., increase) gradually in the proximal direction. 
     In some embodiments, additionally or alternatively, the clip retention member can be sized and shaped differently along its length. Also, although two clip retention members  302 ,  304  are described in connection with  FIGS. 6, 7, and 8 , it should be appreciated that only one of the jaws of a surgical clip applier can include a clip retention member. Furthermore, in some embodiments, more than one clip retention member (e.g., two, three, or more than three) can be formed on or coupled to an inward facing surface of at least one of the jaws of a surgical clip applier. The same or different number of clip retention members can be located on opposed jaws of a surgical clip applier, and the clip retention member can be configured to apply a biasing force to legs of a clip in various manner. 
       FIGS. 9A and 9B  illustrate an embodiment of a jaw  412  of a surgical clip applier having at least one deflectable clip retention member  402  formed on an inward facing surface  403  of a rail defining the clip track in the jaw  400 . As shown in  FIG. 9B , the jaw  400  has a clip guide channel  406  that includes an upper rail defining an upper surface  408   u  of the guide channel  406 , a lower rail defining a lower surface  408   l  of the guide channel, and a sidewall  410  extending between the upper and lower surfaces  408   u ,  408   l . In the illustrated embodiment, the clip retention member  402  can be in the form of a first deflectable clip retention member  402   a  disposed on the upper surface  408   u  and a second deflectable clip retention member  402   b  disposed on the lower surface  408   l  such that the first and second deflectable clip retention members  402   a ,  402   b  engage top and bottom surfaces of a leg of a clip  407  seated therebetween. The clip  407  can be similar to clip  207  in  FIG. 5B , or it can be any other clip having first and second legs and configured to be formed when the jaws clamps tissue therebetween. 
       FIGS. 9A and 9B  illustrate an embodiment of a jaw  412  of a surgical clip applier having at least one deflectable clip retention member  402  formed on an inward facing surface  403  of a rail defining the clip track in the jaw  400 . As shown in  FIG. 9B , the jaw  400  has a clip guide channel  406  that includes an upper rail defining an upper surface  408   u  of the guide channel  406 , a lower rail defining a lower surface  408   l  of the guide channel, and a sidewall  410  extending between the upper and lower surfaces  408   u ,  408   l . In the illustrated embodiment, the clip retention member  402  can be in the form of a first deflectable clip retention member  402   a  disposed on the upper surface  408   a  and a second deflectable clip retention member  402   b  disposed on the lower surface  408   b  such that the first and second deflectable clip retention members  402   a ,  402   b  engage top and bottom surfaces of a leg of a clip  407  seated therebetween. The clip  407  can be similar to clip  207  in  FIG. 5B , or it can be any other clip having first and second legs and configured to be formed when the jaws clamps tissue therebetween. 
       FIG. 9A  illustrates, for the sake of simplicity, one of the clip retention members  402   a ,  402   b , namely the clip retention member  402   b . An opposed jaw of the surgical clip applier is not shown in  FIGS. 9A and 9B  for the sake of brevity, though it should be appreciated that the opposed jaw can have one or more clip retention members similar to the clip retention member  402 . 
     In the embodiment illustrated in  FIGS. 9A and 9B , the at least one clip retention member  402  retains the clip  407  by applying a biasing force thereto. The clip  407  can be press-fit or otherwise releasably engaged between the clip retention members  402   a ,  402   b . Each of the clip retention members  402   a ,  402   b  is configured to apply a biasing force to the leg of the clip  407  in a direction substantially perpendicular to a plane P 1  extending through the jaw  400  and the opposed jaw (not shown). Thus,  FIGS. 9A and 9B  illustrate schematically that the clip retention members  402   a ,  402   b  apply the basing force to the leg of the clip  407  in respective opposed directions substantially perpendicular to the plane P 1 , as shown by arrows  409   a ,  409   b , respectively. In this way, the leg of the clip  407  is engaged between the clip retention members  402   a ,  402   b . Another leg of the clip  407  can be similarly engaged between clip retention members disposed on the opposed jaw (not shown). 
     The clip retention members  402   a ,  402   b  disposed on the inward facing surface  403  of the jaw  400  can have any suitable configuration. For example, each of them can be in the form of a leaf spring extending longitudinally along the jaw  400 , as previously described herein. It should be appreciated, however, that the clip retention members formed on the jaw can have any suitable configurations, including different configurations among the clip retention members. Furthermore, in some embodiments, at least one clip retention member disposed on one jaw of a surgical clip applier can differ from at least one clip retention member disposed on the opposed jaw of the surgical clip applier. The biasing force applied by the clip retention members  402   a ,  402   b  can vary along a longitudinal length of the jaw  400 , similar to the way a biasing force applied by clip retention member  302  ( FIG. 6 ) can vary. For example, a distal portion of the at least one clip retention member  402  can be more flexible than a proximal portion of the at least one clip retention member  402 . 
     As mentioned above, although two clip retention members  402   a ,  402   b  are shown, in some implementations, the at least one clip retention member  402  can be in the form of a single retention member formed on either surface of the upper and lower surfaces of the clip guide channel of the jaw. 
       FIG. 10  illustrates one embodiment of first and second jaws  512 ,  514  of a surgical clip applier  500  that have multiple clip retention members on inward facing surfaces thereof. In particular, as shown, the first jaw  512  has a plurality of clip retention members  502  coupled to a sidewall  510   a  of a clip guide channel  506   a  of the jaw  512 . Similarly, the opposed second jaw  514  has a plurality of clip retention members  504  coupled to a sidewall  510   b  of a clip guide channel  506   b  of the jaw  514 . It should be appreciated that each of the first and second jaws  512 ,  514  is shown to have three clip retention members  502 ,  504 , respectively, by way of example only. Any suitable number (e.g., two, more than three, etc.) of clip retention members can be disposed on opposed jaws of the surgical clip applier, including different number among the jaws. 
       FIG. 10  illustrates one embodiment of first and second jaws  512 ,  514  of a surgical clip applier  500  that have multiple clip retention members on inward facing surfaces thereof. In particular, as shown, the first jaw  512  has a plurality of clip retention members  502  coupled to a sidewall  510   a  of a clip guide channel  506   a  of the jaw  512 . Similarly, the opposed second jaw  514  has a plurality of clip retention members  504  coupled to a sidewall  510   b  of a clip guide channel  506   b  of the jaw  515 . It should be appreciated that each of the first and second jaws  512 ,  514  is shown to have three clip retention members  502 ,  504 , respectively, by way of example only. Any suitable number (e.g., two, more than three, etc.) of clip retention members can be disposed on opposed jaws of the surgical clip applier, including different number among the jaws. 
       FIG. 11  illustrates one embodiment of first and second jaws  612 ,  614  of a surgical clip applier  600  that have multiple clip retention members on inward facing surfaces thereof. In this example, each of the first and second jaws  612 ,  614  has a plurality of clip retention members on upper and lower walls of the clip guide channel. Thus, as shown, the first jaw  612  has a plurality of clip retention members  602   a ,  602   b  coupled to upper and lower surfaces  608   u ,  608   l , respectively, of the upper and lower rails that define a clip guide channel  606   a  of the jaw  612 . Similarly, the second jaw  614  has a plurality of clip retention members  604   a ,  604   b  coupled to upper and lower surfaces  609   u ,  609   l , respectively, of the upper and lower rails that define a clip guide channel  606   b  of the jaw  614 . It should be appreciated that each of the first and second jaws  612 ,  614  is shown to have three clip retention members  602   a ,  602   b  and  604   a ,  604   b  on the respective upper and lower surfaces of the clip guide channels  606   a ,  606   b  by way of example only. Any suitable number (e.g., two, more than three, etc.) of clip retention members can be disposed on the upper and lower surfaces of the clip guide channels of the opposed jaws, including different number among the jaws and different number among the upper and lower surfaces of a clip guide channel of each jaw. 
       FIG. 12  illustrates one embodiment of first and second jaws  712 ,  714  of a surgical clip applier  700  that have multiple clip retention members on inward facing surfaces thereof. In this example, each of the first and second jaws  712 ,  714  has a plurality of clip retention members on upper walls, lower walls, and sidewalls of the clip guide channel. Thus, as shown, the first jaw  712  has a plurality of clip retention members  702   a ,  702   b ,  702   c  coupled to the upper surface, lower surface, and the sidewall, respectively, of a clip guide channel of the jaw  712 . Similarly, the second jaw  714  has a plurality of clip retention members  704   a ,  704   b ,  704   c  coupled to the upper surface, lower surface, and the sidewall, respectively, of a clip guide channel of the jaw  714 . In the illustrated embodiment, the clip retention members  702   a ,  702   b  disposed on the upper and lower surfaces of the clip guide channel of the first jaw  712  are aligned with respect to one another and they have a smaller lateral length than the retention members  702   c  disposed on the sidewall of the clip guide channel of the first jaw  712 . The clip retention members  704   a ,  704   b ,  704   c  of the second jaw  714  are similar to clip retention members  702   a ,  702   b ,  702   c.    
     It should be appreciated that each of the first and second jaws  712 ,  714  is shown to have three clip retention members  702   a ,  702   b ,  702   c , and  704   a ,  704   b ,  704   c  on the respective upper and lower surfaces and sidewalls of the jaw&#39;s clip guide channels by way of example only. Any suitable number (e.g., two, more than three, etc.) of clip retention members can be disposed on any of the surfaces of a jaw&#39;s clip guide channel. 
     In the example of  FIG. 13 , each of the clip retention members  802   a ,  802   b  has a generally curved shape and its height is measured as a distance between a top of the curve and the respective inward facing surface of the jaw. The clip retention members can have various other configurations, and their height can be defined as a distance between a point on the clip retention member that is farthest from the inward facing surface of the jaw on which the clip retention member is disposed. In the example illustrated in  FIG. 13 , a length of the first clip retention member  802   a  is greater than a length of the second clip retention member  802   b , and the clip retention members  802   a ,  802   b  are disposed at a distance from one another. It should be appreciated that the inward facing surface  803  of the jaw  812  can have more than two clip retention members that can be disposed at any suitable distance from one another. A clip guide channel  806   b  on the inward facing surface  805  of the jaw  814  has first and second clip retention members  804   a ,  804   b  that can be configured similarly to the clip retention members  802   a ,  802   b.    
     Opposed jaws of a surgical clip applier can have a plurality clip retention members that are positioned in various ways along inward facing surfaces of the jaws.  FIGS. 14A and 14B  illustrate one embodiment of first and second jaws  912 ,  914  of a surgical clip applier  900  that have clip retention members that are staggered along the inward facing surfaces of each jaw, and are also staggered with respect to the opposed jaw. Thus, the first jaw  912  has first clip retention members  902   a  on an upper surface  908   u  of a clip guide channel  906   a  thereof that are staggered with respect to second clip retention members  902   b  on a lower surface  908   l  of the clip guide channel  906   a . The second jaw  914  has third clip retention members  904   a  on an upper surface  909   u  of a clip guide channel  906   b  thereof that are staggered with respect to fourth clip retention members  904   b  on a lower surface  909   l  of the clip guide channel  906   b . Also, the first and second clip retention members  902   a ,  902   b  of the first jaw  912  can be staggered with respect to the third and fourth clip retention members  904   a ,  904   b  of the second jaw  914 . It should be appreciated that each of the jaws  912 ,  914  is shown to have three clip retention members on the upper and lower surfaces of the jaw&#39;s clip guide channel by way of example only, as the jaws can have any suitable number of clip retention members. Also, although the clip retention members  902   a ,  902   b  and  904   a ,  904   b  are in the form of inwardly curved members, the clip retention members can have any other suitable shapes and they can be disposed at various distances from one another. 
       FIG. 14C  illustrates an embodiment of first and second jaws  942 ,  944  of a surgical clip applier  940 . In this example, each of the first and second jaws  942 ,  944  has clip retention members formed on an upper surface, a lower surface, and a sidewall of a jaw&#39;s clip guide channel, and the clip retention members are similar to those shown in  FIG. 12 . As shown in  FIG. 14C , the first jaw  942  has first, second, and third clip retention members  922   a ,  922   b ,  922   c  formed on the jaw&#39;s upper surface  928   u , lower surface  928   l , and a sidewall  930  extending between the upper and lower surfaces  928   u ,  928   l . As shown, the first and second clip retention members  922   a ,  922   b  are staggered with respect to each other, and the first and third clip retention members  922   a ,  922   c  are aligned with respect to each other. Similarly, as shown in  FIG. 14C , the second jaw  944  has fourth, fifth, and sixth clip retention members  924   a ,  924   b ,  924   c  formed on the jaw&#39;s upper surface  948   u , lower surface  948   l , and a sidewall  950  extending between the upper and lower surfaces  948   u ,  948   l . In this example, the fourth and fifth clip retention members  924   a ,  924   b  are staggered with respect to each other, and the fourth and sixth clip retention members  924   a ,  924   c  are aligned with respect to each other. It should be appreciated that nine clip retention members are shown on each of the jaws  942 ,  944  by way of example only, as the jaws can have any suitable number of clip retention members, including a different number of clip retention members among the different surfaces of a clip guide channel of the same jaw, and a different number of clip retention members among the jaws. 
     The clip retention members described above can be in the form of leaf springs or other suitable elements. The clip retention member in accordance with the described embodiments can be made from any suitable material. For example, it can be made from metal, plastic, or any suitable combination of materials such that the clip retention member is resiliently deformable. The clip retention member can be elastically deformable. In some embodiments, as discussed above, a biasing force applied by the clip retention member on a clip leg can vary. In this way, elasticity of the clip retention member can vary along its length. The clip retention member can be coupled to a respective inward facing surface of the jaw in any suitable manner, e.g., welded, glued, attached using a suitable mechanism, etc. In some embodiments, the clip retention member can be integrally and/or monolithically formed with the corresponding inward facing surface of the jaw. As mentioned above, the clip retention member can be coupled to the inward facing surface at one or more portions of the clip retention member. 
     Retention of a clip by jaws of a surgical clip applier can be improved in other various ways. For example, a jaw of a surgical clip applier can have other features that facilitate retention of a clip by the jaw and proper positioning of a clip prior to its passage through tissue and formation. The jaw can have one or more features that prevent the clip from backing up proximally once the clip is advanced to be seated between the jaws. Such feature(s) can be tabs, protrusions, or any other types of features that facilitate clip&#39;s resistance to proximal pressure exerted thereon by the jaws. The feature can be disposed on the jaw such that the feature has a fixed configuration. Alternatively, the feature can be deflectable such that it can be flush with or align with the surface of the jaw as the clip is advanced distally between the jaws, and the feature can defect once the clip moves distally past the feature. 
     For example, in some embodiments, a clip track of a jaw of a surgical clip applier can include at least one deflectable tab configured to engage a proximal surface of a clip after the clip moves distally past the at least one deflectable tab. Thus, the at least one deflectable tab in the clip track prevents proximal movement of the clip within the clip track.  FIG. 15  shows one embodiment of jaws  1012 ,  1014  of a surgical clip applier  1000  that have deflectable tabs  1020 ,  1022  included in clips tracks  1006   a ,  1006   b  defined in inward facing surfaces of the jaws  1012 ,  1014 , respectively. The tabs  1020 ,  1022  are configured to engage a proximal surface  1007   p  of a clip  1007  after the clip moves distally past the deflectable tab  1020 ,  1022 , as shown in  FIG. 15 . The tabs  1020 ,  1022  are configured to defect towards distal ends  1012   d ,  1014   d  of the jaws  1012 ,  1014 . The tabs  1020 ,  1022  are formed such that they engage areas of legs  1007   a ,  1007   b  of the clip  1007  that are proximal to respective knees  1009   a ,  1009   b  of the legs  1007   a ,  1007   b . The tabs  1020 ,  1022  can be formed on the jaws  1012 ,  1014  in any suitable manner. For example, the tabs  1020 ,  1022  can be coupled to the jaws or they can be integrally formed with the jaws  1012 ,  1014 . The tabs  1020 ,  1022  are shown in  FIG. 15  by way of example only, as any other features can be disposed on jaws a clip applier to prevent proximal movement of a clip within clip tracks of the jaws. 
     It should be appreciated that tabs similar to the tabs  1020 ,  1022 , or tabs having any other configuration, can be formed on the opposed jaws in conjunction with clip retention members. Thus, although  FIG. 15  does not show clip retention members, the jaws  1012 ,  1014  can have clip retention members disposed thereon, such as any of the clip retention members described herein. Also, any of the clip retention members described herein can be disposed on a jaw of a clip applier in association with one or more deflectable tab configured to engage a proximal surface of a clip after the clip moves distally past the deflectable tab(s). 
     In some embodiments, a clip track defined in an inward facing surface of at least one of the jaws is in the form of a groove or channel formed in the jaw. Such a clip track can be formed within the surface of the jaw by stamping or using any other suitable technique. In other embodiments, however, a clip track can be a separate component that is attached to the jaw using a suitable technique. In such embodiments, the clip track can serve as a clip retention member. For example, at least a portion of the clip track coupled to a jaw, such as a portion facing the opposed jaw, can be configured to deflect or deform to conform to a shape of a leg of a clip when the clip is disposed between the jaws. Manufacturing costs and complexity can be reduced to make a jaw having a separate clip track coupled thereto. 
       FIG. 16  illustrates a jaw  1100  of a surgical clip applier having a clip track  1106  coupled to an inward facing surface  1103  thereof. The clip track  1106  is a separate component attached to the jaw  1100  in a suitable manner, for example, by welding, applying adhesive (e.g., an ultraviolet (UV) curable adhesive), or using an attachment mechanism (e.g., a pin, rivet, screw, etc.). In this example, the clip track  1106  has a generally rectangular longitudinal cross-section and it is disposed along a length of the inward facing surface  1103 , as shown in  FIG. 16 . The clip track  1106  is configured to apply a biasing force to a leg of a clip a direction substantially perpendicular to a plane extending through the jaw  1100  and the opposed jaw (not shown). However, in some implementations, the clip track  1106  is configured to apply a biasing force to a leg of a clip a direction of the plane extending through the jaw  1100  and its opposed jaw of the surgical clip applier. Moreover, the clip track can be configured such that it can apply a biasing force in more than one direction. Furthermore, although the clip track  1106  is shown without any additional clip retention members, in some embodiments, the clip track  1106  can have one or more clip retention members coupled thereto. 
     The clip track  1106  can be made from a suitable metal, or any other suitable material or a combination of materials. In some embodiments, a thickness of the clip track walls can be in the range of from about 0.003 inches to about 0.030 inches. The thickness of the clip track can be substantially the same along its length. In some embodiments, the thickness of the clip track can vary along its length—for example, it can decrease from the clip track&#39;s distal end  1106   d  towards its proximal end  1106   p.    
     A clip track formed separately and attached to a jaw, such as the clip track  1106  in  FIG. 16 , or any other clip track, can be at least partially deformable, which can be done in a number of different ways. For example, the clip track can be made (e.g., stamped) from a suitable metal and it can have deformable elements (e.g., springs or other deformable elements) stamped or otherwise introduced onto one or more of surfaces of the clip track.  FIG. 17  shows an example of a pre-formed clip track  1206 . To show that the clip track  1206  is deformable,  FIG. 17  illustrates schematically (arrow  1209 ) that, when manufactured, the walls of the clip track purposely have a partially concave shape, such that they would provide resistive compressive pressure to a clip, once the clip is advanced into these clip track walls, thus straightening the concave shape. The clip track  1206  can have one or more deformable elements (not shown) stamped or otherwise introduced onto one or more of its surfaces. 
     In some embodiments, a clip track can have deformable elements disposed on one or more surfaces thereof. The clip track can be molded (e.g., metal injection molded), and it can deflect or deform to conform to a shape of a leg of a clip.  FIG. 18  illustrates an embodiment of a jaw  1300  of a surgical clip applier having a clip track  1306  coupled thereto that has a deformable tab  1316 . The tab  1316  can be coupled to the clip track  1306  in a suitable manner. In the illustrated embodiment, the tab  1316  extends along a longitudinal length of the clip track  1306  on an inward facing surface  1307  of the clip track  1306  at a proximal end  1306   p  of the clip track  1306 , such as at location  1311 . 
       FIGS. 19A and 19B  illustrate another embodiment of a jaw  1400  of a surgical clip applier having a clip track  1406  coupled thereto that has a deformable tab  1416 . In this example illustrated, the tab  1416  is formed on an inward facing surface  1411  of the clip track  1406  adjacent to a proximal end  1406   p  of the clip track  1406 . The tab  1416  is relatively small such that it extends along a portion of a longitudinal length of the clip track  1406 . 
     It should be appreciated that the tab  1316  ( FIG. 18 ) and tab  1416  ( FIGS. 19A and 19B ) can be disposed at any suitable locations on the respective clip tracks. Also, one or more of these tabs can be similar to tabs  1020 ,  1022  in  FIG. 15 . Each tab can be coupled to the clip track in any a suitable manner. For example, the tab can be molded into the surface of the clip track. Furthermore, in some embodiments, the tab can be integrally formed with the clip track. Also, more than one tabs or other clip retaining feature can be formed on the clip track. Regardless of its specific configuration, size, and position relative to the clip track, at least one tab is configured to assist in proper retention of a leg of a clip by the jaw to which the clip track is attached. 
     A clip retention member can have many various forms. For example, in some embodiments, a clip retention member can be in the form of an elongate member coupled to a clip guide channel and having a plurality of deflectable extensions. The extensions, such as, for example, multiple flexible fingers are configured to provide compliant support to guide a clip and maintain proper position of the clip.  FIGS. 20-22  illustrate examples of clip retention members having a plurality of deflectable extensions.  FIG. 20  shows a jaw  1500  of a surgical clip applier having a clip guide channel  1506  that has a clip retention member  1502 . As shown, the clip retention member  1502 , which can be disposed on a sidewall of the clip guide channel  1506 , has a plurality of deflectable extensions  1511  extending along a longitudinal length of the clip retention member  1502  between proximal and distal ends  1502   p ,  1502   d  of the clip retention member  1502 . The deflectable extensions  1511  can be, for example, fingers or other features that can be coupled to a body  1509  of the clip retention member  1502  by insert molding, using an adhesive (e.g., a UV-activated adhesive), or in any other suitable manner. Alternatively, in some embodiments, the extensions  1511  can be integrally formed with the body  1509  of the clip retention member  1502 . The deflectable extensions  1511  can have any suitable length. Also, in some embodiments, as in the example illustrated in  FIG. 20 , the extensions  1511  are biased in a direction of a movement of a clip—towards a distal end  1500   d  of the jaw  1500 . 
       FIG. 21  illustrates a jaw  1600  of a surgical clip applier having a clip guide channel  1606  that has a clip retention member  1602 . As shown, the clip retention member  1602 , which can be disposed on a sidewall of the clip guide channel  1606 , has a plurality of deflectable extensions  1611  extending along a longitudinal length of the clip retention member  1602  between proximal and distal ends  1602   p ,  1602   d  of the clip retention member  1602 . In this example, length of the deflectable extensions  1611  varies along the longitudinal length of the clip retention member  1602 . In particular, as shown in  FIG. 21 , the length of the extensions  1611  increases from the proximal end  1602   p  of the clip retention member  1602  towards the distal end  1602   d  of the clip retention member  1602 . Similar to extensions  1511  ( FIG. 20 ), the extensions  1611  can be biased towards a distal end  1600   d  of the jaw  1600 , in a direction of a movement of a clip when the clip is positioned between the jaw  1600  and an opposed jaw (not shown). 
     At least one clip retention member having deflectable extensions can be disposed on one or more of upper and lower surfaces, and a sidewall of a clip guide channel of a jaw.  FIG. 22  illustrates an example of a jaw  1700  of a surgical clip applier having a clip retention member  1702  with a plurality of deflectable extensions  1711  disposed on an upper surface  1708   u  of a clip guide channel  1706  of an inward facing surface of the jaw  1700 . 
     Deflectable extensions shown in  FIGS. 20-22 , or other deflectable extensions in accordance with the described techniques, can be formed from any suitable material(s). For example, they can be formed from a suitable plastic. The deflectable extensions can be made from elastomeric material. 
     In some embodiments, the deformable clip retention members are not separate from the clip guide rail surfaces, but are instead in the form of upper and lower jaw rails angled inward, such that a slight interference fit is generated between the jaws and clip&#39;s legs, and the clip&#39;s legs are biased to bottom out on side walls of the jaw guide rail. Thus, in some embodiments, that are discussed in more detail below, jaws of a surgical clip applier and a surgical clip can tapered in axial and transverse directions, in various ways, such that no additional biasing elements (e.g., springs) is required. 
     In some embodiments, clip retention by one or both jaws of a surgical clip applier can be facilitated by releasably engaging the clip with at least one of the jaws using mating features of the jaws and/or the clip. Accordingly, in some embodiments, a jaw of a surgical clip applier can have one or more mating features in a clip guide channel configured to engage a portion of a surgical clip when the clip is positioned between jaws of the clip applier. For example, a mating feature, such as a recess, can be formed in a jaw&#39;s clip guide channel at a location in the clip guide channel where a clip knee is disposed. Thus, the knee of the clip can be mated with the recess, which can facilitate clip retention during forming of the clip.  FIG. 23A  illustrates an embodiment of first and second jaws  1812 ,  1814  of a surgical clip applier  1800 , where at least the first jaw  1812  has a mating feature in the form of a recess  1802  in a sidewall  1810  of a clip guide channel  1806  of the jaw  1812 . The recess  1802  is formed in the sidewall  1810  at a location that corresponds to a location of a knee  1809   a  of a first leg  1807   a  of a surgical clip  1807  shown in  FIG. 23B . In this way, the knee  1809  of the clip  1807  can be received within the recess  1802  when the clip  1807  is advanced into between the jaws  1812 ,  1814 . Although obscured in  FIG. 23A , the second jaw  1814  also has a similar mating feature formed therein and configured to receive a knee  1809   b  of a second leg  1807   b  of the clip  1807 . 
       FIGS. 23C-23E  additionally illustrate one embodiment of first and second jaws  1852 ,  1854  of a surgical clip applier  1840 , where each of the jaws  1852 ,  1854  has a respective mating feature in the form of recesses  1842 ,  1844  in a sidewall of a clip guide channel of the jaws. The recesses  1842 ,  1844  can have any suitable shapes and, in the illustrated embodiments, they are shaped and sized to fit knees of the clip. The first and second jaws  1852 ,  1854  can be similar to the jaws  1812 ,  1814  of  FIG. 23A . Thus, the recesses  1842 ,  1844  are formed in the sidewall of each of the jaws at a location that corresponds to a location of a knee  1819   a  of a first leg  1807   a  of a surgical clip  1807  and a knee  1819   b  of a second leg  1807   b  of the surgical clip  1807 .  FIG. 23C  shows the clip  1807  disposed between the jaws  1852 ,  1854  when it has been initially advanced between the jaws in an unformed configuration.  FIG. 23D  shows that, during an intermediate phase of formation of the clip  1807  (prior to fully forming the clip), distal tips of the clip&#39;s legs  1807   a ,  1807   b  are brought together, such that the clip  1807  becomes diamond-shaped. The recesses  1852 ,  1854  generate additional support for the clip knees  1819   a ,  1819   b , thus resisting any tilting or dislodgement of the clip  1807  during this intermediate phase of clip formation.  FIG. 23E  shows the clip  1807  disposed between the jaws in the fully formed configuration. 
     It should be appreciated that one recess  1802  in  FIGS. 23A and 23C-23E  is shown by way of example only, as any other number (e.g., two, more than two, etc.) of recesses or other types of mating features can be formed on the inward facing surface of the jaw. The at least one recess can have any suitable shape, for example, in the illustrated embodiment, the recess that conform to the shape of the clip&#39;s knee. However, it should be appreciated that the recess can have any other suitable shape—e.g., it can have a generally rectangular, oval, elongated, or any other cross-section, and it can be configured to engage with a portion of a clip rather than a clip&#39;s knee. Regardless of its specific configuration, the recess, or other mating feature configured to mate with a portion of the clip, is configured such that it releasably engages with clip moved between the jaws and thus facilitates retention of the clip by the jaw(s) prior to and during clip formation. 
     In some embodiments, one or both jaws of a surgical clip applier can have at least one mating feature in a clip guide channel configured to releasably engage at least one corresponding mating feature of a surgical clip when clip when the clip is positioned between jaws of the clip applier.  FIGS. 24A and 24B  illustrate an embodiment of a first jaw  1912  of a surgical clip applier  1900 , where the jaw  1912  has at least one male mating feature configured to mate with at least one corresponding female mating feature formed on a surgical clip  1907 . As shown, the first jaw  1912 , which is representative of both jaws of the surgical clip applier  1900 , has a mating feature  1902  in the form of a longitudinal protrusion formed in a sidewall  1910  of a clip guide channel  1906  of the jaw  1912 . The clip  1907  has a corresponding longitudinal groove or recess  1909   a  formed on a first leg  1907   a  thereof. As shown in  FIG. 24B , a second leg  1907   b  of the clip also has a longitudinal recess  1909   b  configured to mate with a protrusion of the jaw opposed to the jaw  1912 . As shown in  FIG. 24A , when the clip  1907  is disposed between the jaws of the surgical clip applier  1900 , the longitudinal protrusion  1902  of the jaw  1912  releasably mates with the recess  1909   a  formed in the clip  1907 . In this example, as shown in  FIG. 24B , the recess  1909   a  is formed along the entire length of a portion the clip&#39;s leg  1907   a  that mates with the jaw during the clip formation. A length of the longitudinal protrusion  1902  of the jaw  1912  can correspond to a length of the recess  1909   a  of the clip  1907 , though it can have any suitable length. 
     As shown in  FIG. 24A , the clip  1907  mates with the jaw  1912  such that the clip  1907  is enclosed by upper and lower rails  1913 ,  1915  of the jaw  1912  having the sidewall  1910  (marked in  FIG. 24B ) extending therebetween. In at least some embodiments, the upper and lower rails  1913 ,  1915  can be removably coupled to the jaw  1912 . For example, the upper and lower rails  1913 ,  1915  can be configured to frictionally engage with respective opposed sides of a jaw&#39;s body  1911 . However, the upper and lower rails  1913 ,  1915  can be configured to be removably coupled to the jaw  1912  in other suitable ways. 
     The recesses  1909   a ,  1909   b  of the clip  1907  can vary in many different ways. For example, although the recesses  1909   a ,  1909   b  are shown as having a generally rectangular cross-section, they can have any other shapes. Similarly, the protrusions of the jaws, such as the protrusion  1902 , can have a rectangular cross-section, as in the illustrated embodiment, or the protrusion formed on each of the jaws can have other configurations in other embodiments. Also, although one recess in a clip is shown to mate with a protrusion of a jaw, in some embodiments, more than one recess can be formed on the clip&#39;s legs and the jaw will thus have more than one corresponding protrusions. 
       FIG. 24C  shows another example of first and second jaws  1912 ′,  1914 ′ of a surgical clip applier that is similar to the clip applier  1900  of  FIGS. 24A and 24B . As shown in  FIG. 24C , each of the first and second jaws  1912 ′,  1914 ′ has a respective protrusion configured to mate with a corresponding recess in first and second legs  1907   a ′,  1907   b ′ of a surgical clip  1907 ′. 
       FIG. 24D  illustrates an embodiment of first and second jaws  1932 ,  1934  of a surgical clip applier  1920  that is similar to surgical clip applier  1900  in  FIGS. 24A and 26B  and is therefore not described in detail. As shown in  FIG. 24D , the jaws  1932 ,  1934  have corresponding longitudinal protrusions  1922   a ,  1922   b  on sidewalls thereof that are configured to mate with respective recesses  1929   a ,  1929   b  formed in first and second legs of a clip  1927 . In this example, the first and second jaws  1932 ,  1934  are shown without upper and lower rails. As mentioned above, the rails can be removable. Thus, although the jaws  1932 ,  1934  are shown in  FIG. 24D  without the rails, the jaws  1932 ,  1934  can be configured to removably mate with suitable upper and lower rails. However, in some embodiments, the clip applier  1920  is configured to operate with its jaws not having the upper and lower rails. 
     As mentioned above, the mating features of a surgical clip and the corresponding (e.g., complementary) mating features of a jaw can have various configurations.  FIG. 24E  shows one embodiment of a jaw  1942  of a surgical clip applier having a male mating feature  1952  in the form of a longitudinal protrusion having a triangular cross-section. As shown, the male mating feature  1952  is configured to mate with a corresponding longitudinal recess  1939  in a surgical clip  1937 , the recess  1939  also having a triangular cross-section. 
     In some embodiments, jaws of a surgical clip applier have at least one female mating feature and legs of a surgical clip have corresponding male mating features.  FIG. 25A  shows one embodiment of first and second jaws  1962 ,  1964  of a surgical clip applier  1960 . As shown in  FIG. 25A , the first and second jaws  1962 ,  1964  have respective female mating features in the form of recesses  1972   a ,  1972   b  configured to mate with corresponding male mating features in the form of protrusions  1959   a ,  1959   b  of first and second legs  1957   a ,  1957   b  of a surgical clip  1957 . In this example, the recesses  1972   a ,  1972   b  and the protrusions  1959   a ,  1959   b  have generally rectangular cross-sections.  FIG. 25B  shows one embodiment of first and second jaws  1962 ′,  1964 ′ of a surgical clip applier  1960 ′. As shown in  FIG. 25A , the first and second jaws  1962 ′,  1964 ′ have respective female mating features in the form of recesses  1972   a ′,  1972   b ′ configured to mate with corresponding male mating features in the form of protrusions  1959   a ′,  1959   b ′ of first and second legs  1957   a ′,  1957   b ′ of a surgical clip  1957 ′. In this example, the recesses  1972   a ′,  1972   b ′ and the protrusions  1959   a ′,  1959   b ′ have generally semi-circular cross-sections. It should be appreciated that the female mating features of the jaws and the corresponding male mating features in the clip can have various configurations. 
     In some embodiments, jaws of a surgical clip applier have first and second female mating features on upper and lower rails and legs of a surgical clip have corresponding male mating features formed on surfaces facing the jaw&#39;s upper and lower rails.  FIG. 26  shows one embodiment of a jaw  2212  of a surgical clip applier  2200 . As shown, the jaw  2212  has first and second female mating features  2202   a ,  2202   b  in the form of longitudinal recesses formed on upper and lower rails  2201   a ,  2201   b  thereof. A leg of a surgical clip  2207  has corresponding first and second male mating features  2209   a ,  2209   b  in the form of longitudinal protrusions facing the jaw&#39;s female mating features  2202   a ,  2202   b  when the clip  2207  is advanced between the jaw  2212  and the opposed jaw (not shown) of the clip applier  2200 . It should be appreciated that the opposed leg of the clip  2207 , which is not shown in  FIG. 26 , has similar male mating features. In this example, the longitudinal recesses of the jaw have a generally triangular lateral cross-section, and the clip&#39;s longitudinal protrusions  2202   a ,  2202   b  also have a generally triangular lateral cross-section. 
       FIG. 27  shows one embodiment of first and second jaws  2312 ,  2314  of a surgical clip applier  2300  configured to mate with a surgical clip  2307 . In this example, first and second legs  2307   a ,  2307   b  of the clip  2307  have respective small protrusions. Thus, the first leg  2307   a  has first and second longitudinal protrusions  2309   a ,  2309   b  on the opposed surfaces facing upper and lower rails of the first jaw  2312 , and the second leg  2307   b  has third and fourth longitudinal protrusions  2309   c ,  2309   d  on the opposed surfaces facing upper and lower rails of the second jaw  2314 . The protrusions  2309   a ,  2309   b ,  2309   c ,  2309   d  are small such that, while they facilitate engagement of the clip  2307  with the jaws during clip formation, they do not interfere with release of the formed clip from the jaws. The protrusions  2309   a ,  2309   b ,  2309   c ,  2309   d  are shown in  FIG. 27  to be generally semi-circular, though they can have any other shapes, including different shapes. 
       FIG. 28  shows one embodiment of first and second jaws  2412 ,  2414  of a surgical clip applier  2400  configured to mate with a surgical clip  2407 . In this example, first and second legs  2407   a ,  2407   b  of the clip  2407  have respective longitudinal recesses formed in opposed upper and lower surfaces thereof and configured to mate with corresponding longitudinal protrusions formed on upper and lower rails of the jaws. As shown, the first clip leg  2407   a  has first and second recesses  2409   a ,  2409   b  configured to mate with corresponding first and second longitudinal protrusions  2402   a ,  2402   b  on the upper and lower rails of the first jaw  2412 . Similarly, the second clip leg  2407   b  has third and fourth recesses  2409   c ,  2409   d  configured to mate with corresponding third and fourth longitudinal protrusions  2402   c ,  2402   d  on the upper and lower rails of the second jaw  2414 . In this example, the longitudinal recesses  2409   a ,  2409   b ,  2409   c ,  2409   d  of the clip have a generally triangular lateral cross-section, and the jaw&#39;s longitudinal protrusions  2402   a ,  2402   b ,  2402   c ,  2402   d  also have a generally triangular lateral cross-section. 
     In some embodiments, as mentioned above, jaws of a surgical clip applier can be at least partially flexible and bendable such that the jaws can be partially, reversibly deformed when a surgical clip is advanced therebetween. Additionally or alternatively, in some embodiments, a surgical clip can be bendable such that it is deformed when advanced between the jaws, for improved retention by the jaws. The jaws and/or the clip can be tapered not only in an axial or longitudinal directions, but only in a transverse direction, to provide biasing forces without a need for additional biasing elements (e.g., springs). 
       FIG. 29A  shows one embodiment of first and second jaws  2512 ,  2514  of a surgical clip applier  2500  configured to engage with a surgical clip  2507  that is at least partially bendable. Thus, as shown in  FIG. 29A , when the clip  2507  is advanced between the jaws  2512 ,  2514 , first and second legs  2507   a ,  2507   b  of the clip are deformed, such that, in this example, bent outward with respect to sidewalls  2510   a ,  2510   b  of the jaws  2512 ,  2514 . In this embodiment, upper and lower rails of the jaws are angled or tapered inward and towards one another. Thus, for example, upper and lower rails  2511   a ,  2511   b  of the first jaw  2512  are tapered inward and towards one another. In this example, as shown, each of the rails is tapered in the transverse direction such that its width increases in a direction away from a jaw&#39;s sidewall. Thus, the upper rail  2511   a  of the jaw  2512  tapers such that its width increases from its portion adjacent to the sidewall  2510   a  towards the rail&#39;s edge  2513 . Other rails of the jaws of the surgical clip applier  2500  are configured similarly. Such tapering of the jaws in the transverse direction facilitates engagement of the clip by the jaws, without a need for an additional biasing element. The clip  2507  can be press-fit into between the jaws (and between the rails of each of the jaws), to be releasably retained between the jaws. When the clip  2507  is formed, its configuration is changed such that its legs are no longer bent as shown in  FIG. 29A . 
       FIG. 29B  illustrates an embodiment of first and second jaws  2532 ,  2534  of a surgical clip applier  2520 , where the jaws are reversibly deformable and have tapered upper and lower rails. In this embodiment, the first and second jaws  2532 ,  2534  are configured such that their upper and lower rails are angled inward and towards one another, as shown  FIG. 29B . It should be appreciated, however, that in  FIG. 29B , the jaws  2532 ,  2534  are schematically shown as angled more than they are angled in an actual surgical clip applier such as the clip applier  2520 , for illustrated purposes only. Also, it should be noted that the jaw&#39;s rails can be tapered such that their width changes in the transverse direction and/or such that the entire rail is angled in the transverse direction, as shown in  FIG. 29B . The first and second jaws  2532 ,  2534  are configured such that their upper and lower rails are biased towards the clip  2527 . Thus, in this example, the jaws  2532 ,  2534  have an approximately dovetail shape (which is exaggerated in  FIG. 29B , as mentioned above), and a center of gravity of each jaw is below an edge of the jaw, as shown by a reference “C” for the second jaw  2534 . When a surgical clip  2527  is advanced between the jaws  2532 ,  2534 , clip&#39;s first and second legs  2527   a ,  2527   b  are advanced into between upper and lower rails of the respective jaw, and force the upper and lower rails slightly apart to allow to be retained by the jaws. Thus, the first leg  2527   a  is forced between upper and lower rails  2521   a ,  2521   b  of the first jaw  2532 , as shown in  FIG. 29B , and the second legs  2527   b  is similarly engaged by the second jaw  2534 . When the clip is formed, the jaws release it and revert to their original configuration. 
     In embodiments in which jaws of a surgical clip applier are configured as shown in  FIG. 29B  (e.g., upper and lower rails of each jaw are angled inward and toward one another), the jaws retain a surgical clip even in some undesirable circumstances. For example, if the clip is (unintentionally) rotated, the jaws will still retain it properly and release the clip once it is formed.  FIG. 29C  shows an example of a scenario when a clip is rotated, and one leg  2527   a ′ of such clip (schematically shown rotated) is shown engaged by a jaw  2532 ′. 
     Jaws of a surgical clip applier can be in various taper relationships with a surgical clip.  FIGS. 30A to 30D  illustrate examples of surgical clip appliers in various taper relationships with surgical clips. It should be noted that  FIGS. 30A to 30D  show the clip appliers and the clips during an initial stage of a clip formation, when the clip has just been advanced between the jaws and the jaws retain the clip while the jaws are still open. Also, in the examples shown in  FIGS. 30A-30D , the jaws and/or the clip (or a portion thereof, such as clip&#39;s legs) can be at least partially and reversibly deformable. 
       FIG. 30A  shows one embodiment of first and second jaws  2612 ,  2614  of a surgical clip applier  2600 , where the jaws  2612 ,  2614  are substantially parallel to one another. As also shown in  FIG. 30A , a surgical clip  2607 , shown disposed between the jaws  2612 ,  2614 , has its legs configured such that they are disposed at an obtuse angle θc 1  with respect to one another. 
       FIG. 30B  shows another embodiment of first and second jaws  2612 ′,  2614 ′ of a surgical clip applier  2600 ′, where the jaws  2612 ′,  2614 ′ are disposed at an obtuse angle θj 1  with respect to one another. As also shown in  FIG. 30B , a surgical clip  2607 ′, shown disposed between the jaws  2612 ′,  2614 ′, has its legs configured such that they are disposed at an obtuse angle θc 2  with respect to one another, where angle θc 2  is greater than angle θj 1  between the jaws  2612 ′,  2614 ′. 
       FIG. 30C  shows another embodiment of first and second jaws  2612 ″,  2614 ″ of a surgical clip applier  2600 ″, where the jaws  2612 ″,  2614 ″ are disposed at an acute angle θj 2  with respect to one another.  FIG. 30B  also shows a surgical clip  2607 ″, shown disposed between the jaws  2612 ″,  2614 ″, which has its legs configured such that they are disposed substantially parallel to one another. 
       FIG. 30D  shows another embodiment of first and second jaws  2812 ,  2814  of a surgical clip applier  2800 , where the first and second jaws  2812 ,  2814  are proximally tapered, and where a surgical clip  2807  is shown disposed between the jaws, the clip having first and second legs that are also proximally tapered. 
     Various clip retention members and other features that facilitate clip retention and alignment can be formed on at least one jaw of a surgical clip applier having any suitable configuration, such as surgical clip applier  100  ( FIGS. 1 to 4B ), or any other clip applier. The various clip retaining features disclosed herein can have a variety of other configurations, as disclosed in U.S. application Ser. No. 15/674,121, filed on even date herewith and entitled “Jaw For Clip Applier,” which is hereby incorporated by reference in its entirety. Regardless of the specific configuration of the clip applier, the clip retention members maintain the clip in alignment with the jaws and thus help ensure proper formation of the clip. 
       FIGS. 31A and 31B  illustrate one embodiment of a method for applying a surgical clip to tissue using a surgical clip applier  2000  having first and second jaws  2012 ,  2014 . The surgical clip applier  2000  can be similar, for example, to surgical clip applier  100  ( FIGS. 1 to 4B ), or it can have any other configuration. Regardless of its specific configuration, the surgical clip applier  2000  can be used to apply a surgical clip to tissue, such as a vessel, duct, shunt, etc., at a surgical site during a surgical procedure. The surgical clip can be applied in a partially or fully closed configuration. 
     In laparoscopic and endoscopic surgery, a small incision is made in the patient&#39;s body to provide access to a surgical site. A cannula or access port can be used to define a working channel extending from the skin incision to the surgical site. It may be required to cease blood flow through the vessels or other ducts during a surgical procedure, and some procedures may thus require the use of a shunt. A surgical clip can thus be used to crimp the vessel or to secure the shunt to the vessel. 
     Accordingly, a surgical clip applier, such as clip applier  2000 , can be introduced through the cannula or otherwise introduced into the surgical site. The first and second jaws  2012 ,  2014  can be manipulated to position tissue  2001  (e.g., vessel, shunt, or other type of tissue) between the first and second jaws  2012 ,  2014 , as shown in  FIG. 31A . Each of the first and second jaws  2012 ,  2014  can have a respective clip track formed therein that is defined in an inward facing surface of the jaw. The clip track can be, for example, a clip guide channel, such as clip guide channel  206  ( FIG. 5A ), clip guide channel  306  ( FIG. 6 ), or a clip track having any other configuration. In some embodiments, as discussed above in connection with  FIGS. 16 and 17 , the clip track can be a separate element coupled to the jaw. 
     The clip tracks of the first and second jaws  2012 ,  2014  can have disposed therein resilient clip retention members  2002 ,  2004 , respectively, which are shown in a first, uncompressed configuration in  FIG. 31A . The clip retention members  2002 ,  2004  can be any of the clip retention members described herein. The clip retention members  2002 ,  2004  can be formed on one or both of an upper surface, lower surface, and sidewall of the clip guide channel. The clip retention members can be leaf springs, other deformable elements (e.g., elastically deformable elements), or any other types of elements. In some embodiments, at least one of the jaws  2012 ,  2014  can have at least one deflectable tab in the clip track that can prevent proximal movement of the clip within the clip track. In some embodiments, at least one of the jaws  2012 ,  2014  can have features configured to mate with corresponding features of a clip, as shown, e.g., in  FIGS. 23A to 30D . Any other features can be formed on the jaw(s) and the clip to facilitate clip retention by the jaws and maintain alignment of the clip with respect to the jaws. 
     After tissue  2001  is positioned between the first and second jaws  2012 ,  2014  as shown in  FIG. 31A , the clip applier  2000  can be actuated (e.g., using a trigger, such as trigger  106  of clip applier  100  of  FIG. 1 ) to move the first and second jaws  2012 ,  2014  from an open position to a closed position to deform a clip  2007  positioned within the clip tracks formed in the first and second jaws  2012 ,  2014  and thereby engage the tissue  2001  between legs of the clip  2007 . The clip  2007 , schematically shown in a deformed configuration in  FIG. 31B , has been advanced distally and into the jaws  2012 ,  2014  by a clip advancing assembly extending through an elongate shaft  2018  of the clip applier  2000 . The clip retention members  2002 ,  2004  of the first and second jaws  2012 ,  2014 , which are shown in  FIG. 31B  in a second, compressed configuration, each apply a biasing force to the clip  2007  to maintain the clip  2007  in alignment with the jaws  2012 ,  2014  as the jaws  2012 ,  2014  are moved from the open position to the closed position. The trigger can then be released to release the closed clip  2007  (which can be partially or fully closed), and the procedure can be repeated if necessary to apply additional clips that can be disposed in the elongate shaft  2018 . 
     In some cases, after multiple uses of a surgical clip applier having at least one clip retention member on at least one of jaws thereof, the clip retention strength of the clip retention member and/or a portion of the jaw interacting with the clip can decline. This can occur due to degradation of the material over time due to fatigue, or damage incurred by clips, staples, or other hard structures (e.g., by another surgical tool). Accordingly, in some embodiments, techniques are provided that allow “healing” of the clip retention member such that its clip retention strength is restored. For example, at least a portion of a jaw of a surgical clip applier, or a clip retention member, can be formed from a poly(urea-urethane) (PUU) material that has self-healing properties and is thus tolerant to mechanical damage. The PUU material, or any other suitable polymeric self-healing material, has the ability to automatically repair damage to itself without any human intervention. The self-healing materials can fully or partially restore their physical and mechanical properties, which can be done using an external stimulus (e.g., a catalyst), or a damage can be healed spontaneously. In this way, when the clip retention member or any portion of the jaw serving to retain a clip is formed from such a self-healing material, degradation of device performance over time is reduced. In addition, PUU material is a bio-compatible material and is therefore suitable for surgical applications. 
       FIGS. 32 to 34  illustrate one embodiment of first and second jaws  2112 ,  2114  of a surgical clip applier  2100  having respective first and second clip retention members  2102 ,  2104 . In this example, each of the clip retention members  2102 ,  2104  is in the form of a clip track coupled to the respective jaw. A clip track  2106   a  of the first clip retention member  2112  has an upper wall  2108   u , a lower wall  2108   l , and a sidewall  2110  extending between the upper and lower walls  2108   u ,  2108   l . The second clip retention member  2114  is a similar clip track  2106   a . It should be appreciated that the clip retention members  2102 ,  2104  are shown in  FIG. 32  by way of example only, as they can have any suitable shapes and sizes. For example, any of the clip retention members described herein can be used additionally or alternatively. The clip retention members  2102 ,  2104  can be separate members made from a plastic elastomer or other resilient material, and they can be coupled to the jaws  2112 ,  2114  in a suitable manner. 
     In this embodiment, at least a portion of each of the clip retention members  2102 ,  2104  includes a self-healing material such as PUU or other self-healing material. For example, the clip retention members  2102 ,  2104  can be coated with such material such that at least a portion of each clip retention member&#39;s surface facing the opposed jaw is formed from the self-healing material. As another variation, the clip retention members  2102 ,  2104  can be at least partially formed from the self-healing material. Also, in embodiments in which portions of the clip applier&#39;s jaws (e.g., inward facing surfaces of the jaws) serve as clip retention features, those portions of the jaws can be formed from the self-healing material, such as, for example, PUU. 
       FIG. 33  shows an example of how a self-healing material used to form the jaws can alleviate any damage to the jaws when a clip is improperly formed. In this example, after a first clip  2107  is formed around tissue, a second clip  2109  is unintentionally applied over the already formed first clip  2107  (rather than onto the tissue). As shown, the jaws  2112 ,  2114  are positioned over a tissue  2101  with a previously applied clip  2107 . The clip applier  2100  is then activated such that the jaws  2112 ,  2114  are clamped over the tissue  2101  and the clip  2107 , so as to form clip  2109  disposed in the clip tracks  2106   a ,  2106   b  of the jaws  2112 ,  2114 . During firing of clip  2109  over tissue  2101  and clip  2107 , clip  2109  is pushed against the surfaces of the clip retention members  2102 ,  2104  applying a biasing force to the clip  2109 . Thus, damage to the clip retention members  2102 ,  2104  can occur, for example, in the form of damages  2113 ,  2115 ,  2117  to surfaces of the retention members  2102 ,  2104 , as schematically shown in  FIG. 33 . The damaged areas  2113 ,  2115 ,  2117  can be scratched, cracked, fractured, chipped, dented, or otherwise affected by the second clip  2109  being formed over the formed clip  2107  such that structural integrity and therefore performance of the clip retention members is compromised. 
     In the illustrated embodiment, because the clip retention members  2102 ,  2104  are coated with or at least partially made from a PUU or other self-healing material, the damages  2113 ,  2115 ,  2117  to the retention members  2102 ,  2104  can self-heal such that the damaged material returns at least in part to its original (pre-damaged) state.  FIG. 34  illustrates that the damaged areas  2113 ,  2115 ,  2117  (shown in  FIG. 33 ) are restored and thus labeled as locations  2113 ′,  2115 ′,  2117 ′ in  FIG. 34 . In this way, decrease in the clip retention strength of the clip retention members is prevented or eliminated. It should be appreciated that any of the clip retention members described herein, or any other clip retention members, can be at least partially made from or can include PUU or other self-healing material. In this way, damage that may occur to the clip retention members during use, can be repaired. 
     A person skilled in the art will appreciate that the devices, systems, and methods disclosed herein have application in conventional minimally-invasive and open surgical instrumentation as well application in robotic-assisted surgery. In some embodiments, the devices, systems, and methods described herein are provided for open surgical procedures, and in other embodiments, the devices, systems, and methods are provided for laparoscopic, endoscopic, and other minimally invasive surgical procedures. The devices may be fired directly by a human user or remotely under the direct control of a robot or similar manipulation tool. However, a person skilled in the art will appreciate that the various methods, systems, and devices disclosed herein can be used in numerous surgical procedures and applications. Those skilled in the art will further appreciate that the various instruments disclosed herein can be inserted into a body in any way, such as through a natural orifice, through an incision or puncture hole formed in tissue, or through an access device, such as a trocar cannula. For example, the working portions or end effector portions of the instruments can be inserted directly into a patient&#39;s body or can be inserted through an access device that has a working channel through which the end effector and elongated shaft of a surgical instrument can be advanced. 
     The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the device can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces and subsequent reassembly. In particular, the device can be disassembled, and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the device can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application. 
     One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.