Patent Publication Number: US-9414844-B2

Title: Surgical clip appliers

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation Application claiming the benefit of and priority to U.S. patent application Ser. No. 12/976,120, filed on Dec. 22, 2010 (now abandoned), which claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 61/306,174, filed on Feb. 19, 2010, the entire contents of each of which are incorporated herein by reference. 
     The present application is also a Continuation-in-Part Application claiming the benefit of and priority to U.S. patent application Ser. No. 13/890,580, filed on May 9, 2013, which is a Divisional Application claiming the benefit of and priority to U.S. patent application Ser. No. 12/540,475, filed on Aug. 13, 2009 (now U.S. Pat. No. 8,465,502), which claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 61/091,467, filed on Aug. 25, 2008, the entire contents of each of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present application relates to surgical instruments, and more particularly, to surgical clip appliers having a plurality of clips for applying the clips to body tissues and vessels during surgical procedures. 
     2. Discussion of Related Art 
     Surgical clip appliers are known in the art and have increased in popularity among surgeons by offering an alternative to conventional suturing of body tissues and vessels. Typical instruments are disclosed in U.S. Pat. No. 5,030,226 to Green et al. and U.S. Pat. No. 5,431,668 to Burbank III et al. These instruments generally provide a plurality of clips which are stored in the instrument and which are fed sequentially to the jaw mechanism at the distal end of the instrument upon opening and closing of the handles at the proximal end of the instrument. As the handles are closed, the jaws close to deform a clip positioned between the jaw members, and as the jaws are opened to release the deformed clip, a new clip is fed from the series to a position between the jaws. This process is repeated until all the clips in the series of clips have been applied. 
     Typically, the surgical clip applier is removed from a surgical site after the last clip has been applied to body tissue. Afterwards, the surgical clip applier is either replaced with a replacement surgical clip applier or the existing surgical clip applier is refilled with replacement surgical clips. However, in certain situations, when the same surgical clip applier is mistakenly used after the last clip has been applied, the jaw members of the surgical clip applier may unwantedly grasp body tissue at the surgical site. As a result, the body tissue may be damaged, which sometimes causes trauma to the patient. 
     The need therefore exists for a surgical clip applier that is configured to lock out the handles after the last clip has been applied. 
     SUMMARY 
     The present disclosure relates to surgical clip appliers having a plurality of clips for applying the clips to body tissues and vessels during surgical procedures. 
     According to an aspect of the present disclosure, a surgical clip applier is provided which includes a housing; at least one handle pivotably connected to the housing; a channel assembly extending distally from the housing; a clip carrier disposed within the channel assembly and defining a channel and a plurality of windows therein; a plurality of clips slidably disposed within the channel of the clip carrier; a wedge plate reciprocally disposed within the channel assembly; and a clip pusher bar reciprocally positioned within the housing and the channel assembly. The pusher bar has a proximal end operatively connected to at least one handle and a distal end defining a pusher. The distal end of the pusher bar is configured for engagement with a distal-most clip of the plurality of clips. A clip follower is slidably disposed within the channel of the clip carrier and disposed proximally of the plurality of clips. The clip follower is configured and dimensioned to lockout the clip applier after a last clip of the plurality of clips has been expelled by the surgical clip applier. 
     The clip applier may further include a jaw assembly that has a pair of jaws extending from an end of the channel assembly, opposite the housing. The jaw assembly is adapted to accommodate a clip therein and is operable to effect formation of a clip in response to movement of the at least one handle. The pusher bar may be movable towards the jaws as the at least one handle is approximated in a first direction in order to move a distal-most clip between the jaws. The pusher bar may be configured and adapted to move towards the housing as the at least one handle is further approximated in the first direction to move the pusher behind a distal-most clip in the plurality of clips. 
     In embodiments, the clip follower may include a window formed in a body portion thereof. Upon the at least one handle being further actuated, the distal end of the pusher tip is disposed within the window of the clip follower. The clip follower may be disposed within a distal end of clip channel and a down force of at least one resilient tang of the clip carrier facilitates retaining the clip follower at the distal end of the clip channel. 
     In embodiments, upon the at least one handle being further actuated, the clip pusher engages a distal end of the window of the clip follower and distally urges the clip follower to move in between the jaws. The jaws are approximated toward one another and the clip follower is urged therebetween thereby preventing the jaws from closing. Upon the at least one handle being further actuated, a ratchet mechanism is partially engaged thereby locking the at least one handle at a position. 
     The clip follower may be configured to lock the at least one handle after a last clip of the plurality of clips has been expelled. Upon the at least one handle being released from an actuated position, the pusher bar returns to a proximal position and, at a substantially same time, the clip follower is advanced distally within the clip carrier. Upon a release of the at least one handle from an actuated position, the clip pusher retracts proximally to a proximal position. 
     In embodiments, the clip follower may define at least one notch along each side thereof. The at least one notch is configured to facilitate bending of the clip follower in a direction transverse to a plane defined by a body portion thereof. The clip follower may also be configured and adapted for selective engagement with the windows of the clip carrier and the apertures of the wedge plate. The clip follower may be configured and adapted to urge the plurality of clips, in a distal direction relative to the clip carrier, upon reciprocal movement of the wedge plate. The clip follower may be actuated by the reciprocating forward and backward motion of a wedge plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present clip applier will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the following drawings, in which: 
         FIG. 1  is a perspective view of a surgical clip applier according to an embodiment of the present disclosure; 
         FIG. 2  is a rear, perspective view of the surgical clip applier of  FIG. 1 , shown with a shipping wedge in position; 
         FIG. 3  is an exploded perspective view of the surgical clip applier of  FIGS. 1-2 ; 
         FIG. 4  is a top, perspective view of a clip follower of the surgical clip applier of  FIGS. 1-3 ; 
         FIG. 4A  is an exploded perspective view of a bell crank gear and accelerator rack assembly of the surgical clip applier of  FIGS. 1-3 ; 
         FIG. 4B  is a perspective view of the accelerator rack of the surgical clip applier of  FIGS. 1-3 ; 
         FIG. 4C  is a perspective view of the bell crank gear of the surgical clip applier of  FIGS. 1-3 ; 
         FIG. 4D  is a top, perspective view of a pivot arm of the surgical clip applier of  FIGS. 1-3 ; 
         FIG. 4E  is a bottom, perspective view of the pivot arm of  FIG. 4D ; 
         FIG. 5  is a longitudinal cross-sectional view of the surgical clip applier of  FIGS. 1-3 , illustrating the surgical clip applier in an unactuated condition; 
         FIG. 6  is an enlarged view of the indicated area of detail of  FIG. 5 ; 
         FIG. 7  is an enlarged view of the indicated area of detail of  FIG. 5 ; 
         FIG. 8  is an enlarged view of the indicated area of detail of  FIG. 5 ; 
         FIG. 8A  is a cross-sectional view of the surgical clip applier of  FIGS. 1-3 , as taken through  8 A- 8 A of  FIG. 8 ; 
         FIG. 9  is a top, perspective view of a distal end of a channel assembly of the surgical clip applier of  FIGS. 1-3 , with a cover removed therefrom; 
         FIG. 10  is a top, perspective view of a distal end of the channel assembly of  FIG. 9 , with the cover and the pusher bar removed therefrom; 
         FIG. 11  is a top, perspective view of a distal end of the channel assembly of  FIG. 9 , with the cover, the pusher bar and a clip carrier removed therefrom; 
         FIG. 12  is a top, perspective view of a distal end of the channel assembly of  FIG. 9 , with the cover, the pusher bar, the clip carrier, the surgical clips and the clip follower removed therefrom; 
         FIG. 13  is an enlarged view of the indicated area of detail of  FIG. 12 ; 
         FIG. 14  is a top, perspective view of the surgical clip applier of  FIGS. 1-3 , illustrated with the upper housing half, the pusher bar and a wedge plate removed therefrom; 
         FIG. 15  is a top, perspective view of a distal end of the channel assembly of  FIG. 9 , with the cover, the pusher bar, the clip carrier, the surgical clips, the clip follower and the wedge plate removed therefrom; 
         FIG. 16  is a longitudinal, cross-sectional view of the distal end of the channel assembly illustrating the surgical clip applier of  FIGS. 1-3  in a locked-out condition following firing of the last surgical clip therefrom; 
         FIG. 17  is a top, perspective view of another embodiment of a clip follower, according to the present disclosure, for use with the surgical clip applier of  FIGS. 1-16 ; 
         FIG. 18  is a top, perspective view of the distal end of a channel assembly of the surgical clip applier of  FIGS. 1-16 , illustrating a pair of retainer tangs retaining a last surgical clip; 
         FIG. 19  is a top, perspective view of the distal end of the channel assembly of the surgical clip applier of  FIGS. 1-16 , illustrating the clip follower of  FIG. 17  at a distal position in the channel assembly; 
         FIG. 20  is a top, perspective view of the distal end of the channel assembly of the surgical clip applier of  FIGS. 1-16 , illustrating with the clip follower disposed and/or advanced between a pair of jaw members; 
         FIG. 21  is a top, perspective view of the distal end of the channel assembly of the surgical clip applier of  FIGS. 1-16 , illustrating the pusher bar being retracted in a proximal direction; and 
         FIG. 22  is a top, perspective view of a clip follower of  FIG. 18  according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of surgical clip appliers in accordance with the present disclosure will now be described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical structural elements. As shown in the drawings and described throughout the following description, as is traditional when referring to relative positioning on a surgical instrument, the term “proximal” refers to the end of the apparatus which is closer to the user and the term “distal” refers to the end of the apparatus which is further away from the user. 
       FIGS. 1-5  illustrate a surgical clip applier in accordance with an embodiment of the present disclosure and is generally designated as  100 . Reference may be made to U.S. Pat. No. 8,465,502, filed on Aug. 13, 2009, entitled “Surgical Clip Applier” and U.S. Pat. No. 8,056,565, filed on Aug. 11, 2009, entitled “Surgical Clip Applier and Method of Assembly,” the entire contents of each of which being incorporated herein by reference, for a detailed discussion of the structure, operation, and method of assembly of surgical clip applier  100 . 
     Briefly, surgical clip applier  100  is a surgical instrument including a handle assembly  102  including a housing  104  having an upper housing half  104   a  and lower housing half  104   b . Handle assembly  102  further includes a pair of handles  106  pivotably secured to housing  104  and extending outwardly therefrom. A channel assembly  108  is fixedly secured to housing  104  and extends outwardly therefrom, terminating in a jaw assembly  110 . 
     As seen in  FIGS. 1-3 , housing halves  104   a  and  104   b  of clip applier  100  fit together by snap fit engagement with one another. Housing  104  defines a window  104   c  formed in lower housing half  104   b  for supporting and displaying a counter mechanism  190 . Housing  104  is formed of a suitable plastic material. 
     As seen in  FIG. 3 , handles  106  are secured to housing  104  by handle pivot posts  104   d  extending from lower housing half  104   b  and into respective apertures  106   a  formed in handles  106 . Handle assembly  102  includes a link member  122  pivotally connected to each handle  106  at a pivot point  106   b  formed in a respective handle  106 . A distal end  122   a  of each link member  122  is pivotally connected to a pivot point  140   a  formed in a drive channel  140  via a drive pin  124 . Each end of drive pin  124  is slidably received in an elongate channel  104   e  formed in a respective upper and lower housing half  104   a ,  104   b . In use, as handles  106  are squeezed, link members  122  push drive channel  140  distally via drive pin  124 . 
     Channel assembly  108  includes a channel or cartridge cover  130  and an outer or lower channel  132  each having a proximal end retained in housing assembly  102 , between upper and lower housing halves  104   a ,  104   b . Cartridge cover  130  includes at least one retention element  130   a  configured and adapted to selectively engage, in a snap-fit engagement, a complementary or corresponding retention element  132   a  provided on outer channel  132 . 
     As seen in  FIGS. 3 and 6-9 , clip applier  100  includes a clip pusher bar  160  slidably disposed beneath cartridge cover  130 . Pusher bar  160  includes a distal end  160   a  defining a pusher  160   c  configured and adapted to selectively engage/move a distal-most clip “C 1 ” stored in surgical clip applier  100 . Pusher bar  160  further includes a proximal end  160   b  defining a proximal window  160   d  therein for slidably receiving drive pin  124  therein. Pusher bar  160  further defines a distal window  160   e  therein for operative engagement with a stabilizer  162 . Pusher bar  160  also includes a fin  160   f  projecting from a side edge thereof and located in relative close proximity to proximal window  160   d.    
     Clip applier  100  further includes a stabilizer  162  configured to overlie and engage pusher bar  160 . Stabilizer  162  includes a distal tab  162   a  configured to engage distal window  160   e  of pusher bar  160 , an elongate window  162   b  defined therein at a location to substantially overlie and be in registration with proximal window  160   d  formed in pusher bar  160 . For a more detailed discussion of stabilizer  162 , please refer to commonly owned U.S. Pat. Nos. 8,465,502 and 8,056,565, the entire contents of each of which incorporated by reference above. 
     As seen in  FIGS. 3 and 4A-4C , clip applier  100  further includes a motion multiplier system having a bell crank gear  154  pivotally supported in housing  104  and an accelerator housing  156  slidably supported in housing  104 . Bell crank gear  154  includes a pivot pin  154   a  configured for pivotable connection to housing  104 , a disk-like body  154   b  supported on pivot pin  154   a , an arm  154   c  extending radially from disk-like body  154   b , and a spur gear  154   d  supported on pivot pin  154   a  or integrally formed therewith and located adjacent disk-like body  154   b . Bell crank gear  154  defines a longitudinally oriented slot  154   f  formed in arm  154   c . Spur gear  154   d  of bell crank  154  defines a plurality of gear teeth  154   g  formed in a side edge thereof and may be a sector gear as best shown in  FIG. 4C . For a more detailed discussion of bell crank gear  154 , please refer to commonly owned U.S. Pat. Nos. 8,465,502 and 8,056,565, the entire contents of each of which incorporated by reference above. 
     With continued reference to  FIGS. 3 and 4A-4C , accelerator rack  156  of motion multiplier system includes a base wall  156   a  defining an elongate, longitudinally extending slot  156   b  formed therein, for slidable receipt of pivot pin  154   a  of bell crank gear  154 . Accelerator rack  156  includes a side wall  156   c  projecting in opposite directions from a side edge of base wall  156   a , and a gear rack  156   d  formed in side wall  156   c  and in registration or alignment with slot  156   b  of base wall  156   a . Gear rack  156   d  is configured for engagement with gear teeth  154   g  of spur gear  154   d  of bell crank gear  154 . 
     Clip applier  100  further includes a biasing member  158  interconnecting accelerator rack  156  and drive channel  140 . 
     Clip applier  100  further includes a clip carrier  170  disposed within channel assembly  108  and beneath pusher bar  160 . Clip carrier  170  is generally a box-like structure having an upper wall  170   a , a pair of side walls  170   b  ( FIG. 8A ) and a lower wall  170   c  ( FIG. 8A ) defining a channel  170   d  ( FIG. 8A ) therethrough. Clip carrier  170  includes a plurality of spaced apart windows  172  formed in upper wall  170   a  and extending longitudinally along a length thereof. Clip carrier  170  includes an elongate window  170   e  ( FIG. 8A ) formed in lower wall  170   c  ( FIG. 8A ) and extending longitudinally along a length thereof. 
     As seen in  FIGS. 3 and 10 , a stack of surgical clips “C” is loaded and/or retained within channel  170   d  of clip carrier  170  in a manner so as to slide therewithin and/or therealong. Channel  170   d  is configured and dimensioned to slidably retain a stack or plurality of surgical clips “C” in tip-to-tail fashion therewithin. 
     As seen in  FIGS. 3, 9, and 10 , a distal end of clip carrier  170  includes a pair of spaced apart, resilient tangs  171 . Tangs  171  are configured and adapted to selectively engage a backspan of a distal-most surgical clip “C 1 ” of the stack of surgical clips “C” retained within carrier  170 . 
     As seen in  FIGS. 3, 4, 7, and 11 , clip applier  100  further includes a clip follower  174  slidably disposed within channel  170   d  of clip carrier  170 . As will be discussed in greater detail below, clip follower  174  is positioned behind the stack of surgical clips “C” and is provided to urge the stack of clips “C” forward during an actuation of clip applier  100 . As will be described in greater detail below, clip follower  174  is actuated by the reciprocating forward and backward motion of wedge plate  180 . 
     As seen in  FIGS. 4 and 7 , clip follower  174  includes body portion  174   a  defining a plane, a distal tab  175  extending substantially upwardly and rearwardly from body portion  174   a,  and a proximal tab  176  extending substantially downwardly and rearwardly from body portion  174   a . Distal tab  175  includes a distal portion  175   a  extending downwardly below the plane defined by body portion  174   a  and a proximal portion  175   b  extending upwardly above the plane defined by body portion  174   a.    
     Proximal portion  175   b  of distal tab  175  is configured and dimensioned to selectively engage windows  172  formed in upper wall  170   a  of clip carrier  170 . In use, engagement of proximal portion  175   b  of distal tab  175  of clip follower  174  in a window  172  formed in upper wall  170   a  of clip carrier  170  prevents clip follower from traveling or moving in a proximal direction. 
     Proximal tab  176  is configured and dimensioned to selectively engage windows  180   b  formed in wedge plate  180 . In use, engagement of proximal tab  176  of clip follower  174  in a window  180   b  formed in wedge plate  180  allows for clip follower  174  to be advanced or moved distally upon a distal movement of wedge plate  180 . 
     As seen in  FIGS. 3, 7, 8, 12, and 13 , clip applier  100  further includes a wedge plate  180  slidably disposed within handle assembly  102  and channel assembly  108 . Wedge plate  180  is positioned or disposed below clip carrier  170 . Wedge plate  180  includes a substantially tapered distal end  180   a  for selective operative interposition between jaws  120 . Wedge plate  180  defines a plurality of spaced apart windows or apertures  180   b  extending longitudinally along a length thereof and formed in a raised section thereof, a distal window or aperture  180   c  located distal of apertures  180   b , and a proximal-most transversely oriented slot  180   d  located proximal of aperture  180   c.    
     As seen in  FIGS. 3, 8, 12, and 13 , clip applier  100  includes a distal lockout  178  supported by cartridge cover  130 . Distal lockout  178  includes a tail or tab  178   a  extending substantially rearwardly and downwardly and being configured and dimensioned for receipt in distal window or aperture  180   c  of wedge plate  180 . 
     As seen in  FIGS. 3, 4D, 4E, 6, and 14 , clip applier  100  includes a wedge plate motion reversing mechanism, in the form of a pivot arm  179 , pivotally supported in lower housing half  104   b  of housing  104  for transmitting the translation of drive channel  140  to a reverse translation of wedge plate  180 . 
     In use, as drive channel  140  is moved distally, after a dwell period (i.e., the length of the longitudinally extending distal portion of slot  140   g  of drive channel  140 ), second stem or finger  179   c  is moved in a distal direction, rotating pivot arm  179  and thereby moving first stem or finger  179   b  in a second direction. As first stem or finger  179   b  is moved in the second direction, first stem or finger  179   b  pulls wedge plate  180  out from between jaws  120  urges against as well as urges or pushes proximally against fin  160   f  of pusher  160  to move pusher  160  in a proximal direction so that pusher bar  160   c  thereof is removed from between jaws  120 , and vice-versa. As wedge plate  180  is moved in a distal direction, as seen n  FIG. 13 , distal end  180   a  of wedge plate  180  cams against an inner surface of jaws  120  to thereby maintain jaws  120  spaced apart from one another. 
     As seen in  FIGS. 3, 6-8, 14, and 15 , clip applier  100  includes a drive channel  140  reciprocally supported in and extending between housing  104  of handle assembly  102  and channel assembly  108 . A proximal end of drive channel  140  is supported between upper and lower housing halves  104   a ,  104   b  of housing  104  and a distal end of drive channel  140  is supported between cartridge cover  130  and outer channel  132  of channel assembly  108 , at a location below wedge plate  180 . 
     A distal end of drive channel  140  is a substantially U-shaped channel including a pair of spaced apart side walls  140   b  extending from a backspan  140   c  thereof, in a direction away from outer channel  132  and toward cartridge cover  130 . Drive channel  140  further defines a drive pin recess  140   a  formed in backspan  140   c  for pivotally receiving drive pin  124  therethrough. Drive channel  140  further defines a rib  140   e  projecting from backspan  140   c  at a location distal of drive pin recess  140   a . Drive channel  140  further defines a reciprocation limiting slot  140   f  formed in backspan  140   c  at a location distal of slot  140   e.    
     As seen in  FIGS. 3, 8-12, and 15 , clip applier  100  includes a drive channel strap  143  secured to drive channel  140 . Strap  143  is secured to uprights  140   b  of drive channel  140  so as to extend transversely thereacross. Strap  143  is secured to drive channel  140  at a location distal of reciprocation limiting slot  140   f . Strap  143  is secured to drive channel  140  such that wedge plate  180  extends beneath strap  143  and above jaws  120 . 
     As seen in  FIGS. 3 and 6 , clip applier  100  further includes an audible/tactile indicator  148  connected to drive channel  140  via drive pin  124 . Indicator  148  includes a resilient finger  148   a  and a pair of bosses  148   b . In use, as clip applier  100  is actuated and drive channel  140  is reciprocated, first resilient finger  148   a  of indicator  148  interacts with corresponding complementary structure or ledge (not explicitly shown) provided in clip applier  100  to create an audible and/or a tactile feedback to the user. Bosses  148   b  of indicator  148  ride within channel  104   e  formed in upper housing half  104   a  and provide support to indicator  148  to prevent indicator  148  from rotating. 
     As seen in  FIGS. 3, 6, and 14 , clip applier  100  further includes a biasing member  146 , in the form of a tension spring, operatively secured to and between a proximal end of drive channel  140  and housing  104 , tending to maintain drive channel  140  in a retracted or proximal-most position. Biasing member  146  functions to retract or facilitate retraction of drive channel  140  following formation of a clip “C” positioned between jaws  120 . 
     As seen in  FIGS. 3 and 14 , a proximal end of drive channel  140  includes a ratchet rack member  141  secured to drive pin  124  and movable with drive channel  140 . Ratchet rack member  141  is configured and adapted to engage with a ratchet pawl  142  supported in housing  104 . Rack member  141  and pawl  142  define a ratchet mechanism  144 . In use, as drive channel  140  is moved axially, rack member  141  is also moved. Rack member  141  defines a series of rack teeth  141   a  having a length which allows pawl  142  to reverse and advance back over rack member  141  when rack member  141  changes between proximal and distal movement as drive channel  140  reaches a proximal-most or distal-most position. 
     Pawl  142  is pivotally connected to lower housing half  104   b  by a pawl pin  147  at a location wherein pawl  142  is in substantial operative engagement with rack member  141 . Pawl  142  is engageable with rack member  141  to restrict longitudinal movement of rack member  141  and, in turn, drive channel  140 . Ratchet mechanism  144  further includes a pawl spring  145  configured and positioned to bias pawl  142  into operative engagement with rack member  141 . Pawl spring  145  functions to maintain the teeth of pawl  142  in engagement with the teeth  141   a  of rack member  141 , as well as to maintain pawl  142  in a rotated or canted position. 
     As seen in  FIGS. 1-3, 8-13, and 15 , clip applier  100  includes a pair of jaws  120  mounted on or at a distal end of channel assembly  108  and actuatable by handles  106  of handle assembly  102 . Jaws  120  are formed of a suitable biocompatible material such as, for example, stainless steel or titanium. 
     Jaws  120  are mounted in a distal end of drive channel  140  via a rivet  122  or the like extending through reciprocation limiting slot  140   f  of drive channel  140  such that jaws  120  are longitudinally stationary relative to outer channel  132  and drive channel  140 . As seen in  FIGS. 9, 10, 13, and 15 , jaws  120  define a channel  120   a  therebetween for receipt of a surgical clip “C 1 ” therein. 
     As seen in  FIGS. 1-3, and 6 , clip applier  100  further includes a counter mechanism  190  supported in housing  104  of handle assembly  102 . Counter mechanism  190  includes a display  192 , a processor  194 , and an energy source  198  in the form of a battery or the like. Display  192  is a liquid crystal display that displays one or more operating parameters of clip applier  100  to the surgeon. The operating parameter displayed may be an amount or number of remaining clips, a number of clips that have been used, a position parameter, a surgical time of usage, or any other parameter of the procedure. For a more detailed discussion of counter mechanism  190 , please refer to commonly owned U.S. Pat. Nos. 8,465,502 and 8,056,565, the entire contents of each of which incorporated by reference above. 
     As seen in  FIG. 2 , clip applier  100  includes a shipping wedge  200  supported on housing  104  and interposed between handles  106 . Shipping wedge  200  functions to maintain handles  106  spaced apart or un-squeezed during a shipment and/or storage of clip applier  100 . Shipping wedge  200  is connected to tab  192   a  of counter mechanism  190 , such that in order for an end user to use clip applier  100 , the end user must remove shipping wedge  200  thereby also removing tab  192   a  to activate counter mechanism  190 . For a more detailed discussion of shipping wedge  200 , please refer to commonly owned U.S. Pat. Nos. 8,465,502 and 8,056,565, the entire contents of each of which incorporated by reference above. 
     Turning now to  FIG. 16 , a distal end of clip applier  100  is illustrated following a complete stroke or squeezing of handles  106  and after a final clip has been expelled therefrom. Following firing of the last clip, as seen in  FIG. 16 , proximal tab  176  of clip follower is disposed within a distal-most aperture or window of apertures  180   b  of wedge plate  180 . In this manner, as wedge plate  180  is moved distally following a firing of a clip, in the manner described above, clip follower  174  is also moved distally. Accordingly, as clip follower  174  is moved distally, distal tab  175  thereof is moved distal of a distal-most window of windows  172  of clip carrier  170 . In this manner, proximal portion  175   b  of distal tab  175  engages against an inner surface of a top wall of clip carrier  170  and is cammed or urged downwardly. 
     As proximal portion  175   b  of distal tab  175  is cammed or urged downwardly, distal portion  175   a  of distal tab  175  engages against an upper surface of tab  178   a  of lockout  178  and cams or urges tab  178   a  of lockout  178  downwardly, across a path of strap  143 , supported on drive channel  140 , and into distal window  180   c  of wedge plate  180 . In this manner, if drive channel  140  is advanced distally, in the manner described above, strap  143  will abut against tab  178   a  of lockout  178  and prevent or block strap  143  and, in turn, drive channel  140  from moving distally. At this stage, pawl  142  is located in a dwell, distal of rack  140   d , and handles  106  are arranged in a fully opened position and are thus not capable of being opened any further. In this configuration, clip applier is locked-out and can no longer be used. 
     Referring now to  FIGS. 17-22 , a surgical clip applier, in accordance with an embodiment of the present disclosure, is generally designated as  300 . Surgical clip applier  300  is substantially identical to surgical clip applier  100  and thus will only be discussed in detail herein to the extent necessary to identify differences in construction and operation thereof. 
     As seen in  FIGS. 18-21 , clip applier  300  includes a clip follower  374  slidably disposed within channel  370   d  of clip carrier  370 . Clip follower  374  is positioned behind the stack of surgical clips “C” and is provided to urge the stack of clips “C” forward during an actuation of clip applier  300 , in a manner similar to clip follower  174  described above. Clip follower  374  is actuated by the reciprocating forward and backward motion of wedge plate (not shown), as shown in  FIGS. 3, 5, 6, and 8-10  with regard to clip follower  174 . In this embodiment, as will be described further below, clip follower  374  is also configured to lock clip applier  300  after a last clip “C L ” has been expelled. 
     As seen in  FIGS. 17 and 22 , clip follower  374  includes body portion  374   a  defining a plane, a distal tab  375  extending substantially upwardly and rearwardly from body portion  374   a , a proximal tab  376  extending substantially downwardly and rearwardly from body portion  374   a , and a slot or window  377  formed on a distal portion  374   b  of body portion  374   a.  Distal tab  375  includes a distal portion  375   a  extending downwardly below the plane defined by body portion  374   a  and a proximal portion  375   b  extending upwardly above the plane defined by body portion  374   a.    
     Proximal portion  375   b  of distal tab  375  is configured and dimensioned to selectively engage windows formed in an upper wall of clip carrier  370 , as discussed above with regard to clip carrier  170 . In use, engagement of proximal portion  375   b  of distal tab  375  of clip follower  374  in a window formed in upper wall of clip carrier  370  prevents clip follower from traveling or moving in a proximal direction. 
     Proximal tab  376  is configured and dimensioned to selectively engage windows formed in a wedge plate (not shown). In use, engagement of proximal tab  376  of clip follower  374  in a window formed in the wedge plate allows for clip follower  374  to be advanced or moved distally upon a distal movement of the wedge plate, as discussed above with regard to wedge plate  180 . 
     As discussed above, clip follower  374  is configured and dimensioned to lockout clip applier  300  after a last clip “C L ” has been expelled. That is, when surgical clip applier  300  has one last clip “C L ” left in the clip channel  370 , the follower  374  abuts the last clip “C L ” and the distal end  360   c  of pusher bar  360  advances the last clip “C L ” into the jaws  320  when the handles  306  are selectively squeezed. 
     In this configuration, when the handles (not shown) are selectively squeezed (i.e., actuated) the last clip “C L ” is expelled from the clip applier  300  to the body tissue. Afterwards, the handles are released and the pusher bar  360  returns to a proximal “home” position, as described above, with regard to clip applier  100 . At substantially the same time, the clip follower  374  is advanced distally within the clip carrier  370  by the wedge plate, as described above. In this configuration, the distal end  360   c  of pusher tip  360  is disposed within window  377  of clip follower  374 . In this configuration of clip applier  300 , clip follower  374  is disposed within the distal end of clip channel  370 . It is contemplated that a down force of resilient tangs  371  may also facilitate retention of clip follower  374  at the distal end of the clip channel  370 . 
     When the handles are squeezed for a second time, distal end  360   c  of clip pusher  360  engages a distal end of window  377  of clip follower  374  and distally urges (i.e., moves) at least a distal end of clip follower  374  in between jaws  320 . At substantially the same time, while the handles are squeezed the strap  343  and drive channel  340  engage an outer surface (i.e., side surface) of jaws  320 . 
     As seen in  FIG. 20 , as drive channel  340  is moved distally, a distal edge of drive channel  340  and/or drive channel strap  343  engages against camming surfaces  320   b  of jaws  320 . In this manner, jaws  320  are approximated toward one another and frictionally contain clip follower  374  therebetween. Since drive channel strap  343  is fixed to drive channel  340  and moves therewith, drive channel strap  343  functions to cap drive channel  340  so as to maintain jaws  320  within drive channel  340  during the approximation of jaws  320  and to maintain the wedge plate within drive channel  340  during operation of clip applier  300 . Then, when the handles are released, clip pusher  360  retracts proximally to the proximal “home” position, as described above. 
       FIG. 22  illustrates the clip follower  374  in a locked-out position when the handles are squeezed for a third time. In this configuration, the ratchet mechanism  144  (as shown in  FIG. 14 ) engages to a certain point and the handles stop substantially half way through a stroke thereof and are thus locked in place. As so configured, jaws  320  are prevented from re-closing, since clip follower  374  is disposed between jaws  320 . In this configuration, clip applier  300  is in a locked-out configuration. 
     In one embodiment, as seen in  FIG. 22 , one or more notches  378  are formed along a side edge of clip follower  374 . Notches  378  facilitate a bending of clip follower  374 , in a direction transverse to the plane of body portion  374   a , when clip follower  374  is wedged or cammed between jaws  320 . In this manner, clip follower  374  may more easily conform to the bend or contour of jaws  320 , as described above. In another embodiment, the clip follower may be manufactured to have a distinguishable color (e.g., red, orange, yellow, green, blue, etc.) from the other components of the clip applier  300 . In this manner, the colored clip follower  374  may indicate to the user that clip applier  300  is in a locked-out state. 
     It should be understood that the foregoing description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications and variances. The embodiments described with reference to the attached drawing figures are presented only to demonstrate certain examples of the disclosure. Other elements, steps, methods and techniques that are insubstantially different from those described above and/or in the appended claims are also intended to be within the scope of the disclosure.