Abstract:
An apparatus comprising a plurality of chambers for receiving an associated plurality of staples, each formed with a shape memory that allows the staple to adopt a straightened configuration, when placed in a stapler, and a deployed configuration for suturing when released from the stapler; and a sleeve moveable relative to the chambers between a first position, in which the staples are trapped by the sleeve within the chambers in the straightened configuration, and a second position, whereby the staples are freed to adopt the deployed configuration, wherein the sleeve is adapted to move between the first and second positions by rotating relative to the chambers.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional patent application Ser. No. 61/162,462, filed 23 Mar. 2009, and is a continuation-in-part of International Application no. PCT/AU2008/000623, filed 2 May 2008, which claims priority to Australian provisional patent application no. 2007902314, filed 2 May 2007, the entire disclosure of each of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The described embodiments relate generally to methods and devices for delivering shape-memory staples. According to some embodiments, the delivered shape-memory staples can be used for securing a graft to another body. 
     BACKGROUND 
     In some types of surgery, it can be advantageous to use staples to affix tissue or grafts to other tissues or grafts. Such staples can serve to keep the tissues and/or grafts together while the body heals or undergoes treatment. 
     Not all medical stapling devices are effective or optimal for each situation in which deployment of staples may be necessary or desirable. 
     The described embodiments address or ameliorate one or more shortcomings or disadvantages associated with previous devices and/or methods for delivering shape-memory staples or at least provide a useful alternative thereto. 
     SUMMARY 
     Some embodiments relate to an apparatus comprising: 
     a plurality of chambers for receiving an associated plurality of staples, each formed with a shape memory that allows the staple to adopt a straightened configuration, when placed in a stapler, and a deployed configuration for suturing when released from the stapler; and 
     a sleeve moveable relative to the chambers between a first position, in which the staples are trapped by the sleeve within the chambers in the straightened configuration, and a second position, whereby the staples are freed to adopt the deployed configuration, wherein the sleeve is adapted to move between the first and second positions by rotating relative to the chambers. 
     Some embodiments relate to a device for delivering shape-memory staples, the device comprising: 
     a handle formed as a pistol grip; 
     a trigger actuator coupled to the handle; 
     a drive mechanism coupled to the trigger actuator and the handle; and 
     a delivery portion coupled to the drive mechanism, the delivery portion comprising retention walls for retaining the staples within the delivery portion in an elastically deformed configuration and release apertures for releasing the staples to adopt a deployed configuration based on their shape memory, wherein the delivery portion is configured to cause one end of each staple to protrude from the delivery portion in response to actuation of the trigger actuator. 
     Some embodiments relate to a device for delivering shape memory staples, the device comprising: 
     a grippable portion; 
     a delivery portion coupled to the grippable portion, the delivery portion comprising retention walls for retaining the staples within the delivery portion in an elastically deformed configuration and release apertures for releasing the staples to adopt a deployed configuration based on their shape memory, wherein the delivery portion is configured to cause one end of each staple to protrude from the delivery portion in response to actuation of the first actuator; and 
     a head portion positioned at a tip of the delivery portion, the head portion being retractable in a proximal direction to cause the tip to flare outwardly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments are described hereinafter in further detail and by way of example, the detailed description of which should be read in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a device for delivering shape-memory staples; 
         FIG. 2A  is an exploded perspective view of the device of  FIG. 1 , showing a proximal drive mechanism in further detail; 
         FIG. 2B  is an exploded perspective view of part of an actuation mechanism of the device of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of the device of  FIG. 1 , showing a striking mechanism in further detail. 
         FIG. 4  is an exploded perspective view of the device of  FIG. 1 , showing a head retraction actuator and barrel in further detail; 
         FIG. 5  is an exploded perspective view of an actuator clutch of the device, showing an outer clutch sleeve and delivery sleeve in further detail; 
         FIG. 6  is an exploded perspective view of the actuator clutch, showing an inner clutch sleeve and expander rod in further detail; 
         FIG. 7A  is an exploded perspective view of the actuator clutch, showing a core rod and drive clutch in further detail; 
         FIG. 7B  is a perspective partial cutaway view of the actuator clutch, illustrating advancement of the core rod and drive clutch; 
         FIG. 8A  is a side cross-sectional view taken along a vertical centre line of the device of  FIG. 1 , showing the device in an unactuated state; 
         FIG. 8B  is a plan view of the device in the unactuated state, as shown in  FIG. 8A ; 
         FIG. 8C  is a cross-sectional view of the actuator clutch and delivery portion, taken along a vertical centre line similar to  FIG. 8A ; 
         FIG. 8D  is a plan view of the actuator clutch and delivery portion corresponding to  FIG. 8C ; 
         FIG. 9A  is a side cross-sectional view taken along a vertical centre line of the device of  FIG. 1 , showing the device in a partially actuated state; 
         FIG. 9B  is a plan view of the device in the partially actuated state shown in  FIG. 9A ; 
         FIG. 9C  is a cross-sectional view of the actuator clutch and the delivery portion, taken along a vertical centre line similar to  FIG. 9A , shown with the device in the partially actuated state; 
         FIG. 9D  is a plan view of the actuator clutch and delivery portion corresponding to the partially actuated state in  FIG. 9C ; 
         FIG. 10A  is a side cross-sectional view taken along a vertical centre line of the device of  FIG. 1 , showing the device in a further actuated state; 
         FIG. 10B  is a plan view of the device as shown in  FIG. 10A  in the further actuated state; 
         FIG. 10C  is a cross-section of the actuator clutch and delivery portion, taken along a vertical centre line similar to  FIG. 10A , showing the actuator clutch and delivery portion in the further actuated state; 
         FIG. 10D  is a plan view of the actuator clutch and delivery portion shown in the further actuated state; 
         FIG. 11A  is a side cross-sectional view taken along a vertical centre line of the device of  FIG. 1 , showing the device in a still further actuated state; 
         FIG. 11B  is a plan view of the device in the still further actuated state shown in  FIG. 11A ; 
         FIG. 11C  is a cross-sectional view of the actuator clutch and deliver portion, taken along a vertical centre line similar to  FIG. 11A , showing the actuator clutch and delivery portion in the still further actuated state; 
         FIG. 11D  is a plan view of the actuator clutch and delivery portion in the still further actuated state; 
         FIG. 12A  is a side cross-sectional view of the actuator clutch and delivery portion, taken along a plane angularly offset from the vertical centre line of the device, showing the actuator clutch and delivery portion in a final actuation state; 
         FIG. 12B  is a plan view of the actuator clutch and delivery portion shown in the final actuation state; 
         FIG. 13A  is a partial cutaway perspective view of a delivery portion of the device of  FIG. 1 , showing the delivery portion in the unactuated state; 
         FIG. 13B  is a partial cutaway perspective view of the delivery portion, with the device in the partially actuated state; 
         FIG. 13C  is a partial cutaway perspective view of the delivery portion, with the device in the further actuated state; 
         FIG. 13D  is a partial cutaway perspective view of the delivery portion, with the device in a further partially actuated state; 
         FIG. 13E  is a partial cutaway perspective view of the delivery portion, with the device shown in the final actuation state; 
         FIG. 14A  is a partial side sectional view of the delivery portion, shown when the device is in the unactuated state; 
         FIG. 14B  is a partial side sectional view of the delivery portion, shown with the device in the partially actuated state; 
         FIG. 14C  is a partial side sectional view of the delivery portion, when the device is in the further actuated state; 
         FIG. 14D  is a partial side sectional view of the delivery portion, when the device is in the still further actuated state; 
         FIGS. 14E ,  14 F and  14 G illustrate a progressive sequence of release of the staples to a deployed configuration, illustrating the delivery portion in partial side cross-section; and 
         FIG. 15  is a partial plan view of a delivery sleeve of the device, showing insertion apertures and a release aperture for the staples. 
     
    
    
     Like reference indicators as between the drawings are intended to indicate like elements, features or functions. The drawings are not to scale and should be considered to be exemplary, for the purposes of illustrating features and functions of the described embodiments. 
     DETAILED DESCRIPTION 
     The described embodiments relate generally to devices for delivering shape-memory staples  910  and staple delivery methods performed using such devices. In some embodiments, a staple delivery device  100  comprises a striking mechanism  190  for delivering a striking blow to cause ends of the staples  910  to protrude in a stabbing manner, thereby enabling the staples  910  to penetrate dense and/or hardened substances surrounding the staple delivery site. 
     In other embodiments, release apertures  554  for releasing the staples  910  from a delivery portion  140  extend in a slight spiral relative to a longitudinal axis of the delivery portion  140 . In still further embodiments, the device  100  comprises a somewhat bulb-shaped portion  660  positioned at a delivery end of the device  100  and configured to be axially withdrawn into the delivery end to cause a substantially cylindrical sheath  550  around the delivery end to slightly flare outwardly. 
     In some further embodiments, the device  100  may comprise a dome-shaped cap  145  at a distal end of the device  100  that is movable between a proximal position, in which an apron  147  at an open end  148  of the domed portion  145  fits around the cylindrical delivery tip  142 , for example to hold a graft in place, where the graft is a substantially tubular graft fitting around at least part of the shaft  130  of the device  100 , and a distal position. In the distal position, the dome-shaped cap  145  does not overlie the cylindrical end tip portion  142  and allows radial protrusion of one end of each staple  910  into the graft, in preparation for delivery of the staples to affix the graft to another body. 
     Embodiments of the device are shown and described in relation to Figures Ito  15 , by way of non-limiting example. As shown in  FIG. 1 , device  100  includes a grippable handle  110  having a palmar grip  111 , a ratchet  112 , a depressible trigger  150  and a finger grip portion  152 . When device  100  is held in a hand, grippable handle  110  is shaped to accommodate palmar grip  111  in a palm and/or thenar area of the hand, with fingers extending around trigger  150  and finger grip portion  152  so that device  100  can be firmly held and operated. Trigger  150  is movable relative to ratchet projections  113   a ,  113   b  and  113   c  by squeezing the third, fourth and fifth fingers of the hand, for example. Ratchet  112  cooperates with an angled trigger foot  155  at the base of trigger  150 , which acts as a ratchet engagement portion, to hinder outward movement of trigger  150  relative to a main body of handle  110 . Trigger foot  155  can be actuated to successively engage ratchet projections  113   a ,  113   b  and  113   c , with ratchet projection  113   a  maintaining trigger  150  in an unactuated state. 
     Trigger  150  is pivotable relative to finger grip portion  152  of handle  110  about an axis defined by a trigger pivot pin  151  received in a pin hole  153  formed in the finger grip portion  152 . Trigger  150  has a split claw  154  formed at an opposite end to trigger foot  155  to engage a proximal drive mechanism  160  described below. 
     As shown in  FIGS. 2A and 2B , handle  110  further comprises a movement limiting bolt  115  positioned in a body of the handle  110  to limit inward movement of trigger  150 . A spring  116  is positioned around movement limiting bolt  115  and is at least partially received within the body of the handle  110  at one end and positioned around a spring registration boss  117  formed on an inner face of trigger  150 . Spring  116  serves to bias trigger  115  outwardly, so that trigger foot  155  sits against a ratchet projection  113   a ,  113   b  or  113   c . Handle  110  also houses a retention bolt  118  to affix the proximal drive mechanism  160  to handle  110 . 
     Ratchet  112  is preferably formed of a flexible spring steel. Ratchet  112  may be secured to a base  114  of handle  110  by base bolts  114   a  received through ratchet apertures  112   a  at one end of ratchet  112 . Ratchet projections  113   a ,  113   b  and  113   c  are formed at an opposite end to apertures  112   a  and ratchet  112  is sufficiently flexible so that trigger  150  can be moved outwardly past one or more ratchet projections  113   a ,  113   b  or  113   c  (to reset trigger  150  after actuation) when ratchet  112  is resiliently deflected downwardly away from the body of handle  110 . 
     Handle  110  is coupled to an actuation portion  120  which comprises a proximal actuation portion  122  and a distal actuation portion  124 . A shaft  130  is coupled to distal actuation portion  124  to communicate actuation movements and forces to a delivery portion  140  positioned at a distal end of device  100 . 
     In the context of this description, positional references are used, assuming that device  110  will be held in the manner of a pistol, with base  114  being oriented generally downwardly and a “barrel” of the “pistol” extending generally outwardly. The relative term “proximal” should be interpreted to indicate a direction or position close to or toward a palm of the hand when the hand is positioned around handle  110  in the intended manner previously described. The term “distal” is intended to indicate a direction or position opposite to “proximal”, which will generally be away from the hand gripping handle  110 . These and other positional references are provided for ease of understanding only and are not intended to limit the actual position or orientation of the device during use. 
     Proximal actuation portion  122  includes proximal drive mechanism  160  and a striking mechanism actuable by a striking actuator  180 . 
     As shown in  FIG. 2A , proximal drive mechanism  160  comprises a proximal drive sleeve  162  coupled to and resting against a top of handle  110 . Proximal drive sleeve  162  has a proximal end insert  164  received through an open proximal end of sleeve  162 . An insert locator pin  211  is received through a correspondingly sized aperture in proximal end insert  164  and through radial aperture  214  formed in proximal drive sleeve  162 . Insert locator pin  211  remains partially received in radial aperture  214  to fix proximal end insert  164  in position within sleeve  162 . A drive spring  212  is also positioned within sleeve  162  so as to have one end of the spring positioned against an internal boss on proximal end insert  164 . Spring  212  is positioned partially around a projecting boss of a proximal end  222  of a first clutch portion  220  that is also received within proximal drive sleeve  162 . Spring  212  serves to bias first clutch portion  220  in a distal direction. 
     Proximal drive sleeve  162  partially houses a second clutch portion  230  that has a further slotted end  232  shaped to mate with a keying end  226  of the first clutch portion  220 . Second clutch portion  230  has a neck portion  234  positioned intermediate first slotted end  232  and a second slotted end  236 . Neck portion  234  is shaped to partially meet and engage with split claw  154  of trigger  150  so that proximal actuation of trigger  150  (i.e. by squeezing the fingers of the hand) causes distal movement of split claw  154 , which engages second clutch portion  230  around neck portion  234  to cause second clutch portion  230  to move distally within proximal drive sleeve  162 . 
     A staple release actuator  165 , generally formed as a projecting lever and indicated as “Lever D” in the drawings is coupled to first clutch portion  220  by a screw threaded coupling through threaded hole  224  formed in first clutch portion  220 . A moment applied to staple release actuator  165  causes rotation of first clutch portion  220  about a longitudinal axis of device  100 . This rotational movement of first clutch portion  220  causes like rotational movement of second clutch portion  230 , which in turn causes like rotation of a drive clutch  740  (described in further detail below) to move part of delivery portion  140  relative to outer delivery sleeve  550  (where permitted by the positioning of release actuator limiting rod  812  within release actuator limiting channel  512 , as described below). 
     Proximal drive sleeve  162  has an enlarged distal end with a male threaded cylindrical wall  218  for threaded engagement with barrel housing  410  ( FIG. 4 ). A top screw  178  is insertable through a screw-receiving aperture  418  in barrel housing  410  and into a threaded aperture  168  formed in the distal end of proximal drive sleeve  162  to fix barrel housing  410  to proximal drive sleeve  162 . 
     A spring  250  and positioning element  260  are received in the distal end of proximal drive sleeve  162  and in the proximal end of barrel housing  410  to receive and position second slotted end  236  relative to a clutch head portion  742  of drive clutch  740 . 
     Proximal drive sleeve  162  has a slotted aperture  216  formed toward a distal end of sleeve  162  to receive a striking transmission portion  188  of anvil  186  therethrough. Striking transmission portion  188  is configured to project downwardly from within a generally cylindrical striking actuator housing  181  through slotted aperture  216  to be received in neck portion  234 . Opposed claws of split claw  154  may be sized to fit around the reduced diameter portion of neck portion  234  and to at least partially receive a lower extremity of striking transmission portion  188 . Thus, movement of either of anvil  186  and trigger  150  causes movement of second clutch portion  230  along its longitudinal axis. 
     As shown in  FIG. 3 , striking mechanism  190  comprises a striking piston  185  axially movable within striking actuator housing  181  (formed as a hollow cylinder) to act as a hammer upon anvil  186  under the action of a striking actuator spring  183  proximally positioned within housing  181 . A striking actuator  180 , formed as a lever, and shown in the drawings as “Lever C”, may be coupled to striking piston  185  by means of screw-threaded engagement. Striking actuator  180  extends radially through an L-shaped guide channel  182  formed in housing  181 . Part of guide channel  182  extends circumferentially to allow for rotational movement of striking actuator  180  and striking piston  185  within housing  181 . However, housing  181  also defines a longitudinal section of guide channel  182  that permits striking actuator  180  to move longitudinally within that section of guide channel  182 . 
     One end of spring  183  is positioned against an end cap  187  secured at a proximal end of housing  181 , for example by screw threaded engagement. The other end of spring  183  acts on an inner cap  184  having a boss around which fits the end of spring  183 . Inner cap  184  abuts a proximal end of striking piston  185  so that, under the action of spring  183 , striking piston  185  is biased in the distal direction. 
     When striking actuator  180  is in an unactuated position, it is received within the circumferential portion of guide channel  182 , in which the part of striking actuator housing  181  that defines guide channel  182  hinders distal movement of striking actuator  180 . In order to actuate striking actuator  180  (move it into an actuated position), striking actuator  180  may have a moment applied to rotate it toward the longitudinal section of guide channel  182  so that striking piston  185  and striking actuator  180  become free to move in the distal direction under the biasing action of spring  183 . 
     Striking actuator housing  181  may be secured to proximal drive sleeve  162  by receipt of a proximal end screw  166  through an aperture formed in a downwardly pending positioning flange  312  formed on or attached to housing  181 . A threaded end of proximal end screw  166  may be received in a matingly threaded proximal end of proximal end insert  164  in order to secure proximal end screw  166  in position and thereby assist in fixedly locating housing  181  on top of, and adjacent to, proximal drive mechanism  160 . Axes of movement of the mechanisms within proximal drive mechanism  160  and striking mechanism  190  are generally longitudinal and parallel. 
     As an additional means of securing housing  181  relative to proximal drive sleeve  162 , a distal end  314  of housing  181  is configured to mate with and receive a positioning boss  322  located toward a distal end of proximal drive sleeve  162 . Positioning boss  322  is fixed relative to the cylindrical barrel of proximal drive sleeve  162  and is positioned to be slightly above a distal end of slotted aperture  216 . 
     Referring also to  FIG. 4 , head retraction actuator  170  and barrel housing  410  are described in further detail. Head retraction actuator  170  comprises a bar  171  received within a bar receiving channel  174  defined by&#39; a head portion of a rotation key  173 . A ball  172  is received in an aperture formed in a shaft of rotation key  173  in order to fix bar  171  in position relative to channel  174 . Rotation key  173  has a cam  175  on an inner end thereof for engaging and proximally shifting inner clutch sleeve  610  ( FIG. 6 ) by a camming engagement of a distal face  611   a  of proximal end flange  611  of inner clutch sleeve  610 . Rotation key  173  is received within registration barrel  176 , which is received by screw-threaded engagement with actuator insert port  414  formed in one side of barrel housing  410 . Registration barrel  176  has a male screw thread  177  for engaging with a corresponding female screw thread within actuator insert port  414 . 
     Barrel housing  410  comprises a threaded proximal end  412  sized to fit around and engage with threaded cylindrical wall  218  of proximal drive sleeve  162 . Barrel housing  410  also comprises an internal annular flange  420  within which sits positioning element  260 . At its distal end, barrel housing  410  has a threaded distal end  416  from which upper and lower registration bosses  422  extend distally to register and mate with registration notches  522  formed at corresponding upper and lower positions on external annular flange  442  of actuator clutch  440 . 
     A retention cap  128  slides over a distal end of actuator clutch  440  to retain actuator  440  within barrel housing  440 . Retention cap  128  has an internal thread  426  to engage with threaded distal end  416  of barrel housing  410  and has an internal annular flange  432  to engage and abut a distal face of external annular flange  442 , to thereby retain actuator clutch  440  within barrel housing  410 . A distal opening in retention cap  128  allows a distal portion of actuator clutch  440  to extend therethrough, along with shaft  130 . 
     Head retraction actuator  170 , also shown in the drawings as “Lever B”, can be partially rotated about a central axis of rotation key  173 , which is normal to the longitudinal axis of device  100 . This rotation causes retraction of a somewhat bulb-shaped expander head  660  within delivery portion  140 , thereby causing delivery sleeve  550  to flare outwardly somewhat adjacent delivery tip  142 . 
     It should be noted that the length of shaft  130  is depicted in  FIGS. 2A ,  3 ,  4 ,  5 ,  6 ,  7 A and  7 B as being quite short. This is done for ease of illustration only and does not represent the actual length of shaft  130 . Rather, the relative length of shaft  130  as shown in  FIG. 1  is intended to more accurately reflect the intended configuration of device  100 , although it is to be noted that the drawings are not to scale. 
     Referring also to  FIGS. 5 and 6 , actuator clutch  440  is shown and described in further detail. Actuator clutch  440  comprises an outer clutch sleeve  510  and an inner clutch sleeve  610 . Outer clutch sleeve  510  mostly surrounds inner clutch sleeve  610 , except for a proximal end flange  611  which extends radially outwardly to an extent that it circumferentially coincides with an outer circumference of outer clutch sleeve  510 . Outer clutch sleeve  510  and inner clutch sleeve  610  have radial apertures  514  and  614  to accommodate a locating cylinder  630  and radial screw apertures  516  and  616  to allow for insertion of a fixation screw  538  to affix inner delivery sleeve  820  an inner rotatable part of actuator clutch  440 . 
     The generally cylindrical wall of outer clutch sleeve  510  defines a release actuator limiting channel  512 , having a generally L-shaped configuration. Release actuator limiting channel  512  receives a head of release actuator limiting rod  812  therein in a manner such that channel  512  limits relative movement between outer clutch sleeve  510  and limiting rod  812 . Limiting rod  812  is coupled to internal parts of actuator clutch  440  and is indirectly coupleable to proximal drive mechanism  160  as described below, and plays an important role in avoiding premature actuation of staple release actuator  165 . 
     Outer clutch sleeve  510  has an outer sleeve proximal end opening  524 , through which a proximal end of inner clutch sleeve  610  is received, and an outer sleeve distal end opening  526 , through which a proximal portion of the shaft  130  extends. A distal end  542  of outer clutch sleeve  510  has a number of circumferentially spaced fixation apertures  537  for receiving fixation screws  536  to secure delivery sleeve  550  within outer sleeve distal end  542 . Outer clutch sleeve  510  also defines an annular wall  546  toward distal end  542 , against which a spring  562  and positioning ring  530  are located. Spring  562  serves to bias some internal components of actuator clutch  440  in the proximal direction. Spring  562  is positioned internally of positioning ring  530 , which has approximately the same inner diameter as inner clutch sleeve  610 . 
     The components of shaft  130  are generally coaxial with inner and outer clutch sleeves  610 ,  510 , barrel housing  410  and proximal drive mechanism  160 , although striking mechanism  190  is axially offset therefrom. 
     Distal actuation portion  124  includes head retraction actuator  170 , barrel housing  410 , actuator clutch  440 , shaft  130  and delivery portion  140 . 
     As shown in  FIG. 5 , outer delivery sleeve  550  has a proximal end received within outer sleeve distal end opening  526  and affixed to outer sleeve distal end  542  by fixation screws  536 . At its distal end, outer delivery sleeve  550  has a number of release apertures  554 , formed as generally longitudinally extending slots in the end of outer delivery sleeve  550 . Release apertures  554  extend all the way to the distal extremity of outer delivery sleeve  550 , thereby defining fingers  552  arranged in an interrupted cylindrical configuration. Fingers  552  define a generally angled inner profile at the distal opening of outer delivery sleeve  550  to accommodate engagement with a corresponding angled outer surface  662  of expander head  660 . When expander head  660  is withdrawn slightly in the proximal direction, angled outer surface  662  engages and slides against angled inner profile  558  which, because fingers  552  are formed of a resiliently deflectable material, causes the fingers  552  to deflect slightly radially outwardly, thereby causing delivery tip  142  to flare outwardly. This outward flaring can assist in forcibly expanding vessel walls, for example, and can enable release of the staples at a radially increased position which, considering the generally circular shape memory of the staples, can lead to improved medical stapling quality. 
     Delivery sleeve  550  also defines insertion apertures  556  through which deformed (i.e. relatively straightened) staples can be inserted so as to be received within staple receiving chambers  826 . Insertion apertures  556  may be formed as slots that are generally parallel to, but offset from, release apertures  556 . Insertion apertures  556  are of a substantially shorter length than release apertures  554  and are positioned close to, but slightly proximally of, the proximal extremity of release apertures  554 . 
     Inner clutch sleeve  610  defines a release actuator limiting channel  612  to permit movement of release actuator limiting rod  812  in proximal and distal directions, but not axially. When limiting rod  812  is allowed to move rotationally within limiting channel  512 , limiting rod  812  causes inner clutch sleeve  610  to rotate along with limiting rod  812 . This causes rotation of expander rod  650  to which inner clutch sleeve  610  is rotatably coupled by a locating cylinder  630 . Specifically, expander rod  650  has its proximal end  652  received through a diametrical through hole  632  formed in locating cylinder  630 . A fixation screw  636  is positioned axially within locating cylinder  630  to fix expander rod  650  relative to locating cylinder  630 . 
     As shown in  FIG. 6 , expander head  660  is positioned at the distal end of expander rod  650  and has staple protrusion slots  664  extending in a generally axial but outward direction on the outside of expander head  660  to accommodate protrusion of staples  910  from within staple receiving chambers  826 . Expander head  660  also has a shoulder  668  against which distal ends  824  of inner delivery sleeve  820  abut when inner delivery sleeve  820  is moved to its distal-most position. Angled outer surface  662  transitions from shoulder  668  to the radial and distal extremity of expander head  660 , which generally positionally coincides with delivery tip  142 . 
     Expander rod  650  comprises a generally hollow cylindrical wall  651  through which core rod  710  passes and is movable. Expander rod  650  is received within inner delivery sleeve  820 , which is in turn received within outer delivery sleeve  550 . Core rod  710  has a rod proximal end  712  and a rod distal end  714 . Distal end cap  145  is positioned at the distal end  714 . Distal end cap  145  may comprise a flexible medical grade plastic apron  147  extending proximally from the distal extremity of distal end cap  145 . Apron  147  is intended to have enough firmness to hold a graft onto distal tip  142  in the unactuated position. 
     Proximal end  712  of core rod  710  is received within a diametrical through-hole  722  of a locating cylinder  720 . Core rod  710  is affixed to locating cylinder  720  by a fixation screw  730  axially received within locating cylinder  720 . Core rod  710  extends through diametrical through-hole  722  to be at least partially received within a central bore  743  of drive clutch  740 . Drive clutch  740  also has a transverse bore  744  to accommodate locating cylinder  720 . This arrangement is such that, when second clutch portion  230  engages clutch head portion  742 , rotational or axial force applied to second clutch portion  230 , for example by any of Levers A, C and D, such force is transmitted to core rod  710  and to components housed within inner clutch sleeve  610 . 
     Drive clutch  740  has distal annular wall portions  746  arranged to interleave with and abut corresponding circumferentially spaced annular wall portions  840  to limit excessive distal movement of drive clutch  740  responsive to second clutch portion  230  and permit a clutching action for rotation transfer. 
     Referring now to  FIGS. 8A to 8D , an unactuated position of device  100  is described. In the unactuated position, first and second clutch portions  220 ,  230 , anvil  186  and drive clutch  740  are located in relatively proximal positions according to their limited freedom of movement within their respective housings. In this state, because of the position of limiting rod  812  within limiting channel  512 , outer clutch sleeve  510  and inner clutch sleeve  610  cannot rotate relative to each other and limiting rod  812  is prevented from rotating relative to outer clutch sleeve  510 . As a result, inner delivery sleeve  820  is prevented from rotating within outer delivery sleeve  550 . 
     In the unactuated state, distal end cap  145  is at its proximal-most position, in which open end  148  of domed-shaped apron  147  partially overlies distal delivery tip  142 , thereby hindering accidental protrusion of staples  910  from delivery tip  142  prior to their intended release. 
     It is intended that staples  910  be inserted into staple receiving chambers  826  in their deformed (straightened) configuration when device  100  is in the unactuated state. 
     Referring now to  FIGS. 9A to 9D , device  100  is described in relation to a first actuation state, which is one of several possible actuation states. The first actuation state is achieved by forcing lever  150  to move proximally, for example by squeezing fingers to cause them to curl inwardly towards a hand gripping handle  110 , so as to move trigger foot  155  inwardly by one ratchet position. The levering action of trigger  150  about trigger pivot pin  151  causes split claw  154  to move distally. This in turn forces second clutch portion  230  in a distal direction, which in turn causes drive clutch  740  and core rod  710  to move distally by a certain amount, such as a few millimeters, for example. 
     After the first actuation, distal annular wall portions  746  of drive clutch  740  advance to be adjacent proximal annular wall portions  840 , so as to be able to rotationally engage therewith. Thus, distal annular wall portions  746  effectively provide interleaving fingers to interleave with corresponding proximal annular wall portions  840  in order to transmit rotational force from drive clutch  740  to annular wall portions  840 , which are in turn rigidly coupled to limiting rod  812  and inner delivery sleeve  820 . In the first actuation state, limiting rod  812  remains in its proximal-most position within limiting channel  512 . The purpose of the first actuation is to distally progress distal end cap  145  so as to allow subsequent protrusion of staples  910  from distal delivery tip  142  and to engage drive clutch  740  with annular wall portions  840  (to act as a clutch). 
     Referring now to  FIGS. 10A to 10D , a second actuation state of device  100  is described in further detail. In the second actuation state, head retraction actuator  170  (Lever B) is twisted so that, instead of bar  171  being generally horizontal and parallel to barrel housing  410 , it is rotated 90 degrees anticlockwise (as seen in  FIG. 10A ) so that bar  171  is positioned vertically. By thus rotating bar  171 , rotation key  173  is caused to rotate counter-clockwise, which causes cam  175  to engage distal face  611   a  of proximal end flange  611  to shift inner clutch sleeve  610  in a proximal direction by an amount configured according to the shape of clutch  175 . For example, inner clutch sleeve  610  may be moved proximally by about 0.5 mm under the action of cam  175 . 
     Retraction in the proximal direction of inner clutch sleeve  610  causes expander rod  650  to be shifted proximally by the same amount, while core rod  710 , outer delivery sleeve  550  and inner delivery sleeve  820  remain unmoved, except for a slight flaring of outer delivery sleeve  550  at distal tip  142 , as described previously. The flaring of delivery portion  140  is caused by the action of the angled outer surface  662  of expander head  660  acting on the angled inner profile  558  of fingers  552 , thereby outwardly deflecting fingers  552 . This flaring of distal tip  142  may be configured to result in an increased diameter of approximately 1 to 2 mm, for example. 
     The second actuation step achievable by actuation of head retraction actuator  170  is not necessary to achieve release of the staples  910 , but may be desirable to provide greater expansion of a vessel wall. It is considered that this may provide improved stapling quality. 
     Referring now to  FIGS. 11A to 11D , third and fourth actuation states are described in further detail. In the third actuation state, trigger  150  is depressed proximally in a further step so that trigger foot  155  rests proximally of ratchet projection  113   c , which causes split claw  154  to further advance second clutch portion  230  in a distal direction. This causes inner sleeve  820  to be pushed distally by drive clutch  740 , thereby advancing staples  910  positioned within staple receiving chambers  826 . When staples  910  are received within staple receiving chambers  826 , jagged or irregular inner chamber walls  822  partially defining the staple receiving chambers  826  serve to frictionally engage staples  910  so as to encourage them to advance within their respective chambers. An additional or alternative advancement means is provided by inward detent  828  formed in inner delivery sleeve  820  to coincide with staple receiving chambers  826 . The inward detents  828  are formed so as to allow each staple  910  to at least partially nest therein based on their shape memory, which is configured to cause them to adopt an approximately circular deployed configuration. As inner delivery sleeve  820  progresses distally, inner chamber walls  822  and/or inward detents  828  assist in moving staples  910  so that one end thereof passes through staple protrusion slots  664  and extends somewhat radially outwardly from tip portion  142 . This third actuation state allows for partial protrusion of the staples  910 , for example to cause them to protrude at least partially through a graft positioned around delivery tip  142 . 
     Inward detents  828  are formed as radially inwardly curved (concave) deformations in inner delivery sleeve  820  adjacent delivery sleeve distal ends  824 . Detents  828  provide axial engagement as well as suitable orientation of the staples  910  so that when freed, the staples  910  have their ends come together at a position outside and away from delivery portion  140  (as illustrated in  FIGS. 13E and 14A ). If the staples  910  are not oriented properly within receiving chambers  826 , their ends may not come together in the right position to achieve the desired stapling effect. 
     In a fourth actuation state, striking mechanism  190  is actuated to deliver a striking blow to inner delivery sleeve  820  within delivery portion  140 . The striking blow is communicated to delivery portion  140  by the application of a moment to lever  180  so as to rotate striking piston  185  and lever  180  into a position where spring  183  biases the striking portion  185  in a distal direction, thereby causing striking piston  185  to act as a hammer upon anvil  186 , which communicates the kinetic impact of the hammer blow to second clutch portion  230  via striking transmission portion  188  of anvil  186 . Second clutch portion  230  thus receives a kinetic impulse in the distal direction, which is communicated to drive clutch  740  through abutting contact of second clutch portion  230  with drive clutch  740 . Drive clutch  740  in turn communicates the kinetic impulse to annular wall  840  which is coupled to the inner delivery sleeve  820 . 
     The distally directed kinetic impulse communicated from the striking mechanism  190  is configured to cause further protrusion of the protruding staples  910  in an approximately stabbing manner. The intention of such stabbing protrusion of staples  910  is to cause protruding ends of staples  910  to be able to break through relatively dense tissue or substances that may have formed on the vessel walls where the join is desired to be made. 
     Delivery of the striking blow in response to actuation of the striking mechanism  190  is an optional step that can be omitted if desired. Additionally, according to some embodiments, striking mechanism  190  may provide more than one circumferential slot position for lever  180 . This is so that greater or lesser compression of spring  183  in the proximal direction may be achieved in order to provide greater or lesser kinetic impact upon anvil  186  when striking mechanism  190  is actuated. 
     Referring also to  FIGS. 12A and 12B , a fifth and final actuation state is described in further detail. Because the advancement of drive clutch  740  also distally advanced annular wall  840  and therefore advanced limiting rod  812  relative to outer clutch sleeve  510 , completion of the third actuation state enables the final actuation state (i.e. release of the staples) to be performed. This is because the distal movement of limiting rod  812  relative to outer clutch sleeve  510  and limiting channel  512  positions limiting rod  812  to be able to slide laterally within limiting channel  512 . This allows rotation of inner delivery sleeve  820  within outer delivery sleeve  550  as shown in  FIGS. 12A and 12B , so that the longitudinally extending staple receiving chambers  826  coincide with release apertures  554 , thereby freeing staples  910  to adopt a circular deployed configuration ( 920 ) according to their shape memory. 
     Because of the thinness of the wire used for staples  910 ,  920  and the strong shape memory induced in such staples, the ends of the staples are sharp enough and come together with enough force to penetrate the tissue surrounding delivery tip  142 . Although  FIGS. 11A to 11D ,  12 A and  12 D show the distal delivery tip  142  being flared, this need not necessarily be the case. Actuation of staple release actuator  165  causes release of staples  910  through release apertures  554  whether delivery tip  142  is flared or not. 
     The rotation of inner delivery sleeve  820  relative to outer delivery sleeve  550  is caused by application of a moment to staple release actuator  165 , such as by pressing it downwardly. Such a downward movement applied to staple release actuator  165  (Lever D) causes rotation of first clutch portion  220 , which transmits rotational movement to annular wall portions  840  via a second clutch portion  230  and drive clutch  740 . As annular wall portions  840  are coupled to inner delivery sleeve  820 , the downward moment applied to Lever D causes the longitudinally extending staple receiving chambers  826  to align with release apertures  554  to allow staples  910  to spring outwardly and adopt their deployed configuration. 
       FIGS. 13A ,  13 B,  13 C,  13 D and  13 E illustrate the unactuated state, the first actuated state, the second actuated state, the third actuated state and the fifth and final actuated state, progressively. Illustration of the further projection resulting from actuation of the striking mechanism  190  is not shown as a&#39;distinct state separate to that of  FIG. 13D , but  FIG. 13D  may be considered to depict the result of a combination of the third and fourth actuation states, as described above. 
     Similarly,  FIGS. 14A to 14G  illustrate the configuration of delivery portion  140  during progressive actuation states.  FIGS. 14A ,  14 B,  14 C and  14 D respectively correspond to the unactuated state, the first actuation state, the second actuation state and third and fourth actuation states.  FIGS. 14E ,  14 F and  14 G progressively illustrate the fifth actuation state, in which the release of staples  910  from release apertures  554  is illustrated for embodiments of device  100  in which release apertures  554  are formed to have a slight spiral (i.e. to be slightly angled relatively to a longitudinal axis, as illustrated in  FIG. 15 ). 
     For embodiments in which the release apertures  554  are angled, the release apertures  554  are configured so that, while distal ends of the staples  910  protrude from delivery tip  142 , at an initial stage of release only a proximal part of release apertures  554  comes into alignment with the underlying staple receiving chambers  826 . This allows a proximal end of each staple  910  to begin to curl outwardly from chambers  826  as a result of its shape memory. This initial protrusion of the proximal ends of staples  910  at the beginning of the release stage is illustrated in  FIG. 14E . 
     As can be seen in  FIG. 14F , as inner delivery sleeve  820  progressively comes more into alignment with release apertures  554 , more of the proximal end of each staple is freed to adopt its deployed configuration, although the staple  910  is not yet completely freed. As  FIG. 14F  illustrates, the proximal end of each staple  910  tends to curl upwardly so that, once the inner delivery sleeve  820  is brought into further alignment with release apertures  554 , as shown in  FIG. 14G  the opposite ends of each staple  910  are allowed to come together in a pinching and piercing action which is considered to be more effective for some stapling purposes than if there were no progressive release of the proximal end of each staple  910 . 
     Although  FIGS. 14A to 14G  illustrate the release of only one staple  910  into a deployed configuration  920 , this is for simplicity of illustration only and it should be understood that multiple staples are released at the same time from a number of different circumferentially spaced positions. Device  100  can be configured to have four, five, six, seven, eight, nine, ten, eleven or twelve release apertures  554  (and a corresponding number of insertion apertures  556 ), depending on which configuration may be suited for a particular stapling application. Additionally, although staples  910  appear to be bent between shoulder  668  and delivery tip  142  in  FIGS. 14A to 14F , such bending of the staple does not occur in quite the way it is illustrated. Rather, such bending, if it occurs, will be rather smooth, instead of being a sharp bend in the wire. 
     The angle of release apertures relative to the longitudinal axis of outer delivery sleeve  550  is relatively shallow, such as about 1 degree to about 7 degrees, for example. The angle may be varied, depending on the number of release apertures  554  provided in delivery portion  140 . 
     The wire used as staples  910 ,  920  may be nitinol wire, for example, with a diameter of between about 0.1 mm to about 0.5 mm. Some specific embodiments are configured to deploy staples of about 0.3 mm or about 0.33 mm in diameter. 
     The use of shape-memory staples as described herein avoids the need for staples to be deformed by being forced against an anvil to adopt the desired staple shape, thus obviating the extra components and logistical difficulties associated with having an anvil at the staple delivery end of the stapler. 
     While embodiments are described herein in specific detail, it is to be understood that such embodiments are described by way of example and are not to be construed to be limiting with respect to equivalents or to limit the scope of the invention. 
     Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 
     PARTS LIST 
     
         
           100  stapler 
           110  handle 
           111  palmar grip 
           112  ratchet 
           112   a  bolt holes 
           113   a, b, c  ratchet projections 
           114  handle base 
           114   a  base bolts 
           115  movement limiting bolt 
           116  biasing spring 
           117  spring registration boss 
           118  retention bolt 
           120  actuation portion 
           122  proximal actuation portion 
           124  distal actuation portion 
           128  retention cap 
           130  shaft 
           140  delivery portion 
           142  delivery tip 
           145  distal end cap 
           147  apron 
           148  open end of apron 
           150  trigger (Lever A) 
           151  trigger pivot pin 
           152  finger grip portion 
           153  pin hole 
           154  split claw 
           155  ratchet engagement portion/trigger foot 
           160  proximal drive mechanism 
           162  proximal&#39;drive sleeve 
           164  proximal end insert 
           165  staple release actuator (Lever D) 
           166  proximal end screw 
           170  head retraction actuator (Lever B) 
           171  bar 
           172  ball 
           173  rotation key 
           174  bar receiving channel 
           175  cam 
           176  registration barrel 
           177  screw thread 
           178  top screw 
           180  striking actuator (Lever C) 
           181  striking actuator housing 
           182  guide channel 
           183  striking actuator spring 
           184  inner cap 
           185  striking piston/hammer 
           186  anvil 
           187  end cap 
           188  striking transmission portion 
           190  striking mechanism 
           211  insert locator pin 
           212  drive spring 
           214  radial aperture 
           216  slotted aperture 
           218  threaded cylindrical wall 
           220  first clutch portion 
           222  clutch proximal end 
           224  threaded hole 
           226  keying end 
           230  second clutch portion 
           232  first slotted end 
           234  neck portion 
           236  second slotted end 
           250  spring 
           260  positioning element 
           312  positioning flange 
           314  distal end 
           322  positioning boss 
           410  barrel housing 
           412  threaded proximal end 
           414  actuator insertion port 
           416  threaded distal end 
           418  screw receiving aperture 
           420  internal annular flange 
           422  registration boss 
           426  internal thread 
           432  internal annular flange 
           440  actuator clutch 
           442  external annular flange 
           510  outer clutch sleeve 
           512  release actuator limiting channel 
           514  aperture for locating cylinder 
           516  screw aperture 
           522  registration notch 
           524  outer sleeve proximal end opening 
           526  outer sleeve distal end opening 
           530  positioning ring 
           536  fixation screw 
           537  fixation aperture 
           536  fixation screw 
           542  outer sleeve distal end 
           546  annular wall 
           550  outer delivery sleeve 
           552  fingers 
           554  release aperture 
           556  insertion apertures 
           558  angled inner profile 
           562  spring 
           610  inner clutch sleeve 
           611  proximal end flange 
           611   a  distal face of proximal end flange 
           612  release actuator limiting channel 
           614  aperture for locating cylinder 
           616  screw aperture 
           618  inner sleeve distal end 
           630  locating cylinder 
           632  diametrical through-hole 
           636  fixation screw 
           650  expander rod 
           651  cylindrical wall 
           652  proximal end 
           660  expander head 
           662  angled outer surface 
           664  staple protrusion slots 
           668  shoulder 
           710  core rod 
           712  rod proximal end 
           714  rod distal end 
           720  locating cylinder 
           722  diametrical through-hole 
           730  fixation screw 
           740  drive clutch 
           742  clutch head portion 
           743  central bore 
           744  transverse bore 
           746  distal annular wall portions of drive clutch 
           812  release actuator limiting rod 
           820  inner delivery sleeve 
           822  chamber inner wall 
           824  delivery sleeve distal end 
           826  staple receiving chambers 
           828  inward detent 
           840  annular wall portions (coupled to inner delivery sleeve) 
           910  staples (deformed configuration) 
           920  staples (deployed configuration)