US20020019642A1 - Anastomosis instrument and method for performing same - Google Patents

Abstract

A surgical instrument for anastomosis of first and second blood vessels includes a housing having distal and proximal ends, a handle and a disposable loading unit removably mounted to the distal end of the housing. The loading unit includes upper and lower fastener support members having a passage defined therethrough for receiving an end of the second blood vessel and configured to releasably support a plurality of surgical fasteners. The loading unit also includes a retractable anvil located at a distal end of the loading unit, the anvil being movable relative to the fastener support member in response to actuation of the handle to simultaneously deform the of surgical fasteners.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application is a continuation-in-part of U.S. application Ser. No. 09/256,260, entitled “ANASTOMOSIS INSTRUMENT AND METHOD” which was filed on Feb. 23, 1999 by Nicholas et al., which is a continuation-in-part of U.S. application Ser. No. 08/877,701, entitled “SINGLESHOT ANASTOMOSIS INSTRUMENT WITH DETACHABLE LOADING UNIT AND METHOD”, which was filed Jun. 17,1997 by Manzo et al., which application is a continuation-in-part of U.S. application Ser. No. 08/685,385, entitled “ANASTOMOSIS INSTRUMENT AND METHOD”, filed Jul. 23,1996 by Hinchliffe et al., now U.S. Pat. No. 5,707,380, the entire contents of all of these disclosures are hereby incorporated by reference.[0001]
BACKGROUND
• 1. Technical Field[0002]
• The present disclosure relates to a surgical instrument and method for performing anastomosis of tubular body structures, and more particularly to an instrument for joining vascular tissues, for example, during coronary artery bypass graft procedures.[0003]
• 2. Background of Related Art[0004]
• Coronary artery disease is often characterized by lesions or occlusions in the coronary arteries which may result in inadequate blood flow to the myocardium, or myocardial ischemia, which is typically responsible for such complications as angina pectoris, necrosis of cardiac tissue (myocardial infarction), and sudden death. In some cases, coronary artery disease may be treated by the use of drugs and/or by modifications in behavior and diet. In other cases, dilatation of coronary arteries may be achieved by such procedures as angioplasty, laser ablation, atherectomy, catheterization, and intravascular stents.[0005]
• For certain patients, a coronary artery bypass graft (“CABG”) is the preferred form of treatment to relieve symptoms and the graft often increases life expectancy. A CABG procedure consists of direct anastomosis of a vessel segment to one or more of the coronary arteries. For example, a reversed segment of the saphenous vein may be grafted at one end to the ascending aorta as an arterial blood source and at the other end to a coronary artery at a point beyond the arterial occlusion. Alternatively, the internal mammary artery (“saphenous vein ”) located in the thoracic cavity adjacent the sternum is likewise suitable for grafting to a coronary artery, such as the left anterior descending artery (“LAD”).[0006]
• The performance of a CABG procedure typically requires access to the heart, blood vessels and associated tissue. Access to the patient's thoracic cavity may be achieved in an open procedure by making a large longitudinal incision in the chest. This procedure, referred to as a median stemotomy, requires a saw or other cutting instrument *to cut the sternum to allow the two opposing halves of the rib cages to be spread apart to expose the internal organs of the thoracic cavity.[0007]
• U.S. Pat. No. 5,025,779 to Bugge discloses a retractor which is designed to grip opposite sternum halves and spread the thoracic cavity apart. The large opening which is created by this technique enables the surgeon to directly visualize the surgical site and perform procedures on the affected organs. However, such procedures that involve large incisions and substantial displacement of the rib cage are often traumatic to the patient with significant attendant risks. The recovery period may be extensive and is often painful. Furthermore, patients for whom coronary surgery is indicated may need to forego such surgery due to the risks involved with gaining access to the heart.[0008]
• U.S. Pat. No. 5,503,617 to Jako discloses a retractor configured to be held by the surgeon for use in vascular or cardiac surgery to retract and hold ribs apart to allow access to the heart or a lung through an operating “window”. The retractor includes a rigid frame and a translation frame slideably connected to the rigid frame. Lower and upper blades are rotatably mounted to the rigid frame and the translation frame respectively. The “window” approach enables the surgeon to gain access through a smaller incision and with less displacement of the ribs, and consequently, less trauma to the patient.[0009]
• Once access to the thoracic cavity has been achieved, surgery on the heart may be performed. Such procedures typically require that the heartbeat be arrested while maintaining circulation throughout the rest of the body. Cardioplegic fluid, such as potassium chloride (KCl) is delivered to the blood vessels of the heart to paralyze the rnyocardium. As disclosed in[0010]WO 95/15715 to Sterman et al. for example, cardioplegic fluid is infused into the myocardium through the coronary arteries by a catheter inserted into the ascending aorta.
• Alternatively, cardioplegic fluid is infused through the coronary veins in a retrograde manner by a catheter positioned in the interior jugular vein accessed at the patient's neck. Such procedures require the introduction of multiple catheters into the blood vessels adjacent the heart, which is a complicated procedure requiring that the desired vessels be properly located and accessed. The progression of the guide wires and catheters must be closely monitored to determine proper placement. Furthermore, the introduction of catheters form punctures in the blood vessels that must be subsequently closed, and there is an increased risk of trauma to the interior walls of the vessels in which the catheters must pass.[0011]
• Alternatively, the CABG procedure may be performed while the heart is permitted to beat. Such a procedure is now commonly referred to as minimally invasive direct coronary artery bypass (MIDCAB) when performed through a thoracotomy (when performed through a sternotomy, the procedure is commonly called open coronary artery bypass (OP-CAB). A surgical instrument is used to stabilize the heart and restrict blood flow through the coronary artery during the graft procedure. Special care must be given to procedures performed on a beating heart, e.g. synchronizing procedures to occur at certain stages in the cardiac cycle, such as between heartbeats.[0012]
• To perform a CABG procedure, the harvested vessel segment, such as the saphenous vein, is grafted to the coronary artery by end-to-side anastomosis. Typically, sutures are used to graft the vessel segments. However, conventional suturing is complicated by the use of minimally invasive procedures, such as the window approach, e.g., limited access and reduced visibility to the surgical site may impede the surgeon's ability to manually apply sutures to a graft. Additionally, it is difficult and time consuming to manually suture if the CABG procedure is being performed while the heart is beating as the suturing must be synchronized with the heart beat.[0013]
• As can be appreciated, the process of manually suturing the harvested vessel segment to a coronary artery is time consuming and requires a great deal of skill on the part of the surgeon. The resulting sutured anastomosis will also be dependent on the skills of the surgeon. In minimally invasive procedures such as in MIDCAB, the ability to suture is even more complicated due to limited maneuverability and reduced visibility. U.S. Pat. No. 5,707,380 to Hinchliffe et al., the entire contents of which are hereby incorporated by reference, discloses an apparatus and a procedure that enable remote anastomosis without piercing of vessels during both conventional and minimally invasive procedures.[0014]
• A continuing need exists, however, for improved surgical instruments and methods for performing remote anastomoses during both conventional and minimally invasive procedures.[0015]
SUMMARY
• The present disclosure relates to a surgical instrument for anastomosis of first and second blood vessels which includes a housing having distal and proximal ends, a handle and a disposable loading unit removably mounted to the distal end of the housing. The disposable loading unit includes upper and lower fastener support members having a passage defined therethrough for receiving an end of the second blood vessel and configured to releasably support a plurality of surgical fasteners and a retractable anvil located at a distal end of the loading unit. The anvil is movable relative to the fastener support member in response to actuation of the handle to simultaneously deform the surgical fasteners.[0016]
• In one embodiment, the loading unit includes two halves which are pivotable relative to one another to release the second vessel after the instrument is fired. Preferably, the fastener support member includes upper and lower fastener support members which support the fasteners in an array-like manner.[0017]
• In another embodiment, the loading unit includes a first retracting sleeve which moves the anvil in response to actuation of the handle. Preferably, loading unit includes first and second retracting sleeves which are movable relative to the fastener support member from a first position wherein the distal ends of the retracting sleeves are disposed relative to the fastener support member to a second position wherein the distal ends of the retracting sleeves are disposed in closer proximity to the fastener support member.[0018]
• In another embodiment, an actuator moves the first and second sleeves relative to the fastener support member. Preferably, continued movement of the handle moves the second sleeve relative to the first sleeve.[0019]
• In another embodiment, the distal end of the first sleeve includes a plurality of elongated channels for supporting the surgical fasteners. Preferably, each of the channels includes a distal and proximal end wherein each distal end is radially offset from the proximal end such that the proximal and distal ends of the surgical fasteners are supported in a radially offset manner. It is envisioned that the second retracting sleeve releasably retains the surgical fasteners within the elongated channels and the anvil has an angled surface such that the distal ends of the surgical fasteners deform proximally upon actuation of the handle.[0020]
• In another embodiment the actuator includes a cam having more than one cam follower. It is also envisioned that the cam may include multiple stages for imparting different, independent and/or varying movement to each of the cam followers upon actuation of the handle.[0021]
BRIEF DESCRIPTIBN OF THE DRAWINGS
• Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanied drawings. It should be understood, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the invention.[0022]
• An illustrative embodiment of the subject surgical instrument and method are described herein with reference to the drawings wherein:[0023]
• FIG. 1 is a perspective view of a surgical instrument constructed in accordance with a preferred embodiment of the present disclosure;[0024]
• FIG. 2 is an enlarged, partial perspective view of a single use loading unit (hereinafter “SULU”) constructed in accordance with a preferred embodiment of the present disclosure;[0025]
• FIG. 2A is an enlarged, perspective view of the indicated area of detail of FIG. 2;[0026]
• FIG. 3 is a perspective view of a surgical fastener which is designed for operative engagement with the SULU for creating vascular anastomosis between two luminal vessels;[0027]
• FIG. 4 is a side view the surgical instrument of FIG. 1;[0028]
• FIG. 4A is a left, side view of a handle/actuator assembly of the surgical instrument of FIG. 1 shown without a cover plate attached thereto;[0029]
• FIG. 5 is an enlarged, perspective view of a distal end of the actuator assembly shown in a pre-loading position to receivingly engage the SULU;[0030]
• FIG. 6 is a reverse, perspective view of the SULU of FIG. 2;[0031]
• FIG. 6A is a reverse, perspective view of a lower half of the SULU of FIG. 2;[0032]
• FIG. 7 is a perspective view with parts separated of the SULU of FIG. 2;[0033]
• FIG. 7A is a greatly enlarged, perspective view of the indicated area of detail of FIG. 7;[0034]
• FIG. 7B is a greatly enlarged, perspective view of the indicated area of detail of FIG. 7;[0035]
• FIG. 7C is an enlarged, perspective view of a base portion of a first retracting sleeve;[0036]
• FIG. 7D is a greatly enlarged, perspective view of the indicated area of detail of FIG. 7C;[0037]
• FIG. 8 is a greatly enlarged, perspective view of the indicated area of detail of FIG. 7;[0038]
• FIG. 9 is a greatly enlarged, perspective view of the indicated area of detail of FIG. 7;[0039]
• FIG. 10 is a perspective view of the actuator assembly with the cover plate shown separated;[0040]
• FIG. 11 is a perspective view the actuator assembly of FIG. 10 shown with parts separated;[0041]
• FIG. 12 is a horizontal cross-sectional view of the surgical instrument of FIG. 1 shown loaded for firing;[0042]
• FIG. 13 is a horizontal cross-sectional view of the indicated area of detail of FIG. 12;[0043]
• FIG. 13A is a greatly enlarged horizontal cross sectional view of the area indicated in detail of FIG. 13;[0044]
• FIG. 14 is a top cross-sectional view of the surgical instrument taken along section line[0045]14-14 of FIG. 12;
• FIG. 15 is a greatly enlarged top cross-sectional view of the area indicated in detail of FIG. 14;[0046]
• FIG. 16 is a front cross-sectional view of the surgical instrument taken along section line[0047]16-16 of FIG. 12;
• FIG. 17 is a perspective view of the SULU with a first vessel inserted therethrough;[0048]
• FIG. 18 is perspective of the SULU with an end of the first vessel everted over a distal end of the disposable unit being inserted into an incision in a second vessel;[0049]
• FIG. 19 is an internal, perspective view of the second vessel with the SULU and the everted first vessel shown inserted therein;[0050]
• FIG. 20 is a side cross-sectional view of the SULU and the everted first vessel shown inserted within the second vessel in pre-firing position;[0051]
• FIG. 21 is a side view of the actuator assembly without the cover plate during a first firing stage of the instrument and showing the internal movement of a first retractor within the actuator assembly;[0052]
• FIG. 21A is a side cross-sectional view showing the relevant positions of the internal working components of the actuator assembly after the first firing stage;[0053]
• FIG. 21B is a side cross-sectional view showing the movement of the SULU during the first firing stage to deform the surgical fasteners;[0054]
• FIG. 21C is a greatly enlarged side cross-sectional view of the area indicated in detail in FIG. 21B;[0055]
• FIG. 21D is a greatly enlarged perspective view of the surgical fastener shown in a “stapled” configuration;[0056]
• FIG. 21E is a side view showing the relevant movement of a locking sleeve after the first firing stage;[0057]
• FIG. 22 is a side cross-sectional view of the actuator assembly during the second firing stage and showing the internal movement of a second retractor within the actuator assembly;[0058]
• FIG. 22A is a side cross-sectional view of the SULU during the second firing stage and showing the movement of a second retracting sleeve which moves as a direct result of the movement of the second retractor to release the surgical fasteners;[0059]
• FIG. 22B is a greatly enlarged side cross-sectional view showing the retracting movement of a finger-like retention prong which moves as a direct result of the movement of the second retractor;[0060]
• FIG. 23 is a perspective view of the SULU showing the pivotable movement of the two supports which open after firing to release the first vessel;[0061]
• FIG. 24 is a view showing a completed anastomosis;[0062]
• FIG. 25 is a view showing an operating “window” with the patient's heart exposed;[0063]
• FIG. 26A is a view showing the surgical fastener staple pattern of the instrument described with respect to FIGS.[0064]1-26; and
• FIG. 26B. is a view showing one possible alternative surgical fastener staple pattern.[0065]
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
• Preferred embodiments of the surgical instrument and method disclosed herein will be described in terms of a coronary artery bypass procedure wherein a vascular anastomosis is created by joining a section of a harvested vessel, e.g., the saphenous vein, to bypass an occlusion in a coronary artery, e.g., the left anterior descending artery (“LAD”) and/or aorta. Alternatively, the presently disclosed surgical instrument may also be utilized in performing anastomosis of other tubular luminal body structures.[0066]
• In the drawings and in the description which follows, the term “proximal”, as is traditional, will refer to the end of the apparatus which is closer to the user, while the term “distal” will refer to the end which is further from the user.[0067]
• Referring now in detail to the drawing figures in which like reference numerals identify similar or identical elements, one embodiment of the present disclosure is illustrated generally in FIG. 1 and is designated therein as[0068]surgical instrument10.Surgical instrument10 includes two principal components, namely, anactuator assembly20 and a disposable loading unit (“DLU”) or a single use loading unit (“SULU”)100, which along with their internal working components, mechanically cooperate to deform asurgical fastener260 to complete an anastomosis between two vessels, e.g., ansaphenous vein320 and an LAD and/or aorta310 (FIG. 21 B).
• The particular[0069]surgical instrument10 shown in the various figures is preferably designed to deform an array of surgical fasteners similar tofastener260 shown in FIG. 3 which is generally L-shaped and includes abase leg264 and an upwardly extendingsupport leg262. Preferably,base leg264 includes adistal end269 which is sufficiently shaped to penetrate thesaphenous vein320 and the LAD and/oraorta310 upon deformation of thesurgical fastener260. The upwardly extendingsupport leg262 is attached tobase leg264 at apivot point265 and includes an inwardly extendingprong267 disposed at its free end designed to penetrate the LAD and/oraorta310 and securesurgical fastener260 in position after anastomosis. Aconvexity263 projects inwardly between thebase leg264 and thesupport leg262 and is preferably sufficiently dimensioned to cooperate with thebase leg264 to retain thesaphenous vein320 against LAD and/oraorta310 in fluid communication after anastomosis as will be explained in greater detail below with respect to FIGS. 21B and 24. It is envisioned that thesurgical fastener260 can be arranged on the SULU in different patterns/arrays depending upon a particular purpose.
• As best seen in FIGS. 1, 4,[0070]10 and11,actuator assembly20 includes aproximal end24, adistal end22 and ahousing26 defined therebetween for storing the internal working components of theactuator assembly20. Preferably, aplate90 covers the internal components of theactuator assembly20 when assembled. More particularly,housing26 includes at least onemechanical interface23awhich reciprocates with a corresponding mechanical interface23b(FIG. 10) disposed oncover plate90 to matingly engage the twocomponents26 and90.
• [0071]Actuator assembly20 also includes ahandle12 which initiates firing of thesurgical instrument10 and a spring-loadedthumb tab30 for loading theSULU100 onto theactuator assembly20 both of which will be explained in greater detail below. Preferably, handle12 is provided with an ergonomic surface which is contoured and configured to be comfortably gripped by the hand of the user during operation of the instrument.
• Turning now to FIG. 11 which illustrates in detail the internal working components of the actuating[0072]assembly20 which are preferably assembled and stored withinhousing26. More particularly, the actuatingassembly20 includes atorsion spring70 which mounts aboutpost21 which protrudes fromhousing26.Spring70 includes alower arm74 which is biased against a lower portion of the housing and anupper arm72 which is biased against a rotating two-stage cam60.
• [0073]Handle12 includes abushing19 which protrudes laterally from the proximal end of thehandle12 and pivotally engages acorresponding recess29 disposed within theproximal end24 ofhousing26 to allow pivotal movement of thehandle12 with respect tohousing26.Handle12 also includes a vertically extendingslot27 disposed at itsproximal end24 which receives the proximal end of alever16 which moves in conjunction with thehandle12. A pair offlanges14aand14bdownwardly extend from thehandle12 and receivelever16 therebetween. Amechanical interface11adisposed onhandle12 engages a corresponding mechanical interface11bdisposed onlever16 to secure thelever16 to thehandle12. Preferably,lever16 has afirst recess17 shaped to engage and control the movement of thecam60 during downward movement of thehandle12, the purpose of which will be explained in more detail with respect to FIG. 21A.Lever16 also includes asecond recess15 which helps to limit lateral movement of thespring70 withinhousing26.
• As mentioned above, actuating[0074]assembly20 also includes a spring-loadedthumb tab30 which rests atophousing26 within alongitudinally extending slot28 disposed near thedistal end22 thereof. As best seen in FIG. 10,slot28 is formed bynotches18aand18bof thehousing26 andcover plate90, respectively.Tab30 includesthumb guide35 which cooperates with a slidingsleeve32 to facilitate proximal movement of thetab30 for loading the SULU. A downwardly dependingflange34 disposed ontab30 engages acorresponding slot33 located in amount31 disposed atop the slidingsleeve32. Preferably, slidingsleeve32 includes apost36 which is dimensioned to receive atension spring38 thereon.Spring38 is biased between ablock47 disposed withinhousing26 and aproximal edge37 of slidingsleeve32 such thatspring38biases sliding sleeve32 to a distal-most position proximatedistal end22. Preferably, adistal end39 ofsleeve32 is arcuate or semi-circular and is dimensioned to slidingly engage acorresponding end82 of afirst retractor80 to lock theSULU100 within theactuator assembly20 after theSULU100 is loaded as will be discussed in more detail below.
• [0075]Actuator assembly20 also includesfirst retractor80 and asecond retractor50 which each move by way of movement of thehandle12 which, in turn, imparts movement to the two-stage cam60.First retractor80 includes distal and proximal ends82 and84, respectively, and is generally tubular in dimension with the exception of anelongated furrow83 extending proximally fromdistal end82 for slidingly supportingsleeve32.Retractor80 also includes aslot85 for receiving apin54 for affixing theretractor80 to thecam60 and another pair ofslots87 and89 located near theproximal end84 for receiving twocam followers51aand51b, respectively. Preferably, theproximal end84 is bifurcated to facilitate insertion of thesecond retractor50 therein.
• As best seen in FIGS. 11 and 16, a[0076]guide81 engages anelongated rib25ainhousing26 and an elongated rib25bincover plate90 to slidingly mount theretractor80 tohousing26.Guide81 is dimensioned slightly longer thanrib25ato permit proximal movement of thefirst retractor80 relative to thehousing26 upon activation of thehandle12. Preferably, aprotective tube95 is telescopically disposed about thefirst retractor80 and moves in conjunction with the slidingsleeve32 by way ofslot96 which securesmount31 of the slidingsleeve32 therein. It is anticipated thatprotective tube95 also helps to restrict lateral movement of thefirst retractor80 during retraction.Tube95 also includes anelongated channel97 which generally aligns withguide81 located in thefirst retractor80 to mount both components toribs25aand25b.
• It is contemplated that proximal movement of[0077]tab30 will impart reciprocating proximal movement to the slidingsleeve32 to exposecarriages86 and88 disposed within thefirst retractor80 which are designed to receive a pair of first and second retractingsleeves110 and120 (FIGS.7-9) of theSULU100. More particularly, and as best seen in FIG. 5,carriage86 is generally circular in shape and is designed to receive anouter lip122 formed by the union ofend122aand122bofsecond retracting sleeve120 of theSULU100. Preferably,carriage86 is dimensioned larger that thelip122 so as to permit proximal movement of thesecond retracting sleeve120 relative to thefirst retracting sleeve110 as will be explained in more detail with respect to FIG. 22A.Carriage88 is likewise circular in shape and receivesouter lip112 of thefirst retracting sleeve110.
• [0078]Actuator assembly20 also includes ahandle lock40 which rests atop thefirst retractor80 and extends laterally between thehousing26 and thecover plate90. More particularly, handlelock40 is mounted withinslots93aand93bas best seen in FIG. 10. Handlelock40 includes a post43 which receives aspring45 for biasinghandle lock40 against aledge49 of the housing26 (FIG. 12). Handlelock40 also includes a pair offlanges42aand42bwhich align withflanges14aand14bdisposed onhandle12. As shown best in FIGS. 21 and 22, downward movement of thehandle12 forces thehandle lock40 initially distally againstspring45 untilflanges14aand14bclear flanges42aand42bat whichpoint spring45 forces handlelock40 proximally to lockflanges42aand42batopflanges14aand14band to lockhandle12 in a downwardly disposed position. Preferably,flanges42aand42bdefine aslot41 for receiving lever.16 therebetween.
• [0079]Actuator assembly20 also includes asecond retractor50 which includes anelongated arm52 having a key-likedistal end53 and a T-shapedheel section56. Preferably, T-shapedheel section56 attaches to atension spring55 disposed proximally thereof.Second retractor50 is preferably bifurcated at its proximal end forming two longitudinally extendingfins58aand58beach having aslot57 andaperture59 for receivingcam followers51 and51 b, respectively. It is contemplated thatspring55 is biased against anelongated stop65 which rests atoparm52 andbiases heel section56 proximally when thesecond retractor50 is retracted which will be explained in more detail below with respect to the operation of thesurgical instrument10.
• As mentioned above, the[0080]first retractor80 is affixed to two-stage cam60 bypin54. More particularly,cam60 includes anaperture61 located near the distal end thereof for receivingpin54 which affixes thecam60 to thefirst retractor80.Cam60 also includes a pair of generally vertical arcuately-shapedslots62 and64 which each include two discrete stages, namely62a,62band64a,64b, respectively, for imparting movement to correspondingfollowers51aand51b. Anub66 is located near the uppermost portion of thecam60 and is dimensioned to slideably engagerecess17 located inlever16 as best illustrated in FIG. 12.
• It is contemplated that during downward movement of[0081]handle12,lever16 will bias nub66 downwardly such thatnub66 rides proximally alongrecess17 and causescam60 to pivot downwardly aboutpin54 as shown best in FIGS. 21A and 22. In turn,Followers51aand51bwill ride alongslots64 and62 and cause the first andsecond retractors80 and50 to move in a proximal direction which will be explained in more detail below. Preferably,recess17,nub66 andslots64 and62 can be dimensioned to control the movement and timing of thecam followers51aand51b. For example, it is envisioned that thestages64a,64band62aand62bcan be dimensioned to control the timing and movement of the first and second retractors which, in turn, can effect the efficiency of the anastomosis.
• [0082]Elongated stop65 is preferably affixed to the distal end ofcam60 and rests atop thesecond retractor50.Elongated stop65 includes adistal end69 and aproximal end67 which includes two extendingportions67aand67beach having anaperture63aand63b, respectively, disposed therethrough. Preferably, end69 ofstop65 is sufficiently dimensioned such that it engages a corresponding biasingpost102 located within theSULU100.
• Preferably, the[0083]second retractor50, thecam60 and theelongated stop65 are pre-assembled prior to insertion into thefirst retractor80. More particularly and as best illustrated in FIGS.10-12,elongated stop65 is positioned atoparm52 of thesecond retractor50 between T-shapedheel section56 andend53. Apertures63aand63bofstop65 align withaperture61 ofcam60 such that once thecam60 and theelongated stop65 are inserted withinslot91 of thefirst retractor80,pin54 locks the twocomponents65 and60 together throughslot85.
• [0084]Cam60 is positioned between the extendingfins58aand58bof thesecond retractor50 such that, when theretractor50 andcam60 are inserted withinslot91 of the first retractor,followers51aand51bare inserted throughslot87 andslot89, respectively, and slideably couple the twocomponents50 and60 within thefirst retractor80. Handlelock40 is then positioned atop thefirst retractor80 as described above.First retractor80 is then mounted onribs25aand25bofhousing26 andcover plate90, respectively andtab30 along with slidingsleeve32 are engaged thereon.Handle12 andlever16 are then assembled as described above and pivotably mounted aboutpost21.Spring70 is then positioned accordingly so as to bias handle12 againsthousing26.
• Turning now to FIGS.[0085]7-9 which show an exploded view of the internal working components of theSULU100 which as mentioned above includes first retractingsleeve110 andsecond retracting sleeve120 which cooperate to deformfasteners260 and securely fasten thesaphenous vein320 to the LAD and/oraorta310 in fluid communication as shown in FIG. 24.
• More particularly and as best seen in FIGS.[0086]7-7D, first retractingsleeve110 includes a tube-like base110aand an arcuate sleeve cap110bwhich together define thefirst retracting sleeve110. Base10aincludes acircular lip112 located at its proximal end and asemi-circular anvil118alocated at the opposite end. Alocking tab116ahaving anelongated slit182alocated therein is disposed betweenlip112 andanvil118a. A longitudinally-extendingslot114ais disposed between thelip112 and thelocking tab116a. At least oneinterface117adownwardly depends frombase110ato mechanically engage a corresponding mechanical interface117bdisposed on sleeve cap110b(FIG. 7). Aflange113ais preferably disposed beneathslot114aand is sufficiently dimensioned to engage corresponding flanges13b₁and113b₂located on sleeve cap110b. Slot114ais sufficiently dimensioned to receive atab138a(FIG. 13) which projects from an uppersurgical fastener support130awhich is explained in more detail below.
• Sleeve cap[0087]110bincludes asemi-circular anvil118band a bifurcated proximal end113 composed of flanges113b₁and113b₂which together define a slot114bfor receiving atab138bwhich projects from a lowersurgical fastener support130bwhich is explained in more detail below. Sleeve cap110balso includes mechanical interfaces117bwhich couples with correspondingmechanical interfaces117adisposed onbase110ato engage sleeve cap110bwithbase110a. Alocking tab116bhaving an elongated slit182blocated therein is disposed between proximal end113 andanvil118b. A longitudinally-extending opening111bis preferably disposedproximate locking tab116band aligns with acorresponding opening111ainbase110a(FIG. 7C) such that thesaphenous vein320 can be received therethrough as seen best in FIGS. 17 and 18.
• FIGS. 2A and 7D show a greatly enlarged view of[0088]anvil118awhich includes a semi-annular array of fastener support channels or cradles119aeach configured and dimensioned to support asurgical fastener260 therein. Sleeve cap110balso includes fastener support channels119bwhich, when base110aand sleeve cap110bare assembled, align to form a circular array about the internal surfaces ofanvil118aand118b. It is envisioned thatanvils118aand118bcan be designed to support different arrays ofsurgical fasteners260 depending upon a particular purpose. Eachchannel119aand119bis preferably separated by ananchor187aand187b(FIG. 7) which releasably retains a projectingfinger124a,124bof second retracting sleeve120 (FIG. 2A).Support channels119aand119beach include proximal ends186aand186banddistal ends184aand184bwhich are radially offset from one another to seatsurgical fastener260 withinchannels119aand119bin a radially offset manner the purpose of which will be explained below with respect to the operation of thesurgical instrument10. Thedistal end184aof eachchannel119ais preferably arched so as to correspond to the arcuate shape of the end of thesurgical fastener260 as best seen in FIG. 13A. It is anticipated that arching thedistal end184awill cause thesurgical fastener260 to deform upwardly and proximally upon retraction of thefirst retracting sleeve110 by thefirst retractor80 as explained below with reference to FIGS.21-22.
• FIGS.[0089]7-7D also show second retractingsleeve120 which includes an upper cuff120a, a lower cuff120band anouter cap128 which together define thesecond retracting sleeve120. More particularly, upper cuff120aincludes asemi-annular lip122aat one end and a plurality ofretention fingers124aat the opposite end. Upper cuff120aalso includes afirst slot101 which preferably aligns withslot114aof thefirst retracting sleeve110ato receivetab138aofupper fastener support130btherethrough (FIG. 20). Asecond slot126areceives lockingtab116awhen cuff120ais slideably mounted atopbase110a.Interfaces129amechanically engage correspondinginterfaces129blocated on lower cuff120b.
• Lower cuff[0090]120bincludes a bifurcatedproximal end107 which comprises flanges107b₁and107b₂which define aslot108 for receivingtab138boflower fastener support130btherethrough and a plurality of retention fingers124bwhich extend from the opposite end thereof. A slot126bis disposed between the flanges107b₁,107b₂and the fingers124bfor receivinglocking tab116bof the sleeve cap110bwhen cuff120bis slideably mounted thereon. A longitudinally-extending opening121bis disposed proximate slot126band aligns with acorresponding opening121ain upper cuff120aand also aligns withopenings111aand111bof thefirst retracting sleeve110 such that thesaphenous vein320 can be received therethrough as seen best in FIGS. 17 and 18.
• A[0091]semi-circular cuff cap128 is disposed atop lower cuff120band mechanically interfaces with upper cuff120asuch thatsemi-circular lips122aand122bforcircular lip122. More particularly,cuff cap128 includes a plurality ofdetents123bwhich mechanically engage a corresponding plurality ofnotches123alocated in upper cuff120asuch that thecuff cap128, upper cuff120aand lower cuff120ball move in unison upon retraction of thesecond retracting sleeve120.Sleeve cap128 is preferably bifurcated at its distalend forming slot109 which is dimensioned to receivetab138b.
• As can be appreciated,[0092]fingers124aand124bmove upon retraction of thesecond retracting sleeve120 to release thesurgical fasteners260 after firing. More particularly and as best seen in FIGS. 2A and 7A, the distal end of eachfinger124ais forked and includes afirst prong127awhich retains asurgical fastener260 within thefastener support channels119aand asecond prong125awhich interlocks withanchor187ato releasably lock thefinger124ato thefirst retracting sleeve110 until released by the second retractor50 (FIGS. 22A and 22B) which will be explained in more detail with respect to the operation of thesurgical instrument10. Likewise, each finger124bof lower cuff120bincludesprongs127band125bwhich operates in the same manner.
• As mentioned previously, the[0093]SULU100 also includesfastener support130 which has anupper support130aand alower support130bwhich, when assembled, internally house the first and second retractingsleeves110 and120, respectively, along with their individual working components.Upper support130aandlower support130beach include adistal end135aand135beach having an array ofbraces137aand137b, respectively, which project radially fromdistal ends135aand135b. As best illustrated in FIG. 2, eachbrace137aand137bsupports an upwardly extendingsupport leg262 of asurgical fastener260 disposed within one of thechannels119aor119b. A plurality of radially extendingslots139aand139bare disposed between eachsupport brace137a,137bfor retaining asurgical fastener260 therein and for restricting unwanted lateral =movement of eachfastener260. It is anticipated that eachsurgical fastener260 is positioned within aslot139a,139bsuch thatconvexity263 projects outwardly frombrace137a,137band, after anastomosis, cooperates with thebase leg264 to retain thesaphenous vein320 against LAD and/or aorta310 (FIGS. 21B and 24).
• Upper support and[0094]lower support130aand130b, respectively, also includehinges136aand136bwhich, when theSULU100 is assembled, matingly engage one another to allow pivotable movement between thesupports130aarid130bfrom an open position (FIG. 23) to a closed position (FIG. 2). Preferably, apin180 secures the two hinges136aand136btogether (FIG. 6). Upper andlower supports130aand130beach include a longitudinally-extending opening133a(FIG. 23) and133bwhich aligns withopenings121a,121b,111aand111bdescribed above to receivesaphenous vein320 therethrough as seen best in FIGS. 17 and 18. Longitudinally orientedslots131aand131bare disposedadjacent openings133aand133bon the upper andlower support members130aand130b, respectively, for receiving lockingtabs116aand116bin much the same manner as described above with respect toslots126aand126bof thesecond retracting sleeve120.
• [0095]Lower support130bincludes a pair ofshoulders132aand132bdisposed on opposite sides of opening133bfor slideably receiving a corresponding pair offlanges144aand144bassociated with anupper locking sleeve140a. More particularly, eachflange144aand144bextends distally from theupper locking sleeve140ato define anotch149aand149b, respectively, therein for receivingshoulders132aand132boflower support130b.
• [0096]Upper locking sleeve140aincludes a C-shapedclip146a(FIG. 8) disposed therein which has pair of opposinghooks147afor snap-lockingly engaging slit182aoflocking tab116aof first retractingsleeve110. Alower locking sleeve140boperates in a similar manner and includes a pair of opposinghooks147bfor snap-lockingly engaging slit182bof locking tab1116bof first retractingsleeve110.Upper locking sleeve140aalso includes anopening141awhich aligns withopenings133a,133b,121a,121b,111aand111bdescribed above to receivesaphenous vein320 therethrough as seen best in FIGS. 17 and 18. It is envisioned that upon retraction of thesecond retracting sleeve120,upper locking sleeve140awill move proximally relative toshoulders132band134band disengageshoulders132a,132bwhich, in turn, will allow the upper andlower supports1130aand130bto pivot aboutpin180 and release the saphenous vein320 (FIGS. 21 E and 23). This will be explained in greater detail with respect to the operation of the instrument as described below.
• [0097]SULU100 also includes a biasingpost102 which mechanically aligns upper andlower supports130aand130bin fixed relation relative to one another. More particularly, biasingpost102 includes aproximal end103 and adistal end105 and has a vertically orientedcavity106 disposed therethrough for receivingtabs138aand138bof the upper andlower supports130aand130b, respectively. As mentioned above,tabs138aand138bpass throughslots114a,114bof thefirst retracting sleeve110 and throughslots101,108 and109 of thesecond retracting sleeve120 and mechanically align with one another withincavity106 as best seen in FIG. 21B.
• Biasing[0098]post102 also includes a taperedspacer104 disposed along the outer periphery thereof for frictionally locking thefirst retracting sleeve110 in a retracted position after thefirst retracting sleeve110 is withdrawn by thefirst retractor80. More particularly, when theSULU100 is assembled and prior to firing thesurgical instrument10, biasingpost102 is disposed relative to thefirst retracting sleeve110 such thatspacer104 is proximal to lip112 (FIG. 13). During retraction of thefirst retracting sleeve110,lip112 is forced overspacer104 and thefirst retracting sleeve110 is locked into retracted position and prevented from recoiling. As explained in greater detail below, locking thefirst retracting sleeve110 in a retracted position also pre-disposes thesecond retracting sleeve120 for retraction relative to the first retracting sleeve (FIG. 22A).
• Turning now in detail to the loading of the[0099]SULU100 withinactuator assembly20 as best seen in FIG. 5,thumb tab30 is moved proximally by way ofthumb guide35 againstspring38 which, in turn, movessleeve32 andprotective cover95 proximally to exposecarriages86 and88. TheSULU100 is then loaded withinactuator assembly20 by placinglip112 withincarriage88 andlip122 withincarriage86. As best shown in FIG. 13,lip122 is positioned near the distal end ofcarriage86 which allowslip122 and, hence, second retractingsleeve120, to move independently from the first retracting sleeve upon activation of thesecond retractor50. In contrast,carriage88 is dimensioned smaller thancarriage86 such thatlip112 fits snugly withincarriage88. Once the SULU is positioned withincarriages86 and88,thumb tab30 is released andspring38biases sleeve32 andprotective cover95 distally overlips112 and122 to lock theSULU100 within theactuator assembly20.
• In use and as shown in FIGS.[0100]17-24,surgical instrument10 facilitates the performance of a vascular anastomosis and either eliminates and/or minimizes the need for manual suturing of the vessels. The method and usage described herein will be addressed in terms of vascular anastomosis performed on a beating heart. However, the presently disclosedsurgical instrument10 may also be used in performing anastomoses of other tubular or luminal body structures without departing from the scope of the present disclosure. For example,surgical instrument10 may be used in conventional open CABG procedures using a median sternotomy or other large incision without stopping the heart. Alternatively, the thoracic “window” procedure may be used to achieve access to the heart. The “window” approach involves a smaller incision and less displacement of the ribs, and therefore is less traumatic to the patient. For this approach, conventional surgical techniques are used to determine the location of the incision to access the chest cavity.
• To gain access to the heart, after an incision is made, a surgical retractor assembly may be used to separate the ribs at the site of the incision as shown in FIG. 25. Specifically, a[0101]base410 is placed on the chest of the patient with the central opening defined by the base being positioned over the operative site.Retractor assemblies430 are mounted to the base410 at various locations. Eachretractor assembly430 includes a blade having a hook to engage either a rib or the sternum therewith. The retractor assemblies are mounted and used to retract ribs until a sufficiently large opening in the chest cavity is defined to provide direct access to the heart. For example, the sternum and the fourth and fifth ribs can be split apart to create a window. Other configurations of spreading the ribs and/or selectively cutting individual ribs away from the sternum may also be utilized for a particular procedure.
• Once the desired access to the heart is achieved, the graft vessel, e.g., the[0102]saphenous vein320 is dissected from the surrounding cartilage and muscle, and a free end of the vessel is exposed. The occluded coronary artery, e.g., the LAD and/oraorta310, is then prepared for receiving thesaphenous vein320 graft. The heart is positioned in the desired orientation either by traction sutures passing through the pericardium or by manipulation with heart manipulation instruments which are held by the surgical personnel or clamped in a fixed orientation to a base such as the retractor assembly base. Blood flow through the LAD and/oraorta310 can be restricted by cardiopulmonary bypass and pericardial cooling. Alternatively, a dampening instrument may be applied directly on the LAD and/oraorta310 to restrict blood flow and reduce movement of the heart near the LAD and/oraorta310.
• Turning now in detail to the operation of the[0103]surgical instrument10 and in particular, the operation of theSULU100 as detailed in FIGS.17-24, once thesaphenous vein320 has been harvested, the user inserts thefree end322 into opening133 of the SULU and pull via a surgical hook or graspers thefree end322 towards the distal end of theSULU100. The user then everts thesaphenous vein320 over theanvils118a,118bof theSULU100 such that thefree end322 of thesaphenous vein320 is retained byend269 of thesurgical fasteners260. Everting of thesaphenous vein320 may be achieved by any suitable known instruments and/or techniques such as by using graspers.
• In some cases it may be preferable to orient the upper and[0104]lower supports130aand130bin a slightly longitudinally offset manner such that an angle is created relative to the transverse plane of the twosupports130aand130bin order to optimize the anastomosis and to facilitate optimal blood flow across the graft site from thesaphenous vein320 to the LAD and/oraorta310. This junction will create a more dramatically visible “heel” and “toe” effect in which an acute or obtuse angle between the vessels is clearly defined.
• The remaining portion of the[0105]saphenous vein320 is preferably positioned away from theinstrument10 to facilitate insertion of thesaphenous vein320 into the LAD and/oraorta310 as shown in FIG. 18. The user then inserts the end of theSULU100 into anincision312 in the LAD and/or aorta such that thedistal end269 of each of the plurality offasteners260 and theeverted end portions322 of thesaphenous vein320 are sufficiently inserted into and through incision312 (FIGS. 19 and 20). As seen best in the enlarged view of FIG. 20, thesupport leg262,convexity263 andprong267 of eachsurgical fastener260 remainsoutside incision312. The instrument is now preset for firing.
• FIGS.[0106]21-22 show the firing sequence ofinstrument10, i.e., when thehandle12 is depressed by the user. As best shown in FIGS. 21 and 21A, ashandle12 is depressed downwardly in the direction of reference arrow “A”,lever16 simultaneously imparts movement to both handlelock40 andcam60. More particularly, downward movement ofhandle12causes flanges14aand14boflever16 to urgeflanges42aand42bofhandle lock40 distally againstspring45 in the direction of reference arrow “B” (FIG. 21). At the same time, handle12causes recess17 oflever16 to biasnub66 which, in turn, causescam60 to deflect downwardly and proximally as best seen in FIG. 21A. Preferably,recess17 inlever16 is dimensioned to control the specific movement ofnub66 withinrecess17 which, in turn, controls the overall movement ofcam60. Downward and proximal movement ofcam60 causescam followers51aand51bto move within the first cam stages64aand62aofslots64 and62, respectively, which, in turn, moves thefirst retractor80 andprotective cover95 proximally in the direction of reference arrow B′.
• As seen best in FIG. 21, as[0107]retractor80 moves proximally as a result of the movement ofcam followers51aand51bwithinslots64 and62,slot85 moves proximally until it abutspin54. Preferably, whenslot85 abutspin54,cam60 is forced more downwardly aboutpin54 such thatcam followers51aand51bmove more proximally to engage thesecond stages64band62bof thecam slots64 and62, respectively.
• As mentioned above, the[0108]first retractor80 retracts the first retracting sleeve110 (FIG. 21) which, in turn, causessurgical fasteners260 to deform as shown in FIGS. 21B and 21D. More particularly and as best shown in FIG. 21 B, proximal movement of thefirst retractor80 causes both thefirst retracting sleeve110 and thesecond retracting sleeve120 to move proximally relative to biasingpost102 until biasingpost102 abuts theend69 ofelongated stop65. As a result,anvils118aand118bdeform the distal ends269 ofsurgical fasteners260 upwardly and proximally towardsbraces137aand137b, respectively, i.e., arc-like distal ends184aand184bcausesurgical fasteners260 to deform upwardly and proximally upon retraction of thefirst retracting sleeve110. At the same time, the LAD and/oraorta310 is forced slightly proximally and extendingprongs267 penetrate to hold the LAD and/oraorta310 in position as best seen in FIG. 22A.
• It is anticipated that the radially offset orientation of the opposite ends[0109]186a,186band184a,184bof thesupport channels119aand119b, respectively will cause the opposite ends267 and269 of thesurgical fasteners260 to deform at an angle a relative to one another as best shown in FIG. 21D. This allowsend269 to deform proximal tobraces137aand137b. Preferably, braces137aand137bhave a tapered cross section to deformend269 ofsurgical fastener260 radially fromend267 during deformation.
• FIG. 21 C shows the resulting position of the[0110]spacer104 of the biasingpost102 after thefirst retractor80 retracts the first and second retractingsleeves110 and120, respectively. More particularly,spacer104 frictionally locks thefirst retracting sleeve110 relative to thesecond retracting sleeve120 and prevents thefirst retracting sleeve110 from recoiling after firing.
• FIG. 21E shows the proximal movement of the locking[0111]sleeve140aas a result of the movement of thefirst retracting sleeve110. More particularly, when thefirst retracting sleeve110 is retracted proximally, lockingtab116aretracts withinslot131aofsupport130aandbiases locking sleeve140ain a proximal direction as well as seen by reference arrow “C”. Proximal movement of the lockingsleeve140arelative to support130adisengages flanges142aand144afromshoulders132band134b, respectively, ofsupport130bwhich, in turn, unlocks supports130aand130bfrom one another thus permitting pivotal movement of thesupport members130a,130bas best seen in FIGS.21E and23.
• Continued downward movement of[0112]handle12 results in both proximal movement of thesecond retractor50 and engagement of thehandle lock40 with thehandle12. More particularly and as best illustrated in FIG. 22, as the user continues to move thehandle12 in a downward direction,flanges14aand14bclearcorresponding flanges42aand42bandspring45 biases handlelock40 proximally in the direction of reference arrow “D” to lock thehandle12 in position. Simultaneously,cam60 is rotated aboutpin54 to a point where thesecond stages64aand62aof thecam slots64 and62 effect the movement of thecam followers51aand51 b. More particularly, ascam60 is forced downwardly, thesecond stage62aofcam slot62moves cam follower51 b proximally which, in turn, moves thesecond retractor50 proximally. Thesecond stage64aofcam slot64 is generally vertically oriented and, as a result,cam follower51amoves vertically upon continued downward movement ofhandle12.Slot57 ofretractor50 allows thesecond retractor50 to slide proximally relative tocam follower51a.
• As mentioned above,[0113]second retractor50 moves the key-like end53 of thesecond retracting sleeve120 withincarriage86 relative to thefirst retracting sleeve110 as illustrated by reference arrow “E” of FIG. 22A. Proximal movement of thesecond retracting sleeve120 retracts theprongs127aand127boffingers124a,124b, respectively, which releases thesurgical fasteners260 as illustrated by reference arrow “E” of FIG. 22B.
• As mentioned above, after[0114]sleeve110 is retracted, lockingsleeve140amoves proximally to allow the twosupports130aand130bto pivot away from one another as shown in FIG. 23 to permit the removal of thesaphenous vein320 from within the SULU thereby completing the vascular anastomosis as shown in FIG. 24.
• FIG. 26A shows a schematic diagram of the surgical fastener staple pattern which is formed upon actuation of the instrument described above with respect to FIGS.[0115]1-26. More particularly, the surgical fasteners are supported by the fastener support braces137a,137bin a normal manner relative to a longitudinal axis “A” (FIG. 5) extending through the SULU. It is envisioned that other surgical fastener staple patterns, e.g., spiral, tangential or angular relative to axis “A”, may be utilized to achieve hemostasis between vessels, FIG. 26B.
• It will be understood that various modifications may be made to the embodiment shown herein. For example, the instrument may be sized to perform an anastomosis for other vessels and luminal tissue. Moreover, although the various internal components of the[0116]instrument10 are shown engaged by particular mechanical interfaces it is envisioned that other types of mechanical interfaces can be employed to achieve the same or similar purpose, e.g., snap-fit, tongue and groove, press fit, etc. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiment. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims (53)

What is claimed is:

1. A surgical instrument for anastomosis of first and second blood vessels, comprising:

a housing having distal and proximal ends and a handle;

a disposable loading unit removably mounted to the distal end of the housing having:

upper and lower fastener support members having a passage defined therethrough for receiving an end of the second blood vessel and configured to releasably support a plurality of surgical fasteners; and

a retractable anvil located at a distal end of the loading unit, the anvil being movable relative to the fastener support member in response to actuation of the handle to simultaneously deform the surgical fasteners.

2. A surgical instrument according toclaim 1 wherein the loading unit further comprises a first retracting sleeve which moves the anvil in response to actuation of the handle.

3. A surgical instrument according toclaim 1 wherein the fastener support member supports the fasteners in an array-like manner.

4. The surgical instrument according toclaim 1 wherein the distal end of the first sleeve includes a plurality of elongated channels for supporting the surgical fasteners.

5. The surgical instrument according toclaim 4 wherein each of the channels includes a distal and proximal end wherein each distal end is radially offset from the proximal end such that the proximal and distal ends of the surgical fasteners are supported in a radially offset manner.

6. A surgical instrument according toclaim 1 wherein the anvil has an angled surface such that the distal ends of the surgical fasteners deform proximally upon actuation of the handle.

7. A surgical instrument according toclaim 4 further comprising a second retracting sleeve for releasably retaining the surgical fasteners within the elongated channels of the first retracting sleeve.

8. A surgical instrument according toclaim 1 wherein the loading unit further comprises second retracting sleeve which is movable in response to actuation of the handle.

9. A surgical instrument according toclaim 8 wherein continued movement of the handle moves the second retracting sleeve relative to the first retracting sleeve.

10. A surgical instrument according toclaim 9 wherein movement of the second retracting sleeve relative to the first retracting sleeve releases the surgical fasteners.

11. A surgical instrument according toclaim 8 wherein the second retracting sleeve includes a plurality of fingers for releasably retaining the surgical fasteners against the anvil.

12. A surgical instrument according toclaim 1 further comprising an actuator which moves the first and second retracting sleeves in response to movement of the handle.

13. A surgical instrument according toclaim 12 wherein the actuator includes a cam.

14. A surgical instrument according toclaim 13 wherein the cam includes more than one cam follower.

15. A surgical instrument according toclaim 13 wherein the cam includes multiple stages.

16. A surgical instrument for anastomosis of first and second blood vessels, comprising:

a housing having distal and proximal ends;

a loading unit having:

a fastener support member for supporting a plurality of surgical fasteners;

first and second retracting sleeves which are movable relative to the fastener support member from a first position wherein the distal ends of the retracting sleeves are disposed relative to the fastener support member to a second position wherein the distal ends of the retracting sleeves are disposed in closer proximity to the fastener support member, and

an actuator for moving the first and second sleeves relative to the fastener13 support member.

17. The surgical instrument according toclaim 16 wherein the actuator includes a handle.

18. The surgical instrument according toclaim 16 wherein the loading unit is comprised of two halves which are pivotable relative to one another.

19. The surgical instrument according toclaim 18 wherein the two halves of the loading unit when closed form an elongated aperture for receiving the second vessel therethrough.

20. The surgical instrument according toclaim 16 wherein the distal end of the first sleeve includes a plurality of elongated channels for supporting the surgical fasteners.

21. The surgical instrument according toclaim 20 wherein each elongated channel includes a distal and proximal end wherein each distal end is radially offset from the proximal end.

22. The surgical instrument according toclaim 16 wherein the fastener support supports the surgical fasteners in an array-like manner.

23. The surgical instrument according toclaim 20 wherein the second sleeve includes a plurality of resilient fingers which releasably secure the surgical fasteners within the elongated channels.

24. The surgical instrument according toclaim 16 wherein continued movement of the actuator moves the second sleeve relative to the first sleeve.

25. The surgical instrument according toclaim 16 wherein the actuator includes a cam.

26. The surgical instrument according toclaim 16 wherein the actuator includes a multi-staged cam.

27. The surgical instrument according toclaim 26 wherein a first stage of the multi-staged cam imparts movement to both the first and second sleeves and a second stage of the multi-staged cam imparts movement to the second sleeve relative to the first sleeve.

28. The surgical instrument according toclaim 16 wherein the actuator includes at least one spring.

29. The surgical instrument according toclaim 16 further comprising a locking mechanism which locks the actuator to the housing after the instrument is fired.

30. The surgical instrument according toclaim 16 wherein the loading unit is releasably mounted to the housing.

31. The surgical instrument according toclaim 16 wherein the instrument further comprises a locking tab for selectively mounting the loading unit to the housing.

32. The surgical instrument according toclaim 31 wherein the locking tab is movable from a first position which enables the loading unit to be mounted to the housing to a second position which secures the loading unit to the housing.

33. The surgical instrument according toclaim 16 wherein the loading unit is disposable.

34. The surgical instrument according toclaim 16 wherein the distal end of the first sleeve includes an anvil for retaining the distal ends of the surgical fasteners and for supporting an everted end of the second vessel.

35. The surgical instrument according toclaim 34 wherein the anvil includes an angled surface which causes the distal end of the surgical fasteners to deform proximally during firing.

36. A surgical instrument for anastomosis of first and second blood vessels, comprising:

a housing having distal and proximal ends;

a loading unit having:

upper and lower fastener support members for supporting a proximal end of a plurality of surgical fasteners in an array-like manner;

first and second retracting sleeves disposed between the upper and lower fastener support members, the retracting sleeves being movable relative to the fastener support members from a first position wherein the distal ends of the sleeves are disposed relative to the fastener support member to a second position wherein the distal ends of the sleeves are disposed in closer proximity to the fastener support members;

an actuator for moving the first and second sleeves relative to the fastener support member.

37. The surgical instrument according toclaim 36 wherein the second sleeve is movable relative to the first sleeve

38. The surgical instrument according toclaim 37 wherein continued movement of the actuator moves the second sleeve relative to the first sleeve.

39. The surgical instrument according toclaim 38 wherein the housing includes a second key-like arm for moving the second sleeve relative to the first sleeve.

40. The surgical instrument according toclaim 36 wherein the first sleeve includes a base and a sleeve cap, the sleeve cap being selectively pivotable relative to the base.

41. The surgical instrument according toclaim 36 wherein the second sleeve includes upper and lower cuffs, the upper cuff being disposed between the upper fastener support and the first retracting sleeve and the lower cuff being disposed between the lower fastener support and the first retracting sleeve.

42. The surgical instrument according toclaim 36 wherein each of the fastener support members includes a plurality of radially inscribed channels for supporting the proximal end of the surgical fasteners.

43. The surgical instrument according toclaim 36 wherein the distal end of the first retracting sleeve includes a plurality of elongated channels for supporting the surgical fasteners.

44. The surgical instrument according toclaim 43 wherein each elongated channel includes a distal and proximal end wherein the distal end is radially offset from the proximal end.

45. The surgical instrument according toclaim 43 wherein the second retracting sleeve includes a plurality of resilient fingers which releasably secure the surgical fasteners within the elongated channels of the first retracting sleeve.

46. The surgical instrument according toclaim 36 wherein the loading unit further comprises a post which upon movement of the actuator bias the first and second retracting sleeves relative to the fastener support members.

47. The surgical instrument according toclaim 46 wherein the post further comprises a spacer for locking the first retracting sleeve relative to the fastener support members to permit subsequent movement of the second retracting sleeve relative to the first retracting sleeve upon continued movement of the actuator.

48. The surgical instrument according toclaim 36 wherein the loading unit is comprised two halves which are pivotable relative to one another.

49. The surgical instrument according toclaim 48 wherein the two halves of the loading unit when closed form an elongated aperture for receiving the second vessel therethrough.

50. The surgical instrument according toclaim 49 wherein prior to actuation of the handle, the two halves of the loading unit are pivotally secured relative to one another and upon actuation of the handle, the two halves are unsecured allowing the halves to pivot relative to one another to release the second vessel from within the aperture.

51. The surgical instrument according toclaim 36 wherein the second retracting sleeve includes a plurality of resilient fingers which releasably secure the surgical fasteners within the elongated channels of the first retracting sleeve.

52. The surgical instrument according toclaim 36 wherein the surgical fasteners are supported normally relative to a longitudinal axis extending through the loading unit.

53. The surgical instrument according toclaim 36 wherein the surgical fasteners are supported in an angular manner relative to a longitudinal axis extending through the loading unit.

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