Abstract:
A surgical stapler assembly for joining a tubular prosthesis to an organic duct such as a blood vessel or artery is disclosed. The assembly has a handle and a set of interchangeable heads attachable to a distal end of the handle. Each head has a staple holder housing a plurality of radially arrayed staples, a plurality of anvils disposed concentrically opposite said staples and an annular gap between the staples and the anvils for receiving the prosthesis and an end of the organic duct. The annular gap of each head in the set has a different median diameter for use with prostheses and organic ducts of different diameters. Hammers are provided to eject the staples through the prosthesis and organic duct in the annular gap and onto the anvils. The heads can be replaceably attachable to the distal end of the handle. The annular gap can be enlarged to facilitate insertion and removal of the organic duct into and from the annular gap prior to and following ejection of the staples. The interchangeable heads can come with a pre-mounted tubular prosthesis having an inside diameter approximating an inside diameter of the annular gap.

Description:
This application claims benefit of Provisional Appln. 60/129,908 filed Apr. 19, 1999. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to surgical stapler assemblies, and more particularly to surgical stapler assemblies with interchangeable heads for connecting tubular prostheses of different sizes with an organic duct such as a blood vessel or artery of a similar size. 
     BACKGROUND OF THE INVENTION 
     In the repair of the aorta with a tubular graft prosthesis, surgeons often wrap the end of the sectioned descending aorta with a length of PTFE felt and suture the felt to the aorta to form a cuff. The graft prosthesis is then sutured to the felt cuff to complete the procedure. Quite often, valuable time is lost attempting to suture the felt cuff onto the end of the aorta which is sometimes friable, and will not adequately hold the suture. In turn, this lengthens the time that the aorta is damped shut. 
     It would be desirable to have available an assembly which would rapidly attach the felt cuff to the end of the aorta so that the procedure can be done quickly and efficiently. 
     U.S. Pat. No. 5,346,115 to Perouse et al. discloses a surgical staple inserter for joining two ducts such as a blood vessel and a blood prosthesis. The staple inserter ejects staples in a radial direction relative to the axis of the ducts. In one embodiment, the patent discloses a staple holder surrounded by the prosthesis and containing a series of staples arranged in at least one ring. All the staples are ejected simultaneously. The staple inserter also includes an anvil outside the organic duct and a device for spacing apart the anvil and the staple holder in relation to their relative working positions. The points of the staples project from the staple inserter and hold the prosthesis in place during the insertion of the staple holder into the ducts. 
     One drawback of the device in Perouse et al. is that a complete assembly of the staple inserter is required for different sizes of aorta. The size of the aorta can vary from 12 to 14 mm on the small end to 24 to 26 mm on the large end. Unfortunately, the surgical staple inserter of Perouse et al. is designed for one size only. 
     Other U.S. Patents of interest include U.S. Pat. No. 5,855,312 to Toledano; U.S. Pat. No. 5,810,240 to Robertson; U.S. Pat. No. 5,732,872 to Bolduc et al.; U.S. Pat. No. 5,720,755 to Dakov; U.S. Pat. No. 5,292,053 to Bilotti et al.; and U.S. Pat. No. 5,188,638 to Tzakis. 
     SUMMARY OF THE INVENTION 
     The present invention uses a set of heads sized to accommodate various organic duct sizes which are interchangeably positioned on the end of the handle. The plurality of heads allows each head to be used with a single handle. Thus, by stocking a set or sets of the replaceable heads, only a small inventory of the handles is required. With just a single handle, a variety of sizes of heads are available to be used to accommodate the correct size of the patient&#39;s organic duct. 
     The present invention provides a surgical stapler assembly for joining a tubular prosthesis to an organic duct such as a blood vessel or artery. The surgical stapler assembly includes a handle and a set of interchangeable heads attachable to a distal end of the handle. Each head comprises a staple holder which includes a plurality of radially arranged staples, an anvil disposed concentrically opposite the staples, and an annular gap between the staples and the anvil for receiving the prosthesis and the end of the organic duct. The annular gap of each head in the set has a different median diameter for use with prostheses and organic ducts of different diameters. A plurality of hammers can be provided for ejecting the staples through the prosthesis and organic duct in the annular gap and oto the anvils. 
     The heads are preferably replaceably attachable to the distal end of the handle. The annular gap is preferably enlargable to facilitate insertion and removal of the organic duct into and from the annular gap, prior to and following ejection of the staples. Each of the interchangeable heads is preferably premounted with a tubular prosthesis having an inside diameter approximating an inside diameter of the annular gap. The handle can indude a proximal end operable for controlling ejection of the staples. Each head can include an inner tubular member housing the staples and an outer member carrying the anvil. The inner and outer members are preferably secured together at a proximal end of the annular gap. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the surgical stapler assembly of the present invention prior to engagement with the end of an organic duct such as a descending aorta. 
     FIG. 2 is a longitudinal section of a handle used in the surgical stapler assembly of the present invention. 
     FIG. 3 is a partial longitudinal section of one embodiment of an interchangeable head used in the surgical stapler assembly of the present invention. 
     FIG. 4 is a partial longitudinal section of the head of the surgical stapler assembly attached to the handle and receiving the end of an organic duct just prior to ejection of the staples. 
     FIG. 5 is a partial longitudinal section of one embodiment of a head of the surgical stapler assembly secured to the distal end of the handle after enlarging the annular gap for release of the organic duct stapled to the tubular prosthesis. 
     FIG. 6 is a view of half of an anvil segment along the lines  6 — 6  in FIG.  3 . 
     FIG. 7 is a partial perspective view of an internal part of the head of the surgical stapler assembly showing the arrangement of staple ejection orifices. 
     FIG. 8 is a section along the lines  8 — 8  in FIG.  3 . 
     FIG. 9 is a section along the lines  9 — 9  in FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIGS. 1-2 a preferred form of the surgical stapler assembly  2  includes a handle  4  and head  6 . The handle  4  can be of a generally elongate form, and preferably to facilitate working in confined spaces, has an elongated proximal tube section  8  and a distal tube section  10  which is angled, more preferably at a right angle, with respect to the proximal tube section  8 . The head  6  includes a tube  12  which carries a cuff  14  for insertion into an organic duct  16  (see FIGS.  4 - 5 ). The cuff  14  is placed over the external surface of the tube  12  in order to be stapled to the organic duct  16  for example a blood vessel or artery, partially covering the cuff  14  at a median region of the tube  12 . The distal end of the tube  12  includes a cap  18  in the shape of a nose cone facilitating penetration of the distal end of the head  6  into the organic duct  16 . The cap  18  and the part of the tube  12  around which the cuff  14  and organic duct  16  are placed constitute a part which is internal with respect to cuff  14  and organic duct  16 . The rest of the head  6  constitutes a part which is external with respect to the cuff  14  and organic duct  16 . 
     A staple holder  20  of cylindrical general shape is arranged at a median section of the tube  12 . It includes hammers  22  for ejecting staples radially. The hammers  22  are controlled by the surgeon by means of a stapling wing nut  24 , mounted so as to rotate on the proximal end of the handle  4 . The wing nut  24  includes a cap  26  fitted with two operating fins  28  and is connected to the hammers  22  in the staple holder  20  by a linkage comprising a rod  30  connected to the staple holder  20  by a beveled gear  32 , a rod  34  and a drive nut  36 . 
     An anvil  38  is disposed outside the tube  36 , at the staple holder  20 , in order to deform the points of the staples which are ejected radially from the staple holder  20 . The anvil  38  is shown in more detail in FIGS. 3 and 6 according to one embodiment. The anvil  38  consists of two anvil segments  38   a ,  38   b , each carried by a support arm  40  of generally semi-cylindrical shape, joined to a heel  42 , forming a collar connected to the tube  12 . The heel  42  is secured to the tube  12  at a proximal end thereof. A shoulder  44  is formed between the heel  42  and the tube  12  for receiving the distal end of distal section  10  in interlocking engagement. A plurality of spring-biased keepers  46  (see FIGS.  2  and  4 - 5 ) mounted on the distal end of tube  10  are received in corresponding slots  48  to connect the head  6  to the handle  4 . Keys  50  formed on the distal end of the tube  12  can also be provided to be received in a corresponding slot in the proximal end of the distal section  10  to further inhibit rotation of the head  6  with respect to the handle  4 . To release the head  6  from the handle  4 , if this is desired, the proximal ends of keepers  46  are depressed to position the distal end of the keepers  46  in a respective recess  51 . 
     The support arms  40  are made, for example, of a relatively elastic metallic material in order to be able to space apart, approximately radially, distal ends carrying the anvil sectors  38   a ,  38   b . Such spacing facilitates the placing of the cuff  14  and of the organic duct  16  over the tube  12 , between the latter and the support arms  40 . 
     A locking hoop  52  allows the sectors of the anvil to be assembled together after having previously disposed the organic ducts to be stapled over the internal part of the staple inserter and having positioned the support arms  40  opposite the staple holder  20 . The hoop  52  can be displaced axially along the external surface of the support arms  40  between the stops  54 , 56  at either end thereof. 
     To mount the hoop  52  on support arms  40 , the support arms  40  are first mounted on the tube  12  and assembled together at their heels  42 . The hoop  52  is then placed around the support arms  40  while compressing them sufficiently so as to dear the stop  54  through the inside diameter of the hoop  52 . Altematively, the stop  54  and/or  56  can be secured to the support arms  40  after the hoop  52  is positioned therearound. 
     To assemble the handle  4 , the two half-handle pieces  58   a ,  58   b  are extended at their ends on the one hand by half-sleeves  60   a ,  60   b  for supporting the wing nut  24 , and on the other hand by half-sleeves  62   a ,  62   b  for fixing onto the outer tube of proximal section  8 . The two half-sleeves  60   a ,  60   b  of the handpiece  58  include two annular interact with annular channels  66  of complementary shape in the internal wall of the wing nut  24 , while allowing free rotation of the wing nut  24  on the handpiece  58 . The proximal end of the tube  8  which is fitted into the half-sleeves  62   a ,  62   b  of the handpiece  58  includes an annular projection  68  for axial positioning of the handpiece  58  and which interacts with an annular groove  70  of complementary shape made on the internal surfaces of the half-sleeves  62   a ,  62   b . 
     In order to mount the handpiece  58 , the stapling wing nut  24  is first dispersed on a support. The two half-sleeves  60   a ,  60   b  for supporting the wing nut  24  are then fitted into the cap  26  of the wing nut  24 . This is done by juxtaposing joining edges  72   a ,  72   b  of the half-sleeves  60   a ,  60   b  which are symmetrically truncated, the effect of which is to form an angle between the two half-handles  58   a ,  58   b . The proximal end  74  of the rod  30 , of square cross-section, is engaged in a hole  76 , of complementary shape, in the cap  26  of the wing nut  24 . The proximal end of the tube  8 , over which a sliding fastening hoop  78  has previously been placed, is disposed between the two half-sleeves  62   a ,  62   b  of the handpiece  58 . The half-handles  58   a ,  58   b  are dosed onto each other and the fastening hoop  78  is slid over the external surfaces of the two half-sleeves  62   a ,  62   b , wedging them together. 
     FIGS. 3 to  9  show an embodiment of the interchangeable head  6  which includes staple holder  20  and of the corresponding anvil  38 . The staple holder  20  and the anvil  38  are disposed horizontally in FIGS. 3-5. The staple holder  20  consists of two flanges  82 ,  84  firmly attached to the tube  12  and carrying a rotating pin  85  onto which is fixed a disc  86  which can rotate between the flanges  82 ,  84 . The disc  86  is pushed onto the median zone of the pin  85  which includes a portion  88  with an irregular surface ensuring better connection between the disc  86  and the pin  85 . The pin  85  is adapted at one end thereof for engagement by the drive nut  36 , the end of the pin  85  having an outer dimension and shape, e.g. square or hexagonal, matching the inner dimensions and shape of the drive nut  36 . 
     The flange  82  is positioned axially inside the tube  12  between an edge  90 , delimiting the opening of the cap  18 , and the disc  86 . The flange  84  is positioned inside the tube  12  between a shoulder  91 , corresponding to an increase in the internal space of the tube  12 , and the disc  86 . The flanges  82 ,  84  are positioned transversely with respect to the tube  12  by means of axial projections  92 ,  93  which interact with notches  92   a ,  93   a  of complementary shape. Also, flanges  82 ,  84  are respectively arranged on the edge delimiting the opening of the cap  18  and on the shoulder  91  of the tube  12 . 
     Staples  94  are disposed flat between opposite faces of the disc  86  and of flanges  82 ,  84 , so as to constitute two superimposed rings of staples. Each ring of staples  94  includes ten staples, for example, distributed over the entire circumference of the tube  12 . FIG. 7 shows how the orifices  95  of the tube  12  are arranged in two superimposed rings, so that the orifices  95  of one ring are staggered with respect to the orifices  95  of the other ring. 
     FIG. 5 shows anvil segment  38   b  which includes cavities  96 , of known shape, intended to receive the points of the staples in order to fold them back during stapling. 
     The means for ejecting the staples  94  will now be described. In this connection, reference will be made to FIGS. 3-5 and  8 - 9 . FIGS. 3-5 and  8  show that each staple  94  is ejected by a hammer  98  of generally flat shape. The hammers  98  are disposed in rings between the opposite surfaces of the disc  86  and of flanges  82 ,  84 . The flanges  82 ,  84  include, on the surfaces thereof opposite the disc  86 , means for guiding the staples  94  and means for guiding the hammers  98 . The means for guiding the staples  94  consist of radially extending recesses  100  in the surfaces of the flanges  82 ,  84 , in which recesses the staples are housed. The means for guiding the hammers  98  consist of radial grooves  102  arranged on the surfaces of the flanges, in the middles of the respective recesses  100 , which interact with guiding projections  104  disposed on respective faces of the hammers  98 . The disc  86  includes means for driving the hammers  98 , which means consist of spiral channels  106 , at constant pitch, arranged symmetrically in opposite faces of the disc. The spiral channels  106  interact with respective drive projections  108  disposed on respective faces of the hammers  98 . 
     FIG. 9 shows how the projections  108  of the hammers  98  are disposed in the spiral ribs  106  of the disc  86 . There are ten projections  108 , corresponding to ten hammers  98 , which simultaneously eject each ring of ten staples. The hammers  98  are set in their initial position, before stapling, at the center of the disc  86 . The position of the projection  108  on each hammer  98  depends on the angular position of the latter in the staple holder. As the spiral channel  106  has a constant pitch, the rotation of the disc  86  in the clockwise direction, along arrow H in FIG. 9, simultaneously drives all the hammers  98 , displacing them radially by an equal distance. 
     The mounting of the staple holder  20  according to this embodiment of the invention will now be described. In a first step, the cap  18  is placed on a support. There are then successively assembled the first flange  82 , on the cap  18 , the disc  86  fixed on the pin  85 , and the second flange  84 . The hammers  98  are next introduced into the staple holder  20 . Since the position of the drive projection  108  on each hammer  98  is a function of the angular position of the latter in the staple holder  20 , it is expedient to dispose the various hammers  98  in the staple holder  32  in a well-defined order. For this purpose, the first step is introducing the first hammer  98  of the series into the staple holder by engaging the drive projection  108  in the spiral channel  106 , through the periphery of the disc  86 , at a recess  100  for guiding the staples. The same procedure is repeated with the other hammers  98  of the series, in the order in which they are disposed in the staple holder. All the hammers  98  are set in their initial position, at the center of the disc  86 , by rotating the disc  86  fully in the counterclockwise direction. The cap  28 /staple holder  20  assembly is then disposed in the distal end of the tube  12 . The means for axial positioning and rotational positioning of the flanges  82 ,  84  which were described hereinabove ensure the correspondence between the orifices  95  for ejecting the staples from the tube  12  and the recesses  100  for guiding the staples  94 . The staples  94  are introduced into the staple holder  20  through the orifices  95  while orienting their points outwards and while placing the crosspiece of each staple  94  in contact with the corresponding hammer  98 . 
     In the use of the assembly  2  to repair a damaged descending aorta, for example, the aorta is sectioned and its exposed diameter is measured. A head  6  having a tube  12 /cuff  14  of a diameter about the same as the end of the aorta is selected. For this application, the set of interchangeable heads  6  are provided in 2 mm increments from 12 mm to 26 mm outside diameter. Owing to the elasticity of the aorta, it is better to use the next larger size of head  6  as the aorta can be stretched slightly. The head  6  is then attached to the handle  4 , first aligning the drive nut  36  with the proximal end of the pin  85 , and then the slots  48  with the keeper  46  which is snapped into place to securely connect the selected head  6  with the handle  4 . With the hoop  52  positioned adjacent the proximal stop  56 , the end of the aorta  16  is slid onto the cap  18  and over the tube  12  and premounted cuff  14  so as to be disposed in the annular gap between the staple holder  20  and the anvil segments  38   a ,  38   b . The hoop  52  is then advanced in position next to the distal stop  54 . Then the wing nut  24  is rotated while firmly gripping the handpiece  58  to eject the staples  94  to secure the cuff  14  to the aorta  16 . The hoop  52  is then retracted in position next to the proximal stop  56  and the assembly  2  is withdrawn from the cuff  14  and aorta  16 . The graft prosthesis (not shown) can then be attached to the cuff  14  by conventional suturing and or stapling. The assembly  2  can be sterilized for reuse and a new cuff  14  mounted in the interchangeable head  6 , or disposed of.