Abstract:
An anastomosis punch device, and method of using same, for creating a circular hole in the aortic wall, where the device also segregates the hole from the blood flow path such that no blood is lost through the hole during attachment of the vein graft. The invention is a hand-held punch having an elongated housing to be gripped by the surgeon, the housing retaining in a coaxially aligned manner a distally extended punch head, a cutting sleeve having a distal cutting rim which cuts a circular plug in cooperation with the punch head, an umbrella-like flexible dam formed of an elastic material and adjoined to the cutting sleeve in a manner which allows it to be deployed radially outward with the enlarged open rim facing the proximal direction, and a deployment ram movable axially relative to the dam to spread open the dam.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/178,980, filed Jan. 28, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention is a medical device and relates generally to the field of punch devices used in performing anastomosis (the joining of a hollow or tubular organ to another hollow or tubular organ), and in particular such devices used in the surgical joining of a vein graft to the aortic wall, where the punch device is used to create the hole in the aortic wall. 
     In coronary bypass surgery, a blocked segment of the coronary artery is bypassed by attaching a vein graft to the aorta above the blocked point and to the artery downstream of the blocked point, such that blood flow is routed around the blockage through the vein graft. In a common technique used to attach the graft, a hole is created in the aortic wall by first creating a small slit using a scalpel. The cutting disk of a punch device is then inserted through the slit. The cutting disk is mounted onto a thin shaft, which is coaxially received by a tubular sleeve member, the end of which is provided with an annular cutting edge or rim. With the aortic wall between the disk and the sleeve, either the disk is retracted into the sleeve or the sleeve is advanced beyond the disk. This operation cuts a circular opening in the aortic wall, and the plug cut from the wall is entrapped within the sleeve and disk. The punch device is then removed and the surgeon proceeds with the anastomotic procedure. 
     It is necessary to temporarily occlude the opening in the aortic wall in some manner after removal of the plug to prevent excessive loss of blood during the anastomotic procedure. The most commonly employed method is to apply a C-shaped surgical clamp to the side of the aortic wall at the proposed site of the anastomosis prior to cutting the aorta and introducing the punch. The clamp compresses only a portion of the aorta, allowing continued blood flow past the clamped area. This technique can be problematic in that application of the clamp may cause damage to the aorta or release plaque fragments or atheromatous debris into the blood stream when the clamp is released. 
     One alternative technique for blocking blood flow through the hole created in the aortic wall by a combination punch device is shown in U.S. Pat. No. 5,944,730 of Nobles et al. The Nobles et al. device, as described in the second embodiment of the disclosure, is a grossly elongated instrument having an occluding inverting member mounted onto the distal end of a long, slender flexible tube, an inverter handle assembly, and an intermediately disposed punch assembly. The punch assembly is joined to the inverter handle assembly in a disconnectable fashion, such that the punch assembly is detached from the inverter handle assembly and slid distally along the flexible tube to remove the plug from the aortic wall, after which it is translated proximally and rejoined to the inverter handle assembly. The inverter handle assembly is then manipulated to cause the inverting member to fold onto itself into a conical configuration and the entire device is pulled in the proximal direction to seal the aortic wall. Each end of the inverting member must be attached to a different elongated tubular member which are slidably movable in the axial direction relative to each other. The provision of separable punch and inverter handle assemblies, the elongated flexible tube on which is mounted the occluding member, and the overly complicated design of the occluding member results in an awkward instrument of excessive length which is difficult to operate in an efficient and straightforward manner. Additionally, there is no structure to block blood flow through the hole in the aortic wall during the time period while the punch assembly is being withdrawn and rejoined to the inverter handle assembly prior to expansion of the inverting member and retraction of the apparatus. 
     It is an object of this invention to provide an anastomosis punch device for creating a hole in the aortic wall, and method of use for same, which has an occluding structure to prevent blood from exiting the hole created in the aortic wall during attachment of the vein graft, where the device comprises an elastic dam membrane having circumferentially spaced longitudinal ribs, where the ribs may be spread to open the membrane into a conical configuration in an umbrella-like manner to surround the hole, then collapsed for withdrawal after the vein has been partially secured, where the dam is affixed to the shaft of the cutting sleeve immediately proximal to the cutting sleeve, where an occluding body is provided to block blood flow through the hole created in the aortic hole prior to expansion of the elastic dam membrane, such that the punch device is a compact instrument which is easily manipulated by the surgeon. 
     SUMMARY OF THE INVENTION 
     The invention comprises an anastomosis punch device, and method of using same, for creating a circular hole in the aortic wall, where the device also segregates the hole from the blood flow path such that no blood is lost through the hole during attachment of the vein graft. The invention is a compact hand-held punch comprising an elongated housing to be gripped by the surgeon, the housing retaining in a coaxially aligned manner a distally extended punch head, a cutting sleeve having a distal cutting rim which cuts a circular plug in cooperation with the punch head, an expandable, umbrella-like, flexible dam formed of an elastic tubular material and adjoined to the sleeve in a manner which allows it to be deployed radially outward with the enlarged open rim facing the proximal direction, and a deployment ram movable axially relative to the dam to spread open the dam. The surgeon inserts the punch head through the aortic wall, then advances the cutting sleeve against and over the punch head to remove a circular plug of aortic wall, with the plug being retained within a chamber defined by the cutting sleeve and the punch head and the cutting sleeve locked in the advanced position. The entire device is then advanced a short distance through the hole in the aortic wall such that the entire flexible dam member is positioned internally to the aortic wall with a portion of the ram member occluding the hole in the aortic wall to prevent blood loss. The ram is then advanced relative to the dam, causing the proximal end of the dam to spread outwardly to form a cone shape, and the ram is locked in position. The rim of the expanded dam is then drawn against the interior wall of the aorta, thus forming a conical dam about the hole. The vein graft is then attached to the aortic wall at the hole using known suturing techniques while the device remains in place. Once the vein is sufficiently attached to the aortic wall in loose manner, the ram is retracted relative to the dam, allowing the dam to collapse into the passive configuration with minimal diameter because of the elastic nature of the membrane. The entire device is then withdrawn between the sutures and completely out of the aorta, with the sutures then quickly tightened to connect the vein graft to the aorta. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an external side view of the device. 
     FIG. 2 is a cross-sectional view showing the punch head of the device as inserted into the aortic wall, taken along line II—II of FIG.  1 . 
     FIG. 3 is a cross-sectional view similar to FIG. 2, showing the plug removed from the aortic wall and the device advanced into the aorta. 
     FIG. 4 is a partial cross-sectional view similar to FIG. 3, showing the ram advanced and the dam deployed against the aortic wall. 
     FIG. 5 is a partial view of the device similar to FIG. 4, showing the ram advanced and the dam deployed against the aortic wall. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the drawings, the invention will now be described in detail with regard for the best mode and the preferred embodiment. 
     As shown generally in FIG. 1, the invention is an anastomosis punch device comprising a generally elongated, tubular instrument housing  10 , a punch assembly  30 , a cutting sleeve assembly  50 , an elastic dam assembly  70  and a deployment ram assembly  90 . The device is configured as an integral apparatus of compact design so as to be easily gripped and manipulated by surgeon. For example, a device having a housing  10  approximately 9 cm in length and approximately 8 mm in diameter, with the distal portion of the punch assembly  30  extending only about 4 cm from the distal end  12  of the housing  10 , is representative of a very suitable size. With reference also to FIG. 2, the elongated instrument housing  10  is shown to comprise a proximal end  11  and a distal end  12 , where the distal end  12  is the end positioned against the aortic wall  100  during use. For purposes of this disclosure, references to the distal direction or a distal element shall mean the direction or element toward the aortic wall  100  with the device in use, while references to the proximal direction shall means the opposite direction, i.e., external to away from the aortic wall  100 . A pair of laterally extending finger grips  18  are externally mounted on the instrument housing  10 , preferably approximately 4 cm from the proximal end  11  of the instrument housing  10  . A first coaxial cylindrical bore  13  extends from the proximal end  11  and meets a second coaxial cylindrical bore  14  within the body of instrument housing  10 , where the second bore  14  extends from the distal end  12  and is larger than the first bore  13 . Cutting sleeve locking means  20 , comprising as shown a transverse bore  15  extending into the first bore  13 , is provided near the proximal end  11  to receive a sleeve locking pin  16 , which is used to secure the cutting sleeve assembly  50  in the advanced position relative to the instrument housing  10 , as shown in FIG.  3 . Equivalent constructions for cutting sleeve locking means  20  may be utilized as well. A longitudinally extending sleeve guide slot or pair of slots  17  is provided in first bore  13 , the sleeve guide slot  17  receiving the guide tabs  59  mounted onto the tubular shaft  52  of the cutting sleeve assembly  50  to prevent rotation of the cutting sleeve assembly  50  within the instrument housing  10  to maintain proper alignment between the transverse bore  15  and a pin receiving aperture  58  located in the tubular shaft  52 . A longitudinally extending ram guide slot  19  is provided adjacent or toward the distal end  12  of the instrument housing  10  to provide a channel for controlled movement of the handle  94  of the deployment ram assembly  90  in either axial direction. 
     Means  60  to create a circular opening  103  in the aortic wall  100  comprise in combination punch assembly  30  and cutting sleeve assembly  50 . Punch assembly  30  is mounted coaxially within instrument housing  10  with a portion extending from the distal end  12  of the instrument housing  10 . Punch assembly  30  comprises a punch head  31  mounted onto a shaft  33 , with the shaft  33  fixed within the instrument housing  10  by detent member  34 . The punch head  31  is a conical or bladed member with a sharp cutting edge or point such that relatively easy penetration can be attained through the aortic wall  100  by direct pressure on the exterior side  102  of the aortic wall  100 . The punch head  31  has an annular rim or disk member  32  on its proximal side, preferably about 3 to 6 mm in diameter, with the edge of the disk  32  having a relatively sharp lip. The outer diameter of the rim  32  is sized to correspond to the internal diameter of the annular cutting rim  55  and cutting sleeve  54  of the cutting sleeve assembly  50 , the outer diameter of disk  32  being only slightly smaller than the internal diameter of cutting rim  55  and cutting sleeve  54 , such that the cutting rim  55  and cutting sleeve  54  can be advanced over the disk  32  to produce a cutting action to remove a circular plug  104  from the aortic wall  100 , as shown in FIG.  3 . 
     Cutting sleeve assembly  50  is coaxially positioned within instrument housing  10 , fitting within first bore  13  such that sliding movement of the cutting sleeve assembly  50  relative to the instrument housing  10  and punch assembly  30  in the axial direction is possible. Cutting sleeve assembly  50  comprises a tubular shaft  52  which extends from both the distal end  12  and the proximal end  11  of the instrument housing  10 . A flange handle or button  51  is mounted onto the proximal end of the tubular shaft  52 , allowing the cutting sleeve assembly  50  to be advanced by pressure from the surgeon&#39;s thumb or palm. A spring member  57  is mounted between the proximal end  11  of the instrument housing  10  and the button  51 , and biases the cutting sleeve assembly  50  in the retracted proximal direction until sufficient pressure is applied to advance it in the distal direction. The tubular shaft  52  defines a coaxial bore  53  which snugly receives the shaft  33  of the punch assembly  30 . A pin receiving aperture  58  is positioned toward the proximal end of the tubular shaft  52 , sized to receive sleeve locking pin  16  when the sleeve cutting assembly  50  is advanced, as shown in FIG.  3 . One or more longitudinally extending guide tabs  59  are provided on the exterior of tubular shaft  52 , the guide tabs  59  being received by sleeve guide slots  17  to preclude relative rotation of the cutting sleeve assembly  50  and the instrument housing  10 . Longitudinal slots  61  are provided on the tubular shaft  52  to allow axial movement of the tubular shaft  52  past the punch detent member  53 . 
     The distal end of the cutting sleeve assembly  50  comprises a tubular cutting sleeve  54  mounted onto the end of tubular shaft  52 , the cutting sleeve  54  extending radially outward to have both a larger internal diameter than the internal diameter of bore  53 , in order to define a chamber  56  which receives both the disk  32  and punch head  31  of the punch assembly  30 , as well as the plug  104  which is removed from the aortic wall  100 , and to have a larger external diameter than the external diameter of tubular shaft  52 . The distal end of the cutting sleeve  54  is beveled or sharpened to provide an annular cutting rim  55 . The size and configuration of the cutting rim  55  and sleeve  54  are such that when they are advanced against and over the punch disk  32  of the punch head  31 , a shearing or cutting action is effected. 
     Affixed immediately to the proximal side of cutting sleeve  54  on tubular shaft  52  is the elastic dam assembly  70 , the means for occluding blood flow through the opening  103  in the aortic wall  100 . Elastic dam assembly  70  comprises a tubular elastic membrane or sheet material  72  impermeable to blood, preferably formed of a polymeric material, which in the passive, non-stretched state has a generally cylindrical or a very tight conical configuration of minimal diameter snugly encircling the tubular shaft  52 . The membrane  72  is mounted onto, is formed integrally with, or encases a plurality of relatively rigid, generally linear struts or rib members  73 , generally aligned in the axial or longitudinal direction and evenly spaced in the circumferential direction. The distal end  75  of the elastic membrane  72  is securely attached to or affixed around the tubular shaft  52  by fixation means or ring member  71 , while the proximal end  76  of the membrane  72  is non-attached to any portion of the cutting sleeve assembly  50  and defines a sealing rim  74 , which may be formed in a beaded or thickened configuration to provide a better seal against the interior side  101  of the aortic wall  100 . The membrane  72  is mounted such that it may be flared outwardly in an umbrella-like fashion into a conical active configuration by advancement of the deployment ram assembly  90  toward the fixed distal end  75  and against the ribs  73 , with the ribs  73  being pushed away from the tubular shaft  52  at an acute angle to stretch, support and extend the elastic membrane  72 , and with the expanded sealing rim  74  thus presenting a relatively large circumference, as shown in FIGS. 4 and 5. When the deployment ram assembly  90  is retracted to remove the pressure against the rib members  73 , the elasticity of the membrane  72  causes it to retract into the passive cylindrical configuration of minimal diameter tightly encircling the tubular shaft  52 . 
     The means to deploy or expand the elastic membrane  72 , deployment ram assembly  90 , is coaxially mounted about the cutting sleeve tubular shaft  52 , and comprises a tubular shaft  93  connected at its proximal end to a transversely extending handle  94 , which is positioned within ram guide slot  19  of instrument housing  10 , such that the ram assembly  90  is movable in the axial direction relative to the housing  10 . The distal portion of the deployment ram assembly  90  extends out of the instrument housing  10  and comprises an occluding body  92  of cylindrical shape, the occluding body  92  having a beveled, curved or cone-shaped head or distal end  91  of greater outer diameter than the tubular shaft  52 . The distal portion of the beveled head  91  of the occluding body  92  fits within the sealing rim  74  of the elastic dam assembly  70  in its passive condition when the deployment ram assembly  90  is advanced toward the fixation ring  71 , such that its movement in the distal direction results in it being positioned internally within the tubular elastic membrane  72  in order to effect expansion of the membrane  72  as it is advanced. The outer diameter and angle of the beveled head  91 , as well as the distance of travel relative to the dam assembly  70 , is such that the membrane  72  is significantly expanded when the ram assembly  90  is fully advanced, with the sealing rim  74  presenting a relatively large circumference to abut the internal side  101  of the aortic wall  100  sufficient distance from the hole  103  to provide room for the surgeon to apply the sutures. Additionally, the outer diameters of the cutting sleeve  54  and the occluding body  92  are substantially equal, such that the occluding body  92  serves to completely fill and block the hole  103  in the aortic wall  100  created by the cutting sleeve  54 , until the elastic membrane  72  is deployed to block blood flow through the hole  103 . The length of the occluding body  92  is preferably less than the axial length of the expanded membrane  72 , such that with the membrane  72  fully expanded and the sealing rim  74  pulled against the internal side  101  of the aortic wall  100 , the occluding body  92  is positioned beyond the aortic wall  100  and no longer fills the hole  103 , the proximal end of the occluding body  92  being disposed distally to the sealing rim  74  of the membrane  72 , thereby providing room for the surgeon to work at the attachment site. Means to lock the deployment ram assembly  90  in the advanced position are provided, and as shown comprises an annular locking collar  95  having of collar slot  96  of sufficient width to allow passage of the ram handle  94  from one side to the other. The locking collar  95  is positioned in an annular collar channel  97  located on the instrument housing  10  such that the collar  96  may be rotated relative to the housing  10 . With the collar slot  96  aligned with the ram guide slot  19 , as shown in FIGS. 1,  2  and  3 , the ram assembly  90  may be advanced to the deployment position, whereupon the locking collar  95  is rotated such that the collar slot  96  is no longer aligned with the ram guide slot  19  and the collar  95  prevents movement of the ram assembly  90  in the proximal direction, as shown in FIGS. 4 and 5. 
     To create the hole  103  in the aortic wall  100  to perform anastomosis of the vein graft, the surgeon creates a small slit with a scalpel in the aortic wall  100  and introduces the punch head  31  of the device into the slit, or using the punch head  31  alone to penetrate the aortic wall  100 , advances the instrument housing  10 such that the punch head  31  is positioned within the interior of the aortic wall  100 , as shown in FIG.  2 . The surgeon next advances the cutting sleeve assembly  50  relative to the instrument housing  10  and the punch head assembly  30 , thereby causing a circular plug  104  to be removed from the aortic wall  100  because of the interaction between the annular cutting rim  55  and the punch disk  32 . The cutting sleeve assembly  50  is then locked in the advanced position, as shown in FIG. 3, by inserting locking pin  16  into the pin receiving aperture  58  of the tubular shaft  52 . By locking the cutting assembly  50  in the advanced positioned, the combination of the punch head disk  32  and the cutting sleeve  54  create a sealed chamber  56 , such that the aortic plug  104  is retained therein and not released into the blood stream. The surgeon then advances the instrument housing  10  distally, such that the dam assembly  70  is positioned interior to the aortic wall  100 , with the occluding body  92  of the deployment ram assembly  90  blocking hole  103  to prevent or significantly reduce blood loss there through. The deployment ram assembly  90  is then advanced relative to the dam assembly  70  and the cutting sleeve assembly  50 , and is locked in the advanced position by rotating locking collar  95 , as shown in FIGS. 4 and 5. This causes expansion of the elastic membrane  72 , the beveled head  91  of the occluding body  92  pressing radially outward against the rib members  73 . With the membrane  72  in the open, conical configuration, the instrument housing  10  is slightly withdrawn, such that the sealing rim  74  of the membrane  72  seats firmly against the interior side  101  of the aortic wall  100 . In this manner, blood within the aorta is prevented from passing through the hole  103  in the aortic wall  100  while the vein graft is being sutured in place. Because the axial length of the occluding body  92  is limited such that the proximal end of the occluding body  92  is positioned within the aorta at this time, such that an open area around the smaller diameter shaft  93  is presented, the surgeon has better access to the aortic wall  100  around hole  103 . The vein graft is loosely sutured in known manner with the device in place. Once the initial suturing is completed, the device is advanced slightly, the locking collar  95  is rotated to align the collar slot  96  with the ram guide slot  19  to allow movement of the handle  94  in the proximal direction and the deployment ram assembly  90  is retracted. With the occluding body  92  withdrawn, the elasticity of the membrane  72  causes it to resume its passive cylindrical shape (as in FIG.  3 ), its outer diameter being smaller than the outer diameter of the cutting sleeve  54  and occluding body  92 . In this passive configuration, the entire device is then removed from the hole  103  in the aortic wall  100  and between the sutures, with the surgeon quickly tightening the vein graft sutures to secure the vein against the aortic wall  100 . 
     It is contemplated that equivalents and substitutions to certain elements set forth above may be obvious to those skilled in the art, and the true scope and definition of the invention therefore is to be as set forth in the following claims.