Abstract:
A device for forming an end-to-side anastomosis of blood vessels includes a first body for engaging an end portion of a blood vessel, a second body having a saddle portion that may be placed partly over a wall of a side portion of a further blood vessel and having a central hole which communicates with the wall for stably engaging the side portion of the further blood vessel. The first and second body are engaged together and in the engaging portion there are provided piercing elements adapted to penetrate the external surface of the wall without penetrating the internal surface of the wall of the further blood vessel so as to avoid direct contact between the piercing elements and the blood inside the vessel.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a device and method for anastomosis of blood vessels. 
     In surgery, the term “anastomosis” is used to mean a connection made surgically between two hollow structures. 
     This invention relates in particular to end-to-side anastomosis, where an end portion of a blood vessel is connected to a side portion of a vessel wall. 
     This specification expressly refers to vascular anastomosis applied to the human body, without thereby restricting the scope of the invention. 
     The earliest method of anastomosing two parts of a blood or lymphatic vessel consists in suturing the free ends of the vessel with thread. 
     This method, commonly known as suture anastomosis, has several disadvantages, the main one being that the suture produces a scar which, however small, prevents original flow from being perfectly restored to the vessel. 
     In this regard, it should be stressed that blood vessels are made up of several layers. The first, innermost layer, called endothelium, is covered by a second, middle layer called tunica media. The tunica media is in turn covered by a third layer, known as tunica adventitia. 
     It is therefore relatively easy for suturing to cause misalignment of some kind between the layers of one end of the vessel and the corresponding layers of the end of the other vessel. This is also a drawback in the case of lymphatic vessels which have a similar layered structure. 
     A second drawback is due to the fact that blood vessel suturing must be done by hand by a specialized surgeon because it is a complex operation that cannot be left to surgeons who are not highly skilled in this specific art. 
     Another known method of anastomosing two parts of a blood or lymphatic vessel is to use mechanical clamping devices designed to turn the ends to be connected inside out and to then join the inside walls of the vessel ends to each other. 
     This surgical technique (mechanical anastomosis by eversion), although simpler than suture anastomosis, is even less effective in re-establishing flow to the vessel. 
     For example, in the specific case of blood vessels, only the intimal layers are in contact with each other. 
     Besides this, mechanical anastomosis by eversion has other serious drawbacks which may be dangerous to a patient&#39;s health. 
     One drawback is due to the fact that everting the vessel ends may cause the ends to break, especially in the case of vessels larger than 3 mm in diameter whose walls are hardened by arteriosclerosis. 
     Another complication, specific to blood vessels, is caused by the fact that the inside layers of the vessel ends, after being turned inside out and placed side by side, are no longer exposed to the blood flow and therefore tend to atrophy, which in turn leads to narrowing of the blood vessel and reduction of the blood flow through it. The smaller the diameter of the vessel being operated on, the more serious this problem is. 
     In other mechanical anastomosis methods (such as the one described in U.S. Pat. No. 6,652,540) the two ends of the vessels to be joined are not placed in contact and, instead, metallic components are left in contact with the blood flowing through the vessel. 
     This produces an extremely dangerous condition which exposes the anastomosis to risk of immediate occlusion caused by the formation of a blood clot and narrowing of the anastomotic lumen. 
     Indeed, it has been found that contact between metal and blood tends to cause stenosis, that is to say, abnormal narrowing of the blood vessel, which may lead to total occlusion of the vessel in a period of 6 months to 1 year. 
     Those in the art have proposed to overcome this problem by chemically coating the metals with anti-stenosis substances, that is to say, substances that inhibit occlusions. 
     This solution has, however, produced serious problems because in many cases, the chemically coated metal parts in contact with the blood favor the formation of thrombi and the onset of acute thromboses that come sharply to a crisis, exposing patients to the risk of heart failure and, in some cases, leading to death. 
     Another drawback of prior art anastomosis devices is the complexity of applying them, especially to the side portions of the vessel. This means that the surgical operation involved tend to be very long, placing the patient at risk not only on account of the technical difficulty of the operation itself but also because of the likelihood of infection which increases with the increased length of time during which the body organs are exposed to the environment. 
     SUMMARY OF THE INVENTION 
     A first aim of the present invention is to provide a device and method for end-to-side anastomosis that overcomes the drawbacks and problems of prior art devices and method due to contact between the metal or artificial parts and the blood. 
     Another aim of the invention is to propose an anastomosis apparatus that permits flow in the blood vessel to be re-established more effectively than prior art devices. 
     A further aim of the invention is to provide a device that is simple to use and minimizes blood loss during the operation without interrupting blood flow in the vessel whose side is anastomosed. 
     These aims are achieved by an apparatus and method according to the main claims. 
     A first advantage of the invention is that contact between the connecting parts and the blood vessel is limited to the vessel wall, leaving the inside surface free, and there is therefore no contact with the blood inside the vessel. 
     Another advantage is that there is no contact between the device and the cut edge of the wall of the anastomosed vessel, which permits the intima of the two vessel parts to be joined in optimum manner. 
     A yet further aim of the invention is to propose a simplified anastomosis apparatus whose use can be learned in a very short time and which permits the formation of anastomoses of constant quality. 
     A still further aim of the invention is to propose an anastomosis apparatus that reduces the time required for the anastomosis operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described with reference to the accompanying drawings which illustrate a preferred embodiment of it and in which: 
         FIG. 1  is a side view of a device according to the present invention; 
         FIG. 2  is a top view of the device of  FIG. 1 ; 
         FIG. 3  is a front view of the device of  FIG. 1 ; 
         FIG. 4  is an exploded view of the device of  FIG. 3  in combination with a device for end-to-end anastomosis; 
         FIGS. 5   a  and  5   b  are, respectively, a partial section and a full side view of the device of  FIG. 4 ; 
         FIGS. 6   a  and  6   b  show a circular scalpel for end-to-side anastomosis applications in a retracted configuration and in an extracted, cutting configuration, respectively; 
         FIG. 7  shows the scalpel of  FIGS. 6   a ,  6   b  applied to a device according to  FIGS. 1 to 3 ; 
         FIGS. 7   a ,  7   b  show a detail of the elements for clamping the device of  FIGS. 1 to 3  to the scalpel of  FIG. 7 , in a clamped and unclamped configuration, respectively; 
         FIGS. 8   a  and  8   b  show a possible applicator for implanting an anastomosis device to an end portion of a blood vessel. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference the accompanying drawings, a device according to the invention comprises a body  1 , clearly shown in  FIGS. 1 to 3 , for connecting a side wall portion  4  of an anastomosed vessel. 
     In the preferred embodiment described here, the body  1  comprises an approximately semicylindrical or “saddle-shaped” element  3  designed to be placed at least partly over the portion  4  and having a central hole  20  in which there is positioned and fixed a cylindrical element  14  whose axis “a” makes an angle, preferably, of 90°, 60°, 45° or 30° with the longitudinal axis of the saddle-shaped portion  3  or of the portion  4  of the anastomosed vessel. 
     The body  1  also comprises a gate valve  5  slidable lengthwise along internal grooves  8  made in the saddle  3  and having a hole  22  in it, this hole  22  being such that, during use, it is alternately aligned with and offset from the hole  20  in the saddle  3 , in such a manner as to open and close the hole  20 , respectively. 
     The inside of the valve  5  preferably has a curved, circular profile which facilitates its sliding into contact with the blood vessel wall and which can be taken right out of the grooves  8 . 
     For attaching the blood vessel, the saddle  3  comprises fixing means consisting of claws  9  designed to clutch the outside wall of the portion  4 . 
     In this embodiment, the claws  9  are made by bending the free pointed ends of two essentially U-shaped lengths  11 ,  11 ′ of wire. 
     The side arms of the “U” can slide along respective grooves  12  made in the outside surface of the saddle  3 , while the central sections  13 ,  15  joining the side arms of the “U” protrude from the outside surface of the saddle and can be accessed by the surgeon. 
     Preferably, the wires  11 ,  11 ′ are held in place by another wire  16  positioned in collar-like fashion around the saddle  3  to prevent the wires  11  and  11 ′ coming out of the grooves  12 . 
     During application to a side portion  4  of an anastomosed vessel, the saddle-shaped element  3  of the body  1  is first placed over the wall of the vessel  1  with the hole  22  of the gate valve  5  preferably in the open position, that is to say, aligned with the hole  20  in the saddle-shaped element  3 . 
     Next, the surgeon, by acting on the sections  13 ,  15  of the wires  11 ,  11 ′ extends the claws  9  as far as possible (in the direction indicated by the arrows in  FIG. 3 ) and then retracts them again in such a way that the claws  9  penetrate the wall of the vessel  1  ( FIGS. 5   a  and  5   b ) and securely connect the body  1  to the vessel wall  4 . 
     At this point, the body  3  is securely attached to the vessel portion  4  and the vessel itself can be incised using a suitable scalpel with a circular head capable of cutting and removing the vessel tissue at the hole  20 . 
     Preferably, the hole can be made using the scalpel illustrated in  FIGS. 6   a ,  6   b  and  7 ,  7   a ,  7   b.    
     The scalpel consist of a control rod  60  having at a first end of it a helical element  64  and a cup-shaped blade  65  positioned coaxially on the outside of the helical element  64 . 
     The rod  60  can both turn freely and slide lengthwise in a coaxial cylindrical sleeve  61  against the force of an opposing spring  63  housed in a crown-shaped cylindrical chamber  66  made in the second end of the rod  60 . 
     The front end of the sleeve  61  has a protrusion  68  whose diameter is substantially the same as the inside diameter of the element  14  and with which it may be aligned precisely, since it has the same outside diameter, with the head  69  of an outside cylindrical slider  67  that is slidable along the sleeve  61 . 
     During use, the scalpel rod  60  is initially in the retracted position ( FIG. 6   a ) since the spring  63  keeps it all the way inside the sleeve  61 . 
     In this configuration, the front end of the sleeve  61  is inserted into the cylindrical element  14  until it engages the protrusion  68  with tabs  16  extending from the cylinder  14  ( FIG. 7   a ) in such a way as to hold the scalpel in place. 
     The rod  60  is now advanced, against the force of the spring  63 , and at the same time turned in such a way as to impart a twisting movement on the helix  64  causing the helix to pierce the vessel wall  1  of the portion  4  and enabling the cup-shaped blade  65  to make an incision at the hole  22  in the saddle  3  and at the hole  20  in the valve  5 . 
     At this point, by releasing and retracting the rod  60  without twisting it, the helix is made to take the cut portion of the wall  1  out with it and the gate valve  5  can be closed to restore the geometrical continuity of the vessel wall with the minimum of blood loss. 
     Once the cut at the hole  22  has been made, the scalpel can be removed by advancing the head  69  of the slider  67  until it is against the protrusion  68 , thus disengaging the tabs  16  ( FIG. 7   b ) and allowing the scalpel to be taken out of the element  14 . 
       FIGS. 4 and 5   a ,  5   b  illustrate a preferred form of connection between the body  1  and an end portion  2  of the anastomosed vessel with a respective end connection device. 
     It will be understood that the side connection device according to the invention may also be used in combination with other types of end connection devices. 
     In the embodiment described here, the apparatus according to the invention comprises a first internal cylindrical element, or “circular staple”,  7  for grasping the an end portion  2  of the blood vessel to be anastomosed, and a second cylindrical element  10  designed to securely engage the internal element  7 . 
     Looking in more detail, the internal cylindrical element  7  consists of an uninterrupted ring-shaped part  23  which has a plurality of longitudinal legs  6  extending from the front of it and whose outside surface has an annular protrusion or stop lip  24 . 
     The middle cylindrical element  10  has an outside diameter equal to the outside diameter of the ring  23  and, on its outside surface, has an annular recess  25  designed to engage the tabs  16  of the cylinder  14 . 
     Further, the inside diameter of the middle cylinder  10  is that the latter can slide over the inner cylinder  7 , with slight mechanical interference, until it comes to a stop against the protrusion  24 . 
     Inside, the cylinder  10  has a tapered profile  28  that converges towards its front portion  26 , so that the inside diameter at the free edge of the front portion  26  substantially coincides with the inside diameter of the first cylinder  7 . 
     Preferably, the front portion  26  of the cylinder  10  also has a set of semicircular indentations  27 . 
     Below is a description, with reference to  FIG. 2 , of how the device is applied to the end portion  2  to be joined. 
     In the working configuration of the device, illustrated in  FIGS. 5   a  and  5   b , a cylinder  7  with the legs  6  facing the free edge  25  of the wall  1  is connected to the end portion  2 , and a middle cylinder  10  is then made to slide over the cylinder  7  until stopping against the protrusion  24 . 
     To enable the inner cylinder  7  to grasp the wall  2 , the cylinder  7  is made to slide lengthwise in the middle cylinders  10  in such a way that the legs  6 , initially coaxial or slightly divergent, are made to bend inwards by contact with the tapered profile  28  so that they converge towards the inside of the cylinder  7 , pressing against the surface of the wall  2  and penetrating the latter close to the free edge  25 . 
     Advantageously, the depth to which the legs  6  penetrate the vessel wall is determined by the special shape of the legs  6  and cylinder  10 , which is such that the legs do not go right through the vessel wall, thus avoiding contact with the blood inside the vessel. 
     As illustrated in  FIGS. 5   a ,  5   b , once the part of the device consisting of the cylinders  7  and  10  has been connected to the vessel end portion  2 , application of the device can be completed by connecting that part to the body  1  by simply inserting the cylinder  10  into the connecting element  14  until the tabs  16  snap into the recess  25  and the gate valve  5  can be opened again and, if necessary, removed. 
     Described below with reference to  FIGS. 8   a ,  8   b  is an applicator apparatus for implanting a device according to the invention to the end portion  2  of a blood vessel. 
     Although the applicator described below is the tool to be used preferably for this purpose, it will be understood that other types of applicators may be used without departing from the scope of the invention. 
     The applicator comprises a rod  30  which is equipped at one end with a nosepiece  43  of measured diameter and which, by means of a threaded coupling  31 , can be screwed into a hollow piston  32  against the action of a spring  39 . 
     The piston  32  is in turn slidable, by means of a second screw coupling  33 , inside a hollow body  34 , whose top end has a number of flexible tabs  35  normally spread outwards and extending frontally past the nosepiece  43 . 
     A slider  36  can also move on the outside of the hollow body  34 , constrained by a tooth  37  that slides in a longitudinal groove  38  made in the body  34 . 
     The slider  36  can adopt a first position in which the tabs are spread apart ( FIG. 8   a ) and a second end position ( FIG. 8   b ) in which the slider has moved towards the end of the body  34  and forced the tabs  35  to converge and close. 
     To use the applicator, a cylinder  10  is inserted into it through the opening defined by the tabs  35  until the front portion  26  stops against the head  41  of the piston  32 . 
     Next, a circular staple  7  is partially inserted into the cylinder  10  without forcing and the tabs  35  are closed and positioned at the back in such a way as to hold the ring portion  8  of the circular staple  7 . 
     By operating the applicator, the surgeon inserts an end portion of a vessel  2  through the circular staple  7  and the cylinder  10  until the edge  25  of the vessel  2  is made to touch on the head  42  of the piston  32 . 
     Preferably, the front portion  26  of the cylinder  10  also has a set of semicircular indentations  27  which, during use, ensure that the vessel end portion  2 ,  4  to which the device is applied is correctly positioned. 
     Advantageously, the indentations  27  of the cylinder  10  ensure that the vessel wall has stopped against the piston  32 . 
     By operating on the grip  40  of the rod  30 , it is now possible to advance the nosepiece  43  into the vessel  2  in such a way that the vessel remains precisely clamped between the nosepiece  43  itself and the inside surface at the front of the cylinder  10 . 
     The nosepiece is preferably variable in diameter and consists, for example, of a helical wire winding extending in the direction of the rod  30 , where the two ends of the helix can turn relative to each other in such a way so as to move closer together/apart and thus vary the radial dimension of the winding. 
     By twisting the grip  41  of the piston  32 , the surgeon can now advance the piston relative to the tab body so that the tabs and the piston come into contact and clamp the circular staple  7  within the cylinder  10 . 
     As described above, when the legs  6  come into contact with the tapered inside surface  28  of the cylinder  10 , they are forced to converge and partially penetrate the vessel wall  2 . 
     Once clamped by the piston  32 , the staple  7  is held by interference in the cylinder  10 , whilst the vessel wall  2  is retained frontally and radially by the legs  6 , with the edge  25  flush with or just protruding from the front  26  of the cylinder  10  and with an internal diameter or lumen defined by the size of the nosepiece  43  used. 
     At this point, it is sufficient to twist the piston  32  in the opposite direction to retract the slider  36  to open the tabs  35  and release the applicator from the vessel wall while leaving the device in place. 
     From the above description, experts in the trade will no doubt appreciate the advantages of joining both the end portion and the side portion of the anastomosed parts in such a way that the free edges are held in close contact with each other without extraneous elements preventing proper healing of the tissue or inducing the formation of stenosis or thrombi in the blood vessel. 
     It is therefore evident that, under these conditions, optimum flow is re-established naturally in the blood vessel without external elements or interruptions leading to the above mentioned vessel healing difficulties and to the possible formation of stenosis due to the contact of extraneous elements with the blood. 
     Further, the anastomosed blood vessel has no foreign objects protruding on the inside of it to interrupt the continuity of its lumen, with the advantage of not contaminating the blood or reducing normal blood flow. 
     Moreover, in the embodiment described with reference in particular to  FIG. 5   a , the legs  6  keep the vessel wall at a precisely measured diameter, which is preferably the same as that of the hole  22  made in it, so that the size and position of the free edges of both the side and end portions are aligned exactly, thus favoring proper healing of the vessel tissue. 
     In particular, the invention may also be generally applied to different ducts of the human body other than blood vessels. 
     In addition it has to be understood that the invention also involves advantages in the surgery tecnique for anastomosis and it makes possible to intervene for example by laparoscopic method in a low-invasive way. 
     This invention has been described with reference to preferred embodiments of it but it will be understood that it may be modified and adapted in several ways without thereby departing from the scope of the inventive concept.