Abstract:
An anastomosis device for forming two lumen-comprising body structures having an un-deployed and a deployed state and switchable from the former to the latter, comprising: a body with an overall cylindrical shape defining a proximal-distal extending axis of and comprising an external essentially cylindrical body part with a lumen and an internal body part at least a portion thereof being deployed within the lumen of the external body part and axially displacable with respect thereto in the switch between the un-deployed and the deployed states; said internal body part having an internal duct extending axially therethrough whereby in the deployed state there is a fluid communication between the distal and the proximal ends of the body; and two tissue-engaging units axially displaced from one another along said axis; at least one of the two units can change its state from a closed state in the un-deployed state of the device to an opened, tissue-engaging state in the deployed state of the device in which said first unit extends in an overall radial direction and is adapted in this state for tight association with internal walls of one of the body structures, such that the combined tissue-engaging action of the two unit holds the two structures together.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to a device and system for connecting two structures within the animal, particularly human body. 
       BACKGROUND OF THE INVENTION 
       [0002]    Anastomosis is a surgical connection between two structures in a mammalian body. It usually means making a connection between two tubular structures such as blood vessels or loops of the intestine, such as after a surgical procedure wherein a segment of the tubular structure(s) has been removed. Many devices have been devised for the anastomosis procedure. In some cases the two tubular structures have similar dimensions and in other cases, they have dissimilar dimensions. 
         [0003]    Some relevant patents and published patent applications in the field include: 
         [0004]    U.S. Pat. No. 4,911,164, to Roth, which describes a suture guide with a curved distal portion. The distal portion of the suture guide has a plurality of exterior axial grooves which can be used to align and guide a curved needle and attached suture. In order to drive the urethral stump to an accessible position, the device is provided with a plurality of outwardly extendable members which engage the lumen of the urethra. These members make it possible to push the urethral stump into approximation with the bladder neck. 
         [0005]    U.S. Pat. No. 5,047,039, to Avant et al., describes a surgical device for the ligation of a dorsal vein and subsequent anastomosis. This device contains a pair of enclosed needles each having an attached suture which needles may be driven from the shaft of the device into adjacent tissue. 
         [0006]    U.S. Pat. No. 5,591,179, to Edelstein, describes a suturing device including a shaft with portions defining an interior channel extending between a proximal and a distal end of the shaft. This channel includes a generally axial lumen which extends to the proximal end of the shaft and a generally transverse lumen which extends from the axial lumen distally outwardly to an exit hole at the outer surface of the shaft. A needle and suture can be back loaded into the transverse lumen of the channel while a generally non-compressible member can be movably mounted in the axial lumen of the channel. At the proximal end of the shaft a handle is provided with means operative to push the member distally through the lumen to deploy or expel the needle. 
         [0007]    PCT Patent Application publication No. WO2004098417, to Scott, describes an anastomotic device for suturing together the urethral stump to the bladder neck. The device consists in an expandable flanged anchor that is introduced into the urinary bladder and one or more suture anchors that are passed into the urethral wall. Pulling on these sutures, which are connected to the bladder anchor, will approximate the urethral stump to the bladder. The sutures are fixed in position by an additional blocking member that is locked to the bladder anchor. 
         [0008]    US Patent Application No. 2005/0070926 A1, to Ortiz, describes an applier for a fastener for a single lumen access anastomosis. 
         [0009]    US Patent Application No. 2005/0165426 A1, to Manzo, describes a method and apparatus for anastomosis including annular joining member. 
         [0010]    US Patent Application No. 2005/0165378 A1 to Heinrich et al., describes a method and apparatus for anastomosis including an expandable anchor. 
         [0011]    US Patent Application No. 2005/0171564 A1 to Manzo, describes a method and apparatus for radical prostatectomy anastomosis. 
         [0012]    US Patent Application No. 2005/0192602 A1 to Manzo, describes a method and apparatus for anastomosis including an anchoring sleeve. 
         [0013]    US Patent Application No. 2005/0251155 A1, to Orban III, describes a method and apparatus for anastomosis. 
         [0014]    US Patent Application No. 2005/0251175, to Weisenburgh II et al., describes anchors for use in attachment of bladder tissues to the pelvic floor tissues following a prostatectomy. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention provides a novel tissue-engaging device for connecting two internal lumens within the human body. Such a device will be referred to herein as an anastomosis device. 
         [0016]    In accordance with the invention a novel anastomosis device is provided which includes a mechanical arrangement that can change from an un-deployed to a deployed state in which in the open state it engages tissue walls. The device of the invention has two tissue-engaging units. 
         [0017]    The term “deployed state” refers to the state of the device in which is left in position in situ within the body, while the term “un-deployed state” refers to the original state of the device in which it is brought into position before being deployed. Thus, the device once in position within the body is switched from an un-deployed to a deployed state. 
         [0018]    The invention provides, by one of its aspects, an anastomosis device having an un-deployed and a deployed state and switchable from the former to the latter, the device comprising: a body with an overall cylindrical shape defining a proximal-distal extending axis of and comprising an external essentially cylindrical body part with a lumen and an internal body part at least a portion thereof being deployed within the lumen of the external body part and axially displaceable with respect thereto in the switch between the un-deployed and the deployed states; said internal body part having an internal duct extending axially therethrough whereby in the deployed state there is a fluid communication between the distal and the proximal ends of the body; and two tissue-engaging units axially displaced from one another along said axis; at least one of the two units can change its state from a closed state in the un-deployed state of the device to an opened, tissue-engaging state in the deployed state of the device in which said first unit extends in an overall radial direction and is adapted in this state for tight association with internal walls of one of the body structures, such that the combined tissue-engaging action of the two unit holds the two structures together. 
         [0019]    The term “having an overall cylindrical shape” denotes that the body has overall contours and side elevations resembling that of a cylinder. While the overall cylindrical shape may also include a perfect cylinder, it should be understood that in the fine details there may be deviations from the cylindrical shape. For example, the two tissue-engaging units, in their closed state, while fitting in the general cylindrical contour, may deviate therefrom in their fine details. 
         [0020]    The switch from an un-deployed to a deployed state of the device is typically achieved, according to an embodiment of the invention, by axially displacing of the inner body part in a proximal direction with respect to the external body part (retraction). 
         [0021]    According to an embodiment of the invention, the device may be removed after deployment for which purpose the device is switchable also from a deployed state to an un-deployed state. As will also be mentioned below, the actuation from a deployed into an un-deployed state may be achieved, according to an embodiment of the invention, through the employment of a release thread. 
         [0022]    The external body part and the internal body part may be engaged to lock in the deployed state by a variety of mechanisms. As will be appreciated, the invention is not limited by the manner in which these two parts are locked with one another in the deployed state. For example, in accordance with an embodiment of the invention, the external body part has one or more first engaging members and the internal body part has one or more second engaging members. In the deployed state of the device the one or more first engaging members engage the one or more second engaging members. A specific example is a flap in one or both of these body parts which fits into and is biased to engage with opposite recesses in the other body part. A typical example are corresponding flaps and recesses in the distal side of these two body parts. Such flaps may typically be linked to a thread, which in the specific example of an anastomosis device used for an anastomosis of the bladder and the urethra, extends outside through the urethra or a catheter tube, such that when the thread is pulled the flap disengages the recess whereupon the two body parts are unlocked and the device can be switched from the deployed to an un-deployed state in which it can be removed. Another example is a ratchet-type engagement mechanism. 
         [0023]    As will be appreciated there may be a variety of mechanisms that can be used for engaging and disengaging the two body parts one from the other and the invention is not limited to a specific manner in which this is achieved. 
         [0024]    In accordance with another embodiment, the engaging members in the two body parts may be made from a biodegradable or a bioerodable material such that their respective biodegradation or bioerosion of these components releases the engagement. It should be pointed out that the device may at times also be entirely made from a biodegradable or a bioerrodable material. 
         [0025]    In a specific, but not exclusive, embodiment of the invention at least one of the two tissue engaging unit, and preferably both, is an integral unit which is integrally formed within the external body part. An integral tissue-engaging unit is typically formed such that in its closed state it blends into the overall cylindrical shape of the external body part and it comprises engaging members that are each pivotally anchored to rigid portions of the external body part through a flexible connecting portion, and in an open state of the device extend in a general radial orientation. 
         [0026]    The term “general axial orientation” is intended to denote that the engaging members are generally arranged in a proximal-distal fashion or define a general longitudinal axis which extends in said direction. Such an axis may at times be parallel to the device&#39;s axis although having a general proximal-distal orientation, may at times define the axis which is not fully parallel. 
         [0027]    The term “general radial orientation” is intended to denote that in the open state the members are generally oriented in a direction away from the device&#39;s axis. In other words, a tangential cross-section through the device will display the members as extending radially. 
         [0028]    In accordance with an embodiment of the invention, the integral unit comprises a plurality of ribs which in the closed state are folded and oriented in a general axial orientation and comprises a membrane that is fitted over either the internal faces (mainly the faces that point inward in the closed state of the tissue-engaging unit), or over the external faces. 
         [0029]    The term “membrane” in the context of the invention, means to denote a sheet or a film, made of the variety of different materials which can form an essentially fluid-tight association with walls of organ or tissue. The membrane may be made of a variety water proof or water-tight materials such as plastic materials or other polymeric materials, rubber, woven or non-woven, typical impregnated fabric, etc. Exemplary materials are polyurethane, polypropylene, silicone and latex. In some embodiments of the invention, the membrane may incorporate or may be impregnated with an anti-microbial substance. 
         [0030]    The membrane is typically made to at least partially cover the unit while in its open state, whereby in said open state such unit can form an essentially fluid-tight contact with the internal walls of the body structure in which it is deployed. 
         [0031]    The membrane is typically made from a non-stretchable or minimally stretchable material and is attached to each one of the members (whether in the form of ribs or other) and is sized such that in the open state of the tissue-engaging unit it is stretched to its maximum thus conferring axial and tangential stability and rigidity to the tissue-engaging unit. 
         [0032]    The term “fluid-tight contact” means to denote that there will be essentially no fluid flow between the membrane and the juxtaposed tissue. It should however be noted that the term “fluid-tight contact” does not mean that there is a hermetic seal that avoids flow of any fluid; rather that such flow would be relatively small and usually negligible. 
         [0033]    An anastomosis device with an engaging unit that incorporates a membrane is novel per se and constitutes an aspect of the invention. In accordance with this aspect there is provided an anastomosis device having an un-deployed and a deployed state and switchable from the former to the latter, the device comprising: a body with an overall cylindrical shape defining a proximal-distal extending axis and two tissue-engaging units axially displaced from one another along said axis; at least one of the two units can change its state from a closed state in the un-deployed state of the device to an opened, tissue-engaging state in the deployed state of the device in which said first unit extends in an overall radial direction and is adapted in this state for tight association with internal walls of one of the body structures, such that the combined tissue-engaging action of the two unit holds the two structures together; said at least one unit having a membrane associated therewith such that in the tissue engaging state said membrane forms a fluid-tight contact with internal walls of the body structure. The body has preferably a structure with an internal and an external body parts, of a kind defined above. The at least one of the tissue-engaging units is preferably integrally formed with said body and typically with the external part thereof, of a kind specified above. 
         [0034]    In one specific embodiment of the invention the external body part has one or two sections that define an integrally formed tissue-engaging unit. Each such unit comprises a plurality of engaging members each of which has a proximal and a distal segment which is linked to the external body part through respective proximal and distal flexible connecting portions, and linked to one another through an intermediate flexible connecting portion. The internal body part, according to this embodiment, has a portion that engages the distal end of the external body part in a manner such that axial displacement of the internal body part towards the proximal end with respect to the external body part exerts an axial force on the distal end and thus gives rise to an axial displacement in the same direction. Upon such displacement, the members then radially open into an open state in which the two segments are angled with respect to one another about the intermediate connecting portion and are each oppositely angled with respect to the external body part about the respective proximal and distal connecting portions. In a typical, although not exclusive example, the tissue-engaging units blend, in their closed state, into the overall cylindrical shape of the external body part. 
         [0035]    In a specific embodiment of the integral tissue-engaging unit, the unit has a structure that comprises a plurality of elongated members that extend in a general axial orientation. Each of such members comprises a proximal and distal segment linked to one another through an intermediate flexible connecting portion at their respective distal and proximal ends. Thus, in an open state the two segments define an overall triangular shape with an apex that is constituted by the intermediate connecting portion. Such a structure is typically fitted with a membrane over an internal or external face, in a manner as described above. In some embodiments of the invention, the two engaging units have each such a structure, with the two units being either identical or being of a different size or shape. 
         [0036]    In accordance with one embodiment of the invention, the tissue-engaging units have an essential axial symmetry. 
         [0037]    In accordance with an embodiment of the invention, at least one engaging unit has a plurality of members with a portion that ends with a pointed, tissue penetrating tip, which in the open state of the device defines a prong that associates with internal walls of a body structure by penetrating in the layers thereof. Such a tissue-engaging unit is typically designed so that the prongs will be slanted, with either a general proximal or distal orientation. A specific example is an engaging unit, integrally formed within the external body part, and which has a plurality of members each of which has one segment that is linked at a point thereof between its proximal and distal ends to the other segment, said one segment having a free end with a pointed, tissue penetrating tip. Thus in the open state, the free ends assume an outwardly slanted orientation and can associate with the internal walls of the body structure as aforesaid. When said one segment is attached to the proximal segment, in accordance with a preferred embodiment, in the open state the free end points in a general distal direction (with a slant). 
         [0038]    An anastomosis device which is characterized in that one of the tissue-engaging units has prong-like portions that can penetrate a tissue, is novel per se and an aspect of the invention. In accordance with this aspect, there is provided an anastomosis device with an un-deployed and a deployed state that is switchable from the former to the latter, and comprises: an essentially cylindrical body defining a proximal-distal extending axis of and having an internal duct extending axially therethrough providing fluid communication between the distal and the proximal ends of the body; an actuation mechanism for switching between the un-deployed and the deployed state of the device; and two tissue-engaging units axially displaced from one another along said axis; at least one of the engaging units has a plurality of members each comprising a segment having a free end with a pointed, tissue-penetrating tip, in the un-deployed state of the device said members blend into the cylindrical shape of the body, and in the deployed state, said free ends have an outwardly slanted orientation and can associate with internal walls of a body structure by penetrating inner layers thereof. In the device according to this aspect, the tissue engaging unit is preferably one that is integrally formed in the external body part, of the kind descried above. Further by some embodiments, the at least one tissue-engaging unit of this embodiment comprises a membrane of the kind described above. 
         [0039]    A preferred, although not exclusive, use of the device of the invention is in linking two lumens, e.g. two cut stumps of organ that need to be connected to one another, e.g. following a surgery or an injury. A typical example is to connect the bladder with the urethral stump, following a prostatectomy procedure. In case of linking two lumens, there is usually a need to ensure flow communication between the two linked body portions and internal duct of the device provides such flow communication. Other possible uses of the device in accordance with the invention is in the anastomosis of two cut segments of the gastrointestinal tract or two cut segments of a blood vessel. 
         [0040]    The invention also provides an anastomosis system that comprises a deployment instrument and device as described above. According to a preferred embodiment of the invention, the deployment instrument comprises a tubular body that after deployment of the device remains attached thereto and serves for catheterization. A typical deployment instrument comprises: an external tubular sleeve having a lumen which in the un-deployed state accommodates the device in its distal end; an inner sleeve accommodated within the lumen of the external sleeve and having a distal end which is engaged with the proximal end of the device and being in flow communication with the duct within said body; and an elongated actuation member accommodated within the inner sleeve for actuation, through axial displacement, of the device from the un-deployed to the deployed state. 
         [0041]    In accordance with an embodiment of the invention said actuation member is tubular and has one or more engaging members at its distal end that engage with the said device in a manner such that axial displacement of the actuation member actuates the device to switch from an un-deployed to a deployed state; said actuation member accommodates a central rod that acts to secure the engagement of the one or more engaging members with said device, pulling of said central rod allowing disengagement of the one or more engaging members. 
         [0042]    In accordance with one specific embodiment of the invention, a system for deployment of an anastomosis device of the kind having an internal and external body part, of a kind described above. The system according to the embodiment has the following functional states: an un-deployed state for inserting the device to its place of deployment within the body, in which said device is accommodated within the distal end of the external sleeve, the distal end of said inner sleeve engages the proximal end of the device, the engaging members at the distal end of the actuation member engage the internal body part of the device, and the central rod is fully inserted within the lumen of the actuation member whereby it secures the engagement of said engaging members to said internal body part; one or two first operational states in which the external sleeve is retracted exposing at least one of the tissue engaging units; corresponding one or two second operational states in which either the actuation member or the internal sleeve (or both) is axially displaced so as to cause opening of the exposed tissue engaging unit; a third operational state in which the internal body part is fully axially displaced in the proximal direction whereupon a continuous fluid path is formed between the internal duct of the device and the lumen of the inner sleeve; a fourth operational step in which the central rod is removed, whereupon the actuation member can be disengaged from the inner sleeve; and a resulting deployed state in which the actuation member is removed, the device is in its deployed state, the inner sleeve remaining engaged with the device serving for catheterization. 
         [0043]    Typically, the first and the second operational states are repeated. In the first repeat, the external sleeve is retracted to expose a first tissue-engaging unit and then the actuation member or the internal sleeve (or both) is axially displaced to actuate the opening of the first unit. Then in the second pair the external sleeve is retracted further to expose a second tissue-engaging unit and the actuation member or the internal sleeve (or both) is axially displaced to actuate the opening of the second unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0044]    In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
           [0045]      FIG. 1  depicts an anastomosis system for use in joining the bladder to the urethra comprising a deployment instrument and a tissue-fastening device carried thereon in accordance with an embodiment of the present invention; 
           [0046]      FIG. 2A  depicts the anastomosis system of  FIG. 1  in an open state of the two tissue-engaging units; 
           [0047]      FIG. 2B  depicts the anastomosis system of  FIG. 1  in an open state of the two tissue-engaging units after removal of the deployment mechanism; 
           [0048]      FIG. 3  is a simplified schematic flowchart of a process for performing an anastomosis, in accordance with some embodiments of the present invention; 
           [0049]      FIG. 4  depicts an isometric view of an anastomosis system of  FIG. 1  deployed in situ showing a tissue-fastening device attached to a catheterization tube which originally constituted part of the deployment apparatus; 
           [0050]      FIG. 5  is an isometric view of a tissue fastening device in accordance with an embodiment of the invention in its close state, detached from the deployment instrument; 
           [0051]      FIG. 6  is an isometric view of the inner body part of the device of  FIG. 5 ; 
           [0052]      FIG. 7  is a longitudinal cross-section of the device of  FIG. 5 ; 
           [0053]      FIG. 8  is a longitudinal cross-section of the device of  FIG. 5  in the opened state of the tissue-engaging units; 
           [0054]      FIG. 9  is an isometric, partially exploded view of the device of  FIG. 5  and the distal portion of the deployment instrument; 
           [0055]      FIGS. 10A-10E  are isometric views of the tissue-fastening device and the distal portion of the deployment instrument according to another embodiment in successive opening and deployment steps of the device; 
           [0056]      FIGS. 11A-11E  are longitudinal cross-sections of the device in a succession of deployment/opening steps corresponding to those of respective  FIGS. 10A-10E ; 
           [0057]      FIGS. 11F-11G  are longitudinal cross-sections showing two additional operational steps, in which  FIG. 11F  shows the disengagement of the puller sleeve while  FIG. 11G  shows the disengagement of the external and inner sleeves from the device. 
           [0058]      FIG. 12  is an isometric view of the tissue-fastening device, according to an embodiment of the invention, fitted with a thread for use in removal of the device from its deployed position; 
           [0059]      FIG. 13A-13C  is an isometric view of a device according to an embodiment of the invention in three successive removal steps; 
           [0060]      FIG. 14-16  are isometric views of tissue-fastening devices according to other embodiments of the invention; 
           [0061]      FIG. 17A-17B  depicts respective closed and open states of a device according to another embodiment of the invention; 
           [0062]      FIG. 18  depicts an anastomosis device attached to a guide wire for guiding instrument thereto; and 
           [0063]      FIG. 19  shows a deployed anastomosis device in accordance with another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0064]    In the following description some embodiments will be illustrated with reference to the annexed drawings, which concern a tissue fastening device and anastomosis system for use in linking the bladder and the urethra, for example, following a surgical prostatectomy procedure. As will be appreciated, the illustrated embodiments are intended to provide examples for the much broader aspect of the invention as described and defined herein, and these should thus not be construed as limiting. For example, applications of the invention may be in uses such as in joining blood vessels, joining segments of the gastro-intestinal tract. Thus, in addition to urological applications, the invention may have applications in gynecology, gastro-enterology, cardiovascular medicine, and others. 
         [0065]    In the following description, like reference numerals in different figures indicate components or part with a similar, at times identical, function. 
         [0066]    Reference is first being made to  FIGS. 1 ,  2 A and  2 B showing an anastomosis system  100  including a deployment instrument generally designated  102  and a tissue fastening device  104  carried on the distal end of deployment instrument  102 . Instrument  102  comprises an external sleeve  106  having a grip  110  at its proximal end, an internal sleeve  112  accommodated within sleeve  106  and having a grip  114  at its proximal end, a puller sleeve  116  fitted with a proximal grip  118  and a central rod  120  (that can be seen more clearly in  FIG. 2B ), ending with a proximal grip  122 . Puller sleeve  116  has two engagement arms  124  at its distal end. Also shown is a device release thread  130  which extends from device  104  through sleeve  112  and out through the proximal end thereof. This string assists in removal of the device as will be explained further below. 
         [0067]    Initially, as shown in  FIG. 1 , the device  104  carried at the end of deployment instrument  102  is in a closed or un-deployed state and almost entirely enveloped by the distal end of external sleeve  106 . In a manner to be explained further below, device  104  can be actuated, through a series of manipulations of deployment instrument  102 , whereupon tissue fastening units  140  and  150  open to assume the state as shown in  FIGS. 2A and 2B . 
         [0068]    The series of operative steps in deployment of the tissue-fastening device  104  is presented schematically in  FIG. 3 . In the first step  302 , the anastomosis device carried at the distal end of deployment device  102 , is inserted through the urethra until device  104  lies partially within the bladder. At the next stage  304 , through pulling of grip  110 , while using grip  114  for a stabilizing bias, external sleeve  106  is retracted exposing first unit  140 . At a next stage,  306 , through pulling on grip  118 , against the provision of a stabilizing bias on grip  114 , puller sleeve  116  is retracted and in a manner to be explained below, causes the opening of unit  140  into a state as shown in  FIG. 2B . Unit  140  is made to open within the bladder and consequently the walls of the bladder are pulled towards the urethra. If needed, at  308  the walls of the bladder may be pulled closer to the urethra by some further retraction of unit  140 . 
         [0069]    At a next stage  310 , grip  110  is further pulled, thus causing additional retraction of external sleeve  106  thus exposing unit  150 . By a further pulling on grip  118 , sleeve  116  is retracted and through a mechanism, also to be explained below, unit  150  opens to its open position as shown in  FIGS. 2A and 2B . Once unit  150  opens, the device is locked in the deployed state at  312 , through a mechanism such as one of those to be described below, and the device remains locked in this position whereby units  140  and  150  remain open. The locking of the device in the deployed state should be such so as not to be destabilized and spontaneously close by normal biasing forces that may be exerted on the device once deployed in situ. 
         [0070]    Device  104  has an internal duct (not shown in  FIGS. 1-2B ) which in the deployed and locked state  314  is in fluid communication with internal sleeve  112 . In this deployed state, at  316  all components of the deployment device are removed other than sleeve  112  and external sleeve  106 . The sleeve  112 , which remains linked to device  104 , serves for catheterization of fluids from the distal end of device  104  which is then drained out through the proximal end of sleeve  112  which can, be connected to a drainage bag or the like. The sleeve  112  remains linked to the internal body of the fastening device through the interdigitation between them and is constrained in this engagement due to the overlap of the external sleeve. 
         [0071]    Reference is now being made to  FIG. 4  showing an anastomosis device  104 , according to an embodiment of the invention, for joining a bladder  460  with a urethral stump  470  and deployed for the purpose. The tissue-engaging device includes a tissue-engaging-unit  140  that consists of a plurality of ribs  516 , that are arranged in a general axial symmetry, and which are associated with a membrane  540 . Once in situ in a deployed and open state as shown, membrane  540  forms a fluid-tight contact with internal walls  461 , 462  of the bladder  460 . As can further be seen in  FIG. 4  once opened within the bladder and brought into close association with the internal walls  461 , 462  of the bladder  460 , a fluid-tight contact between unit  140  and the internal walls of the bladder is thus formed. Device  102  has another tissue-engaging unit  140  with a plurality of pointed prongs  552  that at least partially penetrate inner walls  471 , 472  of urethra  470 . The particulars of the device of this embodiment will be explained in further details below. 
         [0072]    Reference is now being made to  FIGS. 5-7  in which  FIG. 5  is a perspective view of a tissue-fastening device according to an embodiment of the invention.  FIG. 6  shows an internal sleeve of the device and  FIG. 7  in a longitudinal cross-section. Device  104  has an overall cylindrically shaped body that includes an external tubular body part  502  and an internal tubular body part  504  accommodated within the lumen of body  502 . Integrally formed within body part  502  are tissue-engaging units  140  and  150 . Internal tubular body part  504  ends with a distal tapering head portion  506  that has shoulders  508  that engage the distal end portion  510  of external tubular body part  502 . Defined within tubular body part  504  is a duct  512  defining a flow passageway through device  104 . 
         [0073]    Tissue-engaging unit  140  comprises a plurality of axially oriented ribs  516 . Each of ribs  516  has a proximal segment  518  and a distal segment  520  pivotally linked to one another through a flexible connecting portion  522 . Proximal segment  518  is pivotally linked to the proximal part of body  502  through a proximal flexible connecting portion  524 , while distal segment  520  is pivotally linked through a distal flexible connecting portion  526  to distal end portion  510  of the external body part. Connecting portions  522 ,  524  and  526  form integral hinges and are formed with a relatively thinner wall which permits preferential bending at these locations. Overlaying the ribs is a membrane  540 . 
         [0074]    As will be appreciated, and as will also be shown below, upon displacement of internal body part  504  in the direction of arrow  530  ( FIG. 7 ) relative to external body part  502 , shoulder  508  will displace the distal body portion  510  giving rise to deployment of unit  140 , by radial extension of ribs  516  to the state as shown in  FIGS. 4 ,  8  and others. This deployment results from the opposite compression forces exercised on the external body of the fastener  502  within the deploying instrument; by pulling on the pulling sleeve  116  (not shown in these figures) that engage the internal body part  504 , that latter engaging the distal rim of the external body part  510  by the shoulder  508 , the net result being a force on the external body part  502  directed proximally which is against the stationary proximal end thereof. (The proximal end remains stationary in view of its engagement with internal sleeve  112  of the deploying instrument). Internal body part  504  has an annular abutment  602  and the rearward displacement is limited thereby and progresses until annular abutment  602  comes to bear against the base  802  of segment  518 . 
         [0075]    Unit  150  consists of a plurality of members  548 , each with a proximal segment  550  and a distal segment  552 . Segment  550  has a rear section  553  and a pointed tissue-penetrating prong  554 . In  FIG. 5 , unit  150  is seen in an un-deployed state with the prongs being essentially level with the external surface of external body part  502  blending into the overall cylindrical structure. In the deployed state that can be seen in  FIG. 8 , pointed prongs  552  point outwardly and distally. In this position, they can penetrate the internal portion of the walls of the urethra, as can be seen in  FIG. 4 , and thus hold the walls in a fixed position. This improves approximation between the cut distal end of the urethra and the bladder neck. 
         [0076]    Segment  550  is linked to the rear body portion  562  of external body  502  through a flexible proximal connecting portion  564  and to distal segment  552  through flexible intermediate connecting portion  566 . Distal segment  552  is in turn linked to portion  560  of external body part  502  through a flexible connecting portion  568 . Thus, in a similar mariner to the opening of the ribs of tissue-engagement unit  140 , upon application of compression forces, as will be described below, tissue-engagement unit  150  opens to the state as seen in  FIG. 8  in a manner to be described further below. 
         [0077]    Optionally, in some embodiments of the invention, also tissue-engaging unit  150  is at least partially covered by a membrane ( 541 , see  FIGS. 10D-E ,  11 D-E,  FIG. 11G  and  FIG. 12  herein below). 
         [0078]    The proximal end  562  of body part  502  has a generally T-shaped groove  570  which serves for engagement of device  104  with the inner sleeve  112  (see  FIG. 9  and the description also herein below). 
         [0079]    Also provided in portion  562  of external tubular body part  502  are two engagement flaps  574 . Flaps  574  are biased to slightly project internally and can thus engage with the openings  576  (seen in  FIG. 6 ) of internal body part  504  to lock the device  104  in a fully deployed state as seen in  FIG. 8 . Alternatively, it is also possible, by other embodiments for flaps in the internal body part  504  to engage openings in the external tubular body part  502  to lock the fastener device in its fully deployed state. Another embodiment for engagement of the two body parts will be presented below. 
         [0080]    Internal tubular body part  504  has also two lateral openings  578  (seen in  FIG. 6 ) which are intended for engagement with distal engagement arms  124  of puller sleeve  116 . 
         [0081]      FIG. 9  shows a tissue fastening device  104  according to the embodiment depicted in  FIG. 5 . Also depicted in  FIG. 9  are distal components of the deployment instrument. The view of  FIG. 9  is partially exploded to permit clear view of the components of the deployment instrument. 
         [0082]    As can be seen, inner sleeve  112  has a T-shaped engagement projection  902  which has a shape matching opening  570  and can thus be accommodated therein. This ensures a tight and continuous engagement of device  104  and inner tube  112 . The engagement between inner sleeve  112  of deploying instrument and the external body part of the fastening device permits, among others, to exert a counterforce during deploying the device. Also, through such tight engagement, the inner sleeve  112  may serve as a catheter tube for fluid drainage after removing the pulling sleeve  112  and the internal rod  120 , as already explained above, and as will also be explained further below. 
         [0083]    Accommodated within the lumen of inner sleeve  112  is a puller sleeve  116  having terminal engagement arms  124  which engage with openings  578  of inner part  504  of device  104 . Accommodated within puller sleeve  116  is inner rod  120  having a distal end  910  protruding slightly out of the distal opening of tapered head portion  506  of internal body part  504 . As long as inner rod  120  passes between engagement arms  124 , arms  124  are constrained to be in a laterally protruding position, firmly engaged within opening  578  of internal part  504  of device  104 . As will also be explained below, the relative displacement of internal body part  504  and external body part  502  of device  104  is achieved by retraction of puller sleeve  116 , which is facilitated by the tight engagement as aforesaid. Once rod  120  is retracted, engagement parts  124  can disengage from openings  578  of internal body part  504 . 
         [0084]    External sleeve  106  initially envelopes both inner tube  112  and device  104 . Through the gradual retraction of sleeve  106  and by sequential actuation, as will be explained below in  FIGS. 10A-11E , device  104  is opened and deployed. 
         [0085]      FIGS. 10A-10E  and  11 A- 11 E describe a succession of steps for opening of the tissue engagement units while deploying device  104 . Initially, sleeve  106  envelopes most of device  104  other than head portion  506 . As can be seen, slightly protruding out of the opening of head portion  506  is the rounded end  910  of central rod  120 . In the state as shown in  FIGS. 10A and 11A , the distal part of the deployment system with the tissue fastening device is brought into position, e.g. in the case of intended anastomosis of the bladder and the urethra, is introduced through the urethra and advanced through the severed urethral stump and is inserted into the small pelvis, under vision. Then the instrument with said device is introduced into the urinary bladder through the severed bladder neck. At this stage, the sleeve  106  is retracted to the position as shown in  FIGS. 10B and 11B  and then the puller sleeve  116  is retracted by pulling at grip  118 , jointly with central rod  120  and its grip  122 , while counterforce is exercised on the internal sleeve  112  through grip  114 ; and through a mechanism as explained above causes opening of unit  140  to its open state as seen in  FIGS. 10C and 11C . 
         [0086]    At the next stage, sleeve  106  is retracted to the position as can be seen in  FIGS. 10D and 11D  in which unit  150  is exposed, and the entire deployment system is pulled so as to bring the severed stump of the bladder into closer proximity with the severed urethral stump. Upon further retraction of puller sleeve  116 , while applying a counterforce on the internal sleeve  112  through grip  114  and through a mechanism as explained above unit  150  is opened to its open state as seen in  FIGS. 10E and 11E . As can be seen, engagement unit  152  in this embodiment has an associated membrane  541  which is fitted over rear sections  553  of segments  550 , and can thus also form, in its open state, a fluid-tight contact with surrounding walls. 
         [0087]    As a final step shown in  FIG. 11F , internal rod  120  is retracted relieving the constraint imposed on engagement arms  124  at the distal end of pulling sleeve  112  that engaged the internal body part  504 . Then the puller sleeve  116  can be disengaged, retracted, and removed. The external sleeve  106  and inner sleeve  112  are left in place with the external sleeve covering the engagement zone  1120  between the inner sleeve  112  and the proximal portion  562  of the external body part of  502 . This overlap between the external sleeve  106  and the engagement zone  1120  of the internal sleeve and the fastener device prevents disengagement of the internal sleeve from the anastomosis device. Grip  114  can then be removed leaving open the proximal end  1130  of the tube  112  that can now be connected to a urine removal system such as a urine bag 
         [0088]    The inner sleeve  112  may be disengaged from the fastening device as represented in  FIG. 11G  by retracting the external sleeve  106  thus exposing the point of engagement  1120  of the internal sleeve with the external body part  502 . The engagement at the point of engagement  1120  is secured through the stabilizing embrace of external sleeve  106  as it avoids transient deformation of the point of engagement  1120  which is needed for disengagement. Then by pulling on the internal sleeve  112 , the internal sleeve can be easily disengaged from the deployed and locked fastener device and the internal sleeve  112  and external sleeve can be removed leaving the deployed fastening device as a stent for the anastomosis. 
         [0089]    The role of the non-stretchable or minimally stretchable covering membrane is not only to provide sealing and prevent fluid leakage. The additional role is to increase the tangential stability of the deployed ribs. The membrane has to be attached to each rib and when fully deploying the ribs, the membrane is extended to its maximum and induces maximal radial and tangential stability of the tissue-engaging units covered by these membranes. 
         [0090]      FIG. 12  shows another embodiment in which use is made of a release thread  130  that is linked at its distal end to engagement flaps  574  and extends through the lumen of inner sleeve  112  out through its proximal end as shown in  FIGS. 1-2B . Threads  130  are affixed to flaps  574  at their exterior. Upon pulling thread  130 , flaps  574  are slightly radially displaced thereby disengaging openings  576  in internal body part  504 . 
         [0091]    A succession of steps of un-deployment of an anastomosis device  1306  according to another embodiment of the invention is shown in  FIGS. 13A-13C . This device also displays an alternative engagement mechanism between the two body parts than that described above. Device  1306  according to this embodiment has a tissue-engaging unit  1308 , of substantially similar design to tissue-engaging unit  140  in the embodiment described above. Engagement unit  1308  has an associated membrane  1310 . Axially disposed in the proximal direction is a second tissue-engaging unit  1320  which is substantially similar to the tissue-engaging unit  150  in the embodiment described above. 
         [0092]    The proximal portion  1326  of the internal body part is seen in  FIG. 13A  extending out from the proximal end  1324  of the device. Rear end  1326  has annular grooves  1328 . This rear end serves for engagement in a ratchet-type mechanism. Flap  1330  is formed in the rear end of the external body part  1324  and has an internal abutment  1332  which engages one of the grooves and locks the device in a deployed state. The groove external surface of the proximal end  1326  of the device&#39;s inner body part also serves for engagement with the distal end of inner sleeve  112 . 
         [0093]    Flap  1330  is linked through a flexible connecting portion  1334  (which has a relatively thin wall similarly to the above described flexible connecting portions) to an extension flap  1336 . Extension flap is connected to thread  1340  through bifurcating terminal segments  1342  and  1344 , one connecting to extension flap  1336  and the other to its counterpart at the other end. 
         [0094]    Pulling of thread  1340  causes a slight axial displacement of flap  1330  whereupon abutment  1332  disengages the corresponding groove  1328  releasing the internal body part and permitting closure of tissue-engagement unit  1320  to the closed state as seen in  FIG. 13B . The additional pulling exerts a distally directed force as represented by arrow  1350  in  FIG. 13B , on tissue-engaging unit  1308  causing its closure to the fully closed state, seen in  FIG. 13C , and at this un-deployed state the device can be retracted from its position. 
         [0095]      FIGS. 14-16  show different embodiments of design of an anastomosis device in accordance with the invention. Device  1400  seen in  FIG. 14  has two essentially identical tissue-engaging units consisting of a distal unit  1402  and a proximal unit  1404 , each of which has ribs  1406  and an associated membrane  1408 , similar to that of unit  140  of the embodiment described above. Device  1400  according to this embodiment is suitable for anastomosis of tubular organ of a similar cross section, for example, two cut stumps of blood vessels, two cut stumps of intestine, etc. In some cases, units  1402 , 1404  are only partially covered by a membrane  1408 . Device  1400 , as well as device  1500  as seen in  FIG. 15 , have a ratchet-type engagement mechanism for locking the device in the deployed state of a kind described in the embodiment of  FIGS. 13A-13C  and in the embodiment of  FIG. 19 , that will be described further below. 
         [0096]    A device  1500  according to another embodiment of the invention is shown in  FIG. 15 . The device has a relatively small, proximal engagement unit  1502  and a distal larger engagement unit  1504 . Both units consist of respective ribs  1506  and  1508  and are associated with respective membranes  1512  and  1514 . Tissue engagement unit  1502  opens to an essentially symmetrical configuration while unit  1504  comprises ribs that have each a proximal segment  1520  and a distal segment  1522  which is longer than the former whereby segments  1520  assume an essentially right angle with respect to the axis of the device  1500 . 
         [0097]    A tissue fastening device  1600  according to another embodiment of the invention is seen in  FIG. 16 . In this case, the ribs  1602 , rather than having an axial orientation in their closed state, have a somewhat slanted orientation in the closed state. 
         [0098]    A tissue fastening device according to another embodiment of the invention is shown in a closed and open state in  FIGS. 17A and 17B . Device  1700  has two tissue engagement units  1702  and  1704 , each of which has a plurality of ribs with a similar general structure as in the case of device  104 , however, with some asymmetric features. In the case of unit  1702 , the different ribs differ from one another with the relative length of their proximal and distal segments whereby upon opening, some of the ribs  1710  assume a general symmetric open shape, others  1712  assume an asymmetric open shape. 
         [0099]    In unit  1704 , the plurality of ribs are all designed to have a symmetric opened shape, however, different ribs have a different axial position in the device whereby the overall shape of the unit in its open shape is non symmetrical. Thus, a fastening device of this nature may be used to fasten two organs having irregular shape. 
         [0100]    Reference is now being made to  FIG. 18 , showing an anastomosis device  1800  with a general structure as device  104  described above. Device  1800  is fitted with a guide wire  1802  which passes through the internal duct of the device and fastens at its distal end  1804  to the distal end  1806  of the inner body part. This guide wire permits guidance of components of the deployment or un-deployment instruments, such as device-engaging member  1808  which has a distal tubular portion  1810  which thereby guides the distal end of device  1808  into position. 
         [0101]    Reference is made to another embodiment of an anastomosis device  1900  which is seen in  FIG. 19 , in a deployed state linking together two stumps consisting of a proximal stump  1902  and a distal stump  1904  of a tubular body part for example, two stumps of a cut intestine. Unit  1900  which is seen in longitudinal cross-section, consists of an external body part  1908  and an internal body part  1910  which can be axially displaced one with respect to the other in a manner analogous to that described above. Internal body part has a lumen  1912  extending therethrough. 
         [0102]    Device  1900  has two tissue-engaging units—a proximal tissue-engaging unit  1920  and a distal, tissue-engaging unit  1922 , which in the open state as seen in  FIG. 19  have each respective distal segments  1926  and proximal segments  1928  which have a generally right angle orientation with respect to the axis of the device, similarly, as in the case of the tissue-engaging unit  1504  of device  1500  as seen in  FIG. 15 . Covering each of tissue-engaging units  1920  and  1922  are respective membranes  1930  and  1932 . Thus, in the fully open and deployed state seen in  FIG. 19 , the two tissue-engaging units clamp wall portions between them in a fluid tight manner. 
         [0103]    As can be seen, the proximal end  1940  of inner body part  1910  has a grooved surface with a saw-cross-sectional shape whereby it can engage with an annular internal terminal abutment  1942  in the proximal end of the external body part  1908  in a ratchet-type engagement. As can be appreciated, given this engagement mechanism, this device has several locking states rather than a single locking state as, for example, in the device  104  described above. 
         [0104]    The inner body part  1910  has a generally L-shaped groove  1950  which serves for engagement with a deployment instrument. 
         [0105]    According to some embodiments of the present invention, the deployment instrument is typically made out of a metal or alloy, such as stainless steel, or made of a plastic material or a combination thereof. The external sleeve may be made of a metal or of a plastic material, depending on the application requirements. 
         [0106]    The deploying instrument may be straight, bended, rigid, elastic, or deflectable. 
         [0107]    The internal sleeve, which, once deployed, serves as a catheter tube, may be made of plastic, polypropylene polyurethane, polyethylene, silicone, or any other flexible material. 
         [0108]    The device may be made of a plastic material, nitinol, or of bio-erodible or biodegradable material and may, according to some embodiments, be left in situ until it is fully eroded and/or degraded. Additionally, only some of its components such as the locking mechanism may be made of a biodegradable material. 
         [0109]    In some alternative embodiments, the bio-erodible/biodegradable device may be left within the anastomosis until its structural strength weakens sufficiently so that at least a part of the device, such as a blocking mechanism, softens to an extent such that by pulling on the connected thread, the prongs will be pulled out easily from tissue and device will be pulled easily from the urethra or the device will be spontaneously passed through the urethra. 
         [0110]    Additionally, the device may be designed of some biodegradable components such as the prongs and/or the blocking elements and other non-biodegradable elements. 
         [0111]    Alternatively, the device may be designed of a biodegradable material reinforced with a backbone of soft non biodegradable material. In this case the hinges of the flanges may consist of that soft backbone. Biodegradation of the attachment device will result in softening of the device but its structural integrity will be maintained assuring its integral removal. 
         [0112]    The membrane may be made of a waterproof or water-resistant material, such as a polymer, exemplified by polyurethane, polypropylene, silicone, latex, and others.