Abstract:
A medical device and procedure is provided for rapidly forming an anastomosis between two viscera, while minimizing the potential of breaching the mural boundary. The medical device generally includes a first magnet assembly and a second magnet assembly. Each of the magnet assemblies includes a magnetic core defining an axial opening and at leas one includes a transverse passageway. The axial openings are sized to correspond with the size of the desired anastomosis. The transverse passageway is size to permit passage of a wire guide therethrough for placement of the first and second magnet assemblies. The medical device approximates the tissues of the two viscera, such that endoscopic excision and affixation of the tissues may be performed to create the anastomosis.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 60/857,901 filed on Nov. 10, 2006, entitled “RING MAGNETS FOR SURGICAL PROCEDURES” the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to methods and devices for forming an anastomosis between two viscera, and more particularly relates to such methods and devices employing magnets. 
       BACKGROUND OF THE INVENTION 
       [0003]    Historically, gastrointestinal (GI) surgery has been performed to create a channel between two viscera for the purpose of redirecting bodily fluids, i.e. an anastomosis. For example, intestinal contents or bile may be redirected in patients who have developed an obstruction of the bowel or bile duct due to such conditions as tumors, ulcers, inflammatory strictures or trauma. With reference to  FIG. 1 , the relative positions of several organs of the abdominal cavity are shown, including the gall bladder  10 , the bile duct  12 , the stomach  14 , the duodenum  16  and the jejunum  18  of the small intestine. Inflammatory strictures  20 ,  22  of the jejunum  18  and bile duct  12  are shown by the dotted lines in  FIG. 1 . It will be recognized that there may be a need to anastamose many different viscera, such as the jejunum  18  and the stomach  14  (gastrojejunostomy), the bile duct  12  and the duodenum  16 , two sections of the small or large intestines (not shown), or various other combinations of viscera such as during bariatric surgery. 
         [0004]    During surgery to form an anastomosis, the two tissues are often brought together and affixed to one another using fixators such as sutures, staples, or some other fixation means. While fixators are being placed, the tissues of the respective viscera are held in proximity to one another using various means. In open surgery this is usually accomplished with graspers, forceps, or other tissue holding instruments that are manipulated by clinicians. In laparoscopic surgery, similar instruments may be used, except that the laparotic access limits the number of instruments to a few percutaneous “ports,” making the technical challenge of the procedure much greater. 
         [0005]    When these types of GI surgery are performed, there exists the potential to breech the mural boundary. Thus, extreme care must be taken to prevent contamination of the pleural and abdominal cavities with GI contents, which are laden with bacteria that do not naturally occur in those locations. If significant contamination occurs, then serious infection can set-in, which can lead to serious illness or death if not treated early and vigorously. 
         [0006]    To address these limitations and minimize the invasiveness of such surgeries, magnetic anastomosis devices (MADs) have been developed for forming anastomosis. An exemplary MAD is disclosed in U.S. Pat. No. 5,690,656, the disclosure of which is incorporated herein by reference in its entirety. Generally, the MAD of the &#39;656 patent includes first and second magnet assemblies comprising magnetic cores which are surrounded by thin metal rims. The first and second magnet assemblies are positioned in the two viscera between which the anastomosis is desired and brought into close proximity to each other. Due to the magnetic attraction between the two magnetic cores, the walls of two adjacent viscera are compressed between the magnet assemblies and in particular the metal rims, resulting in ischemic necrosis of the walls to produce an anastomosis between the two viscera. 
         [0007]    MADs may be delivered through surgical intervention such as laparotomy, over a wire guide using a pushing catheter (and typically under fluoroscopy), by simply swallowing the magnet assemblies of the MAD and using massage under fluoroscopy to align the two magnet assemblies, or endoscopically using grasping forceps. Within about ten days the visceral tissues surrounding the magnets fuse together, and the magnets and entrapped necrotic tissue subsequently detach from the surrounding tissue to leave an opening between the viscera. The detached magnet pair may pass through the remainder of the GI tract naturally, and uneventfully, but are preferably grasped with forceps (ideally just prior to complete detachment) and removed during a follow-up endoscopic procedure. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention provides a medical device and procedure for rapidly forming an anastomosis between two viscera, while reducing the technical challenge and minimizing the potential of breeching the mural boundary. In this manner, the anastomosis may be formed with surety before the patient leaves the medical facility and eliminates the need for a follow-up procedure. An additional protection against breach of the mural bounding is also provided and there is minimal risk of the anastomosis becoming separated or forming a leak while the patient is not in the medical facility. 
         [0009]    According to one embodiment constructed in accordance with the teachings of the present invention, a medical device for approximating the tissues of two viscera includes a first magnet assembly and a second magnet assembly. Each of the magnet assemblies includes a magnetic core defining an axial opening and a transverse passageway. The axial openings are sized to permit formation of the anastomosis therein. The transverse passageway is sized to permit passage of a wire guide therethrough for placement of the first and second magnet assemblies. Once the tissues have been approximated with the medical device, tissue excision and affixation may be performed, preferably endoscopically. 
         [0010]    According to more detailed aspects of the medical device, the first and second axial openings may be substantially the same size or may be different in size. The first and second magnet assemblies preferably define first and second rims projecting axially from the first and second magnetic cores. The first and second rims are sized to nest within each other. In one embodiment, the first and second rims are positioned proximate the outer periphery of the first and second magnetic cores, and in a second embodiment the first and second rims are positioned proximate the first and second axial openings of the magnetic cores. The first and second rims preferably define atraumatic engagement surfaces such as flat or rounded edges. 
         [0011]    A method for forming an anastomosis between two viscera is also provided in accordance with the teachings of the present invention. Generally, a pair of magnet assemblies is provided having a construction as described above. One magnet assembly is placed into one viscera and the other magnet assembly is placed into the other viscera such that the pair of magnet assemblies are magnetically attracted and compress the tissue of the two viscera between the magnet assemblies. A portion of the tissue of the two viscera located within the axial openings is excised. The tissues of the two viscera are affixed together, thereby forming a secure anastomosis. 
         [0012]    According to more detailed aspects of the method, the placing step preferably includes introducing a wire guide into one of the viscera and translating one of the magnet assemblies along the wire guide into the viscera. The excising step includes introducing a cutting instrument into one of the viscera and manipulating the cutting instrument. The cutting instrument may be an electrosurgical device, although numerous other cutting instruments may be employed. The excising step may be performed endoscopically, and the cutting instrument may be introduced through a working channel of an endoscope. The affixing step includes affixing together the tissue of the two viscera located within the axial openings, such as by suturing or stapling. Preferably, the affixing step is also performed endoscopically. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings: 
           [0014]      FIG. 1  depicts various abdominal organs and anatomy where the medical device and method may be employed in accordance with the teachings of the present invention; 
           [0015]      FIG. 2  is a perspective view, cut to reveal a cross-section, of a medical device for forming an anastomosis in accordance with the teachings of the present invention; 
           [0016]      FIG. 3  is a cross-sectional view of the medical device depicted in  FIG. 2 ; 
           [0017]      FIG. 4  is a cross-sectional view similar to  FIG. 3  showing the step of excising tissue; 
           [0018]      FIGS. 5 and 5   a  are cross-sectional and perspective views, respectively, showing the step of suturing the tissue; 
           [0019]      FIG. 6  is a cross-sectional view of another embodiment of a medical device for forming an anastomosis in accordance with the teachings of the present invention; 
           [0020]      FIG. 7  is a cross-sectional view of yet another embodiment of a medical device for forming an anastomosis in accordance with the teachings of the present invention; and 
           [0021]      FIG. 8  is a cross-sectional view of still yet another embodiment of a medical device for forming an anastomosis in accordance with the teachings of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Turning now to the figures,  FIG. 2  depicts a medical device  30  having a pair of magnet assemblies  32 ,  34 . The first magnet assembly  32  includes a first magnetic core  36  and a first jacket  40  connected to the outer periphery of the first magnetic core  36 . The first jacket  40  projects axially, (i.e., relative to the longitudinal axis LA), beyond the first magnetic core  36  to define a rim sized to receive the second magnet assembly  34 . The second magnetic assembly  34  includes a second magnetic core  38  having a second jacket  42  connected to the outer periphery thereof. Preferably the first and second magnetic assemblies  32  and  34  are disc shaped, although any annular configuration may be employed. The second jacket  42  is sized smaller (i.e., has a smaller outer diameter) than the first jacket  40  such that the pair of magnet assemblies  32 ,  34  are capable of nesting. Specifically, the first and second magnet cores  36 ,  38  have their respective poles oriented such that they are magnetically attracted to one another (when in proximity to one another) to form the nested configuration of the medical device  30  depicted in  FIG. 2 . In this configuration, the tissue  24 ,  26  from the two viscera are compressed between the first and second magnet assemblies  32 ,  34 , thereby approximating the tissues  24 ,  26  so that formation of an anastomosis may be accomplished. The jackets  40 ,  42  define engagement surfaces  43 , and in this embodiment the engagement surface  43  of the jacket  42  presses the tissue  24 ,  26  against the first magnetic core  36 . As such, the engagement surfaces  43  are atraumatically designed. The surfaces  43  are depicted as flat in the figures, although numerous atraumatic shapes may be employed as will be recognized by those skilled in the art, such as rounded edges or the like. 
         [0023]    Turning now to  FIG. 3 , the first and second magnetic cores  36 ,  38  define large axial openings  44 ,  46 , respectively. These large openings  44 ,  46  provide access to the tissue portions  28  held between the first and second magnet assemblies  32 ,  34 , for the introduction of a cutting device  52 . The axial openings are thus sized to correspond with the desired size of the anastomosis and are preferably at least 10 mm for gastrointestinal anastomoses. Each of the magnet assemblies  32 ,  34  includes a smaller transverse passageway  48 ,  50  (respectively) extending generally orthogonal to the longitudinal axis LA. The transverse passageways  48 ,  50  are much smaller in size than the axial openings  44 ,  46 , and are generally sized to receive a wire guide therethrough for introduction of the magnet assemblies  32 ,  34  into the desired viscera over the wire guide, as will be discussed below. 
         [0024]    A method of forming an anastomosis employing the magnetic assemblies  32 ,  34  of the medical device  30  will now be described with reference to  FIGS. 3-5 . Placement of the magnet assemblies  32 ,  34  may be accomplished in many ways, such as by use of a wire guide over which the assemblies are traversed by way of the transverse passageways  48 ,  50  in combination with a pushing catheter, or by swallowing the magnet assembly  32 ,  34  and employing massage under fluoroscopy, or through the use of endoscopic procedures using implements such as grasping forceps, by way of laparoscopic or open surgery, or other controlled insertion through natural orifices. 
         [0025]    As one example, gastrojejunostomy is typically performed by delivery of a first (jejunal) magnet assembly (e.g. magnet assembly  34 ) over a wire guide and through the oral cavity. A pushing catheter (not shown) is used to push the jejunal magnet assembly along the wire guide to a point within the jejunum  16  that is adjacent to the stomach wall  14 . This is usually accomplished with the aid of dynamic radiographic imaging (fluoroscopy). A second (gastric) magnet assembly (e.g. magnet assembly  32 ) is then introduced into the stomach using an endoscope and grasping forceps. When the gastric magnet is manipulated into a position that is near the jejunal magnet, the force of attraction between the magnets increases to a level that is sufficient to approximate the jejunal and stomach walls, thereby compressing these tissues together between the two magnet assemblies, as shown in  FIG. 3 . 
         [0026]    As shown in  FIG. 4 , a portion of the compressed tissue  28  is then excised using the cutting device  52  ( FIG. 3 ) which is manipulated around the large axial opening ( 44  or  46 ). This leaves an excised edge  28   a . Preferably, the cutting device  52  is an electrosurgical instrument which is employed through a working channel of an endoscope, although it will be recognized by those skilled in the art that numerous types of cutting devices may be employed with or without the aid of an endoscope, such as puncturing and dilating devices. Upon removal of the excused portion of the tissues portion, the remaining portion  28   b  of the tissues  24 ,  26  are affixed together as shown in  FIGS. 5 and 5   a . As with the excision, the affixing of the tissues  24 ,  26  is preferably accomplished endoscopically by using, for example, an affixation device such as a suturing instrument to place one or more sutures  54 , although it will be recognized by those skilled in the art that numerous types of affixing devices may be used with or without the aid of an endoscope, such as clips, staples, adhesives, or mechanical closure devices. Upon completion of the affixation, a secure anastomosis  56  is formed in the tissues  24 ,  26  between the two viscera. 
         [0027]    Removal of the magnet assemblies  32 ,  34  may be accomplished by traditional methods used with MADs. For example, grasping forceps can be used to take a hold of one of the magnet assemblies  32 ,  34  and withdraw the magnet assembly from the site. The second magnet may then pass naturally through the body, or may also be removed endoscopically using grasping forces. The second grasping forceps may be used to engage the other magnet assembly to provide sufficient traction to overcome the magnetic force. Finally, it will be recognized that the magnet assemblies  32 ,  34  could be left in place to cause necrosis of the remaining portion  28   b  of the tissues  24 ,  26 , thereby forming an even larger anastomosis than the initial anastomosis  56 . In this case, the jackets  40 ,  42  may be provided with sharp engagement surfaces  43  to facilitate the necrosis of tissues  24 ,  26 , although this is not necessary. After formation of the larger anastomosis, the magnet assemblies  32 ,  34  may be removed manually or naturally or a combination thereof. 
         [0028]    It will be recognized by those skilled in the art that during these anastomosis formation procedures, the ring of compression of the tissues  24 ,  26  provides an additional barrier that guards against leakage of the GI contents or other bodily fluids depending on the viscera involved. Likewise, the anastomosis is formed with surety before the patient leaves the medical facility, eliminating the need for a follow-up procedure. 
         [0029]      FIGS. 6-8  illustrate several variations of the medical device  30  and method for forming an anastomosis. In  FIG. 6 , a medical device  130  includes a pair of magnet assemblies  132 ,  134  having magnetic cores  136 ,  138  and jackets  140 ,  142  connected to the outer periphery of the magnetic cores  136 ,  138 . The magnetic cores  136 ,  138  define first and second axial openings  144 ,  146  which have a substantially similar size, (i.e., diameter). It will be noted that in the prior embodiment of  FIGS. 2-5 , the first and second axial openings  44 ,  46  were generally of a different size and diameter. The similar size of the openings  144 ,  146  allows the user to determine the maximum area of tissue that can be removed from either side of the device  130 . 
         [0030]    In the embodiment of  FIG. 7 , the magnetic device  230  includes a pair of magnet assemblies  232 ,  234  having magnetic cores  236 ,  238  and jackets  240 ,  242 . In the prior embodiment of  FIGS. 2-5 , the jackets  40 ,  42  were connected to the outer periphery of the magnetic cores  36 ,  38 . However, in this embodiment, the jackets  240 ,  242  are connected to the inner periphery of the magnetic cores  236 ,  238 . As such, the jackets  240 ,  242  define the large axial openings  244 ,  246 . It will be recognized that in this embodiment, the engagement surface  243  of jacket  242  is positioned closer to the tissue portion  28  to be excised and affixed. It will also be recognized that the embodiment in  FIGS. 2-5  can also be modified to locate the axially projecting rims defined by the flanges  40 ,  42  at a position closer to the axial openings  44 ,  46 , thereby moving the area of approximated tissue closer to the area of excises tissue. 
         [0031]    In  FIG. 8 , the medical device  330  includes a pair of magnet assemblies  332 ,  334  having magnetic cores  336 ,  338  defining large axial openings  344 ,  346 . The first magnet assembly  332  includes a jacket  340  attached to the outer periphery of the magnetic core  336  as in the embodiments of  FIGS. 2-6 . Unlike the prior embodiments, the second magnet assembly  334  does not include a jacket. As such, the axially-facing surfaces  341 ,  343  of the magnetic cores  336 ,  338  form the engagement area of the medical device  330 . This provides a large surface area over which the tissues  24 ,  26  of the two viscera may be compressed, thereby providing secure approximation of the tissues  24 ,  26  for performing the excision and affixation. 
         [0032]    The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. For example, the medical can be applied in many different situations other than GI surgery, for example in forming anastamoses between vascular structures, or any body structures. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.