Patent Abstract:
A seal element for sealing between tissue lumens includes a first material for allowing tissue ingrowth and a second sealant material.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 11/238,497 filed Sep. 28, 2005, which claims benefit of application No. 60/619,238 filed Oct. 15, 2004, and the disclosures of each of the above-identified applications are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to devices for attaching two tubular tissues. More particularly, seals for use in connection with anastomosis procedures are described. 
     2. Background of Related Art 
     One method for performing a gastrointestinal anastomosis involves the use of a circular stapler apparatus. For example, a device known as the CEEA® (trademark of United States Surgical, a division of Tyco Healthcare Group LP) is utilized after resection of a diseased portion of bowel. The circular anastomosis stapler is utilized to approximate the remaining portions of bowel, staple them together, and cut away excess tissue at the anastomotic joint. 
     Illustrative circular stapling devices are disclosed in certain embodiments of U.S. Pat. Nos. 4,354,628; 5,014,899; 5,040,715; and 5,392,979 the disclosures of which are hereby incorporated herein in their entirety by this reference. Other methods of performing anastomoses, utilizing joining techniques other than stapling that have been contemplated include, for example the use of clip appliers, dissectors and shears, and adhesives. 
     While present anastomosis devices and procedures perform satisfactorily, it would be advantageous to promote tissue growth and good sealing at an anastomosis site. 
     SUMMARY 
     A composite seal element for use in anastomosis is described herein. The seal element can be disposed between the two portions of tubular tissue to be joined to promote tissue growth and reduce the occurrence of leaks. In stapled anastomoses, the seal element is disposed between the proximal and distal ends of an anastomosis before the tissue is approximated and staples are fired. The seal element remains in place during the healing process and then, in certain embodiments is absorbed by the body. 
     One aspect of the present disclosure is a seal element for sealing between tissue lumens, comprising a first material and a second material. The first material comprises a porous material for allowing tissue ingrowth. The second material comprises a sealant. 
     In embodiments, the second material comprises a compressible material that, when compressed between a first tissue lumen and a second tissue lumen, acts as a seal to prevent the escape of the contents of the tissue lumens. Preferably, the first material and the second material are biodegradable, bioabsorbable, or bioresorbable materials. 
     In certain embodiments, the seal element comprises an annular element and the second material is disposed outwardly of the first material. The first and second materials may be adhered to one another, with a biocompatible adhesive, or joined utilizing an overmolding process. 
     Another aspect of the present disclosure is an assembly for disposing a seal element between tissue lumens comprising a circular surgical stapling device, having an anvil assembly and a tubular body portion, the anvil assembly having an anvil member and a first shaft, the tubular body portion carrying a plurality of surgical staples in a circular configuration, the tubular body portion having a second shaft disposed inwardly of the surgical staples, the first shaft being attachable to the second shaft. The assembly includes a seal element comprising a first material and a second material. The first material comprises a porous material for allowing tissue ingrowth. The second material comprises a sealant. 
     Preferably, the second material comprises a compressible material that, when compressed between a first tissue lumen and a second tissue lumen, acts as a seal to prevent the escape of the contents of the tissue lumens. Preferably, the first material and the second material are biodegradable, bioabsorbable, or bioresorbable materials. 
     The seal element desirably has a generally centrally located aperture for being disposed on one of the first shaft and the second shaft of the circular surgical stapling device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure, wherein: 
         FIG. 1  is a perspective view of a seal element in accordance with an embodiment of the present disclosure, shown in an undeployed condition; 
         FIG. 2  is a perspective view of an exemplary annular surgical stapling device; 
         FIG. 3  is a longitudinal, partially cross-sectional view illustrating the anvil rod mounted to the annular stapling device within a surgical site and the seal element of  FIG. 1  in an undeployed condition, disposed between the apposed surfaces of the tissue; and 
         FIG. 4  is a perspective, cross sectional view of the seal element of  FIG. 1  shown in a deployed condition. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As shown in  FIG. 1 , a seal element  10  in accordance with the present disclosure can be a composite of a first material  12  and a second material  14 , and includes a center aperture  15 . 
     In certain embodiments, the first material  12  can be relatively thin (compared to the second material) and optionally is a bioabsorbable material that promotes tissue ingrowth. In certain preferred embodiments, first material  12  can be about 0.010″ to about 0.020″ thick, although other thicknesses can be used. As those skilled in the art will appreciate, tissue ingrowth is promoted more readily by materials having pores formed therein. Thus, for example, first material  12  can be any biocompatible, optionally bioabsorbable porous material, such as, for example, a foam, a mesh, a non-woven structure, or a perforated sheet. In certain preferred embodiments, first material  12  has pores in the range of about 50 μm to about 200 μm. Illustrative examples of suitable bioabsorbable porous materials include an absorbable hernia mesh such as Dexon, an absorbable felt such as Polysorb, or a porous open-cell foam such as polyurethane, suitable homopolymers, glycolide, lactide, caprolactone, trimethylene carbonate, dioxanone, polyalkylene oxides, etc. Other suitable materials are disclosed in certain embodiments of U.S. Pat. Nos. 4,655,221; 4,788,979; 5,543,218; 5,716,376; 5,423,859; and 5,124,103, the disclosures of which are hereby incorporated herein in their entirety by this reference. Without being limited to a particular theory of operation, there is a considerable amount of healing that takes place in this region. Therefore, this material is desirably porous enough to allow tissue to grow through it. 
     The second material  14  desirably forms a seal. Thus, second material  14  can be, for example, either a compressible or expandable optionally bioabsorbable material. In use, compressible second materials  14 , when compressed, act as a seal to prevent the escape of fluid from the connected tubular tissue. In some embodiments, second material  14  is a soft, compliant material that is compressed between the proximal  16  and distal ends  18  of the anastomosis and captured by staples  33 ,  35 . See, e.g.,  FIG. 4 . The compression of this material can serve, for example, as a gasket to prevent bowel contents from leaking into the peritoneum. Illustrative examples of compressible materials include, but are not limited to polyurethane foam, carboxymethyl cellulose (“CMC”), and hydrogels. 
     For expandable second materials  14 , the material may expand in response to contact with fluids, such as the fluids naturally present in the body. In embodiments, second material  14  can be a de-hydrated material that swells upon contact with moisture. For example, second material  14  can be a hydrophilic biomaterial. Illustrative examples of suitable hydrophilic biomaterials include, but are not limited to polymers formed from one or more of the following monomers: methacrylic acid, acrylic acid, n-vinyl pyrrolidone, potassium sulfopropyl acrylate, potassium sulfopropyl methacrylate, acrylamide, dimethylacrylamide, 2-methacryloyloxyethyl phosphorylcholine, 2-hydroxyethyl methacrylate or similar biocompatible water-soluble vinyl monomers. In a particularly useful embodiment, second material  14  is formed of poly(2-hydroxyethyl methacrylate). Where seal element  10  includes a hydrophilic biomaterial as second material  14 , seal element  10  can be prepared using techniques within the purview of those skilled in the art. For example, the seal element can be formed by filling a mold with a composition containing the monomer(s) and, if desired or necessary, initiator, crosslinker, plasticizer and/or biological agent, and polymerizing the composition within the mold. The choice of particular initiators, crosslinkers, etc. will be determined by the specific choice of monomer(s) and can be readily determined by those skilled in the art. A particularly useful hydrophilic biomaterial is poly(2-hydroxyethyl methacrylate) (“PHEMA”). The equilibrium water content (EWC), swelling, and mechanical properties of the PHEMA portion of seal element  10  can be controlled by crosslink density (e.g., the crosslink density can be controlled by radiation conditions or crosslinking agent, such as di(ethylene glycol) dimethacrylate (DEGDMA), concentration). The thickness of the seal element  10  is controlled by the volume of the monomer composition polymerized in the mold. The PHEMA portion of seal element  10  can also be surface modified following formation. For example, the PHEMA portion of seal element  10  can be surface modified with polymeric phospholipids for improved hemocompatibility and tissue interaction using gamma radiation grafting. 
     In embodiments, the surface of the portion of the seal element made from second material  14  can be patterned or templated in the nano-meso-micro scale to accommodate preferential tissue interaction at the tissue/seal interface. Such architecture or patterns can prevent or minimize post-operative tissue adhesions and superfluous collagen deposition, but afford desired mechanical and biophysical support for wound healing. 
     Either or both of first material  12  and second material  14  from which seal element  10  is made may also contain one or more medically and/or surgically useful substances such as drugs, enzymes, growth factors, peptides, proteins, dyes, diagnostic agents or hemostasis agents or any other pharmaceutical used in the prevention of stenosis. Non-limiting examples of suitable medically and/or surgically useful substances include: antimicrobials, antibiotics, anti-fungals, anti-virals, monoclonal antibodies, polyclonal antibodies, antimicrobial proteins/peptides (whole and fragments), enzymes, gene therapy, viral particles, chemotherapeutics, anti-inflammatories, NSAIDS, steroids, telomerase inhibitors, growth factors (TGF family, interleukin superfamily, fibroblast derived GFs, macrophage derived GFs, etc.), extracellular matrix molecules (laminin, thrombospondin, collagen, fibronectin, synthetic ECM, etc.), cell adhesion molecules, polysaccharides (hyaluronic acid, carboxymethyl cellulose, alginate, sulfonated dextran, heparin sulfate, chitosan, etc.) and others. These agents can be incorporated in situ into either or both of first material  12  and second material  14  from which seal element  10  is made or post loaded onto seal element  10  using techniques within the purview of those skilled in the art. For example, the medically and/or surgically useful substances can be freely mixed or loaded, electronically or ionically bound, covalently immobilized, chelated, or encapsulated in particles, micelles, aggregates, or any nano-meso-micro solids of varied dimension, shape morphology and dispersion/suspension ability. 
     Second material  14  can be attached to first material  12  in any manner within the purview of those skilled in the art, including, but not limited to an overmolding process. 
     Seal element  10  desirably has a generally centrally located aperture  15  for being disposed on one of the first shaft and the second shaft of a circular surgical stapling device. The seal element is captured between the proximal and distal ends of a circular, stapled anastomosis to reduce leaks at the site of anastomosis. 
     The dimensions of seal element  10  may vary, according to the particular application. In certain embodiments, the outside diameter is slightly larger than the diameter of the outside staple row of the circular stapling apparatus. The inside diameter will be slightly larger than the diameter of the knife of the circular stapling apparatus. Preferably, the inside diameter may be about the size of shaft  38  of anvil assembly  40  in order to center seal element  10  on the anvil assembly  40 . 
     Referring now to  FIG. 2 , an annular surgical stapling device, for use with the annular structures disclosed herein, is generally designated as  20 . Surgical stapling device includes a handle assembly  22  having at least one pivotable actuating handle member  24 , and an advancing member  26 . Extending from handle member  22 , there is provided a tubular body portion  30  which may be constructed so as to have a curved shape along its length. Body portion  30  terminates in a staple cartridge assembly  32  which includes a pair of annular arrays of staple receiving slots  46  having a staple (not shown) disposed in each one of staple receiving slots  46 . Positioned distally of staple cartridge assembly  32  there is provided an anvil assembly  40  including an anvil member  36  and a shaft  38  operatively associated therewith for removably connecting anvil assembly  40  to a distal end portion of the stapling device. 
     Staple cartridge assembly  32  may be fixedly connected to the distal end of tubular body portion  30  or may be configured to concentrically fit within the distal end of tubular body portion  30 . Typically, staple cartridge assembly  32  includes a staple pusher (not shown) including a proximal portion having a generally frusto-conical shape and a distal portion defining two concentric rings of peripherally spaced fingers (not shown), each one of which is received within a respective staple receiving slot  46 . 
     Typically, a knife (not shown), substantially in the form of an open cup with the rim thereof defining a knife edge, is disposed within staple cartridge assembly  32  and mounted to a distal surface of a staple pusher (not shown). The knife edge is disposed radially inward of the pair of annular arrays of staples. Accordingly, in use, as the staple pusher is advanced, the knife is also advanced axially outward. 
     Reference may be made to U.S. Pat. No. 5,915,616 to Viola et al., the entire content of which is incorporated herein by reference, for a detailed discussion of a suitable annular stapling device. Although the stapling device shown in  FIGS. 2-3  is a circular stapling device, the seal element disclosed herein may be used with staplers of other shapes or configurations, such as, for example, linear staplers or annular staplers that are not circular. In addition, the seal element may be placed using sutures, adhesives, etc. 
     Turning now to  FIG. 3 , there is illustrated the use of surgical stapling device  20  and detachable anvil assembly  40  in an anastomosis procedure to effect joining of intestinal sections  66  and  68 . At the point in the procedure shown in  FIG. 3 , a diseased intestinal section has been previously removed, anvil assembly  40  has been applied to the operative site either through a surgical incision or transanally and positioned within intestinal section  66 , and tubular body portion  30  of the surgical stapling device has been inserted transanally into intestinal section  68 . Intestinal sections  66  and  68  are also shown temporarily secured about their respective components (e.g., shaft  38  of anvil assembly  40 , and the distal end of tubular body portion  30 ) by conventional means such as a purse string suture “P”. 
     According to one method, as seen in  FIG. 3 , if desired or if the surgical procedure requires, seal element  10  may be placed onto shaft  38  of anvil assembly  40  prior to the coupling of anvil assembly  40  to the distal end of tubular body portion  30 . Following positioning of seal element  10  onto shaft  38  of anvil assembly  40 , the surgeon maneuvers anvil assembly  40  until the proximal end of shaft  38  is inserted into the distal end of tubular body portion  30  of surgical stapling device  20 , wherein the mounting structure (not shown) within the distal end of tubular body portion  30  engages shaft  38  to effect the mounting. Thereafter, anvil assembly  40  and tubular body portion  30  are approximated to approximate intestinal sections  66 ,  68  and capture seal element  10  therebetween. The surgical stapling device  20  is then fired thereby stapling intestinal sections  66 ,  68  to one another and cutting the portion of tissue and seal element  10  disposed radially inward of the knife, to complete the anastomosis. 
     As seen in  FIG. 4 , the seal forming second material  14  is compressed between the proximal  16  and distal ends  18  of the anastomosis and captured by the staples  33 ,  35 . The compression of this material serves as a gasket to prevent bowel contents from leaking into the peritoneum. The portion of seal element  10  made from first material  12  is exposed at the site of anastomosis and serves to promote tissue ingrowth and thereby assist in healing of the site. 
     While several particular forms of the seal elements have been illustrated and described, it will also be apparent that various modifications can be made without departing from the spirit and scope of the present disclosure. For example, it is envisioned that each of the seal elements described herein may be used with an annular surgical anastomosing device, not including any staples for securing tissue together, which is capable of approximating, adhering and cutting tissue. Thus, it should be understood that various changes in form, detail and application of the support structures of the present disclosure may be made without departing from the spirit and scope of the present disclosure.

Technology Classification (CPC): 0