Stiffened fabric

Abstract

A stiffened fabric of interlaced filamentary members is disclosed, stiffening of the fabric being effected by joining the filamentary members together at mutual points of contact within the fabric to prevent relative motion of the filamentary members. Joining of the members is effected by heat fusing, chemical fusing or adhesive bonding at selected points to control the stiffness of the fabric. Bio-absorbable materials are used to form some of the filamentary members so that the stiffness and porosity of the fabric changes over time as the bio-absorbable material is absorbed when the fabric is implanted in living tissue.

What is claimed is:  
     
         1 . A stiffened fabric, comprising a plurality of filamentary members interlaced together and engaging one another at mutual points of contact, said filamentary members being substantially rigidly joined together at selected ones of said mutual points of contact to substantially inhibit relative motion between said filamentary members and thereby impart a predetermined stiffness to said fabric, said filamentary members being free to move relatively to one another between said selected ones of said mutual points of contact.  
     
     
         2 . A stiffened fabric according to  claim 1 , wherein said selected ones of said mutual points of contact comprise substantially all of said mutual points of contact between said filamentary members.  
     
     
         3 . A stiffened fabric according to  claim 1 , wherein said plurality of filamentary members comprise a first group of filamentary members having a relatively low melting point interlaced with a second group of filamentary members having a relatively high melting point, said filamentary members of said first group being joined to filamentary members of said second group by heating said fabric to a temperature higher than said melting point of said first group of filamentary members and lower than said melting point of said second group of filamentary members thereby causing filamentary members of said first group to fuse with filamentary members of said second group at said mutual points of contact between said filamentary members of said first and said second groups.  
     
     
         4 . A stiffened fabric according to  claim 3 , wherein said filamentary members of said first group comprise polypropylene and said filamentary members of said second group comprise polyester, said polypropylene having a relatively lower melting point than said polyester.  
     
     
         5 . A stiffened fabric according to  claim 3 , wherein said filamentary members are interlaced by braiding into an elongated rod.  
     
     
         6 . A stiffened fabric according to  claim 5 , wherein said elongated rod comprises: 
 filamentary members of said second group braided together at a predetermined braid angle; and    filamentary members of said first group braided with said first group axially with respect to said rod.    
     
     
         7 . A stiffened fabric according to  claim 3 , wherein said fabric has a relatively greater number of filamentary members of said first group than the number of filamentary members of said second group.  
     
     
         8 . A stiffened fabric according to  claim 1 , further comprising an adhesive positioned at said selected ones of said mutual points of contact to join said filamentary members together, thereby stiffening said fabric.  
     
     
         9 . A stiffened fabric according to  claim 8 , wherein said adhesive comprises a water activated adhesive which joins said filamentary members together when in contact with water, thereby increasing the stiffness of said fabric.  
     
     
         10 . A stiffened fabric according to  claim 8 , wherein said adhesive comprises a water soluble adhesive which releases said filamentary members from one another when in contact with water, thereby reducing the stiffness of said fabric.  
     
     
         11 . A stiffened fabric according to  claim 1 , wherein said plurality of filamentary members includes a first group of filamentary members comprising a material which is absorbable when implanted in living tissue, filamentary members comprising said first group being interlaced with a second group of filamentary members, said filamentary members of said first group being initially joined to filamentary members of said second group at said mutual points of contact to provide a relatively high stiffness to said fabric, said filamentary members of said first group being absorbed upon implantation of said fabric in living tissue and thereby providing a relatively lower stiffness to said fabric as said filamentary members of said first group are absorbed.  
     
     
         12 . A stiffened fabric according to  claim 11 , wherein said filamentary members are interlaced by braiding to form said fabric into an elongated rod shape.  
     
     
         13 . A stiffened fabric according to  claim 11 , wherein said filamentary members are interlaced to form a tube.  
     
     
         14 . A stiffened fabric according to  claim 13 , wherein said filamentary members are interlaced by braiding.  
     
     
         15 . A stiffened fabric according to  claim 11 , wherein said absorbable material comprises polylactic acid.  
     
     
         16 . A stiffened fabric according to  claim 11 , wherein said absorbable material comprises polyglycolic acid.  
     
     
         17 . A stiffened fabric according to  claim 1 , wherein said filamentary member s are interlaced by weaving to provide a plurality of interstices in said fabric having a predetermined size and resulting in said fabric having a first predetermined porosity, said fabric further comprising a plurality of absorbable filamentary members comprising a material which is absorbable when implanted in living tissue, said absorbable filamentary members being interwoven in said fabric in overlying relation with said interstices thereby reducing the size of said interstices and resulting in said fabric having a second predetermined porosity smaller than said first predetermined porosity, said absorbable filamentary members being absorbed when said fabric is implanted in living tissue causing said porosity of said fabric to change from said second predetermined porosity to said first predetermined porosity.  
     
     
         18 . A stiffened fabric according to  claim 17  wherein said absorbable filamentary members comprise polylactic acid.  
     
     
         19 . A stiffened fabric according to  claim 17  wherein said absorbable filamentary members comprise polyglycolic acid.  
     
     
         20 . A stiffened fabric according to  claim 1 , further comprising an elongated core around which said filamentary members are interlaced to form a stiffened sheath surrounding said core.  
     
     
         21 . A stiffened fabric according to  claim 20 , wherein said filamentary members are interlaced by wrapping around said core.  
     
     
         22 . A stiffened fabric according to  claim 21 , wherein a portion of said filamentary members comprise a material which is absorbable in living tissue.  
     
     
         23 . A stiffened fabric, comprising: 
 a plurality of filamentary members interlaced together and engaging one another at mutual points of contact; and    means for substantially rigidly attaching said filamentary members to one another at selected ones of said mutual points of contact, said attaching means being inelastic and substantially preventing relative motion between said filamentary members at said selected ones of said mutual points of contact and thereby imparting a predetermined stiffness to said fabric, said filamentary members being free to move relatively to one another between said selected ones of said mutual points of contact.    
     
     
         24 . A stiffened fabric according to  claim 23 , wherein said attaching means comprises fusing said filaments together at said selected ones of said mutual points of contact.  
     
     
         25 . A stiffened fabric according to  claim 23 , wherein said attaching means comprises adhesively bonding said filaments together at said selected ones of said mutual points of contact.  
     
     
         26 . A method of making a fabric having a predetermined stiffness, said method comprising the steps of: 
 interlacing a plurality of filamentary members together, said filamentary members engaging one another at mutual points of contact;    rigidly joining together said filamentary members at selected ones of said mutual points of contact to substantially prevent relative motion at said selected ones of said mutual points of contact; and    allowing said filamentary members to move relatively to one another between said selected ones of said mutual points of contact.    
     
     
         27 . A method of making a fabric implantable in human tissue and having a stiffness which changes over time, said method comprising the steps of: 
 interlacing a plurality of filamentary members together, said filamentary members engaging one another at mutual points of contact, at least some of said filamentary members comprising a material which is absorbable in living tissue;    rigidly joining together said filamentary members at selected ones of said mutual points of contact to substantially prevent relative motion at said selected ones of said mutual points of contact; and    allowing said filamentary members to move relatively to one another between said selected ones of said mutual points of contact, when said fabric is implanted in living tissue, said filamentary members comprising said absorbable material being absorbed, thereby reducing the stiffness of said fabric.    
     
     
         28 . A method of making a fabric implantable in human tissue and having a porosity which changes over time, said method comprising the steps of: 
 interlacing a plurality of first filamentary members together thereby creating interstices between said filamentary members, said filamentary members engaging one another at mutual points of contact;    interlacing a plurality of second filamentary members comprising a material which is absorbable in living tissue with said first plurality of filamentary members, said second filamentary members being positioned to substantially coincide with said interstices;    rigidly joining together at least said first filamentary members at selected ones of said mutual points of contact to substantially prevent relative motion at said selected ones of said mutual points of contact; and    allowing said filamentary members to move relatively to one another between said selected ones of said mutual points of contact, when said fabric is implanted in living tissue, said second filamentary members comprising said absorbable material being absorbed thereby increasing the porosity of said fabric.