Flexible intramedullary nail

Abstract

A flexible intramedullary nail is disclosed that is manufactured from a biocompatible rigid material and having a substantially cylindrical hollow body, a leading segment with an entry hole at a distal end and at least one securing means and a trailing segment having a trailing edge and an attachment mechanism. The body has at least one flexible center section, each having at least one slot to provide flexibility. In one embodiment the at least one slot follows a sinuous, serpentine path to form a plurality of interlocking teeth that can follow a helical or a concentric path. Each of the slots has a proximal end and a distal end, with the proximal end being spaced from the trailing segment and the distal end being spaced from the leading segment. When multiple slots are incorporated, the proximal end of a slot is spaced from a distal end of a subsequent slot. The first of the at least one flexible center section and a second of the at least one flexible center section can be separated by a non-slotted section. The nail can be used with a flexible insertion shaft or a locking shaft.

What is claimed is: 
     
         1 . A flexible intramedullary nail being manufactured from a biocompatible rigid material having a substantially cylindrical hollow body, said hollow body having:
 a leading segment, said leading segment having an entry hole at a distal end and at least one securing means;   a trailing segment, said trailing segment having a trailing edge and an attachment mechanism;   at least one flexible center section, each of said at least one center section having at least one slot to provide flexibility.   
     
     
         2 . The flexible intramedullary nail of  claim 1  wherein said at least one slot follows a sinuous, serpentine path to form a plurality of interlocking teeth. 
     
     
         3 . The flexible intramedullary nail of  claim 2  wherein said serpentine path of said at least one slot follows a helical oath. 
     
     
         4 . The flexible intramedullary nail of  claim 1  wherein said slot follows a helical path. 
     
     
         5 . The flexible nail of  claim 2  wherein at least one said slot is concentric, 
     
     
         6 . The flexible intramedullary nail of  claim 1  wherein each of said at least one slot has a proximal end and a distal end, said proximal end being spaced from said trailing segment and said distal end being spaced from said leading segment. 
     
     
         7 . The flexible intramedullary nail of  claim 1  wherein each of said at least one slot has a proximal end and a distal end, said proximal end of a slot being spaced from said distal end of a subsequent slot. 
     
     
         8 . The flexible intramedullary nail of  claim 1  wherein said at least one securing means is selected from at least one from the group comprising securing slots, holes, threads, deployable fins, talons, expandable cages, and deployable bone cement. 
     
     
         9 . The flexible intramedullary nail of  claim 1  wherein said trailing segment further comprises at least one securing means selected from at least one of the group comprising securing slots, holes, threads, deployable fins, talons, expandable cages, and deployable bone, cement. 
     
     
         10 . The flexible intramedullary nail of  claim 1  wherein each of said at least one slot has a varied flexibility in relationship to a second at least one slot, said second at least one slot having increased flexibility or decreased flexibility, with respect to said at least one slot. 
     
     
         11 . The flexible intramedullary nail of  claim 1  wherein each of said at least one slot has sufficient width to form an unbound joint permitting limited movement in any direction upon application of tensile, compressive, and/or torsion forces. 
     
     
         12 . The flexible intramedullary nail of  claim 1  wherein each of said at least one slot has an increased width in a first direction compared to a second direction to provide increased flexibility in said first direction. 
     
     
         13 . The flexible intramedullary nail of  claim 11  wherein said varied flexibility is achieved by varying the pitch of the helical slot and helix angle, said helical angle being in the range of about 5 degrees to about 45 degrees and/or the amplitude and frequency of the slot cycle. 
     
     
         14 . The flexible intramedullary nail of  claim 11  wherein said varied flexibility is achieved by varying the width of the helical slot. 
     
     
         15 . The flexible intramedullary nail of  claim 11  further comprising a plurality of the concentric slots, the varied flexibility is achieved by varying the amplitude of the concentric slot and/or the spacing between concentric slots. 
     
     
         16 . The flexible intramedullary nail of  claim 1  wherein said the ratio of the amplitude of the path to the pitch of the slot is in the range from greater than 0.1 to about 0.8. 
     
     
         17 . The flexible intramedullary nail of  claim 1  further comprising an elastomeric material, said elastomeric material interacting with said flexible intramedullary nail from at least one of the group comprising:
 at least one of said at least one slot being filled; 
 at least one portion of said inside core adjacent to said at east one flexible center section being filled; 
 said insider core being filled; 
 elastomeric material extending through and filling said at least one slot; 
 elastomeric material encompassing at least a portion of said exterior diameter of said spinal element; 
 elastomeric material encompassing said exterior diameter, filling and extending through said at one slot 
 elastomeric material encompassing at least a portion of said exterior dirt diameter of said spinal element. 
 
     
     
         18 . The flexible intramedullary nail of claim wherein a first of said at least one flexible center section and a second of said at least one flexible center section are separated by a non-slotted section. 
     
     
         19 . The flexible intramedullary nail of  claim 16  wherein a first of said at least one flexible center section and a second of said at least one flexible center section are separated by a non-slotted section. 
     
     
         20 . The flexible intramedullary nail of  claim 3  wherein the helical path of said at least one slot is about 0.25 to about 5 cycles per diameter length and the helical angle ranges from about 5 degrees to about 20 degrees. 
     
     
         21 . The flexible intramedullary nail of  claim 1  wherein each of said at least one slot has a width between about 0.5% and about 5.0% of the diameter of said flexible nail. 
     
     
         22 - 36 . (canceled)