Expandable spinal prosthesis

Abstract

A device for insertion between spinous processes of adjacent vertebrae is provided and may include a rod having a first threaded portion and a second threaded portion. The first threaded portion may be coupled to the second threaded portion at a joint. A plurality of members may be movable between a compressed condition and an extended condition when the rod is rotated relative to the plurality of members. The first threaded portion and the second threaded portion may be uncoupled at the joint after the plurality of members are moved from the extended condition to the compressed condition.

1 . A device for insertion between spinous processes of adjacent vertebrae comprising:
 a rod having a first threaded portion and a second threaded portion, said first threaded portion coupled to said second threaded portion at a joint; and   a plurality of members movable between a compressed condition and an extended condition when said rod is rotated relative to said plurality of members, said first threaded portion and said second threaded portion being uncoupled at said joint after said plurality of members are moved from said extended condition to said compressed condition.   
     
     
         2 . The device of  claim 1 , further comprising a first collar rotatably supporting said rod at one of said first threaded portion and said second threaded portion. 
     
     
         3 . The device of  claim 2 , further comprising a second collar threadably attached to the other of said first threaded portion and said second threaded portion when said plurality of members are in said extended condition. 
     
     
         4 . The device of  claim 3 , wherein said rod is rotated relative to said second collar when said plurality of members are moved from said extended condition to said compressed condition. 
     
     
         5 . The device of  claim 3 , wherein said second collar is threadably attached to said first threaded portion when said plurality of members are in said compressed condition. 
     
     
         6 . The device of  claim 3 , wherein rotation of said rod causes said second collar to cross said joint and move from said second threaded portion to said first threaded portion during movement of said plurality of members from said extended condition to said compressed condition. 
     
     
         7 . The device of  claim 1 , wherein said joint is disposed between two of said plurality of members when said plurality of members are in said extended condition. 
     
     
         8 . The device of  claim 7 , wherein said joint is disposed externally from said plurality of members when said plurality of members are in said compressed condition. 
     
     
         9 . The device of  claim 1 , further comprising a collar threadably attached to said rod and operable to move along said rod when said plurality of members are moved from said extended condition to said compressed condition. 
     
     
         10 . The device of  claim 9 , wherein said collar is threadably attached to one of said first threaded portion and said second threaded portion when said plurality of members are in said extended condition and said collar is threadably attached to the other of said first threaded portion and said second threaded portion when said plurality of members are in said compressed condition. 
     
     
         11 . The device of  claim 9 , wherein said joint is disposed on one side of said collar when said plurality of members are in said extended condition and is disposed on the other side of said collar when said plurality of members are in said compressed condition. 
     
     
         12 . A device for insertion between spinous processes of adjacent vertebrae comprising:
 a rod having a first threaded portion and a second threaded portion, said first threaded portion coupled to said second threaded portion at a joint;   a plurality of members movable between a compressed condition and an extended condition when said rod is rotated relative to said plurality of members; and   a collar threadably attached to said rod and operable to move along said rod when said plurality of members are moved from said extended condition to said compressed condition, said collar being threadably attached to one of said first threaded portion and said second threaded portion when said plurality of members are in said extended condition and being threadably attached to the other of said first threaded portion and said second threaded portion when said plurality of members are in said compressed condition.   
     
     
         13 . The device of  claim 12 , wherein rotation of said rod causes said collar to cross said joint and move from said one of said first threaded portion and second threaded portion to said other of said first threaded portion and said second threaded portion during movement of said plurality of members from said extended condition to said compressed condition. 
     
     
         14 . The device of  claim 12 , wherein said joint is disposed between two of said plurality of members when said plurality of members are in said extended condition. 
     
     
         15 . The device of  claim 14 , wherein said joint is disposed externally from said plurality of members when said plurality of members are in said compressed condition. 
     
     
         16 . The device of  claim 12 , wherein said joint is disposed on one side of said collar when said plurality of members are in said extended condition and is disposed on the other side of said collar when said plurality of members are in said compressed condition. 
     
     
         17 . A device for insertion between spinous processes of adjacent vertebrae comprising:
 a rod having a first threaded portion and a second threaded portion, said first threaded portion coupled to said second threaded portion at a joint;   a plurality of members movable between a compressed condition and an extended condition when said rod is rotated relative to said plurality of members; and   a collar threadably attached to said rod and operable to move along said rod when said plurality of members are moved from said extended condition to said compressed condition, said joint being disposed on one side of said collar when said plurality of members are in said extended condition and being disposed on the other side of said collar when said plurality of members are in said compressed condition.   
     
     
         18 . The device of  claim 17 , wherein rotation of said rod causes said collar to cross said joint and move from said second threaded portion to said first threaded portion during movement of said plurality of members from said extended condition to said compressed condition. 
     
     
         19 . The device of  claim 17 , wherein said joint is disposed between two of said plurality of members when said plurality of members are in said extended condition. 
     
     
         20 . The device of  claim 19 , wherein said joint is disposed externally from said plurality of members when said plurality of members are in said compressed condition. 
     
     
         21 . The device of  claim 17 , wherein said collar is threadably attached to one of said first threaded portion and said second threaded portion when said plurality of members are in said extended condition and said collar is threadably attached to the other of said first threaded portion and said second threaded portion when said plurality of members are in said compressed condition.