Semi-rigid spinal fixation apparatus

Abstract

A semi-rigid spinal apparatus has a first pedicle screw array and a second pedicle screw array substantially parallel to the first pedicle screw array. A first rod array is associated with the first pedicle screw array and a second rod array is associated with the second pedicle screw array. Each of the first and second pedicle screw arrays include a plurality of pedicle screws for joining to vertebrae of a spine. Each pedicle screw includes a head portion having a plurality of receptacles and a leg portion having a male thread for implanting into a vertebra. Each of the first and second rod arrays include a plurality of rod segments and each rod segment includes a first end coupled to a first receptacle on a first pedicle screw and a second end coupled to a second receptacle on a second pedicle screw adjacent to the first pedicle screw.

1 . A semi-rigid spinal fixation apparatus comprising: 
 a) a first pedicle screw array;    b) a second pedicle screw array disposed substantially parallel to said first pedicle screw array;    c) a first rod array associated with said first pedicle screw array; and    d) a second rod array associated with said second pedicle screw array;    wherein each of said first pedicle screw array and said second pedicle screw array comprise a plurality of pedicle screws for joining to vertebrae of a spine, each pedicle screw of said plurality of pedicle screws comprising a head portion having a plurality of receptacles and a leg portion having a male thread for implanting into a vertebra; and    wherein each of said first rod array and said second rod array comprise a plurality of rod segments, each rod segment of said plurality of rod segments comprising a first end coupled to a first receptacle of said plurality of receptacles on a first pedicle screw of said plurality of pedicle screws and a second end coupled to a second receptacle of said plurality of receptacles on a second pedicle screw of said plurality of pedicle screws, said first pedicle screw being adjacent to said second pedicle screw.    
   
   
       2 . The semi-rigid spinal fixation apparatus according to  claim 1  further comprising a transverse link extending between a first rod segment associated with said first rod array and a second rod segment associated with said second rod array.  
   
   
       3 . The semi-rigid spinal fixation apparatus according to  claim 1 , wherein each rod segment of said plurality of rod segments comprises an elastic section.  
   
   
       4 . The semi-rigid spinal fixation apparatus according to  claim 3 , wherein said elastic section comprises a coil spring shape.  
   
   
       5 . The semi-rigid spinal fixation apparatus according to  claim 3 , wherein said elastic section comprises a wave shape.  
   
   
       6 . The semi-rigid spinal fixation apparatus according to  claim 1 , wherein said head portion of said pedicle screw comprises a reception cavity and wherein said plurality of receptacles comprises a plurality of rod grooves disposed on a bottom surface of said reception cavity.  
   
   
       7 . The semi-rigid spinal fixation apparatus according to  claim 6 , further comprising 
 a) a head cap coupled to said head portion of said pedicle screw, said head cap comprising a second plurality of rod grooves; and    b) a fastener for securing said head cap to said head of said pedicle screw;    wherein said rod segment is secured between a rod groove of said plurality of rod grooves in said reception cavity and a respective rod groove of said second plurality of rod grooves in said head cap.    
   
   
       8 . The semi-rigid spinal fixation apparatus according to  claim 6 , wherein said rod segment further comprises a hook shaped portion at each end and said head portion of said pedicle screw comprises a fixing recess positioned under a rod groove of said plurality of rod grooves, wherein said hook shaped portion is fixed in said fixing recess.  
   
   
       9 . The semi-rigid spinal fixation apparatus according to  claim 1 , further comprising a head cap coupled to said head portion of said pedicle screw.  
   
   
       10 . The semi-rigid spinal fixation apparatus according to  claim 1 , wherein said head portion of said pedicle screw further comprises a reception portion having a female threaded portion on an inner surface of said reception portion, said apparatus further comprising a set screw having a male threaded portion for engaging said female threaded portion, wherein said set screw secures said rod segment to said pedicle screw.  
   
   
       11 . The semi-rigid spinal fixation apparatus according to  claim 1 , wherein said head portion of said pedicle screw comprises a reception cavity and wherein said plurality of receptacles comprises two parallel rod grooves disposed on a bottom surface of said reception cavity and wherein said rod segment comprises a straight bar placed in line with said head portions of said first and second pedicle screws, an elastic section, a support bar having a bending portion extending from an end of the straight bar and bending around an outer surface of said head portion, and a line portion extending from said bending portion, said line portion coupled to a groove of said two parallel rod grooves.  
   
   
       12 . The semi-rigid spinal fixation device according to  claim 11 , further comprising a set screw inserted into said reception cavity for securing said rod segment to said pedicle screw.  
   
   
       13 . The semi-rigid spinal fixation apparatus according to  claim 1 , wherein said plurality of receptacles comprise a plurality of circular grooves disposed on an outer surface of said head portion of said pedicle screw and wherein said rod segment comprises a straight bar placed in line with said head portions of said first and second pedicle screws, an elastic section and a support ring, said support ring coupled to a circular groove of said plurality of circular grooves.  
   
   
       14 . The semi-rigid spinal fixation apparatus according to  claim 1 , wherein said rod segment has a substantially u-shaped cross section.  
   
   
       15 . A semi-rigid spinal fixation apparatus comprising: 
 a) a first pedicle screw, a second pedicle screw and a third pedicle screw, each comprising a head portion having a plurality of receptacles and a leg portion having a male thread for implanting into a vertebra;    b) a first rod segment comprising a first end coupled to a first receptacle of said plurality of receptacles associated with said first pedicle screw and a second end coupled to a first receptacle of said plurality of receptacles associated with said second pedicle screw; and    c) a second rod segment comprising a first end coupled to a second receptacle of said plurality of receptacles associated with said second pedicle screw and a second end coupled to a first receptacle of said plurality of receptacles associated with said third pedicle screw.    
   
   
       16 . The semi-rigid spinal fixation apparatus according to  claim 15  further comprising a transverse link for coupling said first rod segment to a rod segment extending between two additional pedicle screws.  
   
   
       17 . The semi-rigid spinal fixation apparatus according to  claim 15 , wherein said first rod segment and said second rod segment each comprise a respective elastic section.  
   
   
       18 . The semi-rigid spinal fixation apparatus according to  claim 17 , wherein said elastic section comprises a coil spring shape.  
   
   
       19 . The semi-rigid spinal fixation apparatus according to  claim 17 , wherein said elastic section comprises a wave shape.  
   
   
       20 . The semi-rigid spinal fixation apparatus according to  claim 15 , wherein said head portion of each of said first, second and third pedicle screw comprises a respective reception cavity and wherein said plurality of receptacles comprises a plurality of rod grooves disposed on a bottom surface of said reception cavity.  
   
   
       21 . The semi-rigid spinal fixation apparatus according to  claim 20 , further comprising 
 a) a head cap coupled to said head portion of a respective pedicle screw of said first, second and third pedicle screw, said head cap comprising a second plurality of rod grooves; and    b) a fastener for securing said head cap to said head of said pedicle screw;    wherein a respective rod segment of said first and second rod segment is secured between a rod groove of said plurality of rod grooves in said reception cavity and a respective rod groove of said second plurality of rod grooves in said head cap.    
   
   
       22 . The semi-rigid spinal fixation apparatus according to  claim 20 , wherein a rod segment of said first and second rod segment further comprises a hook shaped portion at each end and said head portion of a respective pedicle screw of said first, second and third pedicle screw comprises a fixing recess positioned under a rod groove of said plurality of rod grooves, wherein said hook shaped portion is fixed in said fixing recess.  
   
   
       23 . The semi-rigid spinal fixation apparatus according to  claim 15 , further comprising a head cap coupled to said head portion of a respective pedicle screw of said first, second and third pedicle screw.  
   
   
       24 . The semi-rigid spinal fixation apparatus according to  claim 15 , wherein said head portion of a respective pedicle screw of said first, second and third pedicle screw further comprises a reception portion having a female threaded portion on an inner surface of said reception portion, said apparatus further comprising a set screw having a male threaded portion for engaging said female threaded portion, wherein said set screw secures a rod segment of said first and second rod segment to said respective pedicle screw.  
   
   
       25 . The semi-rigid spinal fixation apparatus according to  claim 15 , wherein said head portion of a respective pedicle screw of said first, second and third pedicle screw comprises a reception cavity and wherein said plurality of receptacles comprises two parallel rod grooves disposed on a bottom surface of said reception cavity and wherein a rod segment of said first and second rod segment comprises a straight bar placed in line with said head portions of said first, second and third pedicle screws, an elastic section, a support bar having a bending portion extending from an end of the straight bar and bending around an outer surface of said head portion, and a line portion extending from said bending portion, said line portion coupled to a groove of said two parallel rod grooves.  
   
   
       26 . The semi-rigid spinal fixation device according to  claim 11 , further comprising a set screw inserted into said reception cavity for securing said rod segment to said pedicle screw.  
   
   
       27 . The semi-rigid spinal fixation apparatus according to  claim 15 , wherein said plurality of receptacles comprise a plurality of circular grooves disposed on an outer surface of said head portion of a respective pedicle screw of said first, second and third pedicle screw and wherein said a rod segment of said first and second rod segment comprises a straight bar placed in line with said head portions of said first, second and third pedicle screws, an elastic section and a support ring, said support ring coupled to a circular groove of said plurality of circular grooves.  
   
   
       28 . The semi-rigid spinal fixation apparatus according to  claim 1 , wherein said first and second rod segment have a substantially u-shaped cross section.