Bio-flexible spinal fixation apparatus with shape memory alloy

Abstract

A spinal fixation apparatus has a segment flexible rod for connecting pedicle screws and a transverse link for spacing out the rods, which are made from a shape memory alloy, thereby easily and simply connecting the rods and the pedicle screws. The rods can be easily and simply fit to the misaligned pedicle screw, even if there is a failure of alignment of the pedicle screws in surgery. The transverse link can be easily set up on a pair of the longitudinal rods, even if the longitudinal rods are declined or are not in parallel.

1 . A spinal fixation apparatus comprising:
 first and second pedicle screw arrays perpendicularly arranged, substantially being in parallel to each other, wherein each of the first and second pedicle screw arrays includes: a plurality of pedicle screws joined to vertebras of human spine, each pedicle screw includes:
 1) a head having a plurality of reception means; and 
 2) a male thread formed on a leg part to be implanted into the vertebras; 
   and first and second rod arrays respectively connected the first and second pedicle screw arrays, wherein each of the first and second rod arrays includes a plurality of segment rods and wherein an end of each the segment rod is safely secured to one of the plurality of reception means, wherein the segment rods are a shape memory alloy.   
   
   
       2 . The spinal fixation apparatus in according with  claim 1 , further comprising at least one transverse link connecting the segment rods. 
   
   
       3 . The spinal fixation apparatus in according with  claim 1 , wherein the segment rod has an elastic section to provide flexibility. 
   
   
       4 . The spinal fixation apparatus in according with  claim 2 , wherein the segment rods are in a martensite phase at a temperature of approximately +10° C. and below and are in an austenite phase at a temperature of approximately +35° C. and over.