Fastener assembly that fastens to polyaxial pedicle screw

Abstract

A fastener assembly including an existing polyaxial pedicle screw that has been previously installed in a spinal structure, the polyaxial pedicle screw including a polyaxial head to which a prosthetic member is secured, a fastening portion fastened to the polyaxial head over the prosthetic member, and a connector element that extends from the fastening portion, the connector element being connected to another spinal structure.

1 . A fastener assembly comprising:
 an existing polyaxial pedicle screw that has been previously installed in a spinal structure, said polyaxial pedicle screw comprising a polyaxial head to which a prosthetic member is secured;   a fastening portion fastened to said polyaxial head over said prosthetic member; and   a connector element that extends from said fastening portion, said connector element being connected to another spinal structure.   
   
   
       2 . The fastener assembly according to  claim 1 , wherein said fastening portion comprises a wedge ring and said connector element comprises a conical ring into which said wedge ring fits, said connector element comprising a connecting member that extends from said conical ring, wherein said wedge ring is sized to fit over said polyaxial head and said conical ring wedges said wedge ring onto said polyaxial head. 
   
   
       3 . The fastener assembly according to  claim 2 , wherein said wedge ring has a conical periphery with a top surface that has a larger outer diameter than a bottom surface thereof, and said conical ring has a top surface with a larger inner diameter than a bottom surface thereof, said larger outer diameter not being greater than said larger inner diameter. 
   
   
       4 . The fastener assembly according to  claim 3 , wherein a plurality of grooves are formed in said conical periphery of said wedge ring. 
   
   
       5 . The fastener assembly according to  claim 4 , wherein at least one of said grooves is open at the top surface and closed at the bottom surface and at least another groove is closed at the top surface and open at the bottom surface. 
   
   
       6 . The fastener assembly according to  claim 1 , wherein said fastening portion comprises a closed ring and said connector element comprises a connecting member that extends from said closed ring, and wherein said existing polyaxial pedicle screw comprises a first mechanical fastener fastened to the polyaxial head, wherein said closed ring is placed over said first mechanical fastener such that said first mechanical fastener protrudes through said closed ring, and further comprising a second mechanical fastener that fastens to said first mechanical fastener and is tightened against said closed ring. 
   
   
       7 . The fastener assembly according to  claim 6 , wherein said closed ring is not flush with said connecting member. 
   
   
       8 . The fastener assembly according to  claim 1 , wherein said fastening portion comprises an open ring that fits over said polyaxial head and a mechanical fastener that fastens end portions of said open ring towards each other so as to clamp said open ring onto said polyaxial head, and said connector element comprises a connecting member that extends from said open ring. 
   
   
       9 . The fastener assembly according to  claim 8 , wherein said end portions of said open ring are angled at an acute angle with respect to a top surface of said open ring. 
   
   
       10 . A method comprising:
 fastening a fastening assembly to a polyaxial head of an existing polyaxial pedicle screw that has been previously installed in a spinal structure, a prosthetic member being secured to said polyaxial head, wherein said fastening assembly comprises a fastening portion fastened to said polyaxial head over said prosthetic member and a connector element that extends from said fastening portion; and   connecting said connector element to another spinal structure.