Polyaxial pedicle screw

Abstract

The present invention is directed at a polyaxial pedicle screw comprising a detachable polyaxial head and bone screw. The detachable polyaxial head may comprise a tulip head, a collet with one or more connectors (e.g., pins) to secure it, and a spherical locking member which may lock onto the bone screw.

1 . A pedicle screw device, comprising:
 a bone screw member having a head portion; and   a head assembly comprising:
 a tulip member, and 
 a locking member having a bottom portion configured to engage with the head portion of the bone screw, wherein the locking member is disposed in the tulip member and is configured to enable polyaxial movement between the tulip member and the locking member. 
   
     
     
         2 . The pedicle screw device of  claim 1 , further comprising a collet member that is received within the tulip member, wherein the collet member sits atop the locking member. 
     
     
         3 . The pedicle screw device of  claim 1 , wherein the locking member is configured with internal threading that engages with a threaded portion of the head portion of the bone screw. 
     
     
         4 . The pedicle screw device of  claim 1 , wherein the locking member further comprises a top portion formed with a drive feature. 
     
     
         5 . The pedicle screw device of  claim 1 , wherein the bottom portion of the locking member comprises a plurality of locking tabs that define an expandable aperture. 
     
     
         6 . The pedicle screw device of  claim 5 , wherein each of the locking tabs are defined and spaced apart by a grove that enables expansion of the expandable aperture. 
     
     
         7 . The pedicle screw device of  claim 1 , further comprising a plurality of protruding tabs extending from a neck portion of the bone screw member, wherein the protruding tabs are positioned between the head portion and a threaded bone portion of the bone screw. 
     
     
         8 . A pedicle screw device, comprising:
 a bone screw member having threaded head portion, a plurality of protruding tabs, and a threaded bone portion, wherein the protruding tabs extend from a neck portion that is between the threaded head portion and the threaded bone portion; and   a head assembly comprising:
 a tulip member; 
 a locking member formed with internal threads configured to engage with the threaded head portion threads of the bone screw member. 
   
     
     
         9 . The pedicle screw device of  claim 8 , wherein the plurality of protruding tabs are spaced apart and aligned around a circumference of the neck portion of the bone screw member. 
     
     
         10 . The pedicle screw device of  claim 9 , further comprising a plurality of locking tabs extending from a bottom portion of the locking member, wherein each of the locking tabs are defined and spaced apart by a grove that enables expansion of the bottom portion of the locking member. 
     
     
         11 . The pedicle screw device of  claim 10 , wherein one or more of the locking tabs has an inner surface configured to engage with one or more of the protruding tabs of the bone screw member to prevent counter-rotation of the locking member about the bone screw member. 
     
     
         12 . The pedicle screw device of  claim 10 , further comprising a set screw and a collet member, wherein the set screw engages with a threaded portion of the tulip member and compresses the collet member toward the locking member to lock the locking tabs in place on the bone screw. 
     
     
         13 . The pedicle screw device of  claim 8 , further comprising a collet member that is received within the tulip member, wherein the collet member sits atop of the locking member. 
     
     
         14 . The pedicle screw device of  claim 13 , further comprising a drive feature formed in a top portion of the locking member and an opening formed in a bottom portion of the collet member to permit a driver to pass through the collet member and into the drive feature of the locking member to threadably engage the locking member with the threaded head portion of the bone screw 
     
     
         15 . A pedicle screw tulip head assembly, comprising:
 a tulip member;   a locking member comprising a top portion formed with a drive feature configured to receive a driver tool; and   a collet member formed with an opening to provide a path for the driver tool to engage with the drive feature of the locking member.   
     
     
         16 . The pedicle screw tulip head assembly of  claim 15 , further comprising one or more connectors insertable into both connector receiving holes formed in the tulip member and connector slots formed in the collet member, wherein the connectors are configured to limit rotation of the collet member within the tulip member. 
     
     
         17 . The pedicle screw tulip head assembly of  claim 15 , further comprising locking member socket formed in the tulip member, wherein the top portion of the locking member rotates polyaxially within the locking member socket. 
     
     
         18 . The pedicle screw tulip head assembly of  claim 17 , further comprising a set screw configured to engage with a threaded portion of the tulip member, wherein threading the set screw to the tulip member presses the collet member toward the locking member to fix the locking member within the locking member socket. 
     
     
         19 . The pedicle screw tulip head assembly of  claim 15 , wherein a bottom portion of the locking member is an expandable aperture configured with a plurality of locking tabs. 
     
     
         20 . The pedicle screw tulip head assembly of  claim 19 , wherein one or more of the locking tabs has an inner surface configured to engage with protruding tabs of a bone screw to prevent counter-rotation of the locking member about the bone screw.