Dual locking polyaxial screw head

Abstract

Systems, methods, and devices for securing a spinal rod are provided. A clamp assembly may include a tulip comprising a first opening and a second opening, wherein an inner surface of the first opening comprises threads; a saddle movably disposed within the tulip between the first and second openings, the saddle comprising a first end and a second end, the first end comprising a portion configured to receive a spinal rod, the second end comprising a cavity configured to receive a pedicle screw, the saddle comprising slots configured to receive a rotating tool; and a threaded locking cap disposed in the first opening.

What is claimed is: 
     
         1 . A clamp assembly comprising:
 a tulip comprising a first opening and a second opening, wherein an inner surface of the first opening is threaded;   a saddle movably disposed within the tulip between the first and second openings, the saddle comprising a first end and a second end, the first end comprising a passage configured to receive a spinal rod, the second end comprising a cavity configured to receive a pedicle screw; and   a threaded locking cap disposed in the first opening, the threaded locking cap comprising an inner portion disposed concentrically within an outer portion, wherein an outer surface of the inner portion is threaded, wherein an inner surface of the outer portion is threaded.   
     
     
         2 . The clamp assembly of  claim 1 , further comprising the spinal rod, the spinal rod extending through the passage. 
     
     
         3 . The clamp assembly of  claim 1 , further comprising the pedicle screw, wherein a head of the pedicle screw is positioned within the cavity. 
     
     
         4 . The clamp assembly of  claim 3 , wherein the pedicle screw extends through the second opening of the tulip. 
     
     
         5 . The clamp assembly of  claim 4 , further comprising a retaining member positioned to abut the head of the pedicle screw. 
     
     
         6 . The clamp assembly of  claim 5 , wherein the retaining member is positioned within the second opening of the tulip. 
     
     
         7 . The clamp assembly of  claim 6 , further comprising cam components housed in the tulip to compress the saddle against the head of the pedicle screw and the retaining member. 
     
     
         8 . A clamp assembly comprising:
 a tulip comprising a first opening and a second opening, wherein an inner surface of the first opening comprises threads;   a saddle movably disposed within the tulip between the first and second openings, the saddle comprising a first end and a second end, the first end comprising a portion configured to receive a spinal rod, the second end comprising a cavity configured to receive a pedicle screw, the saddle comprising slots configured to receive a rotating tool; and   a threaded locking cap disposed in the first opening.   
     
     
         9 . The clamp assembly of  claim 8 , wherein the threads of the tulip are angled. 
     
     
         10 . The clamp assembly of  claim 8 , wherein threads of the threaded locking cap are angled. 
     
     
         11 . The clamp assembly of  claim 8 , wherein an outer surface of the tulip comprises chevron slots to receive a mating tool. 
     
     
         12 . The clamp assembly of  claim 8 , wherein an outer surface of the tulip comprises reduction pockets to receive a mating tool. 
     
     
         13 . The clamp assembly of  claim 8 , further comprising the spinal rod, the spinal rod extending through the saddle. 
     
     
         14 . The clamp assembly of  claim 8 , wherein the pedicle screw extends through the second opening of the tulip. 
     
     
         15 . The clamp assembly of  claim 8 , wherein corners of the threads of the threaded locking cap include chamfers. 
     
     
         16 . The clamp assembly of  claim 8 , wherein corners of the threads of the tulip include radii. 
     
     
         17 . The clamp assembly of  claim 8 , wherein threads of the tulip are square shaped. 
     
     
         18 . The clamp assembly of  claim 8 , wherein threads of the threaded locking cap are square shaped. 
     
     
         19 . A clamp assembly comprising:
 a tulip, wherein an inner surface of the tulip comprises threads; and   a break-off locking cap removably disposed within the tulip.   
     
     
         20 . The clamp assembly of  claim 19 , wherein the break-off locking cap is a threaded locking cap, a set screw, or a quarter turn locking cap.