Top Loading Polyaxial Spine Screw Assembly With One Step Lockup
A top loading polyaxial spinal rod screw assembly is configured for simultaneous or one step lockup of angular orientation of a rod holder portion of the screw assembly relative to a bone screw and of a spinal rod within the rod holder portion of the screw assembly. The spinal rod and the angular orientation of the rod holder holding the spinal rod are thus fixed upon receipt of a lockup component of the present assembly. Components of the present spinal rod screw assembly cooperate to allow reception of a spinal rod in a rod holder that is adapted for pivotal retention on a bone screw and to lock or fix the spinal rod within the rod holder while also locking or fixing the angular orientation of the rod holder relative to the bone screw upon receipt of a lockup cap component of the screw assembly in the rod holder. In one form, the present screw assembly is defined by a three-piece polyaxial screw head assembly for a bone screw. The three-piece polyaxial screw head assembly includes a spine rod holder or head configured for pivotal connection with the bone screw, a head insert configured for reception in the spine rod holder, and a lockup (end) cap configured for reception in the spine rod holder. The lockup cap is configured to interact with the head insert to fix an angular position or orientation of the spine rod holder relative to the bone screw at the same time as fixing a spinal rod that has been received in the spine rod holder relative to the spine rod holder.
1 . A spinal rod reception assembly for a spinal screw, the spinal rod screw assembly comprising:
a spinal rod holder configured to hold a spinal rod and having an axial bore therein defining a first opening and a second opening, the second opening configured to hold a head portion of a spinal screw and to allow polyaxial pivoting of the spinal screw, the first opening configured to receive the spinal rod;
an insert received in the axial bore of the spinal rod holder and configured to receive the spinal rod, the insert defining a first end and a second end, the second end configured to abut the head portion of the spinal screw and to fix an angular orientation of the spinal screw relative to the spinal rod holder upon application of axial pressure on the first end of the insert, and the first end configured to fix a position of the spinal rod relative to the spinal rod holder upon application of the axial pressure on the first end of the insert; and
an end cap receivable in the axial bore of the spinal rod holder and configured to apply axial pressure on the first end of the insert after placement of the spinal rod in the spinal rod holder to fix the angular orientation of the spinal rod holder relative to the spine screw and to fix the spinal rod relative to the spinal rod holder.
2 . The spinal rod reception assembly of claim 1 , wherein fixing of the angular orientation of the spinal rod holder relative to the spine screw and of the spinal rod relative to the spinal rod holder is achieved simultaneously upon reception of the end cap in the spinal rod holder.
3 . The spinal rod reception assembly of claim 1 , wherein:
the axial bore of the spinal rod holder has internal threading; and
the end cap has external threading;
the internally threaded axial bore threadedly receiving the externally threaded end cap whereby through continued threading of the externally threaded end cap into the internally threaded axial bore, the externally threaded end cap provides the application of pressure on the first end of the insert after placement of the spinal rod in the spinal rod holder to fix the angular orientation of the spinal rod holder relative to the spine screw and to fix the spinal rod relative to the spinal rod holder.
4 . The spinal rod reception assembly of claim 3 , wherein the externally threaded end cap includes a detachable portion configured to drive the threading of the end cap into the spinal rod holder.
5 . The spinal rod reception assembly of claim 4 , wherein the detachable portion defines a driver.
6 . The spinal rod reception assembly of claim 1 , wherein:
the second end of the spinal rod holder is internally angled radially inward; and
the second end of the insert is angled for reception on the head portion of the spinal screw.
7 . The spinal rod reception assembly of claim 6 , wherein the insert forms a pocket for the reception of the spinal rod therein.
8 . The spinal rod reception assembly of claim 7 , wherein the first end of the insert is angled radially inward.
9 . A spinal rod reception assembly comprising:
a spinal bone screw;
a spinal rod holder configured to hold a spinal rod and having an axial bore therein defining a first opening and a second opening, the second opening configured to hold a head portion of the spinal bone screw and to allow polyaxial pivoting of the spinal bone screw, the first opening configured to receive the spinal rod;
an insert received in the axial bore of the spinal rod holder and configured to receive the spinal rod, the insert defining a first end and a second end, the second end configured to abut the head portion of the spinal bone screw and to fix an angular orientation of the spinal bone screw relative to the spinal rod holder upon application of axial pressure on the first end of the insert, and the first end configured to fix a position of the spinal rod relative to the spinal rod holder upon application of the axial pressure on the first end of the insert; and
an end cap receivable in the axial bore of the spinal rod holder and configured to apply axial pressure on the first end of the insert after placement of the spinal rod in the spinal rod holder to fix the angular orientation of the spinal rod holder relative to the spine bone screw and to fix the spinal rod relative to the spinal rod holder.
10 . The spinal rod reception assembly of claim 9 , wherein fixing of the angular orientation of the spinal rod holder relative to the spine bone screw and of the spinal rod relative to the spinal rod holder is achieved simultaneously upon reception of the end cap in the spinal rod holder.
11 . The spinal rod reception assembly of claim 9 , wherein:
the axial bore of the spinal rod holder has internal threading; and
the end cap has external threading;
the internally threaded axial bore threadedly receiving the externally threaded end cap whereby through continued threading of the externally threaded end cap into the internally threaded axial bore, the externally threaded end cap provides the application of pressure on the first end of the insert after placement of the spinal rod in the spinal rod holder to fix the angular orientation of the spinal rod holder relative to the spine bone screw and to fix the spinal rod relative to the spinal rod holder.
12 . The spinal rod reception assembly of claim 11 , wherein the externally threaded end cap includes a detachable portion configured to drive the threading of the end cap into the spinal rod holder.
13 . The spinal rod reception assembly of claim 12 , wherein the detachable portion defines a driver.
14 . The spinal rod reception assembly of claim 9 , wherein:
the second end of the spinal rod holder is internally angled radially inward; and
the second end of the insert is angled for reception on the head portion of the spinal bone screw.
15 . The spinal rod reception assembly of claim 14 , wherein the insert forms a pocket for the reception of the spinal rod therein.
16 . The spinal rod reception assembly of claim 15 , wherein the first end of the insert is angled radially inward.
17 . A spinal rod reception assembly for receiving and retaining a spinal rod therein, the spinal rod reception assembly comprising:
a vertebral bone screw;
a spinal rod holder configured to receive and hold a spinal rod, the spinal rod holder having a threaded axial bore therein defining a first opening and a second opening, the second opening configured to hold a head portion of the vertebral bone screw and to allow polyaxial pivoting of the vertebral bone screw, the first opening configured to receive the spinal rod;
a collet received in the threaded axial bore of the spinal rod holder and configured to also receive the spinal rod, the collet defining a first end and a second end, the second end configured to abut the head portion of the vertebral bone screw and to fix an angular orientation of the vertebral bone screw relative to the spinal rod holder upon application of axial pressure on the first end of the collet, and the first end configured to fix a position of the spinal rod relative to the spinal rod holder upon application of the axial pressure on the first end of the collet; and
a threaded lock-up cap threadedly receivable in the threaded axial bore of the spinal rod holder and configured to apply axial pressure on the first end of the collet after placement of the spinal rod in the spinal rod holder to fix the angular orientation of the spinal rod holder relative to the vertebral bone screw and to fix the spinal rod relative to the spinal rod holder.
18 . The spinal rod reception assembly of claim 17 , wherein fixing of the angular orientation of the spinal rod holder relative to the vertebral bone screw and of the spinal rod relative to the spinal rod holder is achieved simultaneously upon threaded reception of the threaded end cap in the spinal rod holder.
19 . The spinal rod reception assembly of claim 18 , wherein the externally threaded end cap includes a detachable driver configured to thread the threaded end cap into the spinal rod holder.
20 . The spinal rod reception assembly of claim 17 , wherein:
the second end of the spinal rod holder is internally angled radially inward;
the second end of the collet is angled for reception on the head portion of the vertebral bone screw; and
the collet forms a pocket for the reception of the spinal rod therein.