Spinal Rod Connectors Configured to Retain Spinal Rods of Varying Diameters
A spinal rod connector is configured to accommodate a range of spinal rod diameters. The present spinal rod connector may take the form of a spinal rod screw head, hook, spinal rod connector or a spinal rod holder. The spinal rod connector has spinal rod reception slots whose sides narrow towards a bottom of the slot. The narrowing of the sides provides a wedging effect such that a spinal rod is wedged into place during locking. The narrowing sides of the slots thus provide for the accommodation of varying rod diameters. The spinal connector also provides significant improvement in spinal rod torsional resistance compared to prior art radial shaped slots. In one form, the spinal rod reception slots are essentially V-shaped. However, other shapes following the principles of the present invention may be used and are contemplated. The width of the slot sides and the rate of curvature of the slot sides thus determine the range of spinal rod diameters that are accommodated by the spinal rod reception slots and therefore the spinal rod connector.
1 . A spinal rod connector for a spinal rod bone screw assembly, the spinal rod connector comprising:
a body defining an upper end, a lower end and an annular side wall between the upper end and the lower end;
a first slot formed in the annular side wall, the first slot defined by a first side wall, a second sidewall and a bottom, the first and second side walls of the first slot angled inwardly towards each other proximate the bottom of the first slot to meet at the bottom of the first slot; and
a second slot formed in the annular side wall, the second slot defined by a first side wall, a second side wall and a bottom, the first and second side walls of the second slot angled inwardly towards each other proximate the bottom of the second slot to meet at the bottom of the second slot.
2 . The spinal rod connector of claim 1 , wherein the first and second slots are formed in the annular side wall diametrically opposite one another.
3 . The spinal rod connector of claim 1 , wherein the first and second angled side walls of the first and second slots are each sized to accept a range of diameters of spinal rods.
4 . The spinal rod connector of claim 3 , wherein the range of diameters of spinal rods comprises 1.35 mm.
5 . The spine rod connector of claim 1 , further comprising a hook formed axially below the lower end, the hook sized to be received on an installed spinal rod.
6 . A spinal rod connector for a spinal rod bone screw assembly, the spinal rod connector comprising:
a body defining an upper end, a lower end and an annular side wall between the upper end and the lower end;
a bore extending from the upper end to the lower end, the bore sized at the upper end to allow a head of a bone screw to pass therethrough and sized at the lower end to retain the head of the bone screw;
a first slot formed in the annular side wall, the first slot defined by a first side wall, a second sidewall and a bottom, the first and second side walls of the first slot angled inwardly towards each other proximate the bottom of the first slot to meet at the bottom of the first slot; and
a second slot formed in the annular side wall, the second slot defined by a first side wall, a second side wall and a bottom, the first and second side walls of the second slot angled inwardly towards each other proximate the bottom of the second slot to meet at the bottom of the second slot.
7 . The spinal rod connector of claim 6 , wherein the lower end of the bore is tapered.
8 . The spinal rod connector of claim 7 , wherein the tapered lower end of the bore provides polyaxial movement of the rod connector relative to the bone screw head.
9 . The spinal rod connector of claim 6 , wherein the first and second slots are formed in the annular side wall diametrically opposite one another.
10 . The spinal rod connector of claim 6 , wherein the first and second angled side walls of the first and second slots are each sized to accept a range of diameters of spinal rods.
11 . The spinal rod connector of claim 10 , wherein the range of diameters of spinal rods comprises 1.35 mm.
12 . The spinal rod connector of claim 11 , wherein the first and second slots are configured to accept spinal rods of a diameter of 5.0 mm up to spinal rods of a diameter of 6.35 mm.
13 . The spinal rod connector of claim 1 , wherein the body includes threads on inner side walls of the annular side wall of the bore.
14 . A spinal rod connector for receiving a spinal rod and retaining the spinal rod onto a bone screw, the spinal rod connector comprising:
a generally cylindrical body defining an upper end, a lower end and an annular side wall between the upper end and the lower end;
a generally cylindrical bore extending from the upper end of the body to the lower end of the body, the bore sized at the upper end to allow a bone screw to pass therethrough but sized at the lower end to retain a head of the bone screw while allowing a shank of the bone screw to pass therethrough;
a first slot formed in the annular side wall, the first slot defined by a first side wall, a second sidewall and a bottom, the first and second side walls of the first slot angled inwardly towards each other proximate the bottom of the first slot to meet at the bottom of the first slot; and
a second slot formed in the annular side wall, the second slot defined by a first side wall, a second side wall and a bottom, the first and second side walls of the second slot angled inwardly towards each other proximate the bottom of the second slot to meet at the bottom of the second slot.
15 . The spinal rod connector of claim 14 , wherein the first and second slots are formed in the annular side wall diametrically opposite one another.
16 . The spinal rod connector of claim 14 , wherein the first and second angled side walls of the first and second slots are each sized to accept a range of diameters of spinal rods.
17 . The spinal rod connector of claim 16 , wherein the range of diameters of spinal rods comprises 1.35 mm.