Systems and methods for correcting spinal deformities
The present invention relates generally to medical devices and methods generally aimed at spinal surgery. In particular, the disclosed system and associated methods relate to performing spinal fixation with the use of a deformity system.
1 . An anchor assembly comprising:
a bone anchor; and
a receiver assembly configured to polyaxially engage with the bone anchor, wherein the receiver assembly comprises:
a receiver; and
a collar positioned within the receiver, the collar configured to couple the bone anchor to the receiver, the collar comprising a first outer convex surface and a second outer convex surface opposite the first outer convex surface, wherein the first outer convex surface and the second outer convex surface are connected by two opposing exterior planar faceted surfaces configured to mate with a rounded feature of the receiver such that an outer shape of the collar is non-circular,
wherein the receiver comprises a base and a pair of arms extending distally from the base.
2 . The anchor assembly of claim 1 , wherein the collet comprises a tapered feature, and the receiver comprises a tapered cavity sized and shaped to slidably mate and frictionally engage with the tapered feature of the collet.
3 . The anchor assembly of claim 2 , wherein the collet further comprises a tooling engagement feature configured to engage with a tool to release frictional engagement between the tapered feature of the collet and the tapered cavity of the receiver.
4 . The anchor assembly of claim 1 , wherein the collet comprises a top surface, a bottom surface, an inner surface, and a slot extending along a longitudinal axis of the collet.
5 . The anchor assembly of claim 4 , wherein the bone anchor comprises a capture structure having a convex surface, wherein the convex surface is articulable on a concave portion of the inner surface of the collet.
6 . The anchor assembly of claim 5 , wherein the slot is compressible to cause the inner surface of the collet to frictionally engage and secure the capture structure of the bone screw.
7 . The anchor assembly of claim 1 , wherein the collet comprises a saddle having a contouring surface configured to receive and mate with a rod within the receiver assembly.
8 . The anchor assembly of claim 1 , wherein each of the pair of arms has an interior advancement structure situated at least partially along a respective inner wall of each of the pair of arms.
9 . The anchor assembly of claim 8 , wherein the anchor assembly further comprises a closure structure having an exterior advancement structure, and wherein the interior advancement structure of the receiver is configured to mate with the exterior advancement structure of the closure structure.
10 . The anchor assembly of claim 1 , wherein each of the pair of the arms comprises a sweeping step recessed inwardly from a respective inner wall of each of the pair of the arms.
11 . The anchor assembly of claim 10 , wherein the collet further comprises a locking ledge, and the sweeping step is configured to guide the locking ledge into position within the receiver.
12 . The anchor assembly of claim 11 , wherein the sweeping step comprises a notch configured to prevent the locking ledge from backing out of the sweeping step.
13 . The anchor assembly of claim 1 , wherein the receiver further comprises a tooling attachment feature on an outer surface thereof, the tooling attachment feature being configured to allow a tool to engage the receiver assembly.
14 . The anchor assembly of claim 1 , wherein the anchor assembly further comprises a closure structure configured to advance into the receiver and to lock a portion of a rod received in the anchor assembly between the closure structure and the collar.