CPC A61B 17/7037 (2013.01) [A61B 17/7038 (2013.01); A61B 17/8605 (2013.01); A61B 17/864 (2013.01)] | 20 Claims |
1. A medical implant assembly for securing an elongate rod to a bone of a patient via tooling and a closure top, the medical implant assembly comprising:
a shank comprising a longitudinal axis, a head at a proximal end, and a body extending distally from the head with an anchor portion configured for anchoring to the bone, the head having an at least partial spherical outer surface with a hemisphere diameter defined as a maximum diameter in a plane perpendicular to the longitudinal axis of the shank;
a receiver comprising a base defining a lower portion of a central bore centered about a vertical centerline axis and configured to receive the head of the shank, and an upper portion defining a first channel configured to receive the elongate rod, the central bore communicating with a bottom of the receiver through a lower opening and extending upward through the first channel to a top of the receiver and including a closure mating structure adjacent the top of the receiver configured to mate with the closure top, a lower locking recess adjacent the lower opening, an upper expansion recess with a distally facing upper stop surface above the lower locking recess, and a discontinuous and non-resilient horizontal ridge protruding inwardly and extending circumferentially around the central bore between the upper expansion recess and the closure mating structure;
an insert uploadable through the lower opening into the central bore of the receiver prior to the head of the shank, the insert having discontinuous top surfaces with adjacent upper side surfaces separated by a second channel that is alignable with the first channel and configured to receive the elongate rod, with the discontinuous top surfaces configured to remain below a top of the elongate rod and the upper side surfaces configured to initially extend at least partially above the horizontal ridge for overlapping engagement with the horizontal ridge so as at least partially hold and inhibit downward movement of the insert in the first channel of the receiver;
a resilient upper open ring uploadable through the lower opening and positionable within the central bore below the insert; and
a resilient lower open ring uploadable through the lower opening and initially positionable within at least one of the lower locking recess or the upper expansion recess below the upper open ring,
wherein the head of the shank is uploadable through the lower opening of the receiver so as to expand the lower open ring within the upper expansion recess until the hemisphere diameter of the head passes upward through the lower open ring, after which the lower open ring is configured to move downward into the lower locking recess so as to capture the head of the shank within the central bore of the receiver, and
wherein prior to positioning the elongate rod in the first channel and the second channel, the insert is configured for downward displacement within the central bore via direct force from the tooling so as to become engageable with the head of the shank, and the upper open ring is configured to occupy simultaneously abut the upper stop surface and the lower open ring when occupying the upper expansion recess so as to inhibit the lower open ring from moving entirely back up into the upper expansion recess and re-expanding therein.
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