Patent ID: 11911075
Assignee: nan
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 0:
1. A pivotal bone anchor assembly for securing an elongate rod to a bone of a patient via a closure top, the pivotal bone anchor assembly comprising:
a receiver comprising a base defining a lower portion of a central bore centered about a vertical centerline axis and communicating with a bottom surface of the base through a lower opening, and an upper portion with opposed internal surfaces extending between a front face and a back face of the receiver to define a channel configured to receive the elongate rod, the central bore extending upward from the base through the upper portion to a top of the receiver and including a guide and advancement structure adjacent the top of the receiver configured for engagement with the closure top, the base including a lower seating surface adjacent the lower opening, the bottom surface of the base extending perpendicular to the vertical centerline axis, the lower opening including a cut-out portion extending radially outward through the bottom surface of the base and defined in part by at least one downward-facing partially annular planar surface extending perpendicular to the vertical centerline axis of the receiver; and
a shank comprising a capture portion, an integral anchor portion opposite the capture portion configured for attachment to the bone, and a neck extending between the capture portion and the anchor portion, the capture portion having a rounded shape including a partially spherical lower outer surface extending outwardly and upwardly from the neck and a partially spherical upper outer surface at an upper end of the capture portion, the capture portion being positionable into the lower portion of the central bore with the shank extending downward through the lower opening, and with the lower outer surface of the capture portion in pivotal engagement with the lower seating surface of the base in an unlocked configuration prior to the pivotal bone anchor assembly being locked by the closure top,
wherein the neck of the shank is positionable in the cut-out portion of the lower opening to provide for increased pivotal angulation of the shank with respect to the receiver in the direction of the cut-out portion when the capture portion is received within the lower portion of the central bore of the base of the receiver.