| CPC A61B 17/7035 (2013.01) [A61B 17/7032 (2013.01); A61B 17/7037 (2013.01); A61B 17/7011 (2013.01)] | 24 Claims |

|
1. A method of assembling a pivotal bone anchor assembly configured to secure an elongate rod to a bone of a patient via a closure, the method comprising:
positioning an insert and a two-part retainer into an axial bore of a receiver,
the receiver comprising a base defining a cavity centered about a vertical axis and communicating with a bottom surface of the base through a bottom opening, and a pair of upright arms extending upward from the base defining an open channel configured to receive the elongate rod, the cavity including a seating surface proximate the bottom opening and extending upward through the open channel to tops of the upright arms to define the axial bore, the axial bore including a discontinuous closure mating structure proximate the tops of the upright arms and integrally formed opposite engagement structures, where prior to the positioning of the insert into the axial bore, the opposite engagement structures protrude inwardly between the closure mating structure and the seating surface,
the insert comprising an upper curvate surface configured to engage the elongate rod and outer side surfaces configured to engage the opposite engagement structures of the axial bore to restrict the motion of the insert relative to the receiver, and
the two-part retainer comprising two separable retainer parts together defining an inner retainer surface, each retainer part having an outer retainer surface engageable with the seating surface; and
uploading an upper capture portion of a bone anchor through the bottom opening and into the two-part retainer that has been pre-loaded into the cavity, the bone anchor comprising the upper capture portion having an outer capture surface complementary with the inner retainer surface and a lower attachment portion opposite the upper capture portion configured for attachment to the bone,
wherein the two retainer parts are configured to at least partially move away from each other and then back toward each other upon the uploading of the upper capture portion into the cavity to operably engage and capture the upper capture portion within the receiver with the bone anchor extending downwardly through the bottom opening, and
wherein a force directed downwardly onto the two-part retainer in operable engagement with the upper capture portion is configured to drive the outer retainer surfaces of the retainer parts into frictional engagement with the seating surface of the cavity to lock the angular orientation of the bone anchor with respect to the receiver.
|