Patent ID: 8876869
Filing Date: 2014-11-04
Classification: A61B

Abstract:
1. A system for in situ coupling of a rod receiver portion of a spinal fixation anchor to a bone screw portion of the fixation anchor, comprising: a bone screw having a shank engageable within a bone structure in a patient and a partially spherical capture structure; a receiver configured for in situ coupling to the bone screw after the bone screw has been anchored to the bone structure, the receiver including a base and a pair of spaced apart arms extending above the base and defining a rod passage dimensioned to receive a spinal fixation rod therein, the base including an interior cavity adjacent a lower opening, the receiver also including a collar situated within the base and configured to receive the capture structure of the bone screw, the collar having an upper edge and a bottom edge, an outer surface, an inner surface, and a slot extending from the upper edge to the bottom edge, the slot permitting expansion of a collar circumference to allow passage of the bone screw capture structure when the collar is advanced over the bone screw capture structure from the bottom edge, the inner surface of the collar having a partially spherical contact surface for articulating engagement with the partially spherical capture structure, wherein the base lower opening has a support surface complementary to the collar outer surface on which the collar rests prior to and after coupling of the receiver and the bone screw, the cavity having a larger circumference above the support surface such that when the collar is advanced over the bone screw capture structure from the bottom edge the collar rises into the cavity where the larger circumference permits expansion of the collar circumference until the partially spherical capture structure rests within the partially spherical contact surface, whereafter the collar descends back into contact with the support surface such that the partially spherical capture structure rests in the collar contact surface and the collar rests in the base support surface in a manner such that the receiver is angularly articulatable relative to the bone screw; and a receiver inserter that releasably couples to the receiver for in situ coupling of the receiver and the bone screw, the inserter including a first shaft having a first distal end that engages and holds the receiver relative to the first shaft and a second shaft that operably translates through a passage in the first shaft such that a second distal end of the second shaft extends beyond the first shaft first distal end delivering a translational force to the capture structure relative to the receiver to verify secure coupling between the receiver and the bone screw.