Poly-axial pedicle screw implements and lock screw therefor
View Patent ↗A lock screw assembly for use with a pedicle screw assembly comprises a lock screw and an upper saddle. The lock screw includes a fastening tool engaging structure at a first end portion thereof and an upper saddle receiving structure at a second end portion thereof. The upper saddle is engaged with the upper saddle receiving structure of the lock screw in a manner allowing the upper saddle to rotate about a centerline axis of the lock screw. A plurality of intersecting spine rod receiving channels extend through a spine rod engaging portion of the upper saddle in a manner such that an outwardly-extending spine rod engaging structure is provided between adjacent ones of the spine rod receiving channels. Upper and lower surfaces of each spine rod engaging structure are acutely angled with respect to each other and wherein a channel edge defined between the surfaces is sharply pointed.
1. A lock screw assembly for securing a spine rod within a spine rod receiving body of a pedicle screw assembly, comprising:
a lock screw including a fastening tool engaging structure at a first end portion thereof and an upper saddle receiving structure at a second end portion thereof, wherein the upper saddle receiving structure includes a passage within an end face at the second end portion of the lock screw, wherein threads are provided on an exterior surface of the lock screw extend at least partially between the first and second end portions thereof; and
an upper saddle having a mounting post extending from a top portion thereof and engaged within the passage within the end face at the second end portion of the lock screw for enabling the upper saddle to rotate with respect to the lock screw about a centerline axis of the lock screw, wherein a plurality of intersecting spine rod receiving channels extend through a spine rod engaging portion of the upper saddle in a manner such that an outwardly-extending spine rod engaging structure is provided between adjacent ones of said spine rod receiving channels, wherein a first one of said spine rod receiving channels extends substantially perpendicular to a second one of said spine rod receiving channels, wherein a longitudinal axis of the mounting post extends through a longitudinal centerline axis of each one of the intersecting spine rod receiving channels, wherein an upper surface of each spine rod engaging structure is downwardly contoured with respect to a lower surface of a respective spine rod engaging structure, wherein said upper and lower surfaces of each spine rod engaging structure are acutely angled with respect to each other, and wherein the upper surface of each spine rod engaging structure intersects a lower surface of the respective spine rod engaging structure to jointly define opposing sharply pointed channel edges of each one of said spine rod receiving channels.
2. The lock screw assembly of claim 1 wherein:
adjacent ones of the sharply pointed channel edges terminate into the outwardly-extending spine rod engaging structure located therebetween; and
the contoured upper surface of each outwardly-extending spine rod engaging structure intersects the contoured upper surface of each adjacent outwardly-extending spine rod engaging structure.
3. The lock screw assembly of claim 1 wherein the contoured upper surface of each outwardly-extending spine rod engaging structure intersects the contoured upper surface of each adjacent outwardly-extending spine rod engaging structure.