A pedicle screw includes a tulip head having an upper opening disposed in a top end of the tulip head and a lower opening disposed in a bottom end of the tulip head opposite the upper opening, wherein the upper and lower openings form a single cavity extending through the tulip head from a top end to the bottom end and the cavity having an interior wall, a retention groove disposed within the interior wall, and a stop disposed between the retention groove and upper opening and extending inwardly from the interior wall； a rod seat disposed within the cavity engaging the stop on a side closest to the lower opening, the rod seat having a rod mating face, a shank mating face opposite the rod mating face, and a hole disposed through the rod mating face and shank mating face； a screw shank having a thread disposed along a length of the screw shank and a connector positioned at an upper end of the screw shank； a retainer collar having a collar body, a pass through aperture disposed through the collar body, a locking ring groove disposed within an outer surface of the collar body, an anti-rotation tab extending from the collar body, and a collar expansion split disposed within the collar body, wherein the retainer collar disposed about the connector of the screw shank； and a locking ring disposed within the retention groove and the locking ring groove, wherein the locking groove has an unloaded outer diameter (D0i) which is greater than a diameter of the lower opening.La présente invention concerne une vis pédiculaire qui comprend une tête de tulipe ayant une ouverture supérieure disposée à l'extrémité supérieure de la tête de tulipe et une ouverture inférieure disposée dans une extrémité inférieure de la tête de tulipe face à l'ouverture supérieure, les ouvertures supérieure et inférieure forment une cavité unique s'étendant à travers la tête de tulipe d'une extrémité supérieure à l'extrémité inférieure de la cavité ayant une paroi intérieure, une rainure de retenue dispos
