초록 ▼

A medical implant assembly includes a polyaxial bone anchor having a shank, a receiver, a lower compression insert with surfaces for closely receiving an elongate connecting member and a dual closure structure that may include a single flange or helical flange. The dual closure structure independent

A medical implant assembly includes a polyaxial bone anchor having a shank, a receiver, a lower compression insert with surfaces for closely receiving an elongate connecting member and a dual closure structure that may include a single flange or helical flange. The dual closure structure independently engages the connecting member and the lower compression insert. A threaded capture connection of the bone anchor includes a shank upper surface exclusively engaging the lower compression insert and a retainer threadably attached to the shank and spaced from the upper surface, the retainer configured for polyaxial motion with respect to the receiver prior to locking.

대표청구항 ▼

What is claimed and desired to be secured by Letters Patent is as follows: 1. A polyaxial bone anchor comprising:a) a shank having a body for fixation to a bone and an integral upper portion, the upper portion having an upper end surface and an outer surface with a first helically wound guide and ad

What is claimed and desired to be secured by Letters Patent is as follows: 1. A polyaxial bone anchor comprising:a) a shank having a body for fixation to a bone and an integral upper portion, the upper portion having an upper end surface and an outer surface with a first helically wound guide and advancement structure thereon;b) a receiver having a top portion and a base, the receiver top portion defining an open channel, the base having a seating surface partially defining a cavity, the channel communicating with the cavity, the cavity communicating with an external of the base through an opening sized and shaped to receive the shank upper portion therethrough;c) a compression insert disposed in the receiver, the insert having a mating surface exclusively frictionally engageable with the upper end surface of the shank upper portion; andd) a retainer having an external surface and a central bore with an internal surface defining the central bore having a second helically wound guide and advancement structure thereon, the first helically wound guide and advancement structure configured to rotatably mate with the second helically wound guide and advancement structure to secure the retainer to the shank upper portion within the receiver, the shank upper portion and the retainer being in fixed relation to one another, both the upper portion and the retainer being in swivelable relation within the receiver, providing selective angular positioning of the shank with respect to the receiver, the retainer external surface being in slidable engagement with the receiver seating surface, the retainer being substantially spaced from the compression insert at any and all angular positions of the shank with respect to the receiver.