Polyaxial bone screw with cam connection and lock and release insert
OwnerRoger P. Jacksoninventor
Life of this patent
Estimating the term…
Abstract
A polyaxial bone screw assembly includes a threaded shank body having an integral upper portion receivable in a receiver, the receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. A retaining member for capturing the shank in the receiver includes a sloping surface for a frictional, press fit, cammed engagement with the shank. A compression insert having a resilient structure provides non-floppy positioning of the shank with respect to the receiver and also independent locking of the shank with respect to the receiver.
Claims31
A medical implant comprising:
- a) a receiver having a lower portion with a cavity and a lower opening communicating with the cavity and an upper portion with an upper opening communicating with a longitudinal connecting member receiving channel, the channel communicating with the cavity;
- b) a bone screw shank having a head and a body for fixation to bone, the head having an engagement surface;
- c) a retaining member for capturing the shank head within the receiver, the retaining member having an interior surface sized and shaped for a locking press-fit, fixed engagement with the shank head engagement surface;
- and
- d) a compression insert positioned in the receiver and being in operative locked engagement with the shank head.
A polyaxial bone screw assembly comprising:
- a) a shank having a body for fixation to a bone and an upper portion with a top surface, the upper portion having an engagement structure, the upper portion further having a lower partial spherical surface having a first radius;
- b) a receiver defining an open channel and having a base with a seating surface partially defining a cavity, the open channel communicating with the cavity, the cavity communicating with an exterior of the base through an opening sized and shaped to receive the shank upper portion therethrough;
- c) a retainer for capturing the shank within the receiver, the retainer and the shank engagement structure being sized and shaped for press fit locking engagement therebetween, the retainer having an external partial spherical surface having a second radius, the retainer partial spherical surface and the shank lower partial spherical surface sized and shaped for initial pivoting and ultimate fixed mating engagement with the receiver seating surface, the first radius being substantially the same as the second radius;
- and
- d) a compression insert positioned in the receiver, the insert being in operative locked engagement with the shank top surface.
A bone anchor comprising:
- a) a receiver having a lower portion with an inner seating surface partially defining a cavity and a lower opening communicating with the cavity and an upper portion with an upper opening communicating with a longitudinal connecting member receiving channel, the channel communicating with the cavity;
- b) a bone attachment structure having a head with a top surface, a first planar surface and a first partial spherical surface, the bone attachment structure also having a body for fixation to bone;
- c) a retaining member having at least a second planar surface sized and shaped for press fit engagement with the first planar surface, the retaining member having a second partial spherical surface, the first and second spherical surfaces having substantially the same radius, both the first and second spherical surfaces receivable by the inner seating surface of the receiver;
- and
- d) a compression insert positioned in the receiver and being in operative locked engagement with the head top surface.
Dependencies are inferred from the claim text.