Patent ID: 8197518

Claim:
A polyaxial pedicle screw system comprising: an anchoring member having a threaded shank and a spherical connector; a connecting assembly defined by a lower connector member coupled to an upper connector member, said lower connector member having a socket for receipt of said spherical connector, said upper connector member having an opening for receipt of a connecting rod member and a bottom with at least one spring pocket formed therein; a retainer ring disposed between said lower connector member and said upper connector member, said retainer ring having a lower spherical surface positionable along an upper surface of said spherical connector and a cylindrically shaped concave upper surface constructed and arranged to engage a connecting rod member from about 5.5 mm diameter to about 6.0 mm, said cylindrically concave upper surface having a clamp angle including a pair of diverging substantially planar surfaces extending into said opening of said upper connector member; at least one biasing member having a first end positionable in said spring pocket of said upper connector member and a second end cooperating with an upper surface of said retainer ring, said biasing member having a first length in a unbiased state and a second shorter length in a compressed state, said biasing member in said compressed state exerting a force upon said retainer ring that in turn exerts a force upon the spherical connector which in turn exerts a force upon said lower connector member; and a fastener element securable to said upper connector member for engaging of said connecting rod member; wherein said connecting assembly can be moved into a predetermined position relative to said spherical connector and maintain said predetermined relative position under the force exerted by said biasing member in the compressed state with said fastener element traversable between an unlocked position and a locked position for controlling polyaxial movement.