Polyaxial bone anchors with pop-on shank, fully constrained friction fit retainer and lock and release insert

In a polyaxial bone anchor, the improvement comprising:

• a) a receiver defining a chamber communicating with a channel, the channel sized and shaped for receiving a portion of a longitudinal connecting member, the chamber having an inner surface further comprising an aperture defined by a first surface formed therein and a second seating surface located near a bottom opening of the receiver, the chamber communicating with the bottom opening;
• b) a shank having a body and a curved upper portion, the shank body extending through the receiver bottom opening;
• and
• c) a resilient open retainer located in the chamber, the retainer having a base and an upper structure having a resilient outwardly extending tab having a top surface that is located on the top of the retainer, the retainer having two positions, a shank loading position and a shank restraining position, while in the shank loading position, the base being expandable in the chamber about the shank upper portion and receiving the shank upper portion therethrough to capture the shank upper portion in the chamber, the tab engaging the first surface of the aperture, and in the shank restraining position, the shank and retainer in combination are lowered in the chamber such that the retainer base is seated on the receiver second seating surface, and the tab expands outwardly through the aperture with the retainer being restrained by the first surface with respect to upward, downward, and rotational movement with respect to the receiver by the tab, the shank being able to be manipulated in a polyaxial direction with respect to the receiver when the retainer is in either the shank loading or shank restraining positions.

A medical implant comprising:

• a) a receiver having a base with an inner cavity and a pair of upstanding opposed arms partially defining a longitudinal connecting member receiving channel, the inner cavity defined in part by a cylindrical lower seating portion and an upper expansion chamber, the upper expansion chamber comprising an aperture defined by a first inner surface, the lower seating portion communicating with a bottom opening of the receiver base and the upper expansion chamber communicating with the rod receiving channel;
• b) a bone screw shank having an upper portion sized for up-loading through the receiver bottom opening;
• c) an open, resilient retaining member having a base and an upper structure, the base sized and shaped for expanding about the shank upper portion when the retaining member base is located in the receiver upper expansion chamber, the retainer upper structure having a top surface that is located on the top of the retainer and being disposed in the aperture in the chamber of the receiver and the retaining member base engaging the cylindrical receiver lower seating portion when the shank is in a locked position with respect to the receiver;
• and
• d) an insert located partially in the chamber, the insert having a surface frictionally engaging the shank upper portion when the retainer base is in the expanded state.

In a polyaxial bone anchor, the improvement comprising:

• a) a receiver defining a chamber communicating with a channel, the channel sized and shaped for receiving a portion of a longitudinal connecting member, the chamber communicating with a lower opening and further comprising an aperture defined by a first inner surface;
• b) a shank having a body and an upper curved portion, the shank body extending through the receiver lower opening;
• and
• c) a resilient open retainer located in the chamber, the retainer having a base and a flexible upper structure, the base expandable in the chamber about the shank upper portion and receiving the shank upper portion therethrough to capture the upper portion in the chamber, the retainer upper structure having a top surface that is located on the top of the retainer and being disposed in the aperture in the chamber of the receiver and the retainer base being fixed against a cylindrical portion of the chamber of the receiver when the shank is in a locked position with respect to the receiver, the shank upper portion being pressed against the retainer base and being in spaced relation with the receiver when in the locked position.

In a polyaxial bone anchor, the improvement comprising:

• a) a receiver defining a chamber communicating with a channel, the channel sized and shaped for receiving a portion of a longitudinal connecting member, the chamber being cylindrical in shape and communicating with a lower opening and further comprising an aperture defined by a first inner surface;
• b) a shank having a body and an upper curved portion, the shank body extending through the receiver lower opening;
• and
• c) a resilient open retainer located in the chamber, the retainer having a base and an upwardly extending spring tab, the base expandable in the chamber about the shank upper portion and receiving the shank upper portion therethrough to capture the upper portion in the chamber, the retainer spring tab having a top surface that is located on the top of the retainer and being disposed in the aperture in the chamber of the receiver and the retainer base being fixed against the cylindrical chamber of the receiver when the shank is in a locked position with respect to the receiver, the shank upper portion being pressed against the retainer base and being in spaced relation with the receiver when in the locked position.

In a polyaxial bone screw, the improvement comprising:

• a) a receiver defining a chamber communicating with a channel, the channel sized and shaped for receiving a portion of a longitudinal connecting member, the chamber communicating with a lower opening and further comprising an aperture defined by a first inner surface;
• b) a shank having a body and an upper portion, the shank body extending through the receiver lower opening;
• and
• c) an open retainer located in the chamber, the retainer having a circular base and an upwardly extending spring tab, the base expandable in the chamber about the shank upper portion and receiving the shank upper portion therethrough to capture the upper portion in the chamber, the retainer spring tab having a top surface that is located on the top of the retainer the spring tab being disposed in the aperture in the chamber of the receiver in a temporary frictional engagement with the receiver allowing for the manipulation of the receiver with respect to the shank prior to locking of the shank in a final position, the base being fixed against a cylindrical surface of the chamber in a locked position.

In a polyaxial bone anchor, the improvement comprising:

• a) a receiver defining a chamber communicating with a channel, the channel sized and shaped for receiving a portion of a longitudinal connecting member, the chamber communicating with a lower opening and further comprising an aperture defined by a first inner surface and an upper expansion portion and a lower seating portion, each portion containing a cylindrical side surface;
• b) a shank having a body and an upper curved portion having a hemisphere, the shank body extending through the receiver lower opening;
• and
• c) a resilient open retainer located in the chamber, the retainer having a base with a substantially cylindrical outer surface and an upper structure, the base being expandable in the upper expansion portion of the chamber about the shank upper portion and receiving the shank upper portion therethrough to capture the shank upper portion in the chamber, the retainer upper structure having resilient arms with a top surface that is located on the top of the retainer and being disposed in the aperture in the chamber of the receiver and the retainer base being fixed against the receiver lower portion cylindrical side surface when the shank is in a locked position with respect to the receiver, the shank upper portion being pressed against the retainer base and being in spaced relation with the receiver when in the locked position.