Anti-backout mechanism for an implant fastener

An implant system, comprising:

• an implant attachable to a bony structure, said implant including a hole extending between upper and lower surfaces of said implant along a central axis;
• a retaining mechanism in said hole including a cylindrical body extending between first and second ends and a bore through said body, said body further including an internal thread profile in an inner wall surface extending about said bore;
• and
• a fastener including a threaded shaft and a head at a proximal end of said shaft, said threaded shaft threadingly engaging said internal thread profile of said retaining mechanism as said threaded shaft is positioned through said bore.

A method for engaging a spinal plate along a spinal column, comprising;

• positioning the plate along at least one vertebra, the plate including at least one hole and a retaining mechanism positioned in the at least one hole;
• threadingly engaging a threaded shaft of a bone fastener through an internal bore of the retaining mechanism as the fastener is engaged to the at least one vertebra;
• and
• radially expanding the retaining mechanism with a non-threaded head at a proximal end of the fastener when the head is seated in the retaining mechanism.