Abstract: The present invention provides methods of forming flexible implant devices and U-bridge implants that drive into curved trajectories to enhance implant fixation in bone. The curved drilling trajectories avoid regions of low bone mineral density, such that flexible implants and/or U-bridge implants driven into the curved drilling trajectories are anchored in regions of high bone mineral density to improve the stability of bone fixation. The flexible implants and U-bridge implants are suitable for several applications, including but not limited to spinal fixation, orthopedic bone fixation, and neurosurgery.