Anchoring devices for rachidian implants, implants, surgical instruments, and surgical systems and methods are disclosed. In some embodiments, an anchor comprises a stiff plate with a longitudinal axis, configured for penetration of its anterior end into a vertebral surface while its posterior end remains engaged with the implant. An implant may include a locking mechanism for the anchor. An anchor may include an abutment configured to abut a complementary abutment of an implant. In some configurations, inserting an anchor in a passage of an implant may displace a locking mechanism, which may resile and lock the anchor in the implant with complementary abutments of the anchor and implant abutting.