A bone screw (10) having a lead portion (12) and a tail portion (14), each comprising a root and a thread (22, 24) (having a thread lead) formed on the root. The thread on each of the lead and tail portions has an approximately constant diameter along a significant portion of its length. The diameter of the thread on the tail portion is greater than that of the thread on the lead portion, and in which the thread lead of the thread on the lead portion is equal to the thread lead of the thread on the tail portion. The screw can be used to achieve fixation to a vertebra with an anterior approach.
