Instruments for bone screws

摘要

An adjustable drill for use in implanting orthopedic screws, such as adjustable compression screws having a separate adjustable head. The adjustable drill comprises a primary drill bit and a countersink drill bit encircling the primary drill bit. The countersink drill bit is configured to selectively slide along the primary drill bit for use in selecting a drill depth. The countersink drill bit is associated with a stop member that is configured to selectively lock the countersink drill bit at one of a plurality of selected positions along the primary drill bit to thereby establish a drill depth. The drill depth corresponds to the size of a selected screw implant, allowing the drill to be used as a trial. The adjustable drill forms a bore having a primary bore and a countersunk entry.