BONE SCREW COMPRISING A DEVICE FOR ELECTROSTIMULATION

摘要

Bone screw (10a) having a hollow, tubular shaft (12a) consisting of metal, such as titanium, the shaft having a head (14a) at one end and a self-tapping external thread (18a) at the other end. The head (14a) has a hexagonal recess (16a) for inserting a turning tool. An electrically insulated metallic end-piece (20a) which tapers in the direction of the end in the form of a cone or pointed arch, is inserted the other end of the shaft (12a). A receiving coil (30a) is located in the hollow shaft (12a), the terminals (36a, 38a) of the coil being electrically coupled to the shaft (12a) and to the end-piece (20a). The space between the end-piece (20a) and the end of the shaft (12a) as well as the interior of the shaft (12a) are filled with a biocompatible insulating compound (26a), such as an epoxy resin. A low-frequency electric voltage can be induced in the receiving coil by an external primary coil which is coupled to an oscillation generator. The electric voltage generates a growth-promoting current in the surrounding tissue, the shaft and the end-piece acting as tissue electrodes (stimulation method according to Kraus and Lechner).