The electrical stimulation of bone using a filamentous carbon cathode.

Filamentous carbon fiber is an extremely compatible biomaterial. It does not corrode and elicits almost no foreign body response. In addition, this material is an efficient electrical conductor in vivo. These desirable characteristics suggest that carbon fiber may be of use as an electrode material for the stimulation of bone and/or soft tissue growth. This possibility has been investigated in a well established laboratory animal model. When used as a cathode material in conjunction with an implantable constant direct current device, carbon fiber was shown to be an effective electrode material for the stimulation of bone and fibrous tissue within the medullary canal of the tibia of the rabbit. Further, adjustment of current levels appear to allow some selectivity in terms of the amount and type of tissue produced. Currents in the 1 microA range produced a maximum amount of bone, whereas a 20 microA current produced a maximum amount of fibrous tissue. Intermediate current levels produced a proportional mix of bone and soft tissue.