NONINVASIVE METHODS FOR STIMULATING OSTEOGENESIS

It would be advantageous to develop a surgically noninvasive method for electrical stimulation of repair processes, in which the stimulatory effect would not be limited to discreet regions. Accordingly, bilateral midfibular shaft osteotomies were created in 60 anaesthesized, mature white New Zealand rabbits. Treaded Steinmann pins were introduced transcutaneously from the medial to the lateral aspect of the tibiae through their proximal and distal methaphyses. To these pins were fastened Lucite sheets with 2 multiplied by 1 in. Mylar-insulated, brass plates attached. These plates were centered over the osteotomies, medial and lateral to the calf with a 0. 5 cm air gap between the insulator and the skin. The active plates were continuously charged with 4 batteries, yielding 100 V, or were uncharged in the contralateral controls. The total air gap between plates was 4 cm, with a 0. 5 cm distance between the lateral and medial plates and the leg. Although potential gradients at the bone level were not determined, the field strength of such an arrangement is 25 V/cm. The present investigation, coupled with more recent findings that pulsed electromagnetic fields, also can affect healing patterns of osteotomies, suggest strongly that voltage fields are ″sensed″ directly by cells in living organisms, as well as in vitro.