THE EFFECTS OF IMPLANTED IONOMERIC AND ACRYLIC BONE CEMENTS ON PERIPHERAL-NERVE FUNCTION

The effects of two experimental ionomeric and one commercial acrylic b one cement and set ionomeric microimplant bone substitute (Ionogran(R) ) on peripheral nerve conduction, 1 and 3 weeks after implantation, ha ve been compared. In 44 experiments the rat saphenous nerve was expose d midway between the ankle and thigh and bone cement placed into a poc ket created in the connective tissue adjacent to the nerve. In termina l experiments, 1 and 3 weeks later, stimulating electrodes were placed on the saphenous nerve at the ankle, and the amplitude and conduction velocity of the compound action potential (CAP) evoked was recorded t hrough another pair of electrodes positioned on the nerve proximal to the implant, in the thigh, One week after placing an ionomeric bone ce ment (HVA or V-4), no neural activity could be recorded. Three weeks, after HVA implantation apparently normal CAPs were recorded indicating a recovery from a temporary nerve conduction block, but 3 weeks after V-4 implantation only small CAPs were recorded and these could be att ributed to axonal regeneration. After implantation of acrylic bone cem ent, small CAPs were recorded after 1 week, and within 3 weeks nerve c onduction appeared to have completely recovered. Three weeks after pla cing set ionomeric microimplant particles the amplitude and conduction velocity of the CAP was similar to the controls.