THE PRIMARY STABILITY OF AUTOGRAFTS AND X ENOGRAFTS FOR INTERVERTEBRAL BODY FUSION

In this study, we tested the stability of the xenograft SURGIBONE(R) a nd of human iliac crest graft depending on the donor's bone density. T he mean load bearing capacity of SURGIBONE(R) was 4816 N, the compress ive strength 32.8 N/mm(2). This even exceeds the values given by the p roducer. Yet in clinical use the material caused problems by collapses or lysis of the graft. According to our results, those failures can n ot be explained by missing primary stability. Perhaps there is a immun ogenic reaction of the host against the remaining protein as it once w as proved for the ''kielspan''-graft. The iliac crest grafts of donors with normal bone density had a load bearing capacity of 3397 N. Graft s of donors with reduced bone density of less than 60 mg/ml Ca-Equival ent showed reduced load bearing capacities of 2265 N. DEXA (Dual-Energ y X-Ray Absorptiometry) seems to be suitable to scan preoperatively th e iliac crest graft stability in order to recognize the danger of redu ced stability by osteoporosis.