An Experimental Study of Sponge and Putty of Demineralized Bone Matrix (DBM) in the Repair of Segmental Defects

摘要

OBJECTIVE This study was to evaluate the osteogenic effects of demineralized bone matrix(DBM) in the forms of sponge and putty. METHODS Rabbits DBM particles and fibers were prepared by demineralized and smashed. The sponge of DBM (sDBM)was prepared by mixing DBM fibers with 2% gelatin solution and lyophilized , the putty of DBM(pDBM) was prepared by placing DBM particles into 2% solution of gelatin and mixed. Then the two forms of DBM were sealed in syringes and sterilized by ethylene oxide gas. A standard procedure was used to make a 10mm long defect bilaterally in the radius of six skeletally mature male New Zealand White rabbits. In each rabbit, one radius defect was grafted into 50mg sDBM while the other defect was grafted into pDBM. To examine spontaneous bone defects healing in this model, one group of rabbits had a control defect that was kept empty. Six weeks after surgery the samples were harvested and evaluated by radiographs , biomechanical strength, bone mineral density(BMD), and histological examination . RESULTS The results of radiographic evaluation showed that 6 weeks after surgery all of the grafted radius defects with both sDBM and pDBM healed, none of empty defects healed. Between the groups of grafted with sDBM and normal radius , the compressive ultimate strength(CUS) was no significant differences(P=0.06) ; but in the pDBM grafted group, the CUS was significantly lower than normal radius(P=0.003). The value of BDM of new bone which grafted with sDBM compared with the normal radius and that grafted with pDBM was lower than normal radius(t-test ,P=0.004). Histological analyses of the grafted sites in both groups showed that most of the DBM was absorbed and substituted for matured new bone. There was no significant statistical difference in mineral aggradational rate (MAR) between the two groups(t-test, P=0.756). CONCLUSIONS In this model, the defects were repaired by grafts both fiber-based sDBM and the particle-based pDBM. The properties of new bone that was induced by grafts with sDBM was superior to pDBM induced in biomechanics.