Paloma Sayegh Arreguy Silva

Plasma rico em plaquetas associado ou não ao osso esponjoso autógeno no reparo de falhas ósseas experimentais

The present study evaluated autogenous platelet rich plasmas (PRP) influence on the reparation process of four bone defects made on rabbits skull, associated or not to autogenous bone graft (EOE). Defect I received PRP only; defect II received 3mg of EOE only; defect III received EOE associated to PRP; defect IV was left to heal naturally, serving as control. After each surgery the animals were randomly divided into three groups that were euthanized at 30, 60 and 90 days. In the mesoscopic evaluation bone ingrowth started from the defects borders to the center and from the bottom to the surface for all observation times on the control (VI) and PRP only (I) groups. In the groups treated with EOE only (II) and EOE associated to PRP (III) new bone was observed in the center of the defects. Radiographic analysis showed greater central radiopacity for groups treated with EOE only (II) and EOE associated to PRP (III) at all observation times. Microscopically in the group treated with EOE associated to PRP (III) at 30 days the graft was indistinguishable from new bone present on the border of the defect, associated to a moderate quantity of a very vascularized and cellular fibrous connective tissue. This tissue showed an extracelular eosinophilic amorphous foamy material, associated to an inflammatory process constituted by lymphocytes and in less number by macrophages and multinucleated giant cells that may have negatively influenced early bone formation. At 60 and 90 days occasional spots of lymphocytic inflammation were observed. Both treatments, PRP associated or not to EOE, were similar for the bone ingrowth at the final time of observation; the graft used alone determined early bone reparation and thromboplastine used for the platelet gel formation incited a foreign body-like reaction that acted negatively on the initial reparation.

Matriz óssea homóloga desmineralizada associada à medula óssea autógena fresca na artrodese vertebral dorsolateral lombar em coelhos

It was evaluated the homologous demineralized bone matrix (HDBM), associated with the fresh autogenous bone marrow (FABM), in the vertebral dorsolateral lumbar union in 24 rabbits (group 1), that was placed on the transverse processes of previously decorticated L5-L6 vertebrae. In other nine rabbits (control group), it was just accomplished the decortications of the transverse processes, which showed insignificant local periostial reaction, without bone union after different evaluations. In the group 1, after five weeks of postoperative interval, 87.5% of the animals presented union (arthrodesis), which was observed by palpation, followed by 75 and 100% after seven and nine weeks, respectively. The arthrodesis indexes to X rays were of 50%, 62% and 75%, in the same evaluation period. According to histological analysis, after five weeks, there were characteristics of osteointegration of HDBM with the decorticated transverse processes, from where the blood vessels that penetrated the bone matrix originated, and the presence of cartilage tissue in the center of the graft. In the following weeks, the endocondral ossification continued and HDBM was almost totally substituted by trabecular bone tissue, forming a bridge of ripe bone among and over the adjacent transverse processes, propitiating larger mechanical resistance to the operated segment in comparison to the adjacent segments. The association of HDBM with the FABM showed as a feasible option with low cost in the vertebral dorsolateral lumbar arthrodesis in rabbits.