[Osteoneogenesis. Preliminary experimental study of the implantation of decalcified bone powder in human surgery].

The allogenic implantation of demineralized bone powder induces the formation of new bone tissue or osteoneogenesis. It is generally admitted that mesenchyme cells differentiate into chondroblasts and osteoblasts. In view of the clinical application of this principle, a series of experiments was performed on the animal. Demineralized bone powder of rat long bones was prepared and implanted in trephine defects of the skull or in the musculus rectus abdominis of young rats. The histologic results are described and illustrated. Very early the implant is invaded by poorly differentiated cells of the mesenchyme type and by blood vessels. It is also surrounded by a thin layer of fibroblasts. At day 10 of the implantation, the formation of cartilage is observed. This cartilage disappears in the following days. At day 20 islets of bone marrow are formed. This tissue is surrounded by osteoblasts in their activation phase. At day 30, these osteoblasts are in a highly active state and produce osteoid, in which osteocytes are enclosed. The osteoid is rapidly calcified. Given the primary localisation of the osteoblasts, the bone marrow lays in the center of newly formed ossicles. Osteoclasts can also be observed. At day 45, the different bone marrow centers tend to fuse laterally and to form larger ossicles. The osteoblasts are in a less active or totally inactive form. Many pieces of the implanted demineralized bone powder are still observable. Inflammatory reactions upon implantation are not observed and the bone tissue formation remains located inside the fibroblast layer surrounding the implant.(ABSTRACT TRUNCATED AT 250 WORDS)