The osteogenic capacity of tubular and membranous bone periosteum. A qualitative and quantitative experimental study in growing rabbits.

A standardized model has been designed to qualitatively and quantitatively study new bone formation from isolated periosteum in situ. A total of 117 operations were performed on the tibia and skull of 92 growing rabbits. For qualitative studies ordinary histological methods were used. Already after two weeks tibial periosteum had formed woven bone. After eight weeks cortical bone and bone marrow of normal amount and almost normal structure had regenerated. The bone formation from the skull periosteum started later and seemed to be lesser in amount and without woven bone as an intermediate stage. After 15 weeks a structurally normal calvarial bone had developed, except for the inner theca. Thus it was found that isolated tibial and skull periosteum in situ give rise to tubular and membranous bone respectively, suggesting an environmental influence. For quantitative studies the newly formed periosteal bone was removed, dried, weighed and ashed. The ashes were dissolved in HCl for spectrophotometric determination of total Ca content and this was used as a quantitative measure of bone amount. After 6-7 weeks tibial periosteum had produced normal quantities of cortical bone and 7 times more bone than the same area of skull periosteum. Calvarial periosteum was not potent enough to restore a skull defect completely. Surgicel which has been used clinically in periosteal repair of maxillary clefts, quantitatively was found to diminish bone formation considerably. The supposed capacity of bone marrow to promote bone formation was not demonstrated in this study.