The growth of vascularized onlay bone transfers.

The growth of vascularized onlay bone (autogenous) transfers on the skulls of 27 newborn New Zealand white rabbits was studied. Freeze-dried bone weight in control newborns and control adults (group 1) was compared with that in experimental adult animals (group 2). In the experimental group, the bone was transferred on the auricularis anterior muscle and neurovascular pedicle. The flap was deliberately maintained without osseous contact or functional-myogenic stress. The myoosseous bone transfers (group 2) exhibited statistically significant osseous enlargement when compared with the control newborns (p = 0.006); however, the weights were significantly less than those of the adult matched controls (group 1, p less than 0.001). Representative histological sections were also studied. Skeletal unit growth of a portion of the New Zealand white rabbit's skull was achieved despite marked alteration in the "functional matrix." The study demonstrated that vascular supply is the other independent factor affecting bone growth. Generally neglected as a variable in the literature of the subject, vascular supply should be considered within the functional matrix concept of craniofacial growth.