ABSTRACT
Transformation of mesenchymal-type tissue into cartilage and bone can be induced by
bone mor-phogenetic protein, and by its parent substratum, demineralized bone matrix.
The authors were interested in transforming muscle island flaps into vascularized
bone that could be used as autogeneic skeletal replacement parts. In Wistar rats,
tubular latissimus dorsi muscle island flaps were created, using microsurgical techniques.
The flaps were inserted by a cylinder of demineralized bone matrix (DBM) and enclosed
in silicone rubber membrane tubes. The animals were followed-up for 10, 21, or 35
days. Rats with DBM implanted in muscle pouches served as controls. Quantitative radiomorphometry
and qualitative histology were performed. A statistically significant linear time-related
increase in radiomorphomet-rically-measured calcified tissue was found in the flaps
with DBM from 10 days to 5 weeks. At 3 and 5 weeks, lamellar and cancellous bone with
fully developed marrow was detected microscopically. There was no significant difference
in bone quantity in the island flaps after 35 days, compared with the muscle pouches
implanted with DBM, although the difference at 21 days was still significantly in
favor of the island flaps.
Using allogeneic DBM in rat muscle island flaps surrounded with a silicone membrane,
it was possible to generate in vivo autogenous new bone with a good vascular supply
and good mobility, allowing later transfer to another site. The experiment provided
a basic technique that can be used as a standard in testing various osteoinductive
substances for the production of vascular-pedicled new bone.
