ABSTRACT
Previous work has shown that corticocancellous bone chips placed in a titanium chamber
with an arteriovenous vascular pedicle will result in a pre-formed vascularized bone
graft. The present study was designed to determine whether these grafts can be transferred
as an island or free vascularized bone graft, and to examine the material properties
of these grafts.
Thirty-two male, New Zealand white rabbits were divided into four groups based on
the time of sacrifice following the initial chamber implantation. Injected molded
cylindrical polyethelyne chambers, measuring 22 mm long and with an 8-mm inner diameter,
were used. Corticocancellous bone chips were placed in the chambers and each chamber
was implanted in the mid-thigh, with saphenous vessels running through the chamber.
The chambers were implanted into the right and left thigh of each animal. To test
the hypothesis of the possibility of transferring this graft as an island or free
vascularized graft, ligation of the distal vascular pedicle on one side was achieved
at re-exploration at 3,6,9, and 12 weeks. The contralateral side served as a control
in which the vascular pedicle was not ligated.
In the controls, bony bridging between the corticocancellous bone chips was observed
after 7 weeks. A solid bone graft was present within the chamber by 10 weeks. However,
histomorphometric evaluation indicated significant bone resorption. By 13 weeks, resorption
progressed to the point where only small islands of bone remained.
Ligation of the distal vessels resulted in thrombosis of the vessels within the chamber.
Necrosis of newly-formed bone was observed in the area adjacent to the vascular thrombosis.
By 9 weeks, viable bone was observed within the chamber, despite thrombosis of the
vascular pedicle. These findings were most probably due to the development of collateral
circulation. This study supports the concept of creating a “molded vascularized bone
graft” with a single vascular pedicle.
