Histomorphometric examinations of free revascularised iliac crest bone after transplantation for mandibular reconstruction.

At the present time the vascularised bone graft is the best procedure for reconstruction of mandibular defects in poor recipient tissues. We obtained 23 drill biopsies from different regions of vascularised bone transplants during the removal of the osteosynthesis plates from 14 patients who had poor recipient tissues. For comparison, we took five biopsies from the native iliac crest and eight biopsies from six patients with avascular bone transfer into unimpaired surrounding tissues. Microradiographs of the bone preparations were used for a computerised semi-automatic morphometric analysis. We evaluated the volumetric density (VV, %) and the mean trabecular diameter (D-TRAB, micron). In the central regions, the revascularised transplants decreased in volumetric density and in mean trabecular diameter. Compared with the average values of iliac crest bone, the avascular grafts increased in both parameters. The revascularised grafts showed significantly lower volumetric density and significantly lower mean trabecular diameters in the central regions than in the regions near to the mandibular stump. The avascular grafts actually showed the reverse effect. The results are discussed with particular reference to the quality of the recipient tissues, to the maintenance of graft viability, to functional stress, and to the design of the transplant.