Fixed membranous bone graft survival after recipient bed alteration

The effectiveness of membranous bone grafting in craniofacial reconstruction is hindered by resorption. The aim of this study was to determine whether alterations of the recipient bed through tissue expansion affect membranous bone graft survival. Eighteen adult rabbits were divided into three groups. Group I rabbits (control) received fixed autologous membranous bone grafts to their snouts. Group II rabbits had self-inflating tissue expanders inserted over their nasal dorsum, inflation for 3 weeks, and then expander removal and placement of fixed autologous membranous bone grafts to their snouts. Group III rabbits varied from group II by delaying bone grafting until 2 weeks after expander removal. One animal from each group was killed at post-grafting days 15 and 45, the remainder at day 90. Results were assessed by volumetric, nondecalcified histologic, and stereologic analysis. Volumetrically, group I grafts demonstrated 82 percent survival, whereas group II demonstrated 101 percent (p = 0.029) and group III 94.5 percent (p = 0.21). Histologically, group I grafts exhibited greater loss (i.e., porosity and resorption) and less labeling activity. Groups II and III showed extensive evidence of trabecularization and incorporation at the graft-host interface. Stereologic measurements such as osteoid seam width (OSW) confirmed the greater survival and activity of groups II and III bone grafts. Group II OSW measured 12.4 microns, group III 12.0 microns, and group I 9.8 microns (p = 0.04). Stereology also demonstrated that groups II and III's OSW approached that of the recipient bed and contralateral zygoma, whereas group I did not (p = 0.029), suggesting an integration of the graft and host architectures.(ABSTRACT TRUNCATED AT 250 WORDS)