Use of a resorbable sheet in iliac crest reconstruction in a sheep model.

Object: Iliac crest bone graft harvesting can result in major complications, the rates of which range from approximately 6 to 8%. The objective of this study was to evaluate the postoperative regeneration of iliac crest donor defects in an animal model after harvesting a full-thickness tricortical graft.

Methods: In skeletally mature sheep, a tricortical iliac crest graft was harvested. The graft sites were allowed to heal unprotected or protected with the resorbable polylactic acid sheet material, MacroPore OS Protective Sheeting. After 6 months of healing, the sites were assessed by examination of undecalcified histological sections. Histomorphometric measurements of the original defect area, the area of new bone within the defect site, and the percentage of defect filled with new bone were quantified for both control and protected groups. In all histological sections, new bone growth within the defect sites appeared normal, with no observed excessive inflammatory cells. The developing bone tissue appeared to be remodeling normally. For the unprotected sites, the area of new bone averaged 16.3 mm2 (+/- 7.2 mm2), and the percentage of the defect area filled with bone averaged 10.7% (+/- 6.5%). In the protected sites, the area of new bone averaged 64.8 mm2 (+/- 11.6 mm2) and the percentage of the defect area filled with bone averaged 25.9% (+/- 1.6%). Both differences in area of new bone growth and percentage of defect area filled were statistically significant. Literature review has indicated that regeneration of donor site defects is desirable.

Conclusions: Based on the results of the present study, MacroPore resorbable Protective Sheeting can improve bone regeneration significantly within the donor site following tricortical iliac crest graft harvesting.