Cranial defect repair using e-PTFE: part I. Evaluation of bone stiffness

Autologous bone grafts are the preferred material for craniofacial reconstruction, but such procedures lead to increased operative time and bleeding, donor site morbidity, and graft resorption. The efficacy of expanded-polytetrafluoroethylene (e-PTFE) sheets to increase bone regeneration and remodeling in cranial defects using a rabbit model was evaluated by mechanical testing. New Zealand white rabbits were divided into 3 groups and sacrificed 6 months after surgery. In the Split Table group, (n = 16), a bilateral bone defect was created on the outer table of the parietal bones. In the Full Table group, (n = 16), a bilateral defect was created through both the inner and outer table of the cranium. The control group, (n = 10) was subjected to a sham operation. Indentation testing was performed to determine the stiffness of newly formed bone in and around the defect. Near the center of the defect, Split Table defects repaired with e-PTFE resulted in significantly stiffer bone than regenerated control bone. The Full Table defects repaired with e-PTFE also resulted in bone significantly stiffer than control regenerated bone around the central region of the defect. The data supports the hypothesis that e-PTFE improves the repair of cranial defects in a rabbit model. It is surmised that the porosity of the e-PTFE provides a stable scaffold for migration of tissue regenerating cells, which may be preferentially localized near the cranial suture lines. This porosity may also provide a barrier to fibrous tissue regenerating cells.