Bone and suture regeneration in calvarial defects by e-PTFE-membranes and demineralized bone matrix and the impact on calvarial growth: an experimental study in the rat.

The aim of this study was to evaluate the effect of: guided tissue regeneration (GTR) alone, implantation of demineralized bone matrix (DBM) alone, and of the combined treatment on the healing of craniectomy defects involving the sagittal cranial suture, and to examine subsequent calvarial growth. Sixty four-week-old rats were used in the study. These animals were randomly assigned to five groups (A-E) of 12 animals. In four groups (A-D), a calvarial defect (5.0 mm) involving the sagittal suture was produced in each animal. Group A: The defect was left untreated. Group B: DBM was implanted into the defect. Group C: The cerebral and the galeal aspect of the defect was covered with an e-PTFE membrane. Group D: The defect was treated with the double membrane technique combined with implantation of DBM. Group E: The animals were sham-operated, no defect was created. In all groups, two gutta-percha points were placed to indicate the lateral borders of the parietal bones. Histological analysis 4 months following surgery showed that the untreated cranial defects (A) had healed with fibrous connective tissue in the midportion of the defect. The DBM grafted defects (B) healed either completely with bone containing DBM particles or partially with bone and connective tissue. The defects (D) treated with DBM combined with GTR healed completely with bone, while the defects (C) treated with membranes alone healed with bone but a suture-like tissue similar to the normal sagittal suture of the sham-operated controls (E) was always present in the midportion of the defect. Cephalometric radiography demonstrated that the membrane-treated (C) and the sham-operated animals (E) exhibited similar coronal growth of the cranial vault following treatment. Craniometric measurements on chemically defleshed specimens showed that sham-operated and membrane-treated animals presented significantly more biparietal width than the animals treated with DBM alone or DBM combined with GTR (P < 0.05). The results demonstrated that predictable osseous healing including the formation of a sagittal suture can be accomplished in craniectomy defects by GTR, and undisturbed cranial growth reestablished. The treatment of the defects with DBM alone or DBM combined with GTR resulted in craniosynostosis and reduced cranial growth.