Regeneration of the sagittal suture by GTR and its impact on growth of the cranial vault

The aim of this study was to investigate the effect of bone grafting, suture transplantation, and guided tissue regeneration (GTR) treatment on healing of craniectomy defects involving the sagittal cranial suture and on the growth of the cranial vault. Fifty 4-week-old rats were included in the study. A 5.0 mm wide trephine defect was created with its midline corresponding to the sagittal cranial suture between the coronal and occipital cranial vault sutures. The animals were randomly allocated to five groups of 10 animals. Group A: The cranial defect was left untreated. Group B: An occipital bone graft was placed into the cranial defect. Group C: A cranial bone graft including a portion of the frontal suture was placed in the cranial defect. Group D: The cerebral and galeal aspect of the defect were covered with an e-PTFE membrane. Group E: The animals were sham-operated, no defect was created. In all animals, two gutta-percha points were placed demarcating the lateral borders of the parietal bones. Histological analysis at 4 months following surgery showed that the untreated cranial defects healed with fibrous connective tissue. The bone-grafted defects healed partially with bone and connective tissue in the periphery of the bone graft. The healing of suture-grafted defects resembled that of the bone-grafted defects, since the transplanted suture became completely obliterated with bone. The membrane-treated defects healed with bone and a suture-like tissue resembling the sagittal suture of the shamoperated controls. Cephalometric measurements demonstrated that membrane-treated and sham-operated control animals exhibited significantly more (P<0.05) coronal growth (<approximate to>1.2 mm) than that of the remaining three groups of animals (approximate to0.7 mm). These findings were supported by the craniometry measurements demonstrating that sham-operated control and membrane-treated specimens presented significantly more cranial width than that of the remaining groups of animals (P<0.05). It can be concluded that complete osseous healing, creation of a new sagittal suture, and increased cranial growth can be achieved by the treatment of craniectomy defects with the GTR technique.