Roles of Periosteum, Dura, and Adjacent Bone on Healing of Cranial Osteonecrosis

Abstract

It has been reported that large cranial osteonecrotic areas can heal. It was hypothesized that optimal healing is possible by the synchronized contribution of the osteogenic structures (periosteum, dura, and adjacent bone) that envelop the necrotic cranium. This hypothesis was tested by preserving or isolating the contribution of these osteogenic tissues. A total of 37 4-old-month rats were included in the study. Twelve animals were killed immediately, and cranial bone samples were taken and processed for examination (from 6 animals as fresh samples [Group A] and from the rest as autoclaved samples [Group B]). Group B was created to test if the bone was completely nonviable. In Group C (n = 25), cranial bone disks 8 mm in diameter were taken from 4-month-old rats, autoclaved, and put back onto the defect area. This group was further divided into the four Subgroups C1 through C4 (n = 7 in C3; n = 6 in C1, C2, and C4). Dura mater was isolated from the overlying bone disk with a polytetrafluoroethylene sheet in Subgroups C1 and C2, whereas the bone contacted the dura in the rest. The bone samples were covered with healthy periosteum in Subgroups C1 and C3 and with skin in Subgroups C3 and C4. These animals were killed after a healing period of 12 weeks, and the relevant bone disks were obtained. Surrounding healthy bone was also harvested from the same animals after they were killed to create Group D. The data of Group A and D were compared with those of the experimental group to comment on the degree of bone healing in the latter group. Quantitative and qualitative assessment was performed by mammography, bone densitometry, computed tomography, and histological examinations to find out the density and cellular content (osteocytes and vessels) of the samples. Examination of Group B samples showed nonviable tissue with a preserved microstructure. Analysis of other samples showed that both the periosteum and, mainly, the dura play an important role in cranial bone healing. The periosteal reaction was observed to be more evident when the dura was not separated. Cellular repopulation was more evident when both structures contributed to the healing process. Newly formed bone progressed centripetally; however, adjacent bone without the support of the dura and periosteum was capable of producing limited neovascularization and bone formation.

The Effects of Nonvascularized Versus Vascularized Bone Grafting on Calvarial Defect Healing

“…The dura is believed to be the dominant factor promoting revascularization and bone healing. 4,21 Limited osteogenic and angiogenic properties have been shown for adjacent bone when bone graft healing is isolated from the dura and periosteum. 4 The dura is theorized to be actively osteogenic as well as promoting adjacent calvarial marrow to form bone through production of growth factors.…”

“…[1][2][3][4][5][6][7][8] It remains uncertain whether bone graft vascularity affects basic mechanisms of dural osteogenesis. Despite this incomplete understanding, the calvarial defect model has been applied within hundreds of basic science studies in the plastic surgery literature, which may confound results when studying the effectiveness of various bone substitutes.…”

117: The Effects of Non-Vascularized Versus Vascularized Bone Grafting on Calvarial Defect Healing

“…4,21 Limited osteogenic and angiogenic properties have been shown for adjacent bone when bone graft healing is isolated from the dura and periosteum. 4 The dura is theorized to be actively osteogenic as well as promoting adjacent calvarial marrow to form bone through production of growth factors. 4,21 Recipient sites in these studies contained N-V bone grafts, which provided an acellular scaffold for bone healing.…”

“…4 The dura is theorized to be actively osteogenic as well as promoting adjacent calvarial marrow to form bone through production of growth factors. 4,21 Recipient sites in these studies contained N-V bone grafts, which provided an acellular scaffold for bone healing. 4,21 Cranial vault surgery may incorporate both N-V and VAS bone segments during reconstruction.…”

“…4,21 Recipient sites in these studies contained N-V bone grafts, which provided an acellular scaffold for bone healing. 4,21 Cranial vault surgery may incorporate both N-V and VAS bone segments during reconstruction. The effects of bone graft vascularity on basic mechanisms of calvarial healing remain unknown.…”