Spontaneous healing capacity of rabbit cranial defects of various sizes

Abstract

PurposeThis study evaluated the spontaneous healing capacity of surgically produced cranial defects in rabbits with different healing periods in order to determine the critical size defect (CSD) of the rabbit cranium.MethodsThirty-two New Zealand white rabbits were used in this study. Defects of three sizes (6, 8, and 11 mm) were created in each of 16 randomly selected rabbits, and 15-mm defects were created individually in another 16 rabbits. The defects were analyzed using radiography, histologic analysis, and histometric analysis after the animal was sacrificed at 2, 4, 8, or 12 weeks postoperatively. Four samples were analyzed for each size of defect and each healing period.ResultsThe radiographic findings indicated that defect filling gradually increased over time and that smaller defects were covered with a greater amount of radiopaque substance. Bony islands were observed at 8 weeks at the center of the defect in both histologic sections and radiographs. Histometrical values show that it was impossible to determine the precise CSD of the rabbit cranium. However, the innate healing capacity that originates from the defect margin was found to be constant regardless of the defect size.ConclusionsThe results obtained for the spontaneous healing capacity of rabbit cranial defects over time and the underlying factors may provide useful guidelines for the development of a rabbit cranial model for in vivo investigations of new bone materials.

Synergistic effect of bone marrow-derived mesenchymal stem cells and platelet-rich plasma on bone regeneration of calvarial defects in rabbits

“…16,17 In previous study using surgically created circular defects of 6, 8, 11, and 15 mm in the craniums of rabbits, the healing capacity from the defect margin was reported to be constant at the same healing period regardless of the defect size. 18 Furthermore, many researchers have selected a defect smaller than the critical sized defect for investigating the early events of regeneration. 19,20 Therefore, we selected the 6 mm defect to investigate the additional effects of PRP and MSC on bone healing capacity during relatively short-term period.…”

Tomographic and histometric analysis of autogenous bone block and synthetic hydroxyapatite block grafts without rigid fixation on rabbit calvaria

“…In the present study, we evaluated the outcome of these graft materials at 4 weeks postoperatively, which represents the early phase of the healing response, and measured properties such as the stability of the materials and host reactions; at 8 weeks postoperatively, which represents the late healing response, we measured processes such as bone incorporation, resorption of materials, bone remodeling, and the amount of bone regeneration [22]. …”

The effects of combined low level laser therapy and mesenchymal stem cells on bone regeneration in rabbit calvarial defects

“…In this study, the bone defects were smaller than the Critical Size Defect (CSD) in rabbits. CSD is known as the smallest defect on a bone of specific species which will not spontaneously repair during its life time [21]. Although a range of 10-15 mm has been considered as the critical size defect of rabbits' calvaria, some studies have concluded that it is not possible to define the exact dimension of CSD [21,22].…”

“…CSD is known as the smallest defect on a bone of specific species which will not spontaneously repair during its life time [21]. Although a range of 10-15 mm has been considered as the critical size defect of rabbits' calvaria, some studies have concluded that it is not possible to define the exact dimension of CSD [21,22]. Furthermore, it has been suggested that the term ''critical size defect" should no longer be used because the repair potential of bony margin was shown to be constant despite defect size [22].…”