Xenograft enriched with autologous bone marrow in inlay reconstructions: a tomographic and histomorphometric study in rabbit calvaria

Reliability of Goldberg Scoring System in the Radiographic Evaluation of Bony Union after Bone Grafting

Background

Evaluation of bony union after bone grafting is very important in orthopedic surgery. The aim of this study was to verify inter- and intraobserver reliability of the Goldberg scoring system for radiographic evaluation of bony union after bone grafting in various situations of animal models.

Methods

Twenty-seven male C57/BL6 mice, which lack the ability to synthesize galactose-alpha-1,3-galactose (GalT KO mice), and 9 C57/BL6 mice carrying a wild-type gene were used as animal models. We divided the mice into four groups. In group 1, syngenic bone grafting and intramedullary fixation were performed (9 wild type C57BL/6 mice). In group 2, allogenic bone grafting was performed (9 GalT KO mice). In group 3, an alpha-galactosidase-treated porcine xenograft was transplanted into the femur to reduce the antigenicity (9 GalT KO mice). In group 4, a non-treated porcine xenobone grafting was performed (9 GalT KO mice). The level of radiographic bony union (Goldberg method) was assessed by three orthopedic surgeons. Intra- and interobserver reliability for radiographic evaluation was assessed.

Results

In the Goldberg scoring system, most of the radiographic measurements showed substantial to almost perfect intraobserver reliability. The total score showed substantial intraobserver reliability. The kappa coefficient (κ) of the first examiner was 0.603, the κ of the second examiner was 0.790, and the κ of the third examiner was 0.758. The scoring system showed substantial interobserver reliability. The κ of the first session was 0.641 and the κ of the second session was 0.649.

Conclusions

The Goldberg scoring system is a reliable tool for radiographic evaluation of bony union after bone grafting.

Repair of Critical Size Bone Defects Using Synthetic Hydroxyapatite or Xenograft with or without the Bone Marrow Mononuclear Fraction: A Histomorphometric and Immunohistochemical Study in Rat Calvaria

Bone defects are a challenging clinical situation, and the development of hydroxyapatite-based biomaterials is a prolific research field that, in addition, can be joined by stem cells and growth factors in order to deal with the problem. This study compares the use of synthetic hydroxyapatite and xenograft, used pure or enriched with bone marrow mononuclear fraction for the regeneration of critical size bone defects in rat calvaria through histomorphometric (Masson's staining) and immunohistochemical (anti-VEGF, anti-osteopontin) analysis. Forty young adult male rats were divided into five groups (n = 8). Animals were submitted to critical size bone defects (Ø = 8 mm) in the temporoparietal region. In the control group, there was no biomaterial placement in the critical bone defects; in group 1, it was filled with synthetic hydroxyapatite; in group 2, it was filled with xenograft; in group 3, it was filled with synthetic hydroxyapatite, enriched with bone marrow mononuclear fraction (BMMF), and in group 4 it was filled with xenograft, enriched with BMMF. After eight weeks, all groups were euthanized, and histological section images were captured and analyzed. Data analysis showed that in groups 1, 2, 3 and 4 (received biomaterials and biomaterials plus BMMF), a significant enhancement in new bone matrix formation was observed in relation to the control group. However, BMMF-enriched groups did not differ from hydroxyapatite-based biomaterials-only groups. Therefore, in this experimental model, BMMF did not enhance hydroxyapatite-based biomaterials' potential to induce bone matrix and related mediators.

Collagen-Based Matrices for Osteoconduction: A Preclinical In Vivo Study

The aim of this study was to evaluate the influence of additional hydroxyapatite (HA) in collagen-based matrices (CM) and membrane placement on bone formation in calvarial defects. Critical size defects in the calvaria of 16 New Zealand White Rabbits were randomly treated with CM or mineralized collagen-based matrices (mCM). Half of the sites were covered with a collagen membrane. Animals were euthanized after 12 weeks of healing. The samples were studied by micro-CT and histology. Newly formed lamellar bone was observed in all samples at the periphery of the defect. In the central areas, however, new bone composed of both woven and lamellar bone was embedded in the soft tissue. Samples treated with mCM showed more residual biomaterial and induced more small bony islands in the central areas of the defects than samples with CM. Nevertheless, a complete defect closure was not observed in any of the samples at 12 weeks. Membrane placement resulted in a decrease in bone density and height. Significant differences between the groups were revealed only between CM groups with and without membrane coverage for bone height in the central area of the defect. Neither mineralization of CM nor membrane placement improved the osteogenic capacity in this particular defect. Nevertheless, mineralisation influenced bone density without a membrane placement and bone volume underneath a membrane. CM may be used as a scaffold in bone regeneration procedures, without the need of a membrane coverage. Further preclinical studies are warrant to optimise the potential of mCM.

Regenerative Effects of Three Types of Allografts on Rabbit Calvarium: An Animal Study

OBJECTIVES

The aim of this study was to histologically compare the regenerative properties of two allografts manufactured by two Iranian companies.

MATERIALS AND METHODS

In this study, four 8-mm defects were produced in the calvaria of 12 rabbits. In three defects, three types of allografts namely ITB, CenoBone and Grafton were placed and one defect served as control. Samples were prepared and histomorphometric evaluations were carried out after healing periods of four weeks (interval 1) and eight weeks (interval 2). Qualitative and quantities variables were compared and analyzed with SPSS software.

RESULTS

Mild inflammation was observed in 45% and 12.5% of the samples in the first and second intervals, respectively. Foreign body reaction was observed in only 5% of the samples. The quality of regenerated bone was immature, mixed and lamellar in 54.5%, 15.9% and 4.5% of the samples, respectively. The rate of allograft resorption was the highest and lowest in the CenoBone and Grafton samples, respectively. The mean amount of regenerated bone was higher in areas containing Grafton; however, the differences were not statistically significant.

CONCLUSION

Despite the differences in the numerical values of bone regeneration, there were no statistically significant differences in bone generation among the material groups, and allografts manufactured in Iran can be suitable alternatives to Grafton with the same good properties. Further studies are necessary to clarify the efficacy of these allografts.

A Novel Restraining Device for Small Animal Imaging Exams: Validation in Rabbits

Objective. To develop, validate, and patent a Restraining Device for Small Animal Imaging Exams (RDSAIE) that allows exams to be comfortably conducted without risks to animals and professionals. Methods. A RDSAIE with a mobile cover and shelf was built with transparent acrylic material. A total of six anesthetized rabbits were used to perform the following imaging exams of the skull: Cone Beam Computed Tomography, Magnetic Resonance Imaging, and Scintigraphy. Results. The device showed great functionality and full visibility of the animal behavior, which remained fully stabilized and immobilized in either the horizontal or vertical position without the need for a person to remain in the test room to assist them. The procedures were performed without difficulty, and images of good resolution and without artifacts were obtained. Conclusion. The RDSAIE is comfortable, safe, efficient, and ergonomic. It allows the easy placement of animals in different body positions, including the vertical, the maintenance of postural stability, and full visibility. It may be constructed for animals heavier than 4 kg and it is adaptable for translational studies in anima nobile.