Melinda Bradford

Evaluation of 45S5 bioactive glass combined as a bone substitute in the reconstruction of critical size calvarial defects in rabbits.

Biomaterial research and tissue engineering have guided new developments in bone replacement. In this study, the osteoconductive and osteoinductive properties of 45S5 Bioglass® (Novabone-C/M®, Porex Surg., Newnan, GA), granules as a bone replacement material for large calvarial defects were evaluated. Rabbit periosteal cells were expanded in culture and used in vivo. Alkaline-phosphatase assay, collagen type I, and calcium expression were applied to confirm osteoblast phenotype. In the in vivo phase, a 15-mm diameter critical size calvarial defect was created in rabbits (n = 14). The defect was reconstructed according to four treatment groups: autogenous bone (n = 2), Bioglass alone (n = 2), Bioglass + bone (n = 5), Bioglass + periosteal cells (n = 5). The animals were killed 12 weeks after surgery, and the samples were analyzed. Periosteal cells grew successfully in vitro. Because of their fast proliferation and potential to differentiate into osteoblasts, they were an excellent source of cells for bone tissue engineering. The best ossification was seen when autogenous bone was used (79.4% ossified), whereas only 8.2% of the defect in the Bioglass group showed ossification. Addition of bone or cells to the Bioglass increased the area of ossification to 42.7% and 30.2%, respectively. Defects replaced with Bioglass showed varying degrees of inflammatory reaction because of the intense cell-mediated biodegradation process. Based on these findings, the use of Bioglass granules to repair large craniofacial defects cannot be advised.

Functional anastomotic relationship between the supratrochlear and facial arteries: an anatomical study.

Background: For the past 15 years, a forehead flap with its pedicle based at or below the medial canthus has been used without any flap loss. This study describes the anatomical vascular relationships allowing this flap design to be successful. Methods: Nine fresh frozen cadaver heads were studied in three groups. Six heads were injected with red latex. In group I, the supraorbital, supratrochlear, and facial arteries of four heads were dissected out under the operating microscope. In group II, using two latex-injected heads, the median forehead flap was elevated in the extended fashion and the arteries within the flap were dissected. The distal portion of the flap was elevated supraperiosteally and the proximal portion was elevated subperiosteally. In group III, the arterial systems of three heads were injected with barium solution after the flaps had been elevated. Radiographic assessment was used to demonstrate the vascular pattern within the flap. Results: Group I showed an anastomotic relationship between the supratrochlear and facial arteries and a consistent relationship between the infraorbital and facial arteries. Group II showed that the above-mentioned connections could be protected during the supraperiosteal and subperiosteal flap elevation. This was confirmed by radiographic assessment in group III. The vascular network of the flap was filled through the facial artery by means of the dorsal nasal and supratrochlear arteries. Conclusions: Within the paranasal and medial canthal region, there is an anastomotic relationship between the supratrochlear, infraorbital, and branches of the facial arteries, and branches from the contralateral side, creating a rich vascular arcade. This allows a median forehead flap to be narrowly based at the level of the medial canthus.

Comparison of Autologous Platelet-Rich Plasma With Bone Dust Versus Platelet-Rich Plasma Alone and Bone Dust Alone in a Rabbit Model

Introduction: When reconstructing bony defects created secondary to tumor excision or remodeling, there exists a need to increase the rate of bone graft acceptance and the degree of development. In our study we intend to show that platelet-rich plasma can be used in craniofacial defects to increase graft densities. Methods and Materials: Twenty-seven New Zealand white rabbits were used as specimens in which cranial osteotomies were performed to create a critical size defect that was then repaired with several combinations of substances. Either the bone dust from the defect, bone dust plus autologous platelet-rich plasma, or autologous plateletrich plasma alone was placed into the graft site. Each specimen was evaluated by DEXA Scan as well as histologic examination. Results: All 27 specimens survived and remained infection free. Thus, the results showed that the combination of platelet-rich plasma and bone dust allowed for superior bone mineral density and prevention of bone reabsorption.