Rapid prototyped PGA/PLA scaffolds in the reconstruction of mandibular condyle bone defects.

BACKGROUND: Craniomaxillofacial bone defects are currently reconstructed by using computer-aided design and manufacturing (CAD/CAM) processes. We have developed a novel digital medical support system that enables us to custom-make scaffolds to repair craniomaxillofacial bone defects using three-dimensional computed tomographic (CT) images and a rapid-prototyping method. METHODS: We created positive molds using CT data, CAD/CAM and a rapid prototyping method using 3D printing. Custom-made poly (glycolic acid) (PGA) and polymers poly (lactic acid) (PLA) scaffolds were prefabricated by a positive-negative mold interchange technique. A laser scanning system was used to evaluate the accuracy of the PGA/PLA scaffold. Bone marrow stem cells were incubated with the scaffold to assess biocompatibility. RESULTS: The mean error was <0.3 mm and confidence was >or=95% when the error was <1 mm. Results from in vitro cell culture demonstrated that the PGA/PLA scaffold had excellent cellular compatibility. CONCLUSIONS: This pilot study suggests that custom-made PGA/PLA scaffolds infiltrated with bone marrow stem cells may be effective for future treatment of craniomaxillofacial bone injuries.

[The expression of activin A and transforming growth factor-beta 1 during rabbit mandibual distraction osteogenesis].

OBJECTIVE: To examine the expression of activin A (ACT A) and transforming growth factor-beta 1 (TGF-beta 1) during mandibular lengthening and elucidate the difference between the role of ACT A and TGF-beta 1 during mandibular distraction osteogenesis. METHOD: Skeletally mature white new zealand rabbits were established right mandibular distraction osteogenesis model. The regenerating tissue of animals' lengthened mandibes were harvested at different time points to have immunohistochemistric research of ACT A, TGF-beta 1 protein and analysis ACT A, TGF-beta 1 mRNA by using RT-PCR semiquantitative mean. RESULTS: AT the end of latency period day, positive stain of ACT A were found in the osteoblasts while positive stain of TGF-beta 1 was found in mesenchymal cells. At the end of distraction phase, fibrosis tissue had no stain of ACT A, but had strong stain of TGF-beta 1. At the period of fixation days of 20 days, both cytoplasm of osteoblasts and extracellular matrix in primary mineralization front were strongly stained of ACT A. The osteoblasts, osteoid and osteocytes in peripheral new bone zone were moderately stained of ACT A. TGF-beta 1 had strongly positive stained in fibrosis zone and weekly positive stained in primary mineralization front and peripheral new bone zone. There were also broad activin A stains in cytoplasm of osteoblasts, osteoid and cytoplasm of ACT A, TGF-beta 1 in osteocytes after distraction for 30 days. Activin A mRNA began to express at the end of latency period. Expression for activin A mRNA increased gradually along with the beginning of distraction and at the peak in distraction of 10 days and 20 days, while TGF beta 1 mRNA increased at the peak at the end of latency period. CONCLUSION: ACT A and TGF beta 1 have different role during rabbit mandibular distraction osteogenesis.

[Staging and management of extracranial arteriovenous malformations].

OBJECTIVE: Congenital arteriovenous malformations(AVM) are considered to be the most difficult and challenging problems in the treatment of hemangiomas and vascular lesions. This study focused on the natural history, the clinical classification, the choice and effectiveness of various treatments. METHODS: This retrospective review included 83 patients with extracranial arteriovenous malformations, who were referred to our department over the past 6 years. The anatomic patterns, clinical staging, respective treatments, influential factors of endovascular treatment, causes of recurrence were analyzed. RESULTS: According to clinical manifestations, arteriovenous malformations were categorized as three clinical stages: the quiescence, the expansion and the decompensation stages. Most AVMS in the quiescence stage only require endovascular treatment while those in the decompensation stage require surgical resection. Angiography was performed not only for diagnosis of AVM but also as an initial therapeutic step in the form of embolization, which might be the only means to some AVM without surgical possibility or necessity. CONCLUSION: The new concept of staging and management is expected to be helpful for diagnosis and treatments of AVM.