Surgical resection of a huge cemento-ossifying fibroma in skull base by intraoral approach.

Cemento-ossifying fibroma, also known as ossifying fibroma, usually occurs in the mandible and less commonly in the maxilla. The huge example in the skull base is even rare. We present a case of a huge cemento-ossifying fibroma arising below the skull base of a 30-year-old woman patient. Radiologic investigations showed a giant, lobulated, heterogeneous calcified hard tissue mass, which is well circumscribed and is a mixture of radiolucent and radiopaque, situated at the rear of the right maxilla to the middle skull base. The tumor expands into the right maxillary sinus and the orbital cavity, fusing with the right maxilla at the maxillary tuberosity and blocking the bilateral choanas, which caused marked proptosis and blurred vision. The tumor was resected successfully by intraoral approach, and pathologic examination confirmed the lesion to be a cemento-ossifying fibroma. This case demonstrates that cemento-ossifying fibroma in the maxilla, not like in the mandible, may appear more aggressive because the extensive growth is unimpeded by anatomic obstacles and that the intraoral approach can be used to excise the tumor in the skull base.

Biomechanical evaluation of four different posterior screw and rod fixation techniques for the treatment of the odontoid fractures.

Problems that screw cannot be inserted may occur in screw-rod fixation techniques such as Harms technique. We compared the biomechanical stability imparted to the C-2 vertebrae by four designed posterior screw and rod fixation techniques for the management of odontoid fractures. A three-dimensional finite element model of the odontoid fracture was established by subtracting several unit structures from the normal model from a healthy male volunteer. 4 different fixation techniques, shown as follows: ① C-1 lateral mass and C-2 pedicle screw fixation (Harms technique); ② C-1 lateral mass and unilateral C-2 pedicle screw fixation combined with ipsilateral laminar screw fixation; ③ Unilateral C-1lateral mass combined with ipsilateral C-1 posterior arch, and C-2 pedicle screw fixation; and ④ Unilateral C1 lateral mass screw connected with bilateral C2 pedicle screw fixation was performed on the odontoid fracture model. The model was validated for axial rotation, flexion, extension, lateral bending, and tension for 1.5 Nm. Changes in motion in flexion-extension, lateral bending, and axial rotation were calculated. The finite element model of the odontoid fracture was established in this paper. All of the four screw-rod techniques significantly decreased motion in flexion-extension, lateral bending, and axial rotation, as compared with the destabilized odontoid fracture complex (P<0.05). There was no statistically significant difference in stability among the four screw techniques. We concluded that the first three fixation techniques are recommended to be used as surgical intervention for odontoid fracture, while the last can be used as supplementary for the former three methods.

[Analysis of virulence-related properties of P. gingivalis clinical isolates].

PURPOSE: To analyze the relation of virulence properties and pathogenicity of Porphyromonas gingivalis (P.gingivals) isolated from Chinese patients. METHODS: Based on the previous analysis of virulence properties, investigations of pathogenicity properties, including the adhesion to host cells, gingipain activities, and resistance to host immune reaction were performed to analyze the diversity of pathogenic properties of these strains. SAS 8.02 software package was used for statistical analyses. RESULTS: Less-virulent type strain showed higher adherence ability to host red blood cells and weaker resistance to serum killing, while virulent type strain showed the opposite reactions. However, the clinic isolates presented just the opposite relationship between virulence properties and pathogenicity. In addition, there was no obvious correlation between gingipain activities and virulence properties of P. gingivalis strains. CONCLUSIONS: The results suggested that there is no obvious linkage between the P. gingivalis virulence properties and pathogenicity diversity.

[Virulent properties of Porphyromonas gingivalis clinical strains].

PURPOSE: To investigate the virulent properties of P. gingivalis clinical strains. METHODS: By using mouse abscess model (MAM), six P. gingivalis clinical strains, L2, L3, L4, L5, L11 and L12 were subcutaneously inoculated into the central back of BALB/C mice. The clinical signs of the mice were observed and the virulent properties of the clinical strains were analyzed by comparison with type strains of W83 and ATCC 33277. SPSS11.5 software package was used for statistical analysis. RESULTS: According to the criteria established in previous reports, L3, ATCC33277, and W83 produced a localized abscess at the site of injection and were categorized as noninvasive. L2, L5, L11, and L12-induced lesions spread to distant organs and may produce severe systemic reactions and these strains were classified as invasive. CONCLUSIONS: Clinical strains from Chinese patients showed similarities to type strains in MAM. The virulent properties of P. gingivalis clinical strains are quite different from each other.

[Correction of progressive hemifacial atrophy using dermis-fat graft and Medpor implant shaped by reverse engineering technique].

OBJECTIVE: To evaluate the therapeutic effect of dermis-fat graft combined with Medpor implant shaped by reverse engineering technique in the correction of the progressive hemifacial atrophy. METHODS: A skull model was made by rapid prototyping and the bony deficiency model was acquired with reverse engineering technique. The Medpor implant was shaped precisely based on the deficiency model and implanted with dermis-fat graft at the same stage. RESULTS: 11 cases were treated successfully without infection, necrosis and rejection. The patients were followed up for six months to one year with satisfactory cosmetic improvement. The dermis-fat graft survived without obvious absorption. CONCLUSION: The technique can correct both the bony and soft tissue deficiency for progressive hemifacial atrophy. It is very practical and easily performed with reliant results and less morbidity.