Vegetal polymer in repair of defects of the orbital floor: an experimental study in rabbits

Background: An experimental study was done to assess the ability of the vegetal polymer miniplates and screws to repair defects of the orbital floor.Methods: An artificial standard-sized defect was created in the bony floor of right orbit of 45 albino rabbits. The animals were divided into three experimental groups: control group (G1) involving animals with orbital floor defect and no treatment; titanium group (G2) containing animals with orbital floor defect repaired by titanium miniplates and screws; vegetal polymer group (G3) composed of animals with similar orbital floor defects repaired by vegetal polymer miniplates and screws. Throughout the course of the experiment, the animals were clinically evaluated. At 15, 30 and 60 days after surgery, the animals were killed. They were X-rayed immediately after the floor defect and at the moment of sacrifice. Histological and morphometric evaluation of inflammatory reaction and bone healing was done. Data were statistically evaluated.Results: No implants were extruded. Bone consolidation was similar in G2 and G3 and better than in G1 group animals. Inflammatory reaction was most pronounced in animals of G3 15 days after surgery, and it subsided over time.Conclusion: Vegetal polymer miniplates and screws induces small inflammatory reaction and had the ability to stimulate bone growth with good integration in the orbital floor defect allowing to consider the vegetal polymer adequate option to treat orbital floor defects. Future studies involving long-term follow-up and biomechanical tests to evaluate material resistance to traction are needed.

Orbital solitary fibrous tumor: Report of two cases and literature review

Background: Solitary fibrous tumor (SFT) is a rare, benign, and very uncommon lesion in the orbit. Because of its complex and variable clinical and histological appearance the SIFT is often misdiagnosed.Cases: Two new cases of orbital SIFT are reported, one in a man and the other in a woman, both unilateral and in the superomedial orbit.Observations: Clinical and tomographical evaluations were conducted and the lesions were excised. The histological evaluation showed the tumors were composed of spindle-shaped cells within colla.-en bundles and vascular channels. Immunohistochemical staining was positive for CD 34 and negative for S-100 protein.Conclusion: Immunohistochemical study is an important adjuvant in determining the SIFT diagnosis. Long-term follow-up is necessary because of the possibility of SFT recurrence after excision. (C) 2003 Japanese Ophthalmological Society.

Submental Endotracheal Intubation: A Valuable Resource for the Management of Panfacial Fractures

Modern techniques for surgical treatment of midfacial and panfacial fractures in maxillofacial trauma lead to special problems for airway management. Usually, in perioperative management of panfacial fractures, the surgeon needs to control the dental occlusion and nasal pyramid assessment. For these reasons, oral and nasal endotracheal intubations are contraindicated for the management of panfacial fractures. Tracheotomy is considered by many as the preferred route for airway management in patients with severe maxillofacial fractures, but there are often perioperative and postoperative complications concerning this technique. The submental route for endotracheal intubation has been proposed as an alternative to tracheotomy in the surgical management of patients with panfacial fractures, besides it is accompanied by low morbidity. Thus, this paper aimed to describe the submental endotracheal intubation technique in a patient experiencing panfacial fracture. The subject was well treated using the submental endotracheal intubation to get good reconstruction of the fractures because the authors obtained free access of all facial fractures.

Crown and crown-root fractures: an evaluation of the treatment plans for management proposed by 154 specialists in restorative dentistry

Traumatic tooth injuries involve function and aesthetics and cause damage that range from minimal enamel loss to complex fractures involving the pulp tissue and even loss of the tooth crown. Technical knowledge and clinical experience are essential to establish an accurate diagnosis and provide a rational treatment. The purpose of this study was to evaluate the knowledge of Restorative Dentistry specialists about the management of crown and crown-root fractures based on treatment plans proposed by these professionals for these cases. A descriptive questionnaire was mailed to 245 Restorative Dentistry specialists with questions referring to their professional profile and the treatment plans they would propose for the management of crown and crow-root fractures resulting from dental trauma. One hundred and fifty-four questionnaires were returned properly filled. The data were subjected to descriptive statistics and the chi-square test was used to determine the frequency and the level of the significance among the variables. The analysis of data showed that in spite of having a specialist title, all interviewees had great difficulty in planning the treatments. As much as 42.8% of the participants were unable to treat all types of dental trauma. Complicated and uncomplicated crown-root fractures posed the greatest difficulties for the dentists to establish adequate treatment plans because these fractures require multidisciplinary knowledge and approach for a correct case planning and prognosis.

In vitro evaluation of conventional and locking miniplate/screw systems for the treatment of mandibular angle fractures

This in vitro study evaluated the influence of the type of miniplate and the number of screws installed in the proximal and distal segments on the stability and resistance of Champy's osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to four groups (n = 15) and sectioned in the mandibular angle region to simulate fracture. The bone segments were fixed by different osteosynthesis methods using 2.0 mm miniplates and 2.0 mm x 6 mm rnonocortical screws. In groups 1 and 2, two conventional (G1) or locking (G2) screws were installed in each bone segment using a conventional (G1) or a locking (02) straight miniplate; in groups 3 and 4, three conventional (03) or locking (04) screws were installed in the proximal segment and four conventional (G3) or locking (04) screws were installed in the distal segment using a conventional (G3) or a locking (G4) seven-hole straight miniplate. The hemimandibles were loaded in compressive strength until a 4 mm displacement occurred between the segments, vertically or horizontally. Locking plate/screw systems provided significantly greater resistance to displacement than conventional ones (p < .01). Locking miniplates offered more resistance than conventional miniplates. Long locking miniplates provided greater stability than short ones.

Orbital Implants Insertion to Improve Ocular Prostheses Motility

The objectives of this study were, through a literature review, to point the differences between orbital implants and their advantages and disadvantages, to evaluate prosthesis motility after orbital implants are inserted, and to point the implant wrapping current risks. Sixty-seven articles were reviewed. Enucleation implants can be autoplastics or alloplastics and porous (including natural and synthetic hydroxyapatite [HA]) or nonporous (silicone). Hydroxyapatite is the most related in the literature, but it has disadvantages, too, that is, all orbital implants must be wrapped. Exposure of the porous orbital implant can be repaired using different materials, which include homologous tissue, as well as autogenous graft, xenograft, and synthetic material mesh. The most used materials are HA and porous polyethylene orbital implant. The HA implant is expensive and possibly subject corals to damage, different from porous polyethylene orbital implants. Porous implants show the best prosthesis motility and a minimum rate of implants extrusion. Implant wraps can facilitate smoother entry of the implant into the orbit and allow reattachment of extraocular muscles. They also serve as a barrier between the overlying soft tissue and the rough surface of the implant, protecting implants from exposure or erosion.

Management of Orbital Reconstruction

One of the concerns after a major trauma to the orbit is to be rebuilt. This can be achieved with care in management of orbital reconstruction, techniques, types of materials, and osseointegrated implants; it allows satisfactory aesthetic recuperation and well-being, whereas psychological therapy allows for patients' re-insertion in social and family environment to make them feel happier and safer.

Clinical evaluation of the bicoronal flap in the treatment of facial fractures. Retrospective study of 132 patients

The aim of the present study was to evaluate the postoperative complications of bicoronal flaps used to treat facial fractures. One hundred and thirty two patients that received bicoronal flaps for the treatment of upper and middle third facial fractures were called for clinical and radiographic examination. Minimum follow-up was 1 year and all patients had charts with adequate information about their perioperative care pertinent to the study. Results showed as complications hypoesthesia (17%), partial unilateral frontal motor deficit (11%), infection (3%), hypertrophic scars (3%), varying degrees of alopecia (18%), seroma or hematoma in the immediate postoperative period (5%). The flap provided wide surgical access to the upper and middle facial thirds with very few serious complications, most frequently allowing good aesthetic results. (C) 2011 European Association for Cranio-Maxillo-Facial Surgery.

Immediate reconstruction of frontal sinus fractures: review of 26 cases

Purpose: the purpose of this study was to evaluate complications occurring after immediate reconstruction of severe frontal sinus fractures, including cases where the fracture was not limited to the anterior wall and also involved the posterior wall and/or sinus floor.Patients and Methods: the records of twenty-six patients presently undergoing follow-up for frontal sinus fracture reconstruction were reviewed. Information regarding demographics, fracture characteristics and causes, associated facial fractures, use of grafts or implants, type of fixation used, nasofrontal duct management, use of antibiotics, and complications were noted. Patients were asked to return for clinical and radiographic follow-up to access late complications.Results: the average age of patients with frontal fractures was 29.1 years and 92.3% were male. Mean follow-up was 3.6 years. The most common causes of fracture were motor vehicle accidents and physical aggression. All patients presented with comminuted and dislocated anterior wall fractures, 34.6% presented with posterior wall fractures, and 46% had sinus floor fractures. Complications occurred in 7 patients (26.92%) and included pneumoencephalus, frontal cutaneous fistula, frontal bone irregularity, and sinusitis.Conclusions: Frontal sinus reconstruction is a good procedure for immediate fracture treatment if there is not excessive comminution, dislocation, or instability of the posterior wall and if the frontonasal duct area is intact or can be repaired. Most complications result from incorrect indication for reconstruction. (C) 2004 American Association of Oral and Maxillofacial Surgeons.

Nebular gas drag and co-orbital system dynamics

Aims. We study trajectories of planetesimals whose orbits decay due to gas drag in a primordial solar nebula and are perturbed by the gravity of the secondary body on an eccentric orbit whose mass ratio takes values from mu(2) = 10(-7) to mu(2) = 10(-3) increasing ten times at each step. Each planetesimal ultimately suffers one of the three possible fates: (1) trapping in a mean motion resonance with the secondary body; (2) collision with the secondary body and consequent increase of its mass; or (3) diffusion after crossing the orbit of the secondary body.Methods. We take the Burlirsh-Stoer numerical algorithm in order to integrate the Newtonian equations of the planar, elliptical restricted three-body problem with the secondary body and the planetesimal orbiting the primary. It is assumed that there is no interaction among planetesimals, and also that the gas does not affect the orbit of the secondary body.Results. The results show that the optimal value of the gas drag constant k for the 1: 1 resonance is between 0.9 and 1.25, representing a meter size planetesimal for each AU of orbital radius. In this study, the conditions of the gas drag are such that in theory, L4 no longer exists in the circular case for a critical value of k that defines a limit size of the planetesimal, but for a secondary body with an eccentricity larger than 0.05 when mu(2) = 10(-6), it reappears. The decrease of the cutoff collision radius increase the difusions but does not affect the distribution of trapping. The contribution to the mass accretion of the secondary body is over 40% with a collision radius 0.05R(Hill) and less than 15% with 0.005R(Hill) for mu(2) = 10(-7). The trappings no longer occur when the drag constant k reachs 30. That means that the size limit of planetesimal trapping is 0.2 m per AU of orbital radius. In most cases, this accretion occurs for a weak gas drag and small secondary eccentricity. The diffusions represent most of the simulations showing that gas drag is an efficient process in scattering planetesimals and that the trapping of planetesimals in the 1: 1 resonance is a less probable fate. These results depend on the specific drag force chosen.

Co-orbital satellites of Saturn: congenital formation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Possibility of collision between co-orbital asteroids and the Earth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cirurgia das fraturas do seio frontal: estudo epidemiológico e análise de técnicas

O trauma do seio frontal não é raro, correspondendo a 8% das fraturas faciais. Pode afetar a lâmina anterior e/ou posterior, com ou sem envolvimento do ducto nasofrontal. Tem alto potencial para complicações e seu manejo ainda é controvertido em algumas situações. OBJETIVO: Apresentar a epidemiologia, o diagnóstico e tratamento clínico e cirúrgico de 24 pacientes com fratura do seio frontal. MATERIAL E MÉTODOS: Estudo retrospectivo, não randomizado, de 24 pacientes com fratura de seio frontal operados no Hospital das Clínicas da Faculdade de Medicina de Botucatu, São Paulo, Brasil. RESULTADOS: Dos 24 pacientes, 16 tinham fraturas da lâmina externa e 8, da lâmina interna e externa. em 2 casos havia lesão do ducto nasofrontal. Vinte (83,4%) pacientes tiveram fraturas faciais associadas e em 13 (54,2%) foram observadas complicações intracranianas. A incisão em asa de borboleta, abaixo da sobrancelha, foi empregada na maioria dos casos cirúrgicos com bom resultado estético. Fixação dos fragmentos ósseos com diferentes materiais (fio de aço, mononylon, miniplacas de titânio) e, se necessário, reconstrução da tábua anterior com material aloplástico ou osso parietal. CONCLUSÃO: A causa principal das fraturas do seio frontal é acidente com veículos. O tratamento depende de sua complexidade, pois comumente há lesões cranioencefálicas associadas. As técnicas cirúrgicas utilizadas são as incisões, retalho bicoronal ou na sobrancelha, infra-orbital (em asa de borboleta), associadas à cirurgia endoscópica em casos de infecção fístula liquórica e complicações orbitárias.

Implantação intra-orbital, após a enucleação transpalpebral, de resina acrílica ou pericárdio em coelhos

Dezoito coelhos, Norfolk, fêmeas, com 45 dias de idade foram divididos em três grupos de seis animais e submetidos a enucleação transpalpebral. Os animais do grupo I receberam na cavidade orbitaria acrílico auto-polimerizável, os do grupo II pericárdio eqüino conservado em glicerina e os do grupo III foram mantidos como controle. Para avaliação macroscópica e histopatológica das cavidades orbitarias, três animais de cada grupo foram sacrificados com 30 e 60 dias após a implantação. Apesar da resina ter sido aplicada na fase pastosa, na qual a alta temperatura que ocorre durante a polimerizaçâo pode ser lesiva aos tecidos, foi o produto que apresentou os melhores resultados.