44 research outputs found

    Metabolic changes in concussed American football players during the acute and chronic post-injury phases

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    <p>Abstract</p> <p>Background</p> <p>Despite negative neuroimaging findings many athletes display neurophysiological alterations and post-concussion symptoms that may be attributable to neurometabolic alterations.</p> <p>Methods</p> <p>The present study investigated the effects of sports concussion on brain metabolism using <sup>1</sup>H-MR Spectroscopy by comparing a group of 10 non-concussed athletes with a group of 10 concussed athletes of the same age (mean: 22.5 years) and education (mean: 16 years) within both the acute and chronic post-injury phases. All athletes were scanned 1-6 days post-concussion and again 6-months later in a 3T Siemens MRI.</p> <p>Results</p> <p>Concussed athletes demonstrated neurometabolic impairment in prefrontal and motor (M1) cortices in the acute phase where NAA:Cr levels remained depressed relative to controls. There was some recovery observed in the chronic phase where Glu:Cr levels returned to those of control athletes; however, there was a pathological increase of m-I:Cr levels in M1 that was only present in the chronic phase.</p> <p>Conclusions</p> <p>These results confirm cortical neurometabolic changes in the acute post-concussion phase as well as recovery and continued metabolic abnormalities in the chronic phase. The results indicate that complex pathophysiological processes differ depending on the post-injury phase and the neurometabolite in question.</p

    Avaliação da cirurgia de avanço mandibular por meio da superposição de modelos tomográficos tridimensionais Assessment of mandibular advancement surgery with 3D CBCT models superimposition

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    OBJETIVO: avaliar mudanças nas posições de côndilos, ramos e mento após a cirurgia de avanço mandibular. METODOLOGIA: foram realizadas tomografias de feixe cônico antes da cirurgia (T1), uma semana (T2) e seis semanas após a cirurgia (T3) em 20 pacientes retrognatas com padrão normal ou horizontal. Modelos 3D computadorizados foram construídos e superpostos através de um método automático utilizando a base do crânio de T1 como referência. Regiões anatômicas de interesse foram selecionadas e analisadas separadamente. Distâncias entre as superfícies anatômicas foram computadas entre T1-T2, T2-T3 e T1-T3. Direções de deslocamento foram visualizadas com métodos de mapas coloridos e semitransparências. RESULTADOS: um deslocamento anteroinferior do mento foi observado em todos os casos entre T1-T2 (>4mm em 87,5%); entre T2-T3, observou-se um movimento anterossuperior em 69% dos pacientes, e com algum componente posterior em 25% (<3mm). Entre T1-T3, observou-se um deslocamento anteroinferior em 87,5% dos casos, e somente anterior em 12,5% (>4mm em 80%). Considerando-se todas as direções de deslocamento, os côndilos apresentaram um movimento menor que 2mm em 77,5% (T1-T2) e 90% (T2-T3 e T1-T3) dos casos, enquanto os ramos deslocaram-se menos de 3mm em 72,5% (T1-T2) e menos de 2mm em 87,5% (T2-T3) e 82% (T1-T3) dos casos. CONCLUSÃO: importantes deslocamentos foram observados nos ramos e côndilos após a cirurgia, mas mudanças após a remoção do splint sugerem uma resposta adaptativa tendendo às posições pré-cirúrgicas. As mudanças no mento após seis semanas sugeriram adaptações aceitáveis na maioria dos casos, mas com considerável variabilidade individual.<br>OBJECTIVES: To assess surgery and short-term post-surgery changes in the position of the condyles, rami and chin after mandibular advancement. METHODS: Pre-surgery (T1), 1 week post-surgery (T2), and 6 week post-surgery (T3) CBCT scans were acquired for 20 retrognathic patients with short or normal face height. 3D-models were built and superimposed through a fully automated voxel-wise method using the cranial base of the pre-surgery scan as reference. Anatomic regions of interest were selected and analyzed separately. Within-subject surface distances between T1-T2, T2-T3, and T1-T3 were computed. Color-coded maps and semi-transparent display of overlaid structures allowed the evaluation of displacement directions. RESULTS: After an anteroinferior chin displacement with surgery in all the cases (>4mm in 87.5%), 25% of the patients showed some kind of posterior movement (< 3mm), and 69% showed an anterosuperior movement after splint removal. Comparing T1-T3, an anteroinferior (87.5% of the cases) or only inferior (12.5%) displacement was observed (>4mm in 80%). Considering all directions of displacement, the surface distance differences for the condyles and rami were small: 77.5% of the condyles moved <2mm with surgery (T1-T2), and 90% moved <2mm in the short-term (T2-T3) and in the total evaluation (T1-T3), while the rami showed a <3mm change with surgery in 72.5% of the cases, and a <2mm change in 87.5% (T2-T3) and in 82% (T1-T3). CONCLUSION: Expected displacements with surgery were observed and post-surgery changes suggested a short-term adaptive response toward recovery of condyle and ramus displacements. The changes on the chin following splint removal suggested an acceptable adaptation, but with considerable individual variability

    Cephalometric evaluation of surgical mandibular advancement

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    The treatment of Class II adult individuals with mandibular deficiency has been the combination of orthodontic treatment and orthognathic surgery. Therefore, a study was conducted in which cephalometric analysis was used to evaluate the influence of dentoalveolar decompensation in Class II patients submitted to orthodontic and surgical treatment for mandibular advancement, by bilateral osteotomy of the mandibular ramus. A sample of 15 leukoderma adult female patients were selected and three cephalometric radiographs of each patient, taken before the orthodontic treatment, before surgery and after at least 6 months postoperatively, were analyzed in a total of 45 roentgenograms. The tracings were made by the manual method and the points were digitalized using software. The results showed that values of SNB increased from 75.6 to 78.6°. The measures BNP and PGNP were reduced from -12.7 to -7.7 mm and -12.7 to -6.6 mm, respectively. For ANB there was a reduction of 3.23° (from 8.1° to 4.9°). Likewise, the values of AOBO were diminished by 6.3 mm (from 7.6 to 1.3 mm), and in the values of OJ there was a reduction of 5.7 mm (from 9 to 3.3 mm). It was concluded that the pre-surgical orthodontic treatment promoted minimal and variable dental and skeletal changes in the final result. The surgical treatment caused significant skeletal changes, especially in the measurements related to the mandible (SNB, BNP, PGNP and SNPM) or indirectly to it (ANB, AOBO and OJ)
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