3 research outputs found

    A comparative study of "plasmacup" and "porous-coated" acetabular components: survival after 10 to 12 years of follow-up

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    OBJECTIVES: Our primary aim was to compare the long-term survivorship rates and the rates of successful osseointegration between two different types of uncemented acetabular components. INTRODUCTION: Two types of alloys have primarily been used for the manufacture of the uncemented acetabular components: titanium-based and cobalt-based alloys. A titanium-based alloy appears to be more effective with regard to interface stress transfer to the host bone because of its lower elastic modulus relative to a cobalt-based alloy. This supposed mechanical advantage of a titanium-based alloy component motivated this comparative study. METHODS: Two uncemented acetabular components, a porous-coated acetabulum and a Plasmacup®, were compared with a focus on long-term prosthesis survivorship and the development of acetabular osseointegration. Five radiographic signs of osseointegration were evaluated at the last follow-up appointment: (1) absence of radiolucent lines, (2) presence of a superolateral buttress, (3) medial stress-shielding, (4) radial trabeculae, and (5) an inferomedial buttress. We considered the presence of any three of these radiographic signs, in the absence of acetabular dislocation or symptoms, to be indicative of successful acetabular osseointegration. RESULTS: Among 70 patients implanted with the porous-coated acetabulum, 80% achieved osseointegration over a mean follow-up time of 11.9 years versus 75.3% of the 73 patients who received a Plasmacup insert over a mean of 10.7 years. Prosthesis survivorship rates were not different between the two groups. Revision surgery due to mild or severe acetabular osteolysis, polyethylene wear, and aseptic loosening occurred in eight patients (11.4%) with a PCA versus nine (12.3%) with a Plasmacup. CONCLUSIONS: We conclude that, during the first ten years after surgery, there is no significant difference between these two types of uncemented cups with regard to either prosthesis survivorship or successful osseointegration

    Estudo anatômico do trajeto da artéria vertebral na coluna cervical inferior humana Anatomical study of the vertebral artery path in human lower cervical spine

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    O aumento da utilização de novas técnicas e materiais de síntese para o tratamento cirúrgico de afecções da coluna cervical baixa foi acompanhado da crescente preocupação em relação às complicações que podem ocorrer. A técnica de fixação transpedicular, amplamente utilizada para os outros níveis da coluna vertebral, quando realizada na coluna cervical, apesar de conferir maior estabilidade quando comparada a outras técnicas, pode cursar com complicações graves como lesão da artéria vertebral, lesão de raiz nervosa, além de lesão da articulação facetária. A vértebra C7, no entanto, é considerada mais segura para a realização de tal procedimento, já que, na grande maioria das pessoas, segundo os estudos anatômicos disponíveis, esta não possui a artéria vertebral dentro de seu forame transverso, pois este vaso irá penetrar tal estrutura apenas na vértebra C6. Como hoje existem apenas estudos de imagem para avaliação do trajeto desta artéria e suas variações anatômicas, realizamos este estudo anatômico dissecando 40 artérias vertebrais de cadáveres para avaliar a incidência das variações anatômicas. Encontramos 3 casos onde a artéria vertebral penetrou o forame transverso já em C7 (7,5%), o que aumentaria o risco de uma técnica transpedicular neste nível. O restante das peças anatômicas possuíam anatomia habitual.<br>The increasing use of new techniques and materials for surgical treatment of lower cervical spine conditions has come along with an increasing concern regarding potential complications that might occur. The transpedicular fixation technique, frequently used in other spine levels, is used on the cervical spine, while providing more stability than other techniques, it may cause serious complications such as vertebral artery injury, nervous root injury, or facet joint injuries. However, the C7 vertebra is considered safer for performing this procedure, since, in the vast majority of people, according to available anatomical studies, does not have a vertebral artery passing through its cross-sectional foramen, because that vessel is inserted into such structure only on C6 vertebra. As there are only imaging studies available today for assessing the path of this artery and its anatomical variables, we conducted this anatomical study by dissecting 40 cadaver's vertebral arteries in order to assess the incidence of anatomical variations. We found 3 cases where the vertebral artery penetrated into cross-sectional foramen at C7 (7.5%), a fact that enhances the risk of an undesired injury with a transpedicular technique at this level. The other remaining specimens showed a usual anatomy
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