RESUMO
The prerequisites for stable crutch supported standing were analyzed in this paper. For this purpose, a biomechanical model of crutch supported paraplegic stance was developed assuming the patient was standing with extended knees. When using crutches during stance, the crutches will put a position constraint on the shoulder, thus reducing the number of degrees of freedom. Additional hip-joint stiffness was applied to stabilize the hip joint and, therefore, to stabilize stance. The required hip-joint stiffness for changing crutch placement and hip-joint offset angle was studied under static and dynamic conditions. Modeling results indicate that, by using additional hip-joint stiffness, stable crutch supported paraplegic standing can be achieved, both under static as well as dynamic situations. The static equilibrium postures and the stability under perturbations were calculated to be dependent on crutch placement and stiffness applied. However, postures in which the hip joint was in extension (C postures) appeared to the most stable postures. Applying at least 60 N x m/rad hip-joint stiffness gave stable equilibrium postures in all cases. Choosing appropriate hip-joint offset angles, the static equilibrium postures changed to more erect postures, without causing instability or excessive arm forces to occur.
Assuntos
Muletas , Articulação do Quadril/fisiopatologia , Modelos Biológicos , Paraplegia/fisiopatologia , Paraplegia/reabilitação , Postura , Simulação por Computador , Elasticidade , Análise de Falha de Equipamento/métodos , Retroalimentação , Prótese de Quadril , Humanos , Equilíbrio Postural , Desenho de Prótese/métodos , TorqueRESUMO
Paraplegic persons can stand with hip-knee-ankle-foot orthoses (HKAFO) and crutches. However, current HKAFOs restrict body movement extensively, which may impede functional upper-body movements. A more compliant body support using a more compliant orthosis or well-controlled functional electrical stimulation system may increase freedom of movement to the user, but should not impede stability and required arm support. In the current study, we investigated the consequences of varying stiffness applied at the hip to postural stability and required crutch force during paraplegic stance. Experiments were performed on five paraplegic persons with spinal cord lesions varying from T1 to T12. Static postures and dynamic responses to perturbations were tested for varying hip stiffness and crutch placements. The minimal hip-joint stiffness for stable stance appeared to depend on lesion level. In contrast to the predictions of a previous modeling study, no statistically significant influences of hip-joint stiffness or crutch-to-foot distance on posture and applied crutch forces were found. It is hypothesized that the main reasons of this discrepancy are the active upper-body efforts the paraplegic HKAFO users are still able to exert and the remaining flexibility of the upper trunk and shoulder region, which is present despite the restrictions of the orthosis.
Assuntos
Muletas , Articulação do Quadril/fisiopatologia , Prótese de Quadril , Paraplegia/fisiopatologia , Paraplegia/reabilitação , Postura , Simulação por Computador , Elasticidade , Análise de Falha de Equipamento/métodos , Retroalimentação , Feminino , Humanos , Masculino , Modelos Biológicos , Equilíbrio Postural , Desenho de Prótese/métodos , Estresse Mecânico , TorqueRESUMO
Searching for your next job is never easy. You generally need all the help you can get. Often, that means working with physician recruiters who have the connections to help you land a great position. But dealing with recruiters can be both rewarding and frustrating. In two ACPE CyberForums facilitated by Barry Herman--one in 1999 and another just a few months ago--participants talked about the role of recruiters, offering advice and tips that can help physician executives carry out a successful job search.
Assuntos
Serviços Contratados/normas , Candidatura a Emprego , Seleção de Pessoal/organização & administração , Diretores Médicos/psicologia , Atitude do Pessoal de Saúde , Mobilidade Ocupacional , Humanos , Internet , Estados UnidosRESUMO
To our knowledge, five cases of Castleman's disease involving only the central nervous system have been reported previously. We report a sixth case, which occurred in a 47-year-old woman with a 3-month history of headaches and a large superior frontal lobe mass on neuroimaging. Excisional biopsy revealed confluent lymphoid nodular areas with multiple well-developed germinal centers surrounded by concentrically layered proliferations of small B lymphocytes typical of Castleman's disease. Ultrastructural study found 100-nm virallike particles within follicular dendritic cells as well as intercellular spaces. These particles were suggestive of a D-type retrovirus. The patient underwent postoperative radiotherapy and was neurologically normal 3 months after surgery.
