Morphometry of the spinal canal at cervical region in asymptomatic military young men Morfometria do canal vertebral no segmento cervical em militares jovens assintomáticos

Spinal canal measurements obtainned from radiographic imaging studies are an integral part of diagnostic evaluation of cervical spine stenosis. Before abnormal spinal morphometry can be determined, it is first necessary to establish normal values for the specific patient population being evaluated. Cervical spinal canal stenosis increase risk of quadriplegia after "minor trauma" in the head or neck, mainly in athletes who participate in contact or collision sports. Prospective and random selection of 500 plain film of the lateral cervical spine in young militaries population in age group 18-20 years old. Those were performed a hundred set of film were for each geographic region, including Manaus, Recife, São Paulo, Porto Alegre and Campo Grande. The first part of this study established normal values for cervical morphometry. The second part determined the most accurate screenning method for detecting cervical spinal stenosis. Normal spinal canal mean value for C3 was 18,27mm, C4 17,98mm, C5 18,33mm and 18,76mm in C6. The TORG ratio was evaluated as a method to detect significant cervical spinal stenosis and was shown to have sensitivity and high positive predictive value. It was observed TORG's ratio of 0,80 or less in 14,4% of the X-rays.<br>A medição do diâmetro sagital do canal vertebral é parte integrante da avaliação diagnóstica de estenose da coluna cervical. Antes de identificar a morfometria anormal é necessário estabelecer valores normais para uma população específica. A estenose do canal cervical pode se converter em fator agravante na vigência de um "trauma menor" na cabeça ou no pescoço, aumentando o risco de dano medular especialmente naqueles que praticam esporte de contato. Foram selecionadas de maneira prospectiva e randomizada quinhentas radiografias em perfil da coluna cervical de militares jovens assintomáticos na faixa etária dos 18 aos 20 anos, agrupados em cem em cada região geográfica, nas cidades de Manaus, Recife, São Paulo, Porto Alegre e Campo Grande. A primeira parte deste estudo estabelece valores normais para a morfometria da coluna cervical. A segunda parte identifica a precisão do índice de TORG para detectar um canal estreito. O valor médio normal encontrado para o diâmetro sagital de C3 foi 18,27mm, C4 17,98mm, C5 18,33mm e 18,76mm em C6. O índice de TORG mostrou ser um método sensível e possui alto valor preditivo positivo, tendo sido observado presença de índice de TORG anormal (menor ou igual a 0,8) em 14,4% das radiografias analisadas

The Value of a Probability Forecast from Portfolio Theory

A probability forecast scored ex post using a probability scoring rule (e.g. Brier) is analogous to a risky financial security. With only superficial adaptation, the same economic logic by which securities are valued ex ante – in particular, portfolio theory and the capital asset pricing model (CAPM) – applies to the valuation of probability forecasts. Each available forecast of a given event is valued relative to each other and to the “marketâ€\x9D (all available forecasts). A forecast is seen to be more valuable the higher its expected score and the lower the covariance of its score with the market aggregate score. Forecasts that score highly in trials when others do poorly are appreciated more than those with equal success in “easyâ€\x9D trials where most forecasts score well. The CAPM defines economically rational (equilibrium) forecast prices at which forecasters can trade shares in each other’s ex post score – or associated monetary payoff – thereby balancing forecast risk against return and ultimately forming optimally hedged portfolios. Hedging this way offers risk averse forecasters an “honestâ€\x9D alternative to the ruse of reporting conservative probability assessments. Copyright Springer Science+Business Media, LLC 2007forecast evaluation, portfolio theory, probability forecast, probability score,