O uso da tomografia computorizada no diagnóstico de hérnias discais no cão
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2014
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As hérnias do disco intervertebral são uma das mielopatias mais comuns encontradas nos cães. É uma doença que se caracteriza pela extrusão ou protrusão de material discal para o interior do canal vertebral, resultando na lesão da medula espinhal e/ou raízes nervosas e no aparecimento de alterações neurológicas. Apesar do diagnóstico presuntivo ser frequentemente baseado nos sinais clínicos e exame neurológico, os exames imagiológicos tornam-se estritamente necessários para o diagnóstico definitivo das hérnias discais, sendo a tomografia computorizada um dos exames mais úteis e precisos. Este trabalho teve como principais objetivos o estudo das características clínicas e tomográficas de cães com hérnias discais de extrusão, estudando em simultâneo a eficácia da tomografia computorizada não-contrastada no diagnóstico das mesmas e as possíveis diferenças entre as hérnias de extrusão cervicais e as toracolombares. Para isso, procedeu-se à análise de 27 cães que possuíam alterações neurológicas compatíveis com hérnias de extrusão, 6 cães com hérnias cervicais e 21 cães com hérnias toracolombares, e que foram sujeitos a uma tomografia computorizada não-contrastada para diagnóstico definitivo no Hospital Referência Veterinária Montenegro. Com este estudo confirmou-se que a tomografia computorizada não-contrastada é de facto um meio de diagnóstico rápido e preciso para a localização e caracterização das hérnias discais de extrusão, tendo identificado em todos os casos a hérnia discal causadora da lesão. Pela mensuração dos valores médios de atenuação do material discal herniado conseguiu-se verificar que esta mensuração pode ser uma ferramenta útil para estimar a cronicidade da lesão. Esses dados foram confirmados pela análise estatística, onde se verificou que os animais com duração crónica dos sinais clínicos evidenciavam valores médios de atenuação do material discal herniado estatisticamente mais elevados que os valores evidenciados pelos animais com duração hiperaguda dos sinais clínicos (p=0,0121). Para além disso, verificou-se que as hérnias de extrusão, com a sua natureza mais explosiva e aguda, podem originar sinais neurológicos menos graves na zona cervical e mais severos na zona toracolombar, que não dependem apenas do grau de compressão da medula espinhal exercido pelo material discal, mas também de outros fatores como o grau de concussão na medula espinhal secundário à extrusão do material discal, os processos vasculares e inflamatórios inerentes à extrusão do material discal, a duração da compressão e o maior ou menor diâmetro do canal vertebral em relação ao diâmetro da medula espinhal.
The intervertebral disc herniation is one of the most common myelopathies found in dogs. It is a disease that is characterized by extrusion or protrusion of disc material into the spinal canal, resulting in spinal cord injury and/or nerve roots and in the appearance of neurological disorders. Although the presumptive diagnosis is often based on clinical signs and neurological exam, the imaging exams become strictly necessary for the definitive diagnosis of the disc herniations, being the computed tomography one of the most useful and accurate exams. This work has as main objective the study of the clinical and tomographic characteristics in dog with intervertebral disc extrusion, simultaneously studying the effectiveness of non-contrast computed tomography in the diagnosis of these and the possible differences between cervical and thoracolumbar disc extrusion. For this, we proceeded to the analysis of 27 dogs that had neurological changes consistent with disc extrusion, 6 dogs with cervical herniations and 21 dogs with thoracolumbar herniations, and which were subject to a non-contrasted computed tomography for a definitive diagnosis, in the Hospital Veterinary Reference Montenegro. With this study it was confirmed that non-contrast computed tomography is in fact a diagnostic mean for quick and accurate localization and characterization of disc extrusion, having in all cases identified the disc herniation that causes the injury. By measuring the average attenuation values of the herniated disc material we could note that this measurement may be a useful tool to estimate the chronicity of the lesion, which may help in future medical and surgical decisions These data were confirmed by statistical analysis, where it was found that the animals with chronic clinical signs evidenced mean values of attenuation of the herniated disc material statistically higher than the values obtained from animals with peracude clinical signs (p=0,0121). Furthermore, it was found that disc extrusion, with its most acute and explosive nature, may lead to less severe neurological signs in the cervical area and more severe neurological signs at the thoracolumbar area, which not only depend on the degree of spinal cord compression exerted the disc material, but also other factors such as vascular and inflammatory processes inherent in the extrusion of disc material, the degree of concussion in the spinal cord secondary to the extrusion of the disc material, the duration of compression and the ratio of spinal cord diameter to vertebral canal diameter.
The intervertebral disc herniation is one of the most common myelopathies found in dogs. It is a disease that is characterized by extrusion or protrusion of disc material into the spinal canal, resulting in spinal cord injury and/or nerve roots and in the appearance of neurological disorders. Although the presumptive diagnosis is often based on clinical signs and neurological exam, the imaging exams become strictly necessary for the definitive diagnosis of the disc herniations, being the computed tomography one of the most useful and accurate exams. This work has as main objective the study of the clinical and tomographic characteristics in dog with intervertebral disc extrusion, simultaneously studying the effectiveness of non-contrast computed tomography in the diagnosis of these and the possible differences between cervical and thoracolumbar disc extrusion. For this, we proceeded to the analysis of 27 dogs that had neurological changes consistent with disc extrusion, 6 dogs with cervical herniations and 21 dogs with thoracolumbar herniations, and which were subject to a non-contrasted computed tomography for a definitive diagnosis, in the Hospital Veterinary Reference Montenegro. With this study it was confirmed that non-contrast computed tomography is in fact a diagnostic mean for quick and accurate localization and characterization of disc extrusion, having in all cases identified the disc herniation that causes the injury. By measuring the average attenuation values of the herniated disc material we could note that this measurement may be a useful tool to estimate the chronicity of the lesion, which may help in future medical and surgical decisions These data were confirmed by statistical analysis, where it was found that the animals with chronic clinical signs evidenced mean values of attenuation of the herniated disc material statistically higher than the values obtained from animals with peracude clinical signs (p=0,0121). Furthermore, it was found that disc extrusion, with its most acute and explosive nature, may lead to less severe neurological signs in the cervical area and more severe neurological signs at the thoracolumbar area, which not only depend on the degree of spinal cord compression exerted the disc material, but also other factors such as vascular and inflammatory processes inherent in the extrusion of disc material, the degree of concussion in the spinal cord secondary to the extrusion of the disc material, the duration of compression and the ratio of spinal cord diameter to vertebral canal diameter.
Descrição
Dissertação de Mestrado Integrado em Medicina Veterinária
Palavras-chave
Cães , Deslocamento do disco intervertebral , Tomografia computadorizada por Raios X