Myelopathy

Myelopathy is an inclusive term, referring to pathology leading to a neurologic deficit related to the spinal cord. The clinical diagnosis of myelopathy requires a detailed history and physical examination to define the clinical syndrome. Neuroimaging is indicated in most instances of new-onset myelopathy. It is indicated also when the worsening of a myelopathy is unexplained. Advances in neuroimaging have proved to play a vital role in diagnosis. Appropriate diagnosis and treatment are dependent upon an adequate imaging evaluation to establish the presence of mechanical stability, extrinsic spinal cord compression, or an intramedullary lesion. The most frequent etiology of myelopathy is related to degenerative disease of the spine from osteophyte or extruded disc material causing compression of the spinal cord in the cervical or thoracic spine. The next common etiologies are spinal cord compression due to extradural masses caused by metastatic disease to bone or blunt trauma. In these cases, emergency imaging should be performed to assess the nature of the lesion causing the myelopathy and plan the most appropriate treatment. Also urgent imaging should be performed when an abscess in the spinal canal is suspected. Less urgent is imaging of primary neoplasms of the meninges, roots, or spinal cord, as well as noninfectious inflammatory processes, such as multiple sclerosis, and neurodegenerative, vascular, nutritional, or idiopathic disorders leading to myelopathy. Although a survey of the entire spinal cord can be performed with imaging, it is more appropriate to define from the clinical findings what levels of the spine and spinal cord should be imaged. This approach helps limit the likelihood of false-positive imaging findings that may encourage needless attempts to fix what is not broken. Similarly, the most appropriate imaging study and protocol should be selected in order to provide a timely and accurate diagnosis. To do so requires detailed knowledge regarding the strengths and limitations of the multiple imaging modalities available. This chapter outlines an approach to proper study selection based on the likely etiology of myelopathy from the clinical findings. Chapters 33-39 cover these disorders in detail.