With regard to aortic aneurysm surgery, paraplegia is uncommon after procedures performed on the infrarenal segment but occurs as frequently as 5 to 10 percent following repair of thoracoabdominal aneurysms. Again emphasized here is the not easily explained observation that up to a quarter of these myelopathies do not appear for several days postoperatively (8 days in one of our patients). The article by Lintott and colleagues may be consulted for further details.
In the past, aortography was sometimes complicated by an acute myelopathy; we had observed a number of such cases and Killen and Foster reviewed 43 examples of this accident. The most striking examples, fortunately rare, are now the result of complications of vertebral angiography, resulting in high cervical infarction, similar in most ways to the aforementioned spinal infarction from extracranial dissection of the vertebral artery. The onset of sensorimotor paralysis is immediate, and the effects are often permanent. The syndrome of painful segmental spasms, spinal myoclonus, and rigidity, mentioned earlier, has also been observed under these conditions. It was presumed that vascular spasm and occlusion resulted in infarct necrosis. The frequency of this complication was greatly reduced by the introduction of less toxic contrast media.
Treatment Whether the acute effects of spinal infarction can be modified by high-dose corticosteroids, agents that increase blood flow, or anticoagulation is not known. There are case reports of improvement in paraplegia following aortic dissection by the use of CSF drainage, for example, as in the cases reported by Blacker and colleagues and by Killen and associates, but other factors may have contributed. Many surgical services insert a spinal drain prior to aortic procedures in order to reduce spinal fluid pressure, ostensibly reducing the incidence of cord infarction. There may be gradual improvement after spinal cord infarction, as Robertson and colleagues have reported in perhaps the largest series available, but most patients remain with substantial difficulties.
This unusual nontraumatic athletic problem has been described by Thompson and colleagues from Hawaii. It mainly affects novice surfers who were prone for prolonged times on the surfboard and then engaged in vigorous movements, followed by assuming a standing position. Within an hour of surfing, there was characteristic severe upper lumbar or thoracic pain after, followed by progressive paraparesis or paraplegia, and urinary retention. In several reports, MRI showed signal changes in a long extent of the thoracic spinal cord and when the proper imaging sequences have been performed, some cases have restricted diffusion in the affected region. On the basis of the latter finding and preservation of proprioception some patients (implicating ischemia of the anterior portion of the spinal cord), a vascular mechanism has been proposed. In the series reported by Chang and colleagues, improvement was inconsistent.
Hemorrhage of the Spinal Cord (Hematomyelia) and Spinal Canal
Hemorrhage into the spinal cord is rare compared with the frequency of cerebral hemorrhage. The apoplectic onset of symptoms that involve spinal tracts (motor, sensory, or both), associated with blood and xanthochromia in the spinal fluid are the identifying features of hematomyelia. Aside from trauma, hematomyelia is usually traceable to a vascular malformation or a bleeding disease and particularly to the administration of anticoagulants. Actually, most vascular malformations of the spinal cord do not cause hemorrhage, but instead produce a progressive, presumably ischemic myelopathy as described later and mentioned in the earlier section on the Foix-Alajouanine type of subacute necrotic myelopathy.