Laminectomy and decompression are appropriate to prevent irreversible compressive effects and infarction of the cord for rapidly growing tumors that have caused recent and severe loss of function below the level of compression. Cases that have been allowed to progress can be operated on if paraplegia has occurred within one or perhaps two days or less and the overall state of the patient’s cancer makes survival likely for at least several weeks. An often cited trial comparing radiation and surgery by Patchell and colleagues suggested that ambulation is preserved for a longer time with surgery. All these comments, and the trial, refer to compression of the cord at a single level. If the maximal safe radiation dosage had previously been applied to the spinal column, or the diagnosis can only be made from tissue obtained from the site of spinal compression, surgical palliation is usually undertaken.
Intradural–extramedullary tumors should generally be removed if this can be accomplished safely, and this applies to benign extradural tumors that are symptomatic as well. Laminectomy, decompression, excision in isolated cases, and radiotherapy constitute the treatment of intramedullary gliomas. Such patients may improve and lead useful lives for a decade or longer. Constantini and colleagues, based on a large experience with intramedullary lesions, mainly gliomas in children and young adults, recommend a radical excision of the tumor, but this approach has not been subjected to a trial.
Other Causes of Spinal Cord Compression
Epidural fat deposition (epidural lipomatosis) with spinal cord compression occurs in Cushing disease and after the long-term use of corticosteroids, but also in the absence of these disorders. The clinical picture may suggest discogenic disease (Lipson et al). Copious amounts of normal adipose tissue are found at laminectomy and removal of this tissue is curative. Lowering the dose of steroid and caloric restriction may help mobilize the fat and relieve the symptoms. An intra-spinal lipoma is also a component of the developmentally tethered cord, but in this process the essential problem is a conus medullaris myelopathy from stretching of the cord, rather than compression (see
Chap. 37 and Thomas and Miller.)
Arachnoid diverticula—intraor extradural outpouchings from the posterior nerve root—are rare causes of a radicular-spinal cord syndrome, first described by Bechterew in 1893. They tend to occur in the thoracic or lumbosacral regions. The symptoms, in order of decreasing frequency, are pain, radicular weakness and sensory disorder, gait disorder, and sphincteric disturbances, as described by
Cilluffo et al. The frequent association of arachnoid diverticula with osteoporosis, ankylosing spondylitis, and arachnoiditis makes it difficult to interpret the role of the diverticula themselves. Surgical obliteration of the pouches has yielded unpredictable results. They have attained clinical importance more often as the source of spontaneous CSF leaks and a low-pressure syndrome (see Chap. 29).
Spinal cord compression with paraplegia may be caused by extramedullary hematopoiesis in cases of myelosclerosis, thalassemia, cyanotic heart disease, myelogenous leukemia, sideropenic anemia, and polycythemia vera. A similar phenomenon occurs with ossification of the posterior longitudinal ligament, as described earlier.
Solitary osteochondromas of vertebral bodies and multiple exostoses of hereditary type are other reported causes of spinal cord compression. In the case reported by Buur and Morch, the clinical syndrome was one of pure spastic paraparesis of several months’ progression.
Lathyrism (See Also Chap. 41)
From the interesting historical review of Dastur, one learns that this disease was known to Hippocrates, Pliny, and Galen in Europe, to Avicenna in the Middle East, and to the ancient Hindus. The term lathyrism was applied by Cantani, in Italy, because of its recognized relationship to the consumption of Lathyrus sativus (chickling vetch, vetch pea, or grass pea).