When the theca of the cord is directly infected the spinal symptoms predominate at first, but as the condition progresses it involves the cerebral membranes, and symptoms of acute general lepto-meningitis ensue.
Once the condition has started little can be done to arrest its progress, but the symptoms may be relieved by repeated lumbar puncture.
Spinal Myelitis.—The term “myelitis” is applied to certain changes which occur in the spinal cord as a result, for example, of hæmorrhage into its substance (hæmorrhagic myelitis); or of pressure exerted on it by fragments of bone, blood-clot, tuberculous material, or new growths (compression myelitis).
In another group of cases myelitis is a result of the action of organisms or their toxins. Syphilis is a common cause, but the condition may follow on infections with ordinary pyogenic cocci, pneumococci, the influenza bacillus or the bacillus coli.
In addition to the use of anti-syphilitic remedies, or of sera directed to neutralise the toxins of the causative organism, attention must be directed to the bladder, and steps taken to prevent cystitis and the formation of bed-sores.
Congenital Deformities of the Spine
Spina Bifida.—Spina bifida is a congenital defect in certain of the vertebral arches, which permits of a protrusion of the contents of the vertebral canal. It is due to an arrest of development, whereby the closure of the primary medullary groove and the ingrowth of the mesoblast to form the spines and laminæ fail to take place. The cleft may implicate only the spinous processes, but as a rule the laminæ also are deficient. The defect usually extends over several vertebræ ([Fig. 219]). While the protrusion varies much in size, there is no constant ratio between the dimensions of the swelling and the extent of the defect in the neural arches.
| Fig. 219.—Meningo-myelocele of Thoracico-lumbar Region. | Fig. 220.—Meningo-myelocele of Cervical Spine. |
The condition is comparatively common, being met with in about one out of every thousand births. It is most frequent in the lumbar and sacral regions ([Fig. 219]), but occurs also in the cervical ([Fig. 220]) and thoracic regions. It is not uncommon to find spina bifida associated with other congenital deformities such as hydrocephalus, club-foot, and extroversion of the bladder.
Varieties.—Four varieties are usually described according to the character of the protrusion. They are analogous, to a certain extent, to the varieties of cephalocele ([p. 387]). (1) Spinal meningocele, in which only the membranes, filled with cerebro-spinal fluid, are protruded. (2) Meningo-myelocele, the form most commonly met with clinically, in which the cord and some of the spinal nerves are protruded, and spread out over the inner aspect of the sac ([Figs. 219], [220]). (3) Syringo-myelocele, in which there is a dilatation of the central canal in the protruded part of the cord. In these three forms the protrusion may be covered by healthy skin, or by a thin, smooth, translucent membrane through which the contents are visible. Frequently this thin covering sloughs or ulcerates, and permits the cerebro-spinal fluid to drain away. (4) In the myelocele, this skin, as well as the vertebral arches and membranes, is absent, and the cord lies exposed on the surface. This form is comparatively common, but as the infants are either dead born or die within a few days of birth, it seldom comes under the notice of the surgeon.