Syringomyelia is a type of progressive myelopathy. In syringomyelia, cavities are formed in the central part of the spinal cord in the area of the central canal. By its origin, syringomyelia is an abnormality of the development of the spinal cord. Sometimes syringomyelia can form after:
- spinal cord injuries
- primary intracerebral (intramedullary) tumors
- external compression with necrosis of the central part of the spinal cord
- spinal arachnoiditis
- hematomyelia or necrotic myelitis
In the case of congenital syringomyelia, the disease begins with a lesion of the middle parts at the cervical level and then spreads up to the medulla oblongata and down to the level of the lumbar spinal cord. Often syringomyelic cavities are located eccentrically, which causes patients to have a neurological clinic of a unilateral conductor character or an asymmetry of tendon and periosteal reflexes.
In many cases of syringomyelia, patients also experience a combination with congenital anomalies of the neck and head structures (craniovertebral anomalies):
- Arnold-Chiari anomaly
- basilar impression (platybasia)
- atresia of the foramen of Magendie
- Dandy-Walker cyst
Clinical symptoms of syringomyelia and syringobulbia
The main clinical symptoms of syringomyelia resemble the syndrome of the central lesion of the upper segments of the cervical spinal cord. Neurological symptoms in syringomyelia will depend on the extent of the syringomyelitic cavity and its associated developmental abnormalities. Typical neurological manifestations of syringomyelia include:
- loss of sensitivity in the patient according to the dissociated type (pain and temperature sensitivity is lost, but tactile and vibration sensitivity are preserved) on the back surface of the neck, shoulders, and upper limbs (distribution according to the type of "cape") with possible brush involvement
- atrophy of the muscles of the lower part of the neck, as well as the muscles of the shoulder girdle, arms, and hands, asymmetric loss of tendon and periosteal reflexes
- deformity of the spine in the form of kyphoscoliosis of the upper part of the thoracic spine
More often, symptoms in patients with syringomyelia manifest themselves asymmetrically in the form of a unilateral decrease in sensitivity. In some patients, pain sensitivity on the face may be reduced, which is caused by damage to the nucleus of the spinal pathway of the trigeminal nerve at the level of the upper cervical segments of the spinal cord. Cough provocation of headache and neck pain occurs in a patient with a combination of syringomyelia with an Arnold-Chiari malformation.
In idiopathic cases of syringomyelia, neurological symptoms form in adolescents or young adults and progress unevenly. Often, neurological symptoms stop progressing in the future for several years. Some patients with syringomyelia do not become disabled, but most of them are not able to serve themselves and move independently. Loss of pain sensitivity (analgesia) in patients with syringomyelia contributes to the appearance of injuries, burns, and trophic ulcers on the fingertips.
At the advanced stages of the course of syringomyelia, neurogenic arthropathy (Charcot's joint) of the shoulder, elbow, and knee joints may develop. The pronounced weakness in the lower extremities or increased reflexes (hyperreflexia) indicates a concomitant abnormality of the cervical-cranial (craniovertebral) articulation.
Syringobulbia is a type of syringomyelia. As a result of syringobulbia, syringomyelic cavities extend to the level of the medulla oblongata and sometimes the bridge. In syringobulbia, the syringomyelic cavity usually occupies the lateral parts of the brain covering. A patient with syringobulbia may experience paralysis of the soft palate and vocal cord, dysarthria, nystagmus, dizziness, atrophy of the tongue, and Gorner's syndrome.
The slow enlargement of the syringomyelic cavity leads to a narrowing or complete blockage of the subarachnoid space around the spinal cord. Syringomyelic cavities may be separated from the central canal, but are usually connected to it.
Diagnosis of syringomyelia
The diagnosis of syringomyelia is made based on clinical signs and is confirmed by the detection of an enlarged cervical spinal cord during myelography, as well as by the results of a CT scan of the spinal cord performed a few hours after the introduction of a water-soluble contrast agent into the subarachnoid space. Cystic cavities are best seen by MRI imaging of the spinal cord. In connection with the possibility of the patient having another congenital malformation, it is also necessary to conduct an additional study of the cervical-occipital junction.
Treatment of syringomyelia
Treatment of syringomyelia is neurosurgical and is aimed at decompression of the syringomyelitic cavity. Neurosurgeons perform decompression of the syringomyelitic cavity in patients with syringomyelia to prevent progressive damage and decompress the spinal canal in the case of spinal cord expansion. In cases where patients have a combination of cervical spinal cord expansion with Arnold-Chiari anomaly, they are shown laminectomy and suboccipital decompression, as a result of which the bone window expands and the compression of the spinal cord, cerebellum, and medulla oblongata from the occipital bone and the vertebral arch is eliminated.