Syringomyelia is the development of a fluid-filled cyst within the spinal cord. When syringomyelia extends to the medulla oblungata it is referred to as syringobulbia. The most common cause of syringomyelia is Chiari Malformation. Other etiologic factors include hydrocephalus, vertebral trauma, medullary tumors and arachnoiditis. Syringomyelia, secondary to the malformation of Chiari 1, generally interests the cervical or cervical-dorsal marrow; more rarely it affects the whole spinal cord (“holocord” syringomyelia).
The development of syringomyelia results in a dissociated sensory loss (i.e. loss of the sense of pain and temperature with preservation of the sense of fine touch and the position sense). These alterations may lead to the development of painless ulcers, typically on the hands, caused by the lack of pain perception. In severe forms, patients have experienced progressive weakness, due to lesions of the motor neurons of the spine with consequent muscle hypotrophy, which is particularly evident in the upper limbs.
In case if suspected syringomyelia, an MRI of the entire spine is recommended. This test is suggested to all patients who are diagnosed with a Chiari Malformation.
Also recommended are the diagnostic examinations of somato-sensory evoked potentials and motor responses.
Surgical treatment of Chiari malformation reverses the pathophysiological progression of syringomyelia or substantially reduces it in approximately 80% of all patients.