Adult syringomielia. Classification, pathogenesis and therapeutic approaches.

Syringomyelia is characterized by the presence of cystic cavities inside the spinal cord, with an incidence estimated of 8.4 new cases/year/100 000 people. The cavities are usually located inside the cervical cord, although they can extend upwards and/or downwards. The underlying cause of all types of syringomyelia is an alteration in physiologic cerebrospinal fluid (CSF) flow dynamics. Four different main types may be described in descending order of frequency: associated with Chiari I malformations, associated with vertebral trauma, associated with basilar invagination and associated with hydrocephalus. Conservative treatment is not recommended as the surgical procedure stops the progress of the disease with clinical improvement being the rule. Early surgical treatment is highly recommended before the establishment of gross neurological deficits occurs. Treatment is urged in case of clinical deterioration or when the follow-up MRI studies show increase in size and extension of the syringomyelic cavity. The first step in the surgical treatment is a precise diagnosis of its etiology to direct the treatment to the underlying cause. Treatment directed to normalize CSF flow homeostasis should be case tailored. Surgical measures that aim to reconstruct the continuity of the subarachnoid space at the site of the block are the first treatment option. Shunting is advocated when reestablishment of the pathways proves impossible or as a second procedure.