Martin A Nogues MD (Dr. Nogues of the University of Buenos Aires has no relevant financial relationships to disclose.)
Matthew Lorincz MD PhD, editor. (Dr. Lorincz of the University of Michigan has no relevant financial relationships to disclose.)
Originally released December 5, 2001; last updated August 11, 2016; expires August 11, 2019


Syringomyelia and associated conditions, such as arachnoiditis and the Chiari I anomaly, are now readily diagnosed by MRI. An associated Chiari anomaly may be overlooked by MRI in the supine position, and it may be revealed during the surgical procedure in the sitting position. Misdiagnosis may occur if sagittal imaging alone is used because sagittal MRI might overestimate the degree of tonsillar ectopia in Chiari I malformation. Together with neurologic examination, MRI allows distinction between syringomyelia and hydromyelia. Advances in neuroradiology have considerably improved the prognosis of syringomyelia and hydromyelia. Aquaporin-4 expression has been implicated in water accumulation in posttraumatic syringomyelia. In this article, the author reviews the early and late neuro-ophthalmologic manifestations of syringobulbia, the differential diagnosis of syringomyelia and hydromyelia, and the 90% chance of long-term stabilization or improvement with surgical treatment in Chiari-related syringomyelia. Clinical manifestations, differential diagnoses, and management techniques are also described. Syringomyelia may complicate intracranial hypotension due to a CSF leak. A retrospective review has shown that most tonsillar herniations are asymmetrical leading to eccentricity of the syrinx.

Key points


• MRI is the diagnostic modality of choice for syringomyelia and associated conditions, such as Chiari I anomaly or arachnoiditis, and for the differential diagnosis of syringomyelia and hydromyelia.


• Preventive measures for the development of syringomyelia include the careful use of epidural anesthesia and the avoidance of a traumatic or prolonged labor and maneuvers that may induce “craniospinal” dissociation, such as Valsalva maneuver.


Pain is a frequent and disabling manifestation of syringomyelia and a persistent symptom in a significant percentage of patients despite successful drainage of the syrinx.


• Some patients show progressive neurologic deterioration and disabling pain despite proper surgical drainage of the syrinx and correction of the associated craniovertebral anomaly.

Historical note and terminology

Ollivier d'Angers first coined the name "syringomyelia" in 1824 (Ollivier d'Angers 1824), but the condition was first recognized by Stephanus in 1545 (Stephanus 1545). Schultze first described its clinical picture (Schultze 1882); its relation to Chiari malformation was first outlined by John Cleland (Cleland 1883). Abbe performed the first reported surgical drainage of a syrinx in 1891 (Abbe 1892), although claims were made that Horsley aspirated a syrinx in 1890 (Putnam and Warren 1899). The “hydrodynamic” theory of syringomyelia was proposed by Gardner (Gardner 1965) and modified by Williams' “craniospinal pressure dissociation” theory (Williams 1978).

The term “syringomyelia” is used to indicate the presence of a fluid-filled cavity within the spinal cord. "Hydromyelia" refers to dilatation of the central canal of the spinal cord: cavities partially or completely lined by ependymal cells. Syringomyelia indicates cavities that lie outside the central canal and do not have ependymal lining but may have partial connection with the central canal. “Communicating” syringomyelia refers to cavities with a direct communication with the fourth ventricle through the obex and is usually associated with hindbrain malformations. “Noncommunicating” syringomyelia refers to cavities without communication with the fourth ventricle and is usually secondary to trauma and tumors of the spinal cord but is also associated to hindbrain malformations.

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