The term syringomyelia describes many pathogenetically different disorders, and a variety of attempts to group these based on different criteria have been proposed in the literature. As a consequence a lack of consensus regarding classification and terminology exists. This inconsistency extends to the ICD-10 classification of diseases in regards to syringomyelia (G95.0) and hydromyelia (Q06.4).
Blegvad et al., have shown that the use of classifying terminology for fluid-filled cavities in the spinal cord is indiscriminate and inconsistent. Even though a general agreement on the believed pathogenetic mechanism exists, and the general treatment methods are used in accordance with this mechanism, the terminology fails to function as a simple and universal link between theory and treatment.
They propose a new causal concept for an ICD classification with syringomyelia (G95.0) as the only describing terminology, thus abandoning the use of hydromyelia (Q06.4). Syringomyelia is divided into five subgroups according to the associated pathologies. The classification is based on applied diagnostics and serves as a clinical guidance for treatment 1).
Its incidence after traumatic spinal cord injury (SCI) is approximately 15%.
Syringomyelia is associated with pathologies related to the disturbance of cerebral spinal fluid flow found in conditions such as Chiari I malformations, spinal malignancy, spinal cord tethering, trauma, or arachnoid adhesions.
Syringomyelia secondary to cervical spondylosis is a rare entity to encounter in clinical practice. There is a potential causal association between cervical spondylosis and syringomyelia. MRI CSF flow studies may help in deciding the course of treatment in such cases. A subset of patients with cervical spondylosis and concurrent spinal cord signal intensity changes may show reversal of the same following intervention 2).
Ventriculoperitoneal (VP) shunt malfunction commonly presents as raised intracranial pressure. Rarely, when the central canal of the spinal cord communicates with the 4(th) ventricle, shunt malfunction can present as an expanding syrinx.
Cystic cavitation of the spinal cord.
The underlying pathophysiology leading to syringomyelia is elusive with multiple flow-related theories constituting our current limited understanding of the disease process.
It involves abnormal CSF flow mechanics.
Clinical presentation of syringomyelia can mimic a variety of neuromuscular disorders. A misdiagnosis can result in progressive pressure on the spinal cord, causing the development of severe irreversible neurologic deficits.
Severe untreated cases can result in irreversible spinal cord injury. Prompt diagnosis with magnetic resonance imaging is important in both establishing diagnosis and directing further surgical management 3).
Surgical intervention for syringomyelia is considered when conservative medical treatment fails and neurological symptoms progress.
In conditions such as Chiari I malformations, spinal malignancy, spinal cord tethering, trauma, or arachnoid adhesions, surgical intervention involves directly removing the source causing the syrinx formation. Malignancy resection, decompressive, and untethering procedures with adhesion removal and duraplasty have been successful in removing offending pathologies creating the syringomyelia condition.
In cases where these methods have failed, the use of syrinx shunting, whether syringoperitoneal shunt, syringopleural shunt, or syringosubarachnoid shunt, has been advocated as a procedure of last resort. Many shunting procedures have been described and the results have been erratic.
Include fibrosis with subsequent obstruction, shunt migration, and shunt infections, which minimize the success of this surgical treatment.
For patients with syringomyelia and history of prior posterior fossa decompression (PFD), intradural intraarachnoid decompression is required. The prior history of decompression was associated with unfavorable outcomes. The use of duraplasty was associated with longer duration of hospital stay and higher complication rate. Further large cohort prospective study is needed to provide any recommendation on the indication of intra or extradural decompression for a given Chiari malformation I patient 4).
Data from long-term studies on shunting procedures for syringomyelia suggest 12-53% of patients improve, 10-56% unchanged, and 12-32% regress.