Syringomyelia

Syringomyelia is a condition in which an abnormal fluid-filled cavity called a syrinx develops within the spinal cord itself. As the syrinx expands, it damages the surrounding spinal cord tissue, causing progressive neurological symptoms. It requires careful evaluation to identify and treat the underlying cause.

Syringomyelia is almost always secondary to another condition obstructing normal cerebrospinal fluid flow. The most common cause is a Chiari malformation — a brain condition closely linked to this spinal complication. Other important causes include Arachnoiditis, which creates scar tissue that impedes CSF flow, Spinal Tumors, and Tethered Cord Syndrome. In children, syringomyelia is also a recognized cause of Scoliosis through asymmetric muscle weakness.

Causes

Chiari malformation.

The most common cause of syringomyelia is a Chiari I malformation, in which brain tissue (the cerebellar tonsils) extends into the upper spinal canal, disrupting the normal flow of cerebrospinal fluid (CSF) and creating pressure waves that drive fluid into the spinal cord over time.

Other causes

Syringomyelia can also develop following spinal cord injury, spinal arachnoiditis (scarring of the spinal membranes), spinal tumors, tethered cord syndrome, or as a consequence of meningitis or other infections. In some cases no identifiable cause is found (idiopathic syringomyelia).

Symptoms

Symptoms develop gradually and depend on the size and location of the syrinx within the cord. Classic early features include a cape-like pattern of pain and temperature loss across the shoulders and arms (dissociated sensory loss), while touch and position sense are preserved. As the syrinx enlarges, patients may develop arm and hand weakness, muscle wasting, chronic pain, spasticity, and in severe cases, paralysis and bowel or bladder dysfunction. Scoliosis can develop in children with syringomyelia due to uneven muscle weakness.

Diagnosis

MRI of the entire spine and brain is the essential diagnostic tool, clearly visualizing the syrinx as a fluid-filled cavity within the spinal cord. A cervical spine MRI is typically the first study obtained, as syrinxes most commonly begin in the cervical cord, but lumbar spine MRI may also be needed to evaluate the full extent of the cavity and identify contributing lesions such as tethered cord. Brain MRI is also necessary to identify associated Chiari malformation or other intracranial pathology. The size, location, and extent of the syrinx guide treatment decisions.

Classification

Syringomyelia is classified based on its underlying cause, which directly influences treatment strategy.

• Communicating syringomyelia: Associated with CSF flow obstruction, most commonly from Chiari malformation.
• Post-traumatic syringomyelia: Develops after spinal cord injury, often months to years later.
• Tumor-associated syringomyelia: Secondary to intramedullary or extramedullary spinal tumors.
• Idiopathic syringomyelia: No identifiable underlying cause despite thorough evaluation.

Treatments

Treatment of syringomyelia is directed at addressing the underlying cause. When the cause is successfully treated, the syrinx often stabilizes or shrinks over time.

Asymptomatic or slowly progressive syrinxes in patients without an identifiable cause may be monitored with periodic MRI surveillance and neurological assessment.

Treating the underlying cause: For Chiari-related syringomyelia, posterior fossa decompression surgery — removing a small portion of the skull base to restore normal CSF flow — is often effective in halting or reversing syrinx progression. Spinal cord tumors causing syringomyelia are addressed surgically when safe to do so.

Direct syrinx treatment

When the syrinx causes significant neurological deterioration and the underlying cause cannot be corrected, direct surgical drainage of the syrinx using a shunt — a small tube that diverts fluid out of the cord — may be performed. This is reserved for carefully selected cases, as the procedure carries risk of spinal cord injury.

Related Spine Conditions

• Arachnoiditis
• Spinal Tumors
• Tethered Cord Syndrome
• Scoliosis
• Transverse Myelitis
• Back to all Spine Conditions