• Clinical science

Syringomyelia

Abstract

Syringomyelia is a condition in which an abnormal fluid-filled cavity, or syrinx, develops within the central canal of the spinal cord. The syrinx is a result of disrupted CSF drainage from the central canal, commonly caused by a Chiari malformation or previous trauma to the cervical or thoracic spine. In select cases, the syrinx may occur in the brainstem, and is then referred to as syringobulbia. The syrinx initially compresses and permanently damages crossing fibers of the spinothalamic tract. Further expansion may affect other tracts of the spinal cord. Symptoms include dissociated sensory loss, presenting as a cape-like distribution of decreased sensitivity to pain and temperature, and flaccid atrophic paralysis in the upper extremities. MRI is the diagnostic modality of choice. Treatment depends on clinical features and associated findings. Symptomatic treatment commonly suffices in stable courses of disease, while patients with progressive neurological deterioration require surgical decompression.

Epidemiology

  • 3–4% of patients with traumatic spinal cord injury (SCI) develop symptomatic syringomyelia.
  • Sex: > , especially in SCI-related syringomyelia
  • Age range: 30–40 years; however SCI-related syringomyelia may occur in all age groups

References:[1][2]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Syringomyelia is an abnormal fluid-filled dilation of the central canal of the spinal cord occurring as a result of impaired CSF flow.

References:[1][2][3]

Pathophysiology

  • Obstructed central canal of spinal cord ; (usually cervical spine, may affect the thoracic or lumbar spine) → impaired CSF drainage → formation of a dilated fluid-filled cavity in central spinal cord; (syrinx: from Greek: "syringa” = pipe; a cavity in the spinal cord) → compression and damage (with reactive gliosis) to crossing neural fibers of the lateral spinothalamic tract first (which affect pain and temperature) → bilateral dissociated sensory loss and dysesthetic pain
  • Expansion of the syrinx may damage:
  • A hydromyelia is an abnormal widening of the central canal of the spinal cord in which CSF collects, despite there being a connection to the 4th ventricle of the brain.

References:[1][4][5]

Clinical features

References:[1]

Diagnostics

  • X-ray or CT: to detect scoliosis and assess the bony spine
  • MRI (confirmatory test): detection of the syrinx (may be septated) and adjacent spinal cord lesions (e.g., tumors, adhesions in arachnoiditis)

References:[1]

Differential diagnoses

References:[1][6]

The differential diagnoses listed here are not exhaustive.

Treatment

Conservative therapy is usually sufficient, but definitive surgical treatment is recommended for; patients with progressive neurological symptoms.

Surgical treatment

  • Removal of the tumor (if present)
  • Decompression by drainage of CSF fluid from the cavity
    • Cerebral shunt
    • Laminectomy and syringotomy
    • Suboccipital and cervical decompression
    • Neuroendoscopic decompression
    • Terminal ventriculoscopy (indicated in patients without Chiari malformation.)

Supportive therapy

References:[7][1]