What are the symptoms and treatment options for a syrinx (syringomyelia)?

Syringomyelia: Symptoms and Treatment

Symptoms

Syringomyelia typically presents with progressive neurological deficits including paraparesis or tetraparesis, sensory disturbances in a "cape-like" distribution over the shoulders and upper back, and pain. 1, 2

Key clinical manifestations include:

• Motor deficits: Progressive weakness affecting the legs (paraparesis) or all four limbs (tetraparesis), which is the most common presenting symptom 1, 2
• Sensory loss: Dissociated sensory loss (loss of pain and temperature sensation while preserving light touch and proprioception) in a segmental distribution 3
• Pain: Neuropathic pain in the neck, shoulders, or arms 2
• Autonomic dysfunction: Urinary retention or bladder dysfunction may occur 4
• Scoliosis: Particularly in younger patients, with 2-4% of adolescents with scoliosis having an underlying syrinx 5

Important caveat: Headaches associated with syringomyelia are typically due to an underlying Chiari malformation (the most common cause of syringomyelia, occurring in 25-50% of cases), not the syrinx itself. 6, 7 A thoracic syrinx alone does not cause headaches. 7

The clinical course is generally chronic and slowly progressive 4, though rare cases of acute syrinx expansion can occur, particularly when associated with hydrocephalus. 4

Diagnostic Approach

MRI of the brain and complete spine is the gold standard for diagnosis. 6

The American College of Radiology recommends:

• Complete spine imaging is essential when syringomyelia is suspected, as the syrinx may extend beyond the initially imaged region 5, 6
• Brain imaging should be included to evaluate for Chiari malformation, the most common underlying cause 5, 6
• T1 and T2-weighted sequences are standard, with T2 showing the fluid-filled syrinx cavity as hyperintense 6, 1

Treatment

Surgical Management

Posterior fossa decompression with or without duraplasty is the first-line surgical treatment for Chiari malformation-associated syringomyelia (the most common type). 6

The surgical approach depends on the underlying cause:

For Chiari-Associated Syringomyelia (Most Common):

• Posterior fossa decompression is the primary intervention, which may include duraplasty and cerebellar tonsil reduction 6
• Both with and without duraplasty show benefit for symptom relief and syrinx reduction 6
• Cerebellar tonsil reduction may be added to improve outcomes (Grade C recommendation) 6

For Communicating Syringomyelia with Hydrocephalus:

• Ventriculoperitoneal shunt should be considered first, as the central canal acts as a "fifth ventricle" 4, 8
• This can result in prompt resolution of both hydrocephalus and syringomyelia 4
• In older series, shunting procedures provided better and longer-lasting improvement than posterior fossa decompression alone 8

For Arachnoiditis-Associated Syringomyelia:

• Hindbrain arachnoiditis: Craniocervical decompression with arachnoid lysis shows good outcomes 2
• Non-hindbrain arachnoiditis: Syringo-peritoneal or syringo-subarachnoid shunting may be necessary, though results are more variable 1, 2
• Local decompression with arachnoid lysis is the preferred approach when feasible 1, 2

Postoperative Monitoring

Allow 6-12 months for syrinx reduction after initial surgery before considering additional intervention. 6, 9

The Congress of Neurological Surgeons recommends (Grade B):

• Monitor with MRI for syrinx reduction over 6-12 months 6, 9
• Do not rush to reoperation, as many syringes resolve during this timeframe 9
• Consider additional neurosurgical intervention only if there is no radiographic improvement after 6-12 months 6, 9

Critical Pitfalls to Avoid

• Do not assume symptom resolution correlates with syrinx collapse: Complete syrinx collapse does not eradicate all symptoms, and conversely, symptoms may improve despite persistent syrinx 9, 8
• Do not attribute headaches to a thoracic syrinx: Look for Chiari malformation or other causes first 7
• Do not perform isolated syrinx shunting without addressing the underlying cause: The problem always lies elsewhere (obstruction of CSF flow, Chiari malformation, arachnoiditis) 2

Expected Outcomes

In surgical series of Chiari-associated syringomyelia:

• 51-81% achieve very good outcomes (complete remission or marked improvement) 3
• 29% show good outcomes (slight improvement) 3
• Syrinx collapse or decrease occurs in 67% of patients by 2 years postoperatively 3
• Long-term neurological improvement is sustained in 94% of patients 3

However, repeat procedures are common, with some patients requiring additional shunting 2 months to 12 years after initial surgery. 1