What is the treatment approach for a cervical spinal cord syrinx without spinal cord compression?

Treatment and Causes of Cervical Spinal Cord Syrinx Without Compression

The treatment of a cervical spinal cord syrinx without spinal cord compression should focus on identifying and addressing the underlying cause, with surgical intervention indicated for progressive neurological deterioration, while conservative management may be appropriate for stable, asymptomatic cases.

Diagnostic Approach

When evaluating a cervical syrinx without obvious compression on MRI, a thorough diagnostic workup is essential:

1. MRI with contrast: MRI without and with IV contrast is the gold standard for evaluating syrinx and potential underlying causes 1. This helps distinguish between:

   • Syrinx (fluid-filled cavity)
   • Tumor
   • Edema
   • Vascular malformations

2. Additional imaging considerations:

   • Dynamic MRI with flexion/extension views to identify position-dependent cord compression 1
   • CT myelography if arachnoid web/cyst is suspected 1

Common Etiologies of Syrinx Without Obvious Compression

Several conditions can cause syringomyelia without apparent cord compression:

1. Arachnoid pathology:

   • Arachnoid webs/adhesions disrupting normal CSF flow 2
   • Arachnoid cysts creating focal CSF flow blockage 1

2. Vascular malformations:

   • Spinal dural arteriovenous fistulas/malformations causing venous hypertension 1

3. Subtle cervical spondylosis:

   • Intermittent or position-dependent cord compression not visible on standard MRI 3
   • Craniospinal pressure dissociation from intermittent compression 3

4. Post-inflammatory/infectious:

   • Previous meningitis or spinal inflammation causing adhesions 1

5. Idiopathic:

   • No identifiable cause despite thorough investigation 4

Treatment Algorithm

1. Asymptomatic or Stable Syrinx

• Conservative management with regular clinical and MRI follow-up
• Monitor for development or progression of neurological symptoms
• Follow-up MRI every 6-12 months initially, then annually if stable

2. Symptomatic or Progressive Syrinx

Treatment depends on the identified underlying cause:

• For arachnoid web/adhesions:

  • Laminectomy at the level of the web
  • Lysis of adhesions
  • Duraplasty to restore normal CSF flow 2
  • Syrinx fenestration may be performed concurrently 4

• For vascular malformations:

  • Endovascular embolization or surgical resection of the malformation 1

• For intermittent compression from spondylosis:

  • Anterior decompression and stabilization at the affected level(s) 3

• For idiopathic syrinx with progressive symptoms:

  • Syringosubarachnoid shunt or syringoperitoneal shunt 5
  • Shunting procedures are particularly effective for large syrinx (>35% of cord diameter) 5

Monitoring and Outcomes

• Radiographic follow-up: Post-treatment MRI to assess syrinx size reduction
• Clinical monitoring: Regular neurological examinations to assess symptom improvement
• Long-term surveillance: Continued monitoring as syrinx can recur

Important Considerations and Pitfalls

1. Avoid overlooking subtle compression:

   • Dynamic MRI studies may reveal position-dependent compression missed on standard MRI 1
   • Cervical spondylosis can cause intermittent compression leading to syrinx formation 3

2. Don't assume all syrinxes require treatment:

   • Asymptomatic, stable syrinxes may be monitored without intervention
   • Surgical intervention carries risks and should be reserved for progressive or symptomatic cases

3. Consider the entire neuraxis:

   • Thoracic pathology can cause syrinx with rostral expansion to cervical levels 2, 6
   • Evaluate the full extent of the syrinx and search for causative lesions throughout the spine

4. Post-surgical monitoring is essential:

   • Even after successful treatment, syrinx can recur
   • Regular clinical and radiographic follow-up is necessary

In summary, the management of cervical syrinx without obvious compression requires thorough investigation to identify the underlying cause, followed by targeted treatment of that cause rather than the syrinx itself. Surgical intervention should be considered for progressive neurological deterioration, while stable, asymptomatic cases may be managed conservatively with regular monitoring.