What is a syrinx (fluid-filled cavity)?

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Last updated: April 24, 2025View editorial policy

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From the Guidelines

Syrinx diagnosis and treatment should prioritize early intervention, particularly in patients with scoliosis and risk factors, as it may improve long-term management and outcomes. A syrinx is a fluid-filled cavity that develops within the spinal cord, a condition known as syringomyelia, which can expand over time, compressing and damaging the spinal cord from within 1. Symptoms typically include pain, weakness, stiffness in the back, shoulders, arms, or legs, and loss of temperature sensation in the upper limbs.

Key Considerations

  • The diagnosis of underlying neural axis anomalies, such as syrinx, changes long-term management and outcomes in only selected patients 1.
  • Some studies suggest that a clinically asymptomatic and isolated syrinx does not have substantial prognostic or treatment implications, while others have suggested that underlying syrinx detection may be important, particularly in the setting of Chiari I malformation 1.
  • Treatment depends on the underlying cause, with Chiari malformation being the most common, and surgical intervention is usually recommended to address the underlying cause and prevent progression 1.

Treatment Options

  • Decompression surgery to create more space around the spinal cord and improve cerebrospinal fluid flow is the most common procedure 1.
  • Some patients may require shunting procedures to drain the syrinx directly.
  • Not all syringes require treatment, especially if they're small and not causing symptoms.

Monitoring and Follow-up

  • Regular monitoring with MRI scans is essential to track any changes in the syrinx and prevent progression 1.
  • Early intervention is crucial, particularly in patients with scoliosis and risk factors, as it may improve long-term management and outcomes, with studies suggesting that 87% of syringes decreased or resolved after craniocervical decompression surgery 1.

From the Research

Definition and Causes of Syrinx

  • A syrinx is a fluid cavity extending beyond several segments within the spinal cord, comprising a pathologic entity that is not a disease, but a condition with many possible causes 2
  • Hindbrain herniation with or without associated arachnoid thickening is the most common cause, followed by spinal arachnoiditis, especially with paraplegia and also intraspinal tumors 2

Symptoms and Diagnosis

  • The presentation may be variable, particularly in the hindbrain-related cases, and the final clinical picture is convergent because the pattern of destruction of the cord is determined by planes of weaknesses 2
  • Symptoms attributed to spinal cord damage have no significant relationship to the size of the syrinx on MR images 3
  • Diagnosis is typically made by MRI of the craniospinal junction 4

Treatment Options

  • Posterior fossa decompression is a safe procedure with a considerable chance of clinical improvement, although total syrinx collapse is not as frequently seen as in syrinx shunting procedures 4
  • Syringosubarachnoid, syringoperitoneal, and syringopleural shunts are accepted treatment options for patients with persistent syringomyelia 5
  • The choice of surgical technique depends on the presence of symptoms of posterior fossa compression and the size of the syrinx on MR imaging 3

Outcomes and Complications

  • Clinical improvement or arrest of disease was recorded in 73% of patients after surgery 3
  • The rate of clinical improvement was estimated as 61% for syringosubarachnoid, 64% for syringoperitoneal, and 71% for syringopleural shunts 5
  • The rate of clinical deterioration following placement was estimated as 13% for syringosubarachnoid, 13% for syringoperitoneal, and 10% for syringopleural shunts 5
  • Syringoperitoneal shunts have a greater rate of malfunction requiring surgical revision 5

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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