What is the difference between myelomalacia and myelopathy?

Myelopathy vs. Myelomalacia: Understanding the Difference

Myelopathy is a general term referring to any pathologic process affecting the spinal cord, while myelomalacia specifically describes softening of the spinal cord tissue due to chronic compression or injury, representing irreversible damage to neural tissue. 1

Key Differences

Definition and Nature

• Myelopathy:

  • Umbrella term for any pathologic condition affecting the spinal cord 2
  • Represents the clinical syndrome resulting from spinal cord dysfunction
  • Can be acute, subacute, or chronic in presentation 3
  • May be reversible depending on the underlying cause and timing of intervention

• Myelomalacia:

  • Specific pathological state characterized by softening of the spinal cord tissue 1
  • Represents permanent, irreversible damage to neural tissue
  • End-stage manifestation of severe or prolonged spinal cord injury
  • Often follows chronic compression, ischemia, or trauma to the spinal cord 4

Etiology

• Myelopathy causes:

  • Extrinsic compression (disc herniation, spondylosis, tumors)
  • Inflammatory/demyelinating conditions (MS, NMO)
  • Vascular disorders (ischemia, hemorrhage)
  • Metabolic/nutritional causes
  • Infectious processes
  • Traumatic injuries 1, 5

• Myelomalacia causes:

  • Typically results from prolonged or severe:
    • Spinal cord compression
    • Ischemic injury
    • Traumatic injury with subsequent degeneration
    • Post-surgical complications 4

Imaging Characteristics

• Myelopathy:

  • MRI findings vary based on underlying etiology
  • May show cord compression, edema, or signal changes
  • Changes may be reversible in early stages 6

• Myelomalacia:

  • Characteristic MRI findings include:
    • Hyperintense signal on T2-weighted images
    • Cord thinning/atrophy in advanced cases
    • Cystic changes within the cord
    • Ill-defined lesional borders
    • Relative increase in signal intensity compared to CSF 1, 4

Clinical Implications and Prognosis

• Myelopathy:

  • Clinical presentation depends on the level and extent of spinal cord involvement
  • May be reversible with appropriate and timely treatment
  • Treatment targets the underlying cause 7

• Myelomalacia:

  • Represents irreversible spinal cord damage
  • Important prognostic factor for neurosurgical outcomes
  • Often requires surgical intervention when present
  • Associated with poorer neurological outcomes 1, 4

Diagnostic Approach

• MRI is the gold standard for diagnosing both conditions 6, 1
• MRI without contrast is the initial evaluation for most cases
• MRI with contrast is recommended for:
  • Suspected demyelinating disease
  • Suspected infection or inflammation
  • Suspected neoplasm
  • Post-surgical evaluation
  • Vascular malformations 1

Management Considerations

• Early diagnosis and intervention are crucial to prevent progression from myelopathy to myelomalacia
• Surgical intervention is typically required when myelomalacia is present, with indications including:
  • Progressive neurological deficits
  • Development of myelopathic signs
  • Significant impact on quality of life 1
• In cases of progressive posttraumatic myelomalacic myelopathy, lysis of intradural adhesions may result in symptomatic improvement 4

Clinical Pearls

• Myelomalacia on imaging represents a poor prognostic sign, indicating permanent tissue damage
• Not all myelopathies progress to myelomalacia if treated promptly and appropriately
• Diffusion-weighted imaging can show signal alteration in the spinal cord earlier after symptom onset compared with T2-weighted images in cases of ischemic myelopathy 6
• The presence of intramedullary cord signal changes on MRI in patients with spondylotic myelopathy represents important prognostic factors for neurosurgical outcome 6