What are the mechanisms that can lead to cord compression syndrome?

Mechanisms Leading to Cord Compression Syndrome

Cord compression syndrome can result from multiple mechanisms including traumatic injury, degenerative changes, neoplastic processes, vascular events, and inflammatory conditions that exert pressure on the spinal cord, leading to neurological dysfunction.

Traumatic Mechanisms

• Hyperextension injuries: Particularly common in older individuals with pre-existing cervical spondylosis or congenitally narrow spinal canals, causing central cord syndrome (CCS) 1

  • Compression occurs between hypertrophic spondylotic disc-osteophyte complex anteriorly and buckled ligamentum flavum posteriorly
  • Results in disproportionate upper extremity weakness compared to lower extremities, bladder dysfunction, and variable sensory loss

• Hyperflexion injuries: Can cause cord compression through 2:

  • Vertebral subluxation or dislocation
  • Retropulsion of disc material or bone fragments into the spinal canal
  • Compression of the anterior spinal cord

• Fractures and dislocations: Direct compression from 1:

  • Vertebral body fractures with retropulsion of bone fragments
  • Facet dislocations causing malalignment and cord compression
  • Burst fractures with canal compromise

• Spinal epidural hematoma: Can occur even after minor trauma, causing cord compression through bleeding into the epidural space 1

Degenerative Mechanisms

• Disc-osteophyte complexes: Progressive formation of osteophytes at vertebral margins combined with disc material causing stenosis 3

  • Most commonly affects cervical spine
  • Can cause gradual or sudden compression with hyperextension movements

• Spondylotic myelopathy: Degenerative changes leading to 1, 3:

  • Canal stenosis from disc bulging, osteophyte formation, and ligamentum flavum hypertrophy
  • Dynamic compression worsened with certain neck positions

• Ossification of posterior longitudinal ligament (OPLL): Progressive calcification of the ligament causing anterior cord compression 1

Neoplastic Mechanisms

• Metastatic epidural spinal cord compression (MESCC): Occurs in approximately 5% of cancer patients 4

  • Direct extension of tumor from vertebral body to epidural space
  • Pathologic fracture with retropulsion of bone fragments
  • Most common in lung, breast, prostate cancer, and multiple myeloma 5

• Primary spinal tumors: Intramedullary, extramedullary-intradural, or extradural tumors causing direct compression

Vascular Mechanisms

• Spinal cord infarction: Rare but can occur due to 1:
  • Aortic dissection
  • Complications of aneurysm
  • Thromboembolism
  • Systemic hypotension

Inflammatory and Infectious Mechanisms

• Epidural abscess: Infection in the epidural space causing compression
• Granulomatous disease: Inflammatory processes like sarcoidosis causing cord compression

Diagnostic Approach

• MRI of the spine: Gold standard for evaluating cord compression 1

  • Should be performed emergently in patients with suspected cord compression
  • Sagittal T1-weighted MRI with or without gadolinium of the entire spine is recommended for patients with new onset back pain or focal neurologic deficit

• CT spine: Excellent for identifying fractures but limited in detecting cord injury and compressive epidural processes 1

  • Considered gold standard for identification of spine fractures with 94-100% sensitivity
  • Useful in acute setting to detect fracture, subluxation, and dislocation

Management Considerations

• Corticosteroids: Should be administered immediately upon clinical suspicion of cord compression, even before radiographic confirmation 1

  • High-dose dexamethasone (96 mg/day) improves ambulation outcomes
  • Caution regarding significant toxicity (11-29% side effect rate)

• Surgical intervention: Indicated for 1:

  • Spinal instability
  • Bony retropulsion causing cord compression
  • Patients with recent onset paralysis (< 48 hours)

• Early decompression: Surgical decompression within 24 hours of injury results in superior neurological recovery 1

  • Only 20-50% of SCI patients are transferred to appropriate centers for surgical decompression within this critical window

Clinical Pearls and Pitfalls

• Recognize high-risk patients: Older individuals with degenerative spine disease are at higher risk for central cord syndrome even with minor trauma 1, 6

• Don't delay treatment: Cord compression is a medical emergency requiring rapid diagnosis and treatment to prevent permanent paralysis 5, 4

• Consider the entire spine: When evaluating for cord compression, image the entire spine as multiple levels may be affected, especially in metastatic disease 1

• Monitor for systemic complications: High thoracic and cervical injuries can cause respiratory failure and cardiovascular instability due to sympathetic disruption 1