II. Epidemiology

  1. Epidural Spinal Cord Compression occurs in 5% of cancer patients

III. Pathophysiology

  1. Mechanism
    1. External compression from epidural lesions, typically metastases (90% of causes) or
    2. Vertebral body metastases may impinge on thecal sac
    3. Pathologic Fractures of spine with fragment retropulsion and cord compression
  2. Distribution
    1. Thoracic Spine is most common site of metastases (60-70%)
      1. Breast Cancer and Lung Cancer have predilection for Thoracic Spine
      2. Large blood supply
      3. Half the Vertebrae of entire spine
      4. Narrow spinal canal
      5. Most common site of Vertebral compression
    2. Lumbar Spine (25% of metastatic spine lesions)
      1. Prostate Cancer has predilection for Lumbar Spine
    3. Cervical Spine (15% of metastatic spine lesions)

IV. Causes: Benign Primary Spinal Tumors

V. Causes: Malignant Primary Spinal Tumors

  1. Sarcoma
  2. Multiple Myeloma (most common in adults)

VI. Causes: Metastatic Tumors of the Spine

  1. General
    1. Spine is third most common metastatic site
    2. More common than primary spine tumors by 25 fold
  2. Sources in Adults
    1. Breast Cancer (20%, most common cause of malignant Epidural Spinal Cord Compression)
    2. Lung Cancer (20%)
    3. Prostate Cancer (20%)
    4. Multiple Myeloma
    5. Renal Cell Cancer
    6. Non-Hodgkin's Lymphoma
    7. Thyroid Cancer
  3. Sources in Children
    1. Sarcoma
    2. Lymphoma
    3. Neuroblastoma

VII. Symptoms

  1. Back pain (80-95% of cases, new onset back pain is most common presenting symptom)
    1. Worse at rest, lying supine
    2. May awaken patient at night
    3. Precedes other symptoms by 2 months
    4. Midline focal tenderness to percussion
  2. Later changes
    1. Weakness (75%)
    2. Autonomic or sensory symptoms (50%)
    3. Urinary Incontinence

VIII. Signs: Neurologic Exam (Motor Exam)

  1. Symmetric motor weakness
    1. In Epidural Spinal Cord Compression, motor deficits are more common than sensory
    2. However sensory deficits are also present in 40-90% of cases
  2. Pain on Vertebral body compression
  3. Early changes
    1. Flaccidity
    2. Hyporeflexia
  4. Later changes
    1. Cauda Equina Syndrome (esp. bowel and Bladder changes)
    2. Spasticity
    3. Hyperreflexia

IX. Labs

X. Imaging

  1. Approach
    1. Image entire spine (multiple sites throughout the spine are present in at least one third of cases)
    2. Back pain with Myelopathy or radiculopathy
      1. Mild: MRI within 24 hours
      2. Severe or progressive: Emergent MRI now
        1. Also administer empiric Dexamethasone (below)
    3. Back pain without Myelopathy or radiculopathy
      1. Consider starting with plain film Spine XRay
      2. Spine XRay negative: Bone Scan or MRI
      3. Spine XRay positive: Obtain MRI
  2. Spine MRI with gadolinium contrast (first line test)
    1. Evaluates for cord compression
    2. Test Sensitivity: 93%
    3. Test Specificity: 97%
  3. CT with myelography
    1. Indicated in patients unable to undergo MRI
  4. Xray Spine
    1. May demonstrate solid tumors
  5. Bone Scan
    1. Consider in combination with XRay as alternative to MRI
  6. Post-Void Residual
    1. Bladder Ultrasound after voiding

XI. Management: Neurologic compromise (emergency)

  1. Precautions
    1. Permanent paralysis (Paraplegia) may occur even with delay of hours
  2. Indications (see complications below)
    1. Epidural Spinal Cord Compression
    2. Sudden Myelopathy
  3. Systemic Corticosteroids (Pretreatment)
    1. Indicated in all cases of neurologic involvement
      1. Reduces spinal cord edema
      2. Alleviates pain
    2. Protocol
      1. Start as soon as diagnosis is suspected
        1. Delay in diagnosis can result in Paraplegia
      2. Dexamethasone
        1. Protocol 1: 10 mg IV, followed by 4 mg orally every 6 hours
        2. Protocol 2: 6 mg IV every 6 hours
        3. Older, high dose regimens (up to 100 mg) are not typically used
          1. Heimdal (1992) J Neurooncol 12:141-4 [PubMed]
  4. Immediate Consultations
    1. Neurosurgery Consultation
    2. Radiation Oncology Referral
  5. Mass Reduction
    1. Radiation Therapy (Standard)
      1. Localized radiation up to 3000 Gy
    2. Surgery Indications
      1. Unsure diagnosis
      2. Unstable spine
      3. Severe, rapid, progressive neurologic deterioration
      4. Radiation Therapy not expected to be effective

XII. Complications

  1. Epidural Spinal Cord Compression
    1. Thoracic Spine (66%)
    2. Lumbosacral Spine (20%)
    3. Cervical Spine (14%)
  2. Acute Myelopathy Causes
    1. Irradiation
    2. Paraneoplastic necrotizing Myelitis
    3. Ruptured intervertebral disc
    4. Meningeal carcinomatosis

XIII. Prognosis

  1. Best prognosis is based on ambulation and neurologic status

XIV. References

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