Spinal Cord Injury (SCI)

Spinal Cord Injury (SCI)

David Ray Velez, MD

Table of Contents

Injury Patterns
ASIA Impairment Scale
Spinal Shock
Neurogenic Shock
General Management

Injury Patterns

Anterior Cord Syndrome

  • Injury: Anterior 2/3 of the Spinal Cord
  • From Anterior Spinal Artery Injury
  • Presentation:
    • Bilateral Motor and Pain/Temperature Loss
    • Spares Sensation

Brown-Sequard Syndrome

  • Injury: Cord Hemisection
  • Presentation:
    • Ipsilateral Motor and Sensation Loss
    • Contralateral Pain/Temperature Loss

Central Cord Syndrome

  • Injury: Swelling of the Central Spinal Cord
  • From Hyperflexion of C-Spine
  • Presentation:
    • Bilateral Motor and Pain/Temperature Loss
    • “Cape-Like” Distribution Affecting Arms More Than Legs

Cauda Equina Syndrome

  • Injury: Compression of the Cauda Equina
  • Presentation:
    • Saddle Anesthesia
    • Bowel/Bladder Dysfunction
    • Bilateral Lower Extremity Weakness

Spinal Cord Injury Without Radiographic Abnormality (SCIWORA)

  • Newer Term: Spinal Cord Injury Without CT Evidence of Trauma (SCIWOCTET)
  • Definition: Clinical Findings of Spinal Cord Injury but Negative XR/CT
  • 2/3 Will Have Evidence of Injury by MRI
  • Most Common in the Cervical Spine
    • Less in the Thoracic Spine Due to Rib Cage Splinting Protection
  • Primarily Occurs in Children Due to Increased Elasticity and Proportionally Larger Heads with Weaker Cervical Musculature
  • Evaluate with MRI and Manage by Cervical Collar

Spinal Cord Lesions 1

Brown-Sequard: (1) Level of Lesion, (2) Motor/Sensation Loss, (3) Pain/Temperature Loss 2

ASIA Impairment Scale

Grade A Injury

  • Complete Injury
  • No Sensation or Motor Function in Sacral Segments S4-S5

Grade B Injury

  • Sensory Incomplete Injury
  • Distal Sensation is Preserved Below the Neurologic Level of Injury and Includes Sacral Segments S4-S5
  • No Motor Function ≥ 3 levels Below the Neurologic Level of Injury on Either Side

Grade C Injury

  • Motor Incomplete Injury
  • Distal Sensation is Preserved Below the Neurologic Level of Injury and Includes Sacral Segments S4-S5
  • Distal Motor Function is Preserved Below the Neurologic Level of Injury (> Half of the Key Muscle Functions Have a Muscle Grade < 3)

Grade D Injury

  • Motor Incomplete Injury
  • Distal Sensation is Preserved Below the Neurologic Level of Injury and Includes Sacral Segments S4-S5
  • Distal Motor Function is Preserved Below the Neurologic Level of Injury (≥ Half of the Key Muscle Functions Have a Muscle Grade ≥ 3)

Grade E Injury

  • Normal
  • Normal Sensation and Motor Function

Spinal Shock

Definition: A Sudden, Temporary Loss of Spinal Cord Function Below the Level of an Injury

  • A Sequela of Severe Spinal Cord Injury

Presentation

  • Temporary Paralysis, Areflexia, and Loss of Sensation Below the Level of Injury
  • Usually Resolves Within 48 Hours but May Last Weeks-to-Months
  • No Circulatory Compromise (Compared to Neurogenic Shock)
    • Injuries Above T6 May Result in Neurogenic Shock

Pathophysiology

  • A Two-Stage Process
  • Primary Injury: From the Initial Impact and Continued Cord Compression from Fracture, Ligamentous Injury, and Disc Rupture
  • Secondary Injury: Further Injury from Inflammation, Ischemia, Calcium-Mediated Mechanisms, Free Radicals, and Cell Death

Bulbocavernosus Reflex (BCR)

  • Also Known As:
    • Bulbospongiosus Reflex
    • Osinski Reflex
  • A Spinal Cord Reflex Involving S1-S3
  • Reflex: Anal Sphincter Contraction in Response to Squeezing of the Glans of the Penis, Clitoris, or Tugging on the Foley Catheter
  • Carries Prognostic Value:
    • Absence of Reflex Demonstrates Continued Spinal Shock – May See More Functional Improvement Once Spinal Shock Resolves
    • Presence of Reflex Demonstrates Resolution of Spinal Shock

Neurogenic Shock

Definition: Hemodynamic Shock Caused by a Loss of Sympathetic Tone from Severe Traumatic Brain Injury (TBI) or Spinal Cord Injury

  • Seen in Spinal Injuries Above the T6 Level

Incidence

  • Cervical Spine Injury: 19.3%
  • Thoracic Spine Injury: 7%

Presentation

  • Hypotension
  • Bradycardia and Bradycardic Arrest
    • Bradycardia Can Be Exacerbated by Gastric, Urinary, or Rectal Distention
  • Extremities Remain Warm from Vasodilation
  • Flushed Skin
  • May See Priapism from Vasodilation

General Management

General Management

  • Management is Mostly Supportive Outside of Possible Surgery for Spinal Fractures
  • Monitor for Cardiovascular and Respiratory Complications in High Spinal Injuries
    • Monitor Vital Capacity – Decreases May Indicate Respiratory Failure and Need for Intubation
  • High Risk for VTE – May Consider Long-Term Anticoagulation for 2-3 Months
  • High Risk for Pressure Sores

Controversial Therapies

  • Goal MAP > 85-90 mmHg for 7 Days to Improve Spinal Cord Perfusion Pressure – Poor Quality Evidence to Support
  • Systemic Steroids – Primarily Given if Symptoms are Worsening to Decrease Swelling

Treatment of Neurogenic Shock

  • Hemodynamic Shock: IV Fluids and Vasopressors
    • Vasopressor Choice:
      • Norepinephrine – Generally Preferred
      • Phenylephrine – May Cause Reflex Bradycardia
    • Consider Midodrine for Prolonged Support
  • Acute Bradycardia: Atropine, Dopamine, Epinephrine, or External Pacing
    • Persistent Bradycardia May Require Permanent Pacemaker Placement
    • Additional Supportive Measures to Consider:
      • NG Tube Decompression – Gastric Distention Can Exacerbate
      • Foley Catheter – Urinary Distention Can Exacerbate
      • Bowel Regimen/Rectal Tube – Rectal Distention Can Exacerbate
    • Theophylline – Antagonize Endogenous Adenosine at the SA and AV Nodes
      • Can Be Used Long-Term and May Be Able to Prevent Pacemaker Placement for Persistent Bradycardia

References

  1. Olson N. Wikimedia Commons. (License: CC BY-SA-3.0)
  2. Rhcastilhos, PbBR8498. Wikimedia Commons. (License: CC BY-SA-3.0)