SCI and ASIA Impairment Scale Flashcards

Spinal Cord Injury (SCI) Overview

• Most common cause of spinal cord injury is motor vehicle accidents (MVA).
• Mechanism of injury often dictates the type of SCI.

Sites of Injury

• Flexion injuries typically occur at C5-C6.
• Extension injuries usually occur at C4-C5.

Types of Damage

• Two types of spinal cord damage include primary (initial trauma) and secondary (extension of injury).

General Types of SCI

• Complete SCI: No motor or sensory function preserved below the injury.
• Incomplete SCI: Some motor or sensory function preserved below the injury.

Syndromes Related to SCI

Anterior Cord Syndrome

• Caused by flexion injuries.
• Results in loss of motor function, pain, and temperature sensation bilaterally below the lesion.
• Injuries spinothalamic and corticospinal tracts.

Brown-Sequard Syndrome

• Characterized by hemi-section of the spinal cord.
• Ipsilateral spastic paralysis and loss of position sense, with contralateral loss of pain and thermal sense.

Cauda Equina Syndrome

• Injury occurs at L1 level and below, resulting in lower motor neuron lesions.
• Symptoms include flaccid paralysis, areflexia, and bowel/bladder impairments.

Central Cord Syndrome

• Results from compression and damage to the central cord, often due to cervical hyperextension.
• Symptoms include weakness or paresthesia, with upper extremities affected more than lower.

Posterior Cord Syndrome

• Rare injury from compression of the posterior spinal artery.
• Causes bilateral loss of proprioception, vibration, and pressure while preserving motor function and pain sensation.

Assessment of SCI

• Motor level is determined by the most caudal key muscles with a strength of 3 or greater with the immediately superior segment being normal.
• Motor Index Score: Tests key muscles using a scale of 0-5, totaling 100 points across extremities.
• Sensory Level: Identified by the most caudal dermatome with normal scores for pinprick and light touch.

ASIA Impairment Scale

• A grading scale for assessing degree of impairment and injury severity.
• Various grades:
  • A: Complete - No function preserved in S4-S5.
  • B: Sensory Incomplete - Sensory function preserved below neurologic level, no motor function more than 3 levels below.
  • C: Motor Incomplete - Voluntary anal contraction or sensory incomplete with less than half key muscles graded 3 or more.
  • D: Motor Incomplete - At least half key muscles functioning at grade 3 or more.
  • E: Normal - Sensory and motor functions normal after prior deficits.

Key Muscles for Testing

• C5: Elbow flexors
• C6: Wrist extensors
• C7: Elbow extensors
• C8: Finger flexors (1-3)
• T1: Small finger abductors
• L2: Iliopsoas
• L3: Quadriceps
• L4: Ankle dorsiflexors
• L5: Long toe extensors
• S1: Plantar flexors

Sensory Testing

• Test light touch and pinprick for C2-S5 with grading:
  • 0 = Absent
  • 1 = Impaired/Hyperesthesia
  • 2 = Intact