A 35-year-old man sustains a C5 fracture-dislocation in a diving accident and has complete motor and sensory loss below C5 immediately post-injury. 48 hours later, examination shows no recovery. According to the ASIA impairment scale (AIS), he is classified as:

• A AIS Grade A — complete injury (no sensory or motor function preserved in the sacral segments S4-S5) ✓
• B AIS Grade B — sensory incomplete (sensory but not motor function preserved below the neurological level, including S4-S5)
• C AIS Grade C — motor incomplete (motor function preserved below the neurological level with more than half of key muscles having grade <3)
• D AIS Grade D — motor incomplete (most muscles grade ≥3)

Explanation

ASIA Impairment Scale (AIS) Grade A denotes a complete spinal cord injury defined as no motor OR sensory function preserved in the sacral segments S4-S5 (tested by anal sphincter contraction and perianal sensation). Even if some segmental reflexes exist below the injury, the injury is 'complete' if sacral sparing is absent after 48 hours of spinal shock resolution. Grade B retains sacral sensory function. The distinction between complete (A) and incomplete (B-D) injuries at 48–72 hours is the most important prognostic indicator, as any sacral sparing predicts some recovery.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.