In ASIA classification, what defines a 'sensory incomplete' injury (AIS B)?

In ASIA classification, what defines a 'sensory incomplete' injury (AIS B)?

• A. Voluntary anal contraction with motor function in half of key muscles below NLI.
• B. Presence of DAP or sensory function at S4-S5 with no motor function caudal to the injury.
• C. Normal sensory and motor function in all segments.
• D. Preservation of motor function more than three levels below the injury.

Answer: (B)

Sensory incomplete (AIS B) means there is preserved sensory function below the level of injury, including the sacral segments S4-S5, but no motor function below the injury. The sacral sparing is tested by detecting sensation in the S4-S5 region or looking for deep anal pressure (DAP). If you have this preserved sensory function below the injury yet no motor function in the segments below, it fits AIS B. This differs from a complete injury (no sensory or motor below S4-5) and from motor-incomplete cases where some motor function below the injury is present. In short, preserved sacral sensation with absent motor function below the injury defines sensory incomplete.

Sensory incomplete (AIS B) means there is preserved sensory function below the level of injury, including the sacral segments S4-S5, but no motor function below the injury. The sacral sparing is tested by detecting sensation in the S4-S5 region or looking for deep anal pressure (DAP). If you have this preserved sensory function below the injury yet no motor function in the segments below, it fits AIS B. This differs from a complete injury (no sensory or motor below S4-5) and from motor-incomplete cases where some motor function below the injury is present. In short, preserved sacral sensation with absent motor function below the injury defines sensory incomplete.