Early AIS Classification After a C5 Fracture: Timing, Confounders, and the Family Conversation
A 38-year-old man underwent C4-C6 posterior fusion 48 hours ago for a C5 burst fracture after a motorcycle crash. He was intubated for 30 hours and received propofol and fentanyl; he was extubated yesterday and is drowsy but follows commands. He is on oxycodone and ketorolac. Examination today: deltoid 4/5 on the right and 3/5 on the left, biceps 2/5 bilaterally, wrist extensors 0/5 bilaterally with grimacing but no visible contraction, light touch and pinprick intact at C4 and C5 and absent at C6 and below, and no sacral sparing. The bulbocavernosus reflex is present. The resident documents 'C5 AIS A, complete, will never walk' and tells the family. The nurse asks whether the examination should be repeated.
1. Was the resident's examination and classification appropriate at 48 hours? What should be documented now, and what should be done at 72 hours?
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Not appropriate. At 48 hours he is 24 hours post-extubation, on opioids, and drowsy; pain and sedation can depress motor grades, and the wrist extensors cannot be reliably graded when he grimaces but shows no visible contraction. That is NT (not testable), not 0/5. A grade of 0 requires no visible or palpable contraction. The ISNCSCI examination should be performed when the patient is stable and alert; a baseline within 72 hours is standard, but the classification should be labeled preliminary and repeated. Document each key muscle and dermatome, mark untestable muscles NT, and avoid assigning a definitive NLI or prognosis. The resident's statement to the family is not supported and can cause lasting harm. At 72 hours, repeat the full examination off confounding medications if possible, then classify. If he remains drowsy or in pain, continue to document the examination as limited rather than forcing a grade.
2. At 72 hours he is alert and off opioids. Biceps is 3/5 bilaterally, wrist extensors are 0/5, sensation is intact at C5 and absent at C6 and below, there is no sacral sparing, and the bulbocavernosus reflex is present. Assign the AIS grade, neurological level, and zone of partial preservation, and explain how you would counsel the family about walking.
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Biceps 3/5 is the C5 key muscle and is at least 3/5 with no rostral key muscles below 5/5, so the motor level is C5. Light touch and pinprick are intact at C5 and absent at C6, so the sensory level is C5. The neurological level is C5, the most caudal segment with intact sensory and motor function. No sacral sparing means AIS A. Because there is no sensory or motor function below C5, there is no zone of partial preservation; record it as none. If any function were present below the NLI, the ZPP would be the most caudal such segment, and a ZPP extending at least three levels below the NLI would carry a higher chance of conversion. Counseling: say the injury is currently complete at C5. Walking is unlikely, and the expected mobility is a power wheelchair with hand controls, but avoid the word never. Re-examine at discharge and follow-up, because a small percentage of AIS A patients convert, especially those with a ZPP.
3. What does the presence of the bulbocavernosus reflex tell you, and what does it not tell you?
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Return of the bulbocavernosus reflex indicates that spinal shock is resolving. It is a sacral S2-S4 reflex and does not require volitional or corticospinal connection. It does not predict whether he will convert to AIS B, C, or D, and it can be present in complete injuries. Its practical importance is that as spinal shock resolves, autonomic dysreflexia can appear, so blood pressure monitoring and trigger avoidance become important; the flaccid bladder may also begin to show reflex activity, which affects bladder management. It should not be used to tell the family that he will recover. The reflex is a marker of the phase of injury, not a prognosis.