Table 2.

Grading criteria for determining dorsal band and syringomyelia severity (Adapted from Ref. 2)

Grade	Atlantoaxial Band Severity	Severity of Syringomyelia
0	None	None
1	Underlying SAS reduced, but not eliminated	<33% of spinal cord
2	Underlying SAS eliminated, questionable spinal cord compression	33–60% of spinal cord
3	Underlying spinal cord compressed/deformed	>60% of spinal cord

SAS, subarachnoid space.