Table 3: SOSA classification.

0

NCC 18-16 mm without myelopathy

1

NCC 15-13 mm without myelopathy

2a

NCC 12-11 mm without myelopathy

2b

NCC 12-11 mm with myelopathy

3a

NCC 10-7 mm without myelopathy

3b

NCC 10-7 mm with myelopathy

4

NCC 6 mm or less with myelopathy

NCC = Narrow Cervical Canal.