Table 1.

Cervical degenerative index (CDI) factor scoring

Factors	CDI score
	0	1	2	3
Disc space narrowing	None	25%	50%	75%
Endplate or facet sclerosis	None	Minimal	Moderate	Severe
Osteophytes	None	<2 mm	2–4 mm	>4 mm
Olisthesis	None	<3 mm	3–5 mm	>5 mm