Table 1. Histological grading based on all staining showed microstructural disc degeneration after injury, which was clinically classified as being grade III.

Category	Score	Histological features	Observed score
			Normal disc	Injured disc
AF morphology	0	Well-organized AF, half-ring–shaped structure, collagen lamellae	0
	1	Partly ruptured AF; loss of half-ring–shaped structure		1
	2	Completely ruptured AF; no intact half-ring–shaped collagen lamellae
NP cellularity	0	Normal cellularity; no cell clusters	0
	1	Mixed cellularity; normal pattern with some cell clusters
	2	Mainly clustered cellularity; chondroid nests present		2
NP matrix	0	Intense staining; blue staining dominates	0
	1	Reduced staining; mixture of blue and slight red staining
	2	Faint blue staining; increased red staining		2
Boundary between AF and NP	0	Clear boundary between AF and NP tissues	0
	1	Boundary less clear; loss of annular-nuclear demarcation
	2	No distinguishable boundary between AF and NP tissues		2
		Total score	0	7