Histological difference in ligament flavum between degenerative lumbar canal stenosis and non-stenotic group: A prospective, comparative study

Table 1 Demographic profile of the groups

Categories		LSS (n = 34)	Non-LSS (n = 40)	P value
Age in years, mean (SD)		49.2 (8.9)	43.1 (14.3)
Sex in %		M:F – 59:41	M:F – 60:40
Duration in weeks, mean (SD)		44.1 (11.6)	9.4 (8.1)
Level	One	30 (88.2)	32 (80)	0.553
	Two	3 (8.8)	7 (17.5)
	Three	1 (2.9)	1 (2.5)
Diagnosis		Lumbar canal stenosis	PIVD – 18
			Trauma – 8
			Potts spine – 7
			Tumour – 5
			Epidural abscess (non-TB) – 2

Table 2 Histological differences between the groups

Variable	Histological features	Stenotic (n = 34)	Non stenotic (n = 40)	P value (Chi square test)
Elastin degeneration	1+ and 2+	9 (26.5)	22 (55)	0.010
	3+	25 (73.5)	18 (45)
Fibrosis	1+ and 2+	10	17	0.002
	3+	24	13
Calcification	Absent	28	38	0.081
	Present	6	2
Chondroid metaplasia	Absent	22	26	0.979
	Present	12	14
Haemorrhage	Absent	17	23	0.519
	Present	17	17

Table 3 Morphometric differences between the groups

Factor		mean	SD	t	df	P value
% Elastin fragmentation	NS (40)	29.50	16.9	-9.51	71	< 0.0001
	S (34)	66.47	16.3
Collagen content (area %)	NS (40)	54.94	6.41	-4.38	53.2	< 0.0001
	S (34)	63.59	10.36
Elastic content (area %)	NS (40)	34.73	8.36	4.36	72	< 0.0001
	S (34)	26.94	6.71
Elastin/Collagen ratio	NS (40)	0.63	0.14	6.01	71.27	< 0.0001
	S (34)	0.43	0.13
Width of elastin fibers	NS (39)	4.37	1.07	5.44	71	< 0.0001
	S (34)	3.27	0.54
Ligamentocyte numbers	NS (40)	53.45	26.85	2.6	72	< 0.0001
	S (34)	39.11	19.05

Table 4 Subgroup analysis among groups > 40 years

Factor		mean	SD	t	df	P value
% Elastin fragmentation	NS (25)	31.80	18.123	-7.4	43.93	< 0.0001
	S (31)	67.10	16.96
Collagen content (area %)	NS (25)	55.12	7.62	-3.4	53.19	0.001
	S (31)	63.58	10.75
Elastic content (area %)	NS (25)	34.898	7.92	4.20	46.6	< 0.0001
	S (31)	26.57	6.60
Elastin/Collagen ratio	NS (25)	0.63	0.14	5.54	50.09	< 0.0001
	S (31)	0.43	0.13
Width of elastin fibers	NS (25)	3.75	0.98	4.42	31.94	< 0.0001
	S (31)	2.77	0.49
Ligamentocyte numbers	NS (25)	46.56	22.4.0	1.88	41.03	0.66
	S (31)	36.612	15.41