Table 4. Lumbar MCs: distribution according to disc degeneration, spinal level and age.

	MCtype	Disc degeneration grade					Spinal level					Age range (yrs)
		I	II	III	IV	V	L1/2	L2/3	L3/4	L4/5	L5/S1	<40	40 ˜49	50 ˜59	>60
Group 1	0	1865	1617	1504	748	47	1212	1203	1192	1126	1048	2015	1867	1149	750
	I	1	9	15	28	5	3	3	8	12	32	14	21	16	7
	II	6	19	75	140	33	7	17	23	85	141	31	91	83	68
	III	0	1	0	2	0	1	0	0	0	2	0	1	2	0
	Total	1872	1646	1594	918	85	1223	1223	1223	1223	1223	2060	1980	1250	725
Group 3 *	0	412	1393	533	44	0	493	487	482	462	458	863	882	475	162
	I	2	0	9	6	2	0	3	2	6	8	13	10	4	1
	II	0	13	43	22	4	4	6	13	29	30	62	37	15	2
	III	0	0	1	0	1	0	1	0	0	1	1	1	1	0
	Total	414	1406	586	72	7	497	497	497	497	497	895	930	495	165

*Data from patients in Group 3 with back pain.