Table 1.

Patient Demographics

Variables	Total	Group A	Group B	Group C	p-value
Patients, n	93	31	31	31
Age (years)					0.50
Mean	66.7	68.2	67.4	64.5
Range	40–90	43–83	42–90	40–89
Sex (n)					0.81
Male	44	16	15	13
Female	49	15	16	18
Duration of symptoms (months)					0.92
Mean	10.9	10.4	11.2	11.3
Range	3–24	4–18	3–24	4–22
Diagnosis, n (%)					0.83
Moderate to severe lumbar spinal stenosis	15 (16.1%)	7 (22.6%)	4 (12.9%)	4 (12.9%)
Mild spondylolisthesis (Grade I or II)	23 (24.7%)	6 (19.4%)	10 (32.3%)	7 (22.6%)
Giant herniated intervertebral disc with disc space narrowing	35 (37.6%)	13 (41.9%)	11 (35.5%)	11(35.5%)
Lumbar degenerative instability	11 (11.8%)	4 (12.9%)	3 (9.7%)	4 (12.9%)
Postoperative recurrence of lumbar disc herniation	4 (4.3%)	1 (3.2%)	1 (3.2%)	2 (6.5%)
Adjacent segmental disease	5 (5.4%)	0	2 (6.5%)	3 (9.7%)
Levels Fused, n (%)					0.01
L2-3	9 (9.7%)	2 (6.5%)	4 (12.9%)	3 (9.7%)
L3-4	22 (23.7%)	13 (41.9%)	2 (6.5%)	7 (22.6%)
L4-5	59 (63.4%)	16 (51.6%)	25 (80.6%)	18 (58.1%)
L2/3 + L3/4	1 (1.1%)	0	0	1 (3.2%)
L3/4 + L4/5	2 (2.2%)	0	0	2 (6.5%)