Table 2

Bivariate analysis of outcomes after surgical treatment for lumbar disc herniation.

Variable	Outcome
	Absolute Change Threshold (3.5 points)			Resolution of Radicular Pain			Resolution of Neurological Symptoms
	Success	Failure	P	Success	Failure	P	Success	Failure	P
Total	42 (41.2%)	60 (58.8%)	-	43 (37.1%)	73 (62.9%)	-	31 (34.4%)	59 (65.6%)	-
Age, y	47 ± 15.1	48 ± 16.6	0.8776^{^b}	48 47 ± 15.7	47 ± 15.6	0.6518^{^b}	43 ± 17.9	49 ± 13.7	0.0611^{^b}
Female sex	18 (41.9%)	25 (58.1%)	>0.99^{^a}	20 (40.8%)	29 (59.2%)	0.560^{^a}	16 (39.0%)	25 (61.0%)	0.505^{^a}
BMI	28 ± 5.0	29 ± 5.3	0.4132^{^b}	29 ± 5.2	29 ± 5.5	0.7526^{^b}	28 ± 4.4	29 ± 5.7	0.3399^{^b}
Medical/surgical history
Diabetes mellitus	4 (28.6%)	10 (71.4%)	0.388^{^a}	6 (40.0%)	9 (60.0%)	0.783^{^a}	2 (22.2%)	7 (77.8%)	0.713^{^a}
Current smoker	5 (35.7%)	9 (64.3%)	0.774^{^a}	9 (56.3%)	7 (43.8%)	0.101^{^a}	3 (33.3%)	6 (66.7%)	>0.99
Osteoporotic disease	2 (50.0%)	2 (50.0%)	>0.99^{^a}	4 (100.0%)	0 (0.0%)	0.017^{^a}	3 (100.0%)	0 (0.0%)	0.038^{^a}
Prior spine surgery	1 (7.7%)	12 (92.3%)	0.013^{^a}	5 (29.4%)	12 (70.6%)	0.592^{^a}	5 (33.3%)	10 (66.7%)	>0.99^{^a}
Prior fusion surgery	0 (0.0%)	7 (100.0%)	0.039^{^a}	4 (44.4%)	5 (55.6%)	0.724^{^a}	4 (50.0%)	4 (50.0%)	0.439^{^a}
Level of injury
L2–L3	3 (60.0%)	2 (40.0%)	0.400^{^a}	3 (50.0%)	3 (50.0%)	0.669^{^a}	1 (50.0%)	1 (50.0%)	>0.99^{^a}
L3–L4	4 (26.7%)	11 (73.3%)	0.265^{^a}	8 (50.0%)	8 (50.0%)	0.274^{^a}	6 (50.0%)	6 (50.0%)	0.327^{^a}
L5–S1	21 (52.5%)	19 (47.5%)	0.068^{^a}	14 (28.0%)	36 (72.0%)	0.085^{^a}	15 (39.5%)	23 (60.5%)	0.501^{^a}
History of injury
Preoperative back pain	27 (37.5%)	45 (62.5%)	0.275^{^a}	36 (42.4%)	49 (57.6%)	0.055^{^a}	23 (35.4%)	42 (64.6%)	0.810^{^a}
Time from symptom onset to surgery, wk	28 ± 31.8	55 ± 72.3	0.0584^{^b}	38 ± 59.4	37 ± 49.6	0.5971^{^b}	33 ± 39.2	25 ± 26.0	0.5034^{^b}
Preoperative NRS	8 ± 1.7	6 ± 2.6	0.0002^{^b}	7 ± 2.6	7 ± 2.3	0.1886^{^b}	7 ± 2.4	7 ± 2.5	0.9548^{^b}
Preoperative physical therapy	11 (26.8%)	30 (73.2%)	0.032 ^{^a}	9 (20.9%)	34 (79.1%)	0.021 ^{^a}	5 (17.2%)	24 (82.8%)	0.026 ^{^a}
Operative time, min	72 ± 40.6	84 ± 38.6	0.016^{^b}	80 ± 37.8	79 ± 39.5	0.5932^{^b}	71 ± 24.3	81 ± 40.1	0.4085^{^b}
Surgical technique
Use of intraoperative microscope	7 (38.9%)	11 (61.1%)	>0.99^{^a}	9 (40.9%)	13 (59.1%)	0.809^{^a}	4 (23.5%)	13 (82.4%)	0.399^{^a}
Open microdiscectomy	38 (44.7%)	47 (55.3%)	0.176^{^a}	35 (36.5%)	61 (63.5%)	0.802^{^a}	27 (35.1%)	50 (64.9%)	>0.99^{^a}
Tubular (MIS) microdiscectomy	3 (23.1%)	10 (76.9%)	0.229^{^a}	5 (33.3%)	10 (66.7%)	>0.99^{^a}	3 (27.3%)	8 (72.7%)	0.742^{^a}
Decompression without discectomy	1 (33.3%)	2 (66.7%)	>0.99^{^a}	2 (66.7%)	1 (33.3%)	0.554^{^a}	0 (0.0%)	1 (100.0%)	>0.99^{^a}
Fat graft	16 (43.2%)	21 (56.8%)	0.835^{^a}	15 (36.6%)	26 (63.4%)	>0.99^{^a}	13 (38.2%)	21 (61.8%)	0.649^{^a}

Abbreviations: BMI, body mass index; MIS, minimally invasive surgery.
Note: Data presented as n (%) or mean ± SD. Boldface indicates statistically significant findings at P < 0.05.
↵a Fisher Exact.
↵b Mann-Whitney U Test.