Table 2.
Characteristics of all respondents, including those with and without FBSS
| Social and demographic characteristics | Overall, N=1842 (%) | Non-FBSS, n=1462 (%) | FBSS, n=380 (%) | P-value |
|---|---|---|---|---|
| Sex | ||||
| Male | 1321 (71.7) | 1041 (71.2) | 280 (73.7) | 0.371a |
| Female | 521 (28.3) | 421 (28.8) | 100 (26.3) | |
| Age, years (mean±SD) | ||||
| <65 (%) | 1679 (91.2) | 1349 (92.3) | 330 (86.8) | <0.005a |
| ≥65 (%) | 163 (8.8) | 113 (7.7) | 50 (13.2) | |
| Average±SD | 42.6±14.4 | 41.7±14.0 | 45.8±15.3 | <0.001c |
| Severity of low back pain | ||||
| None | 146 (7.9) | 135 (9.2) | 11 (2.9) | <0.001b |
| Mild pain (1–3) | 667 (36.2) | 577 (39.5) | 90 (23.7) | |
| Moderate pain (4–7) | 803 (43.6) | 616 (42.1) | 187 (49.2) | |
| Severe pain (8–10) | 226 (12.3) | 134 (9.2) | 92 (24.2) | |
| Pain intensity (NRS 0–10) (average±SD) | 4.3±2.6 | 4.0±2.6 | 5.4±2.5 | <0.001c |
| Surgical diagnosis (n) | ||||
| Disc herniation | 1273 (69.1) | 1045 (71.5) | 228 (60.0) | <0.001a |
| Canal stenosis | 260 (14.1) | 183 (12.5) | 77 (20.3) | <0.001a |
| Spondylolisthesis | 87 (4.7) | 59 (4.0) | 28 (7.4) | <0.01a |
| Low back pain | 68 (3.7) | 59 (4.0) | 9 (2.4) | 0.168a |
| Fracture | 52 (2.8) | 41 (2.8) | 11 (2.9) | 0.863a |
| Tumor | 27 (1.5) | 21 (1.4) | 6 (1.6) | 0.812a |
| Spondylolysis | 27 (1.5) | 19 (1.3) | 8 (2.1) | 0.236a |
| Infection | 16 (1.1) | 10 (0.7) | 6 (1.6) | 0.116a |
| Scoliosis | 12 (0.9) | 10 (0.7) | 2 (0.5) | >0.999a |
| Others | 20 (0.7) | 15 (1.0) | 5 (1.3) | 0.584a |
| Number of operations | ||||
| 1 | 1503 (81.6) | 1233 (84.3) | 270 (71.1) | <0.001a |
| ≥2 | 339 (18.4) | 229 (15.7) | 110 (28.9) | |
| Period from surgery, weeks (average±SD) | 167.9±132.9 | 167.7±133.0 | 168.8±133.0 | 0.879c |
| Surgery | ||||
| Fusion | 412 (22.4) | 308 (21.1) | 104 (27.4) | <0.01a |
| Decompression | 1294 (70.2) | 1046 (71.5) | 248 (65.3) | |
| Unknown | 136 (7.4) | 108 (7.4) | 28 (7.4) | |
| Utility value of EQ-5D (average±SD) | 0.79±0.19 | 0.83±0.17 | 0.65±0.17 | <0.001c |
| K6 score (average±SD) | 5.7±4.9 | 5.2±4.7 | 7.7±5.2 | <0.001c |
Notes: P-value:
a
Fisher’s exact test;
b
Mann–Whitney U test;
c
unpaired t-test. Participants were considered FBSS if they fulfilled two conditions: “dissatisfied” or “somewhat dissatisfied” with their surgery on a four-grade scale and the existence of at least one symptom in any residual symptoms (low back pain, low back dull ache, numbness in legs, coldness in feet, or paresthesia on the sole).
Abbreviations: EQ-5D, EuroQol-5 dimensions; FBSS, failed back surgery syndrome; K6, Kessler psychological distress scale; SD, standard deviation.