Table 1.
Demographics and anatomical characteristics
| Variables | N = 110 |
|---|---|
| Demographics | |
| Age (year) | 59.3 ± 11.1 |
| Gender | |
| Male | 41 (37.3%) |
| Female | 69 (62.7%) |
| Body mass index (m/kg2) | |
| Normal (< 25) | 81 (73.6%) |
| Obesity (≥ 25) | 29 (26.4%) |
| Bone mineral density | −1.6 ± 1.5 |
| Diagnosis | |
| Degenerative instability | 47 (42.7%) |
| Degenerative spondylolisthesis | 31 (27.3%) |
| Isthmic spondylolisthesis | 13 (11.8%) |
| Recurred HNP | 19 (17.3%) |
| Operation time (minute) | 150.7 ± 43.6 |
| Estimated blood loss (cc) | |
| <400 | 60 (54.5%) |
| ≥400 | 50 (45.5%) |
| Fusion level | |
| 1-level | 86 (78.2%) |
| 2-level | 24 (21.8%) |
| Side of approach | |
| Right | 48 (43.6%) |
| Left | 56 (50.9%) |
| Bilateral | 6 (5.4%) |
| Anatomical characteristics | |
| Lumbar Cobb angle (°) | |
| AP | 5.2 ± 6.3 |
| Lateral | 30.1 ± 21.8 |
| Multifidus | |
| Cross-sectional area (mm2) | 770.6 ± 205.6 |
| Atrophy | |
| Normal | 21 (19.1%) |
| Mild | 41 (37.3%) |
| Moderate | 36 (32.7%) |
| Severe | 12 (10.9%) |
| Entry point depth (mm) | 53.3 ± 8.8 |
Values are expressed as the number (%) for categorical variables, and as the mean ± standard deviation for continuous variables