Demographic characteristics of patients receiving 1-level posterior lumbar fusion.
| Variables | With Interbody | Without Interbody |
| Total (N = 763) | Total (N = 420) | |
| Age, y, mean ± SD | 59.2 ± 11.6 | 61.6 ± 13.2 |
| Gender: men, n (%) | 334 (43.8%) | 195 (46.4%) |
| Race: White, n (%) | 676 (88.6%) | 372 (88.6%) |
| Body mass index, mean ± SD | 31.3 ± 6.6 | 30.5 ± 6.2 |
| Comorbidities, n (%) | ||
| 1 or 2 | 468 (61.3%) | 267 (63.6%) |
| >2 | 150 (19.7%) | 95 (22.6%) |
| Coronary artery disease, n (%) | 108 (14.2%) | 72 (17.1%) |
| Hypertension, n (%) | 453 (59.4%) | 280 (66.7%) |
| Congestive heart failure, n (%) | 21 (2.8%) | 8 (1.9%) |
| Chronic obstructive pulmonary disease, n (%) | 26 (3.4%) | 21 (5.0%) |
| Osteoporosis, n (%) | 14 (1.8%) | 10 (2.4%) |
| Diabetes, n (%) | 157 (20.6%) | 95 (22.6%) |
| Active smoker, n (%) | 122 (16.0%) | 58 (13.8%) |
| Preoperative anticoagulation/antiplatelet usage, n (%) | 15 (2.0%) | 9 (2.1%) |
| Insurance, n (%) | ||
| Private | 381 (49.8%) | 169 (40.2%) |
| Medicare/Medicaid/Tenncare | 301 (39.5%) | 216 (51.4%) |
| VA/Government (including Tricare) | 74 (9.7%) | 34 (8.1%) |
| Uninsured/not applicable | 7 (1.0%) | 1 (0.3%) |
| Currently employed, n (%) | 328 (43.0%) | 139 (33.1%) |
| Intend to return to work, n (%) | 311 (94.8%) | 133 (95.6%) |
| Preoperative ambulation, n (%) | ||
| With assistance | 200 (26.2%) | 139 (33.1%) |
| Independent | 556 (72.9%) | 275 (65.5%) |
| Wheelchair bound | 3 (0.4%) | 5 (1.2%) |
| Duration of symptoms, n (%) | ||
| <3 mo | 39 (5.1%) | 17 (4.0%) |
| 3–12 mo | 168 (22.0%) | 94 (22.4%) |
| >12 mo | 408 (53.5%) | 223 (53.1%) |
| Diagnosis, n (%) | ||
| Stenosis | 156 (20.4%) | 88 (21.0%) |
| Herniated disc | 65 (8.5%) | 26 (6.2%) |
| Fracture | 4 (0.5%) | 3 (0.7%) |
| Deformity/scoliosis | 34 (4.5%) | 18 (4.3%) |
| Spondylolisthesis | 478 (62.6%) | 230 (54.8%) |
| Pseudarthrosis | 17 (2.2%) | 29 (6.9%) |
| Others | 9 (1.3%) | 26 (6.1%) |
| Revision, n (%) | 227 (29.8%) | 160 (38.1%) |
| Reason for revision, n (%) | ||
| Adjacent segment disease | 56 (7.3%) | 47 (11.2%) |
| Pseudarthrosis/instrumentation failure | 23 (3.0%) | 28 (6.7%) |
| Same level recurrent stenosis | 50 (6.6%) | 42 (10.0%) |
| Same level recurrent disc herniation | 43 (5.6%) | 14 (3.3%) |
| Others | 55 (7.2%) | 29 (6.9%) |