Overview of the study population.
| Characteristics and Variables | Mean | Range |
| Age (years) | 50.1 | 19–81 |
| N | % | |
| Gender | ||
| Female | 301 | 53.0% |
| Male | 267 | 47.0% |
| Symptoms | ||
| Radiculopathy | 508 | 89.4% |
| Neurogenic claudication | 13 | 2.3% |
| Both | 47 | 8.3% |
| Level operated | ||
| L2-3 | 1 | 0.2% |
| L3-4 | 5 | 0.9% |
| L4-5 | 143 | 25.2% |
| L5-S1 | 419 | 73.8% |
| Fusion technique | ||
| Stand-alone ALIF | 247 | 43.5% |
| ALIF + PI | 321 | 56.5% |
ALIF, anterior lumbar interbody fusion; PI, posterior instrumentation.