Demographics, spine surgery history, and preoperative radiographic parameters of the study population.
| Variable | Value |
| Demographics | |
| N | 67 |
| Sex, women, n (%) | 47 (70.1) |
| Age, y, mean (SD) | 66.2 (10.1) |
| BMI, mean (SD) | 28.6 (5.7) |
| Previous spine surgery | |
| Total, n (%) | 34 (50.7) |
| With instrumentation, n (%) | 29 (43.3) |
| Previous instrumented fusion levels, median (range) | 2 (1, 14) |
| Preoperative radiographic sagittal alignment parameters | |
| PI−LL mismatch, degrees, mean (SD) | 21.0 (16.2) |
| PT, degrees, mean (SD) | 23.8 (8.6) |
| T1PA, degrees, mean (SD) | 25.0 (10.1) |
Abbreviations: BMI, body mass index; PI−LL, pelvic incidence minus lumbar lordosis; PT, pelvic tilt; T1PA, T1 pelvic angle.