Table 3.

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.