Demographic characteristics of study participants.
| Characteristic | n (%) |
| Age at time of surgery, y, mean (SD) | 48.5 (11.4) |
| Age group | |
| <40 y | 303 (22.7) |
| 40–65 y | 946 (70.9) |
| >65 y | 86 (6.4) |
| Review type | |
| Chart (2005–2008) | 263 (19.7) |
| PACS image (2009–2019) | 1072 (80.3) |
| Cage type | |
| Brantigan (2005–2009) | 374 (28.0) |
| STALIF (2010–2013) | 381 (28.5) |
| Australis (2014–2019) | 580 (43.4) |
| ALIF level | 1614 (100.0) |
| L2–L3 | 3 (0.2) |
| L3–L4 | 52 (3.9) |
| L4–L5 | 279 (20.9) |
| L5–S1 | 1273 (95.4) |
| S1–S2 | 7 (0.5) |
| ALIF group | |
| Higher (cases with L2–L3 and L3–L4) | 54 (4.0) |
| Lower (cases with L4–L5 and lower) | 1281 (96.0) |
| Single level | 1072 (80.3) |
| L2–L3 | 1 (0.1) |
| L3–L4 | 4 (0.3) |
| L4–L5 | 46 (3.4) |
| L5–S1 | 1018 (76.3) |
| S1–S2 | 3 (0.2) |
| 2-Level | 247 (18.5) |
| L3–L4/L4–L5 | 7 (0.5) |
| L3–L4/L5–S1 | 26 (1.9) |
| L4–L5/L5–S1 | 210 (15.7) |
| L5–S1/S1–S2 | 4 (0.3) |
| 3-Level | 16 (1.2) |
| L2–L3/L3–L4/L4–L5 | 1 (0.1) |
| L2–L3/L4–L5/L5–S1 | 1 (0.1) |
| L3–L4/L4–L5/L5–S1 | 14 (1.0) |
Abbreviations: ALIF, anterior lumbar interbody fusion; PACS, picture archiving and communication system.
Note: Data presented as n (%) unless otherwise noted.