Table 1 The characteristics of the study population
Number (%) | All patients | Cervical fusion | Lumbar fusion | P |
|---|---|---|---|---|
42,060 | 11,784 (28.02%) | 30,276 (71.98%) | ||
Age (years) |  |  |  |  < 0.0001 |
 20–29 | 514 (1.22%) | 206 (1.75%) | 308 (1.02%) |  |
 30–39 | 1,933 (4.60%) | 1,092 (9.27%) | 841 (2.78%) |  |
 40–49 | 5,905 (14.04%) | 3,455 (29.32%) | 2,450 (8.09%) |  |
 50–59 | 11,770 (27.98%) | 4,032 (34.22%) | 7,738 (25.56%) |  |
 60–69 | 12,247 (29.12%) | 1,928 (16.36%) | 10,319 (34.08%) |  |
  ≥ 70 | 9,691 (23.04%) | 1,071 (9.09%) | 8,620 (28.47%) |  |
Mean age (SD) | 59.47 ± 11.93 | 52.74 ± 11.36 | 62.09 ± 11.08 | 0.0012 |
Gender, female, n | 23,587 (56.08%) | 4,318 (36.64%) | 19,269 (63.64%) |  < 0.0001 |
Diabetes, n | 16,610 (39.49%) | 4,067 (34.51%) | 12,543 (41.43%) |  < 0.0001 |
Associated comorbidities, n | 20,268 (48.19%) | 4,937 (41.90%) | 15,331 (50.64%) |  < 0.0001 |
Hospital types | ||||
 Tertiary-referral hospital | 11,179 (25.58%) | 3,711 (31.49%) | 7,468 (24.67%) |  < 0.0001 |
 General hospital | 12,507 (29.74%) | 3,142 (26.66%) | 9,365 (30.93%) |  |
 Hospital | 17,956 (42.69%) | 4,842 (41.09%) | 13,114 (43.31%) |  |
 Clinic | 418 (0.99%) | 89 (0.76%) | 329 (1.09%) |  |
Surgical approaches |  |  |  |  < 0.0001 |
 Anterior | 11,698 (27.81%) | 11,040 (93.69%) | 658 (2.17%) |  |
 Posterior | 30,362 (72.19%) | 744 (6.31%) | 29,618 (97.83%) |  |