Table 1.
Study population demographic data stratified by presence of subsidence.
| No Subsidence | Subsidence | Total | p Value | ||||
|---|---|---|---|---|---|---|---|
| Participants | 86 | 18 | 104 | ||||
| CDA numbers, n | 118 | 35 | 153 | ||||
| Sex | 1.000 | ||||||
| Female | 43 | (50.0%) | 9 | (50.0%) | 52 | (50.0%) | |
| Male | 43 | (50.0%) | 9 | (50.0%) | 52 | (50.0%) | |
| Age, years | 49.00 | (43.00, 54.25) | 49.00 | (43.25, 55.00) | 49.00 | (43.00, 54.75) | 0.976 |
| Smoking, n | 26 | (30.2%) | 5 | (27.8%) | 31 | (29.8%) | 1.000 |
| Follow-up period, months | 43.50 | (16.50, 75.75) | 71.00 | (48.00, 135.50) | 51.00 | (20.75, 89.75) | 0.007 ** |
| Operative levels | 0.597 | ||||||
| Single level cases | 47 | (54.7%) | 8 | (44.4%) | 55 | (52.9%) | |
| Two level cases | 39 | (45.3%) | 10 | (55.6%) | 49 | (47.1%) | |
| Segments | 0.594 | ||||||
| Single level | 47 | (37.3%) | 8 | (29.6%) | 55 | (35.9%) | |
| Two level | 79 | (62.7%) | 19 | (70.4%) | 98 | (64.1%) | |
| C3–C4 | 11 | (8.7%) | 2 | (7.4%) | 13 | (8.5%) | 1.000 |
| C4–C5 | 38 | (30.2%) | 6 | (22.2%) | 44 | (28.8%) | 0.553 |
| C5–C6 | 68 | (54.0%) | 15 | (55.6%) | 83 | (54.2%) | 1.000 |
| C6–C7 | 9 | (7.1%) | 4 | (14.8%) | 13 | (8.5%) | 0.247 |
| pre-OP Mean-DH | 5.36 | (5.19, 5.52) | 4.0 | (3.7, 4.3) | 5.05 | (4.88, 5.22) | <0.001 ** |
| ΔAP, mm | 0.17 | (0.15, 0.19) | 0.21 | (0.16, 0.25) | 0.18 | (0.16, 0.19) | 0.056 |
| ΔLat, mm | 0.14 | (0.12, 0.16) | 0.14 | (0.1, 0.19) | 0.14 | (0.12, 0.16) | 0.970 |
| ΔDH, mm | 0.59 | (0.57, 0.61) | 0.67 | (0.62, 0.72) | 0.61 | (0.59, 0.63) | 0.002 ** |
| AP ratio | 0.92 | (0.91, 0.92) | 0.9 | (0.88, 0.92) | 0.91 | (0.91, 0.92) | 0.075 |
| Lat ratio | 0.94 | (0.93, 0.95) | 0.94 | (0.92, 0.96) | 0.94 | (0.93, 0.95) | 0.917 |
| BMD | 1.136 | (1.09, 1.16) | 0.998 | (0.96, 1.03) | 1.13 | (1.05, 1.15) | 0.072 |
| T score | 0.3 | (0.05, 0.35) | −1 | (−1.21, −0.75) | 0.1 | (−0.6, 0.3) | 0.064 |
CDA, cervical disc arthroplasty; pre-OP, pre-operation; DH, disc height; AP, anteroposterior; Lat, lateral; ΔAP, difference in width between endplate and CDA in AP view; ΔLat, difference in width between endplate and CDA in Lat view; ΔDH, difference in height before and after CDA in Lat view; BMD, bone mineral density. Brackets: Median (Interquartile Range). ** p < 0.01.