Table 2. Morphological findings on coronal reconstructed CT images.
| OP group [n = 19] | Non-VS group [n = 70] | VS group [n = 10] | P value | |||
| Odontoid height (mm) | 31.9 (27.6–35.5) | 32.2 (27.1–38.9) | 29.7 (27.4–32.0) | 0.236 | ||
| LMH(C1) (mm) | L | 11.1 (7.5–15.2) | 9.4 (6.1–14.5) | 7.5 (4.1–10.5) | 0.075 | |
| R | 10.9 (7.0–13.7) | 9.7 (6.4–15.7) | 7.1 (3.1–10.4) | 0.075 | ||
| LMH(C2) (mm) | L | 12.2 (9.8–14.1) | 12.6 (9.4–17.0) | 9.4 (3.8–13.8) | 0.001 | |
| R | 12.7 (10.9–15.7) | 12.9 (10.6–16.8) | 9.8 (8.4–13.0) | 0.001 | ||
| FA(C1) (°) | L | 59.3 (47.8–70.0) | 55.6 (35.2–71.4) | 49.7 (42.1–58.0) | 0.075 | |
| R | 63.5 (51.3–76.5) | 54.8 (33.6–75.7) | 41.7 (8.5–58.5) | 0.013 | ||
| FA(C2) (°) | L | 22.6 (17.2–28.9) | 21.1 (11.1–31.3) | 21.3 (14.0–29.7) | 0.658 | |
| R | 24.2 (16.8–31.1) | 21.3 (11.6–34.8) | 20.8 (9.3–27.0) | 0.286 | ||
| AOJ changes | Normal | L | 15 (78.6) | 35 (50.0) | 1 (10.0) | |
| R | 15 (78.6) | 35 (50.0) | 1 (10.0) | |||
| Erosive | L | 4 (21.4) | 30 (42.9) | 6 (60.0) | L: < 0.001 | |
| R | 4 (21.4) | 30 (42.9) | 4 (40.0) | R: < 0.001 | ||
| Ankylosing | L | 0 (0.0) | 5 (7.1) | 3 (30.0) | ||
| R | 0 (0.0) | 5 (7.1) | 5 (50.0) | |||
| AAJ changes | Normal | L | 17 (89.5) | 38 (54.3) | 1 (10.0) | |
| R | 16 (64.2) | 34 (48.6) | 2 (20.0) | |||
| Erosive | L | 2 (10.5) | 27 (38.6) | 5 (50.0) | L: < 0.001 | |
| R | 2 (10.5) | 31 (44.3) | 3 (30.0) | R: < 0.001 | ||
| Ankylosing | L | 0 (0.0) | 5 (7.1) | 4 (40.0) | ||
| R | 1 (5.3) | 5 (7.1) | 5 (50.0) | |||
| Bone defects in the odontoid process | Spot | 9 (47.4) | 34 (48.6) | 0 (0.0) | < 0.001 | |
| Small | 5 (26.3) | 31 (44.3) | 6 (60.0) | |||
| Large | 5 (26.3) | 5 (7.1) | 4 (40.0) | |||
Data of parameters are expressed as means (range) and non-parametrical data are expressed as the number of patients (%).
AAJ, atlantoaxial joint; AOJ, atlanto-occipital joint; CT, computed tomography; FA, facet angle; L, left; LMH, lateral mass height; NS, not significant; OP, postmenopausal osteoporosis; R, right; VS, vertical subluxation.
Mann-Whitney’s U test was used to compare between non-VS and VS groups. Pearson’s chi-square test or Fisher’s exact test, when appropriate, was employed for comparisons.
P values were derived by the comparison between non-VS and VS groups.