Table 2.
Craniomorphometric and Volumetric Evaluation of Subjects With Chiari I Malformation
| Variable | FD/MAS + craniofacial FD | FD/MAS | No FD/MAS | |
|---|---|---|---|---|
| Chiari 1 malformation (n = 10) |
No Chiari 1 malformation (n = 148) |
No craniofacial FD (n = 13) |
Controls (n = 10) |
|
| Clivus length (mm) | 45.1 (36.9–51.8) | 44.1 (31.3–60.8) | 45.3 (39.1–49.3) | 45.3 (39.0–50.4) |
| Foramen magnum length (mm) |
30.6 (24.4–36.8)b,c | 34.1 (20.3–41.5) | 35.8 (33.3–38.7) | 36.0 (31.5–40.5) |
| Supraocciput length (mm) | 41.3 (33.6–48.9) | 40.7 (30.6–58.8) | 40.9 (34.0–45.4) | 39.9 (33.7–45.5) |
| Boogaard angle (degrees) | 133 (117–152)b,c | 124 (104–153)b | 117 (109–129) | 120 (113–123) |
| Basal angle (degrees) | 121 (115–130) | 118 (100–134) | 118 (110–129) | 120 (107–124) |
| Occipital angle (degrees) | 131 (113–137) | 131 (97–161) | 131 (124–144) | 133 (121–142) |
| Tentorial angle (degrees) | 85 (76–106) | 89 (56–107) | 91 (75–105) | 93 (83–106) |
| Odontoid position (mm) | 2.6 (−1.5 to 20.7)a,b,c | −0.6 (−10.1 to 14.9) | −2.1 (−8.6 to 1.6) | −1.7 (−6.4 to −0.5) |
| Tonsillar position (mm) | 8.3 (5.5–15.5)a,b,c | −0.4 (−17.8 to 4.3) | 1.5 (−3.4 to 3.7) | −0.8 (−4.1 to 1.9) |
| Posterior cranial fossa volume (cm3)d |
159.8 (147.9–172.1)b,c | 175.4 (150.3–211.4) | 175.6 (157.9–193.0) | 183.2 (161.7–216.6) |
Variables expressed as medians with absolute ranges in parentheses.
FD = fibrous dysplasia; MAS McCune-Albright syndrome.
a
Significant compared to no¼Chiari 1 malformation group (p < 0.05).
b
Significant compared to no craniofacial FD group (p < 0.05).
c
Significant compared to control group (p < 0.05).
d
Posterior cranial fossa volume sub-analysis was performed in the following subjects: Chiari I malformation (n = 10), no Chiari 1 malformation (matched by age and skeletal disease burden; n = 20), no craniofacial FD (n = 10), controls (n = 8).