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Table 2 Mean variables (± SD) measured on pelvic CT sections in the prospective trauma cohort (n = 344), stratified by sacral morphology.

From: Prevalence of sacral dysmorphia in a prospective trauma population: Implications for a "safe" surgical corridor for sacro-iliac screw placement

Variable Normal sacral morphology
(n= 295)
Dysmorphic sacral morphology
(n= 49)
Statistical test applied P-value
Age 36.50 ± 13.35 39.35 ± 14.13 Student's t-test 0.171
S1FAC 17.69 ± 2.50 15.43 ± 2.93 Student's t-test <0.001
S2FAC 11.45 ± 2.28 12.01 ± 2.49 Student's t-test 0.117
TS1BHT 46.93 ± 7.55 38.29 ± 13.73 Student's t-test <0.001
SS1BHT 22.84 ± 3.35 21.21 ± 6.02 Mann-Whitney-U 0.028
S1SAG.mean 31.02 ± 3.54 28.69 ± 5.09 Mann-Whitney-U 0.001
TS2BHT 31.53 ± 6.62 34.36 ± 7.19 Student's t-test 0.06
SS2BHT 15.71 ± 3.74 16.45 ± 3.40 Mann-Whitney-U 0.078
S2SAG.mean 24.97 ± 3.72 25.12 ± 5.12 Student's t-test 0.817
ANGLE1A 19.65 ± 3.19 17.02 ± 3.37 Student's t-test <0.001
ANGLE1C 19.33 ± 3.34 17.38 ± 4.70 Mann-Whitney-U 0.003
ANGLE2A 13.10 ± 2.94 13.13 ± 2.67 Mann-Whitney-U 0.811
ANGLE2C 15.50 ± 2.92 16.02 ± 3.18 Student's t-test 0.258
  1. Statistically significant differences were found for all measurements in all 3-dimensional planes between patients with normal versus dysmorphic sacral morphology at the S1 level. In contrast, differences at S2 were not statistically significant. Patients with sacral dysmorphia showed a trend towards increased mean S2 vertebral body heights, implying the S2 route as a "safe" alternative for placement of SI = screws in presence of sacral dysmorphia. See table 1 for abbreviations.
  2. Abbreviations: S1FAC and S2FAC = S1 and S2 foramen-anterior cortex
  3. TS1BHT and T2SBHT = tallest coronal S1 and S2 body height/the sagittal S1 and S2 mean body height
  4. SS1BHT and SS2BHT = smallest S1 and S2 body height
  5. S1SAG.mean and S2SAG.mean = S1 and S2 sagittal mean height
  6. Angle 1A/2A and 1C/2C = axial S1 and S2 angle and coronal S1/S2 angle