The imaging evaluation and clinical significance of sacral vestibule / 中华骨科杂志

ABSTRACT

Objective:To measure the anatomical parameters of three-dimensional available space of S 1 and S 2 vestibules on Chinese adults by imaging methods, and discuss their clinical values. Methods:Data of 200 cases of pelvic CT with complete posterior ring were collected from January 2015 to January 2021, included 110 males and 90 females. The ages ranged from 21 to 63 years (average, 40.72±10.70 years). Then the parameters of both the left vestibule and the right vestibule of S 1 and S 2 such as vestibular width, vestibular height and vestibular area were measured by the three-dimensional CT reconstructions. Statistical analyses were performed among the groups which were classified according to the gender, side of vestibule to compare the difference of vestibular morphological characteristics among different groups. Results:The average vestibular area of S 1 was 425.71± 45.07 mm 2 (range, 296.3-604.4 mm 2), which was 449.80±28.62 mm 2 (range, 338.3-604.4 mm 2) in males and 388.25±34.01 mm 2 (range, 296.3-498.4 mm 2) in females. The average vestibular width was 28.52±4.34 mm (range, 17.1-36.3 mm), 31.77±2.33 mm (range, 22.46-36.30 mm) in males and 24.55±2.55 mm (range, 17.1-26.1 mm) in females. The mean vestibular height was 21.05±2.29 mm (range, 17.5-32.0 mm), with 21.34±2.37 mm (range, 18.5-32.0 mm) of men and 20.69±1.60 mm (range, 17.5-25.6 mm) of women. The mean S 2 vestibular area was 230.19±35.57 mm 2 (range, 142.5-297.3 mm 2), which was 258.91±28.04 mm 2 (range, 218.3-297.3 mm 2) in males and 205.61±24.12 mm 2 (range, 142.5-258.6 mm 2) in females. The average vestibular width was 15.94±1.72 mm (range, 12.4-20.3 mm), 16.51±1.59 mm (range, 14.4-20.3 mm) in male and 15.25±1.63 mm (range, 12.4-18.1 mm) in female. The mean vestibular height was 14.30±1.20 mm (range, 12.9-17.8 mm), 15.49±1.46 mm (range, 13.6-17.8 mm) in males and 13.73±0.93 mm (range, 12.9-16.1 mm) in females. There were significant differences in vestibular width, height and area between S 1 and S 2 (vestibular width t=3.934, P< 0.001; vestibular height t=3.692, P< 0.001; vestibular area t=4.816, P< 0.001). There were significant differences in S 1 vestibular width, S 1 vestibular height, S 1 and S 2 vestibular area between male groups and female groups (S 1 vestibular width t=2.969, P=0.003; S 1 vestibular height t=0.316, P=0.049; S 1 vestibular area t=1.975, P=0.049; S 2 vestibular area t=2.023, P=0.044). While there was no significant difference in S 2 vestibular width and height between the two gender groups. There were significant differences in S 1 and S 2 vestibular width, height and area between male and female groups ( P < 0.001). There were no significant difference in parameters between the left and right values of the same vestibular site. Conclusion:The parameters of S 1 sacral vestibule are larger than that of S 2. It implies that S 1 was more feasible to insert iliosacral screws than S 2; lesser diameter iliosacral screws should be selected to insert into S 2. The female S 1 vestibule is smaller than the male, so the iliosacral screws placement has more stringent requirements on the selection of the insertion point and the direction of the screw. And the surgeon can utilize the intact contralateral sacral vestibule as the damaged side to proceed the iliosacral screw inserted simulation.