Radiographic analysis of the sacral-2-alar screw trajectory

Table 1 Comparison of individual parameters in males and females

	Male (n = 48)			Female (n = 52)
	Left	Right	P	Left	Right	P
Length of the screw trajectory (mm)	47.18 ± 3.91	45.46 ± 4.37	< 0.01	44.80 ± 3.66	44.01 ± 3.72	0.024
Sagittal angle (°)	29.06 ± 4.00	23.33 ± 4.26	< 0.01	32.14 ± 5.48	25.12 ± 5.19	< 0.01
Coronal angle (°)	13.31 ± 6.95	14.88 ± 6.84	0.014	16.04 ± 7.74	16.67 ± 8.34	0.337
Distance between the entry point and the spinous process (mm)	21.0 (3.7)^a	22.8 (2.9)^a	0.001^b	21.8 (2.8)^a	21.6 (2.7)^a	0.004^b
Minimum diameter of the screw trajectory (mm)	17.1 (2.3)^a	16.9(3.1)	0.638^b	17.1 (5)^a	17(4.5)^a	0.059^b

The Shapiro–Wilk test showed that the length of the nail track, the angle of the sagittal plane, and the angle of the coronal plane were all normally distributed (P > 0.05); the distance between the nail entry point and the spinous process and the minimum diameter of the nail path had a non-normal distribution
^athe median (quartile spacing), ^bthe Wilcoxon sign rank sum test

ISSN: 1749-799X